Stock/Arrow/Torrie

[outnumbered]

Curiosity was killing me, so I took the car to JTSVP so Tony could work with Torrie on creating a new tune. We ran all three tunes in 80+degree weather. I'm happy.17363

[DZnutz]

This is on a completely stock car? kinda hard to believe that the Torrie tune net 52 rwhp and 43 rwtq

[outnumbered]

Sorry not stock. The car has a full exhaust

[dewilmoth]

Sorry not stock. The car has a full exhaust

Still impressive. I assume the dyno curve for arrow was with the aftermarket exhaust as well? Nice gains from the arrow.

[7TH_SIGN]

What was the a/f? Did the car have the exhaust on with the Arrow PCM? Great numbers on the Torrie tune!

Also was this remote dyno tuning? So you only gained 20whp and 9wtq over stock with the Arrow PCM??? Something doesn't add up.

[Steve M]

Nice gains for sure...there would probably be much less of a difference in cooler weather, but that graph right there shows you just how much power the stock and Arrow PCMs pull when the temps start climbing.

[outnumbered]

What was the a/f? Did the car have the exhaust on with the Arrow PCM? Great numbers on the Torrie tune!

Also was this remote dyno tuning? So you only gained 20whp and 9wtq over stock with the Arrow PCM??? Something doesn't add up.

I don't have that printed, but I believe it was a pretty flat 12.x.

And yes, the full exhaust was on for all runs. We ran the Arrow tune first, then stock, then tuned for the final.

I did however lose my decel pop :(

[7TH_SIGN]

I don't have that printed, but I believe it was a pretty flat 12.x.

And yes, the full exhaust was on for all runs. We ran the Arrow tune first, then stock, then tuned for the final.

I did however lose my decel pop :(

You can get the decal exhaust note back but damn the power you picked up with Torrie is very nice!

[Steve M]

What was the a/f? Did the car have the exhaust on with the Arrow PCM? Great numbers on the Torrie tune!

Also was this remote dyno tuning? So you only gained 20whp and 9wtq over stock with the Arrow PCM??? Something doesn't add up.

You are missing the affect of the ambient temps on the stock and Arrow numbers...both the stock and Arrow PCMs pull a fair amount of timing and add fuel with ambient temps that high. You can keep it from doing that with HPTuners.

[outnumbered]

What was the a/f? Did the car have the exhaust on with the Arrow PCM? Great numbers on the Torrie tune!

Also was this remote dyno tuning? So you only gained 20whp and 9wtq over stock with the Arrow PCM??? Something doesn't add up.

Yes remote tuning. Torrie basically took over the computer. You could sit there and watch him making the changes on the screen.

[outnumbered]

You can get the decal exhaust note back but damn the power you picked up with Torrie is very nice!

I was quite pleased. The car definitely feels stronger.

[zzmike]

This is awesome data, and may help a number of owners, myself included, in choosing the direction to go with their cars.

Thank you for sharing this!

[Murpowa]

Impressive numbers

[Strykerviper2014]

I was quite pleased. The car definitely feels stronger.

Torrie is tuning my car Wednesday , doing the same thing , I live in Canada , thanks for the feed back

[outnumbered]

Torrie is tuning my car Wednesday , doing the same thing , I live in Canada , thanks for the feed back

Best of luck!

[Dave1968]

Yah I agree, and we still haven't answered why. Its fairly common knowledge we are due a 30 whp gain and much more than 9 wtq with the ARROW PCM. So what is happening, and is it affecting the accuracy of the stats for the Torrie tune. I would want this little mystery solved first before I made my decision.

[7TH_SIGN]

^
Yeah it just seems like we are missing variables affecting the results of each tune. Others have logged 30whp/wtq gains with the Arrow.

[outnumbered]

The Arrow tune actually had the longest cool down period, and was tested with the lowest outside temp.

[Steve M]

Yah I agree, and we still haven't answered why. Its fairly common knowledge we are due a 30 whp gain and much more than 9 wtq with the ARROW PCM. So what is happening, and is it affecting the accuracy of the stats for the Torrie tune. I would want this little mystery solved first before I made my decision.

I already answered why...the stock tune and Arrow PCM both pull timing when ambient temps get that high, and it's not an insignificant amount.

The Arrow tune has to be safe for everyone, including cars that are running balls to the wall on the track for 30+ minute sessions. Because of that, the Arrow tune has to be more conservative...with HPTuners, you can tune it for the conditions your car will see. The tune I run on the street isn't the same tune I'd be running on a road course, and I can change that with a few mouse clicks and about 60 seconds to upload the new file to the PCM. HPTuners is nothing more than another tool in the toolbox to make your car faster...if you know what you are doing, you can make really impressive gains. If you don't, it's just like any other tool - you can cause more harm than good. Torrie clearly knows what he's doing.

[donk_316]

Yeah no thanks. A remote tune for your car on a dyno? Let's hope nothing melts down on the hwy or driving around town.

Arrow tune is built by Arrow. For the Arrow engine. In all scenarios

So if you go across country do you have to fine tune based off altitude, weather conditions and engine load?

[Steve M]

Yeah no thanks. A remote tune for your car on a dyno? Let's hope nothing melts down on the hwy or driving around town.

Arrow tune is built by Arrow. For the Arrow engine. In all scenarios

So if you go across country do you have to fine tune based off altitude, weather conditions and engine load?

No...the mass air flow and manifold air pressure sensors would compensate. A well done HPT tune will be every bit as robust as the Arrow tune.

These cars are actually very simple to tune for the basic bolt-ons...the MAF tables take care of the WOT fueling, and you need to dial in some additional spark in a few areas and get rid of some of the nannies (like cat-overtemp protection). That's really about it as far as power production is concerned.

[donk_316]

Thanks Steve for the explanation. I just would feel better once I see some miles on this sort of thing before passing judgement.

The dyno graph as posted is suspect. Such a small gain from the Arrow which has been proven over and over to give much more than this. Then a massive jump for the remote tune? Just looks screwed to me.

I'll wait for more real world testing, I appreciate the OP doing this though.

[Steve M]

Thanks Steve for the explanation. I just would feel better once I see some miles on this sort of thing before passing judgement.

The dyno graph as posted is suspect. Such a small gain from the Arrow which has been proven over and over to give much more than this. Then a massive jump for the remote tune? Just looks screwed to me.

I'll wait for more real world testing, I appreciate the OP doing this though.

This isn't the first time I've seen something just like it:

http://driveviper.com/forums/threads/8027-Dyno-Results-Stock-vs-Arrow-ECU-vs-Arrow-ECU-amp-ARH-Headers?highlight=arrow+gains

[outnumbered]

Yeah no thanks. A remote tune for your car on a dyno? Let's hope nothing melts down on the hwy or driving around town.

Arrow tune is built by Arrow. For the Arrow engine. In all scenarios

So if you go across country do you have to fine tune based off altitude, weather conditions and engine load?

A remote tune is no different than if he is sitting there at the dyno. The tuner see's everything that the car is doing. This is not a "canned" tune. I guess the only omission is the sound.

Pdv25 had the same setup--I believe he made 607 with his orange TA, and he had many (according to all his videos) high speed passes with no issues. My car will more than likely not be pushed that hard.

[outnumbered]

I can see certain situations where I would still run the Arrow tune. I'm glad I have both.

[SRT BILL]

Question, When changing from stock PCM to the arrow and back to stock is the effect of the new calibrations immediate. I believe I've read that there may be a relearn process that takes some driving to fully complete the change over. Could this be the reason for the apparent lower looking Arrow numbers?

[outnumbered]

Question, When changing from stock PCM to the arrow and back to stock is the effect of the new calibrations immediate. I believe I've read that there may be a relearn process that takes some driving to fully complete the change over. Could this be the reason for the apparent lower looking Arrow numbers?

I don't think in this particular case, as the Arrow tune was the first one on the dyno. It's been in the car for the last 4000-5000 miles

But to your point, when going from stock to the Arrow tune, yes, my throttle had to learn the new settings.

[Sub Driver]

A custom tune is always better than a canned tune. Not surprising that a custom tune makes more power than the arrow.

[7TH_SIGN]

Remote tuning is just as good as the tuner being there physically.

I'm not surprised the least in regards to how much the Torrie tune made. Actually I expect those numbers 590-600whp.

My surprise comes from how low in power the Arrow PCM made. That's a big difference in power between the two and if you were to line both tunes against each other you would see the Torrie tune put a couple car lengths on the Arrow.

I actually was going to go with the HP Tuner however couldn't get a confirmation on remote tuning availability so I went with the Arrow.

[outnumbered]

Remote tuning is just as good as the tuner being there physically.

I'm not surprised the least in regards to how much the Torrie tune made. Actually I expect those numbers 590-600whp.

My surprise comes from how low in power the Arrow PCM made. That's a big difference in power between the two and if you were to line both tunes against each other you would see the Torrie tune put a couple car lengths on the Arrow.

I actually was going to go with the HP Tuner however couldn't get a confirmation on remote tuning availability so I went with the Arrow.

You won't be disappointed with the Arrow. The sound alone is worth the money. In addition, the throttle response, as well as the hp bump are noticeable. I do not think the Arrow retards timing as dramatically as stock. It's definitely a good investment. Remember, you will ultimately spend more on the HP Tuner, for the tuning and dyno time.

[7TH_SIGN]

You won't be disappointed with the Arrow. The sound alone is worth the money. In addition, the throttle response, as well as the hp bump are noticeable. I do not think the Arrow retards timing as dramatically as stock. It's definitely a good investment. Remember, you will ultimately spend more on the HP Tuner, for the tuning and dyno time.

Thanks man. Yeah I have no regrets going with the Arrow PCM but your gains on the HP Tuner I definitely envy lol. I'm a very hungry person when it comes to horsepower. The reason I went with the Arrow PCM is because of the lack of response and customer service for the HP Tuner (I'm not a tuner and leave that to the pros). I called multiple vendors of the unit and emailed them as well. Never could get a call back or even an email response and when I am going to be relying on remote tuning service where communication is vital for setting up dyno sessions on multiple individuals schedules I just don't have the time to deal with that. I would call and email Andy and he would answer every single damn time lol. He was awesome to deal with and why I went with the Arrow PCM. The best customer service always wins my business.

When its time for TT I will be upgrading to a Motec or Infinity so either way the Arrow or the HP Tuner would have to be retired.

Get some vids of your Carbon Snake when you get a chance!

[Steve M]

Question, When changing from stock PCM to the arrow and back to stock is the effect of the new calibrations immediate. I believe I've read that there may be a relearn process that takes some driving to fully complete the change over. Could this be the reason for the apparent lower looking Arrow numbers?

The relearn process you are thinking of is the throttle relearn, which is a basic calibration process that you either do with a WiTech for the Arrow PCM or with the HPTuners scanner. That relearn process is a one time only thing, and has nothing to do with power production...if it isn't done right, the car simply won't run (it'll go into limp mode). There are some other adaptives that do some learning (like fuel trims), but those only affect part throttle operation.

Calibration changes to WOT fueling (which is what we're talking about here) are immediate. WOT on these cars is open loop, so what is commanded is what you get. Anytime I make a calibration change that affects WOT fueling, I don't have to drive it for 500 miles for it to learn anything...it just does what it's told, and does so right away. Swapping in the Arrow PCM would be no different.

[Vipes]

Yeah no thanks. A remote tune for your car on a dyno? Let's hope nothing melts down on the hwy or driving around town.

Arrow tune is built by Arrow. For the Arrow engine. In all scenarios

So if you go across country do you have to fine tune based off altitude, weather conditions and engine load?

If anything a remote tune is usually better vs a canned tune. I'm still skeptical about calling somebody up, listing your mods on the phone and having them mail you a tune based on a baseline of somebody else who had similar mods to you. Everybody seems to have great experiences with the arrow tune but I'm used to another car/life where canned tunes usually didn't end well. A remote tune would be the same as a local custom tune but it just takes a little more time between pulls to send the results out to tune then back to upload them into the car and repeat.

[Bruce]

Doesn't the HPTuner support a parameter called something like decel fuel trim? If so, why can't Torrie just dump more fuel by adjusting this parameter and get the decel pops back???

[Steve M]

Doesn't the HPTuner support a parameter called something like decel fuel trim? If so, why can't Torrie just dump more fuel by adjusting this parameter and get the decel pops back???

It's deceleration fuel cutoff (DFCO), and the flag is either set on or off. If on, there is no popping, if off, it keeps a little bit of fuel in it, which causes popping. It still pops with HPT, just not as much as it does with the Arrow calibration. I'm almost 100% certain Arrow advances the cam under decel to enhance the popping - HPT does allow cam control, but the one table available doesn't affect the cam under decel or idle conditions. I've asked them to look for an additional parameter or table that would allow this, but additional Viper development is extremely low on the priority list due to the amount of time required to reverse engineer this particular PCM. Proprietary source code + a single, limited production platform = extremely limited profit potential for HPTuners.

You might be able to add fuel to the cells in the MAF table that are being referenced during those conditions, but I'm not sure if it would just get trimmed out...I might give it a look this summer to see if it is possible, but since there is zero performance benefit to it, it's not real high on my list of things to try.

[outnumbered]

It's deceleration fuel cutoff (DFCO), and the flag is either set on or off. If on, there is no popping, if off, it keeps a little bit of fuel in it, which causes popping. It still pops with HPT, just not as much as it does with the Arrow calibration. I'm almost 100% certain Arrow advances the cam under decel to enhance the popping - HPT does allow cam control, but the one table available doesn't affect the cam under decel or idle conditions. I've asked them to look for an additional parameter or table that would allow this, but additional Viper development is extremely low on the priority list due to the amount of time required to reverse engineer this particular PCM. Proprietary source code + a single, limited production platform = extremely limited profit potential for HPTuners.

You might be able to add fuel to the cells in the MAF table that are being referenced during those conditions, but I'm not sure if it would just get trimmed out...I might give it a look this summer to see if it is possible, but since there is zero performance benefit to it, it's not real high on my list of things to try.

Torrie turned it off on mine. But like you said, not as pronounced as the Arrow.

[dewilmoth]

It's deceleration fuel cutoff (DFCO), and the flag is either set on or off. If on, there is no popping, if off, it keeps a little bit of fuel in it, which causes popping. It still pops with HPT, just not as much as it does with the Arrow calibration. I'm almost 100% certain Arrow advances the cam under decel to enhance the popping - HPT does allow cam control, but the one table available doesn't affect the cam under decel or idle conditions. I've asked them to look for an additional parameter or table that would allow this, but additional Viper development is extremely low on the priority list due to the amount of time required to reverse engineer this particular PCM. Proprietary source code + a single, limited production platform = extremely limited profit potential for HPTuners.

You might be able to add fuel to the cells in the MAF table that are being referenced during those conditions, but I'm not sure if it would just get trimmed out...I might give it a look this summer to see if it is possible, but since there is zero performance benefit to it, it's not real high on my list of things to try.

I know everybody raves about the decel pop, but I can't imagine dumping unburned fuel down the exhaust does much to help the already high door sill temps. If there's no performance benefit, I don't understand the draw.

[donk_316]

No actual data shows higher temps on the cats.the only time it would be an issue is for people running stock cats. Hiflo cats or no cats then it isn't an issue anymore.

I haven't swapped my exhaust yet and I haven't noticed any increase in sill temp with the arrow.

[7TH_SIGN]

All this talk about decel pops. I get to experiance it on my catless exhaust this Friday when I get the Arrow PCM installed.

That being said, I'd rather have 40whp extra over exhaust note.

[donk_316]

AND calling it "decel pops" isnt even correct. Decel popping makes me think of old glasspacks or chery bombs mufflers. This is a decel burble.

The F-type burbles on decel. This is the sound that the Arrow makes. It doesnt "pop" or "snap"

I had the HPT in the "shopping cart" and backed out and went Arrow. Just not super comfortable with that just yet.

[Dman]

19hp from exhaust and Arrow PCM.

Seems like false advertising to me.

We have major vendors saying 60hp at the wheels.

I don't know how you explain away that much power difference.

I think anyone who spent that kind of time and money on those mods and got 19hp would be livid.

This would suggest all you should do is get he Hap tune and anything else, including exhaust is a bit of a waste of money for so little hp return.

[The_Ruski_Driver]

19hp from exhaust and Arrow PCM.

Seems like false advertising to me.

We have major vendors saying 60hp at the wheels.

I don't know how you explain away that much power difference.

I think anyone who spent that kind of time and money on those mods and got 19hp would be livid.

This would suggest all you should do is get he Hap tune and anything else, including exhaust is a bit of a waste of money for so little hp return.

Exhaust makes all the difference in sound and gives you power under the curve. The cats on these cars are where the majority of the restriction is. Personally, I plan to run HI-flows so I don't have to breath in the awful smell for 5HP

[Dman]

Exhaust makes all the difference in sound and gives you power under the curve. The cats on these cars are where the majority of the restriction is. Personally, I plan to run HI-flows so I don't have to breath in the awful smell for 5HP

That's fine, under curve yea, we're talking peak advertised numbers. When we have SRT and our major vendors saying these parts provide 60rwhp, and attest to it in dozens of dynos and installs, and you get 19rwhp. That's with full exhaust. Um, if any aftermarket vendor were advertising 60rwhp for mods and we dyno'd and saw 19rwhp, the thread would go apocalyptic and the aftermarket vendor would join the ranks of Hennessy.

I'm NOT a dyno warrior, I have always compared mods by 1/4 mile MPH numbers myself, vs going and strapping onto rollers, but a 40rwhp shortfall on the same dyno is .... A LOT.

[outnumbered]

19hp from exhaust and Arrow PCM.

Seems like false advertising to me.

We have major vendors saying 60hp at the wheels.

I don't know how you explain away that much power difference.

I think anyone who spent that kind of time and money on those mods and got 19hp would be livid.

This would suggest all you should do is get he Hap tune and anything else, including exhaust is a bit of a waste of money for so little hp return.

Dave, just for clarification, all my pulls had a full Belanger exhaust. So where the dyno states "stock", that is on the stock tune WITH a full exhaust. I don't know what the car made stock (without the exhaust)

[Dman]

Dave, just for clarification, all my pulls had a full Belanger exhaust. So where the dyno states "stock", that is on the stock tune WITH a full exhaust. I don't know what the car made stock (without the exhaust)

Gotcha, just seems the car must've been rather weak upfront, or something going on. With SRT putting out their dyno video showing 538rwhp as a typical rwhp number, showing 540rwhp with full exhaust .... almost seems like something was awry and the Arrow didn't correct for it, but Torrie nailed whatever it was and you got the performance you should be getting. I know a gen5 here dyno'd 534, they rolled it off the drums and installed the ARH full exhaust and back on the dyno the next day for a 571rwhp pull. Arrow install took it to 589rwhp, all corrected. Same dyno all in 24 hrs, pretty good comparison. But it could be a fluke, the thing with vipers is there are so few with particular mods it seems we're always in new territory with things. I know we see Torrie generally gets more HP from posts I've seen, 30+ more rwhp is cray cray. I think if I do another viper, which is likely at this point, I'd try Torrie's tune. I've had great results from Lund remote tunes on my mustangs for years, and Torrie has the same type stellar reputation and results.

[outnumbered]

Gotcha, just seems the car must've been rather weak upfront, or something going on. With SRT putting out their dyno video showing 538rwhp as a typical rwhp number, showing 540rwhp with full exhaust .... almost seems like something was awry and the Arrow didn't correct for it, but Torrie nailed whatever it was and you got the performance you should be getting. I know a gen5 here dyno'd 534, they rolled it off the drums and installed the ARH full exhaust and back on the dyno the next day for a 571rwhp pull. Arrow install took it to 589rwhp, all corrected. Same dyno all in 24 hrs, pretty good comparison. But it could be a fluke, the thing with vipers is there are so few with particular mods it seems we're always in new territory with things. I know we see Torrie generally gets more HP from posts I've seen, 30+ more rwhp is cray cray. I think if I do another viper, which is likely at this point, I'd try Torrie's tune. I've had great results from Lund remote tunes on my mustangs for years, and Torrie has the same type stellar reputation and results.

I had a great experience with him in the past. Unofficially, I had the record (from what we could tell) for a naturally aspirated SRT10 Ram. Torrie took it to 601 at the wheels. Obviously that was with a good cam and a good set of heads from Greg Good. But it all had to come together with a tune, and Torrie delivered.

[The_Ruski_Driver]

So to get this Torrie tune, we would need to have access to a Dyno? you guys have a dyno in your garage?

[Stealth]

These results do seem a bit strange. FWIW, my '14 GTS has been running the Arrow PCM, Stock CATS and Corsa CAT-back exhaust on 91 octane for 3,000-4,000 mi. with no known adverse effects (my car has 7,000 mi. currently). As I have noted previously, my feeling is that the Arrow tune is the tune that would be preferred by the factory as the OEM tune, except for regulations, etc. The car just seems to run better and sound better, with better throttle response. I have never felt a "night and day" difference in power just based on the Arrow PCM.

[Malu59RT]

So to get this Torrie tune, we would need to have access to a Dyno? you guys have a dyno in your garage?

You have to rent a dyno from a local performance shop. Prices range from $175-$300/hr around here, although it has been a while since I've checked.

[outnumbered]

So to get this Torrie tune, we would need to have access to a Dyno? you guys have a dyno in your garage?

If you are anywhere close to Charlotte NC, I can help make it really easy for you.

[7TH_SIGN]

The dyno is a tuning tool more so than a scale of measument against others. I think what's important is your own before/after numbers on that same dyno.

Below is a members gains from the Arrow PCM.


I know others have already posted similar threads but still wanted to share my results and impressions. Upon initial start up I was disappointed to hear no audible change in the exhaust note. I already had the Corsa cat back installed but if anything, it seemed a bit quieter at idle. My disappointment subsided once I began to drive it however as the decel burble is quite loud and pronounced! I found myself taking my foot off the accelerator repeatedly on the way home just to listen to it. :D I wasn't sure if my SOTP meter was playing tricks on me but it certainly felt like it was accelerating more quickly now as well.

I had a baseline dyno done the day before the installation and a follow up dyno the day after. My only "performance" upgrade besides the new PCM is the Corsa cat back. I used the best of 3 pulls from each session to get the below results:

http://viper.c-myweb.com/images/forums/compare.jpg

640BHP/600BTQ at 15% drivetrain loss = 545RWHP/510RWTQ so my before looks about right
Using the same 15% in reverse on my after yields 690BHP/638BTQ... not to shabby for a simple PCM swap. I am extremely pleased with the purchase; thanks Mark!

http://viper.c-myweb.com/images/forums/dyno.jpg

Temps for the final pull before PCM installation
http://viper.c-myweb.com/images/forums/temps1.jpg

Temps for the final pull after PCM installation
http://viper.c-myweb.com/images/forums/temps2.jpg

[outnumbered]

Now those are good numbers!

[donk_316]

In this thread, bolt on with Arrow PCM gains are discussed. 590-600 whp.
http://driveviper.com/forums/threads/13410-Full-stage-1-upgrade-good-for-690hp

[FLATOUT]

Yes the numbers quoted in this thread are pretty far off of the mark in terms of what we see at ViperExchange regarding both tuning methods. I have had BOTH a Torrie tune on my car and the Arrow controller with a full exhaust and they were 5rwhp a part. I kept the Arrow tune because it was a much better overall calibration. Winkles has access to the entire ECU and has more than a little experience tuning the Viper V10. Aggressive dyno tunes are fun until the motor starts pinging in the summer months.




Gotcha, just seems the car must've been rather weak upfront, or something going on. With SRT putting out their dyno video showing 538rwhp as a typical rwhp number, showing 540rwhp with full exhaust .... almost seems like something was awry and the Arrow didn't correct for it, but Torrie nailed whatever it was and you got the performance you should be getting. I know a gen5 here dyno'd 534, they rolled it off the drums and installed the ARH full exhaust and back on the dyno the next day for a 571rwhp pull. Arrow install took it to 589rwhp, all corrected. Same dyno all in 24 hrs, pretty good comparison. But it could be a fluke, the thing with vipers is there are so few with particular mods it seems we're always in new territory with things. I know we see Torrie generally gets more HP from posts I've seen, 30+ more rwhp is cray cray. I think if I do another viper, which is likely at this point, I'd try Torrie's tune. I've had great results from Lund remote tunes on my mustangs for years, and Torrie has the same type stellar reputation and results.

[donk_316]

I have had BOTH a Torrie tune on my car and the Arrow controller with a full exhaust and they were 5rwhp a part. I kept the Arrow tune because it was a much better overall calibration. Winkles has access to the entire ECU and has more than a little experience tuning the Viper V10. Aggressive dyno tunes are fun until the motor starts pinging in the summer months.

:owned:

[outnumbered]

I wonder if it's possible that my particular Arrow pcm was missing a certain calibration? We made 3 pulls with the Arrow; all with similar results. Actually the one I posted was the highest. The car is definitely stronger with the HP Tune. So I know the Dyno numbers aren't giving me a false reading.

[98intrigue]

I'll hopefully have results later this week or next. I dynoed my stock car with 1000 miles on the odometer less than 2 weeks ago. I've since added an underdrive puller, Belanger headers/exhaust, and just waiting for my Arrow PCM to arrive. So although not all on the same day, I'll get a pretty accurate idea of what the mods add with the PCM.

[The_Ruski_Driver]

I'll hopefully have results later this week or next. I dynoed my stock car with 1000 miles on the odometer less than 2 weeks ago. I've since added an underdrive puller, Belanger headers/exhaust, and just waiting for my Arrow PCM to arrive. So although not all on the same day, I'll get a pretty accurate idea of what the mods add with the PCM.

I'm very interested to see the results. Good choice in Belanger, they sound great from what I hear!

[Steve M]

I wonder if it's possible that my particular Arrow pcm was missing a certain calibration? We made 3 pulls with the Arrow; all with similar results. Actually the one I posted was the highest. The car is definitely stronger with the HP Tune. So I know the Dyno numbers aren't giving me a false reading.

Dyno both when it is cooler out...I'll bet that you'll see a smaller difference between the two results (HPT will probably stay about the same, and the Arrow numbers will go up).

Tuning these cars ain't rocket science...they'll only take a certain amount of timing in certain areas, and 12.6-12.8 AFR is about right for the fueling. There just isn't much else to do in terms of power production, but as you can see from your results, it is certainly easy to remove power under certain conditions depending on the calibration. To me, it looks like the Arrow PCM reduces power about as aggressively as the stock PCM when the IATs get into the upper 80s and higher.

[ACR]

Can knock events be logged on this pcm? If there isn't any change in knock and afr is on target, there shouldn't be much to be concerned with

[Steve M]

Can knock events be logged on this pcm? If there isn't any change in knock and afr is on target, there shouldn't be much to be concerned with

With HPTuners, yes...not with the stock or Arrow PCMs.

[FLATOUT]

I wonder if it's possible that my particular Arrow pcm was missing a certain calibration? We made 3 pulls with the Arrow; all with similar results. Actually the one I posted was the highest. The car is definitely stronger with the HP Tune. So I know the Dyno numbers aren't giving me a false reading.

Stranger things have happened honestly so you never know.

[Dave1968]

Is it fair to say then, that the HP tuner's setup may give a little more power, however, it will have an effect on longevity, whereas the Arrow is the way they really wanted to tune this car and it will last "forever"?

[Steve M]

Is it fair to say then, that the HP tuner's setup may give a little more power, however, it will have an effect on longevity, whereas the Arrow is the way they really wanted to tune this car and it will last "forever"?

I personally think it's more accurate to say that the Arrow tune has to be more conservative because it has to work for absolutely everyone under the worst conditions, whereas a custom tune is tailored to each individual application. It makes no sense to tune a car to run on a road course when it will only see spirited romps on the street...you'll end up leaving power on the table. With HPTuners, you aren't stuck with one tune...you can change it as many times as you want. For example, if it is going to be hot outside, I'll pull 2° of timing across the WOT region so I know my car will run safe. When the temps go back down, I put that timing back in for more power. It's really that simple. I get to make the choices, not someone sitting in Detroit conjecturing about how I might use my car, knowing full well that if the customer's car blows up, there will be hell to pay. If my junk blows up, that's on me...I've gone through about 70 different iterations of the tune on my car over the past couple of years, and it's still in one piece.

I'll keep saying it until someone finally believes me: HPTuners is nothing more than a tool. The end results are up to the person using it. You can run HPTuners and leave the tune stock if you really felt so inclined, or go even more conservative. Hell, you could set your rev limiter to 2,000 RPMs and let your kid drive it. Tuning software is all about having choices...with Arrow, you get one: theirs. Arrow found a niche market with the Viper community because it tends to be filled with people that have neither the time nor the inclination to learn how to tune a vehicle...they just want a plug and play solution. If that's you, then so be it...you at least have that choice, which is far better than where we were a few years ago.

[donk_316]

Good post Steve. I think you hit the nail on the head there.

[outnumbered]

Dyno both when it is cooler out...I'll bet that you'll see a smaller difference between the two results (HPT will probably stay about the same, and the Arrow numbers will go up).

Tuning these cars ain't rocket science...they'll only take a certain amount of timing in certain areas, and 12.6-12.8 AFR is about right for the fueling. There just isn't much else to do in terms of power production, but as you can see from your results, it is certainly easy to remove power under certain conditions depending on the calibration. To me, it looks like the Arrow PCM reduces power about as aggressively as the stock PCM when the IATs get into the upper 80s and higher.

Steve, I think you're idea on the temp difference is very plausible. Based on genVer's info above, there does seem to be a significant temp decrease, while making the pull with the Arrow pcm.

[v10tt]

Outnembered: I can tell you on my full bolt on car with Arrow PCM and IAT in the 70s I can blow the tires off if I stab it at 4k in 2nd gear, does not happen once IAT goes into the 80s and above.
I can blow them off on 1st gear at will even with IAT in the low 100s.

How does your car behave with both calibrations at different IATs??

[98intrigue]

Outnembered: I can tell you on my full bolt on car with Arrow PCM and IAT in the 70s I can blow the tires off if I stab it at 4k in 2nd gear, does not happen once IAT goes into the 80s and above.
I can blow them off on 1st gear at will even with IAT in the low 100s.

How does your car behave with both calibrations at different IATs??
Ditto. Unfortunately, we see IATs above 80 11 out of 12 months of the year. There's a significant difference in the pull with IATs in the 80s vs IATs in the 70s.

[Dave1968]

I personally think it's more accurate to say that the Arrow tune has to be more conservative because it has to work for absolutely everyone under the worst conditions, whereas a custom tune is tailored to each individual application. It makes no sense to tune a car to run on a road course when it will only see spirited romps on the street...you'll end up leaving power on the table. With HPTuners, you aren't stuck with one tune...you can change it as many times as you want. For example, if it is going to be hot outside, I'll pull 2° of timing across the WOT region so I know my car will run safe. When the temps go back down, I put that timing back in for more power. It's really that simple. I get to make the choices, not someone sitting in Detroit conjecturing about how I might use my car, knowing full well that if the customer's car blows up, there will be hell to pay. If my junk blows up, that's on me...I've gone through about 70 different iterations of the tune on my car over the past couple of years, and it's still in one piece.

I'll keep saying it until someone finally believes me: HPTuners is nothing more than a tool. The end results are up to the person using it. You can run HPTuners and leave the tune stock if you really felt so inclined, or go even more conservative. Hell, you could set your rev limiter to 2,000 RPMs and let your kid drive it. Tuning software is all about having choices...with Arrow, you get one: theirs. Arrow found a niche market with the Viper community because it tends to be filled with people that have neither the time nor the inclination to learn how to tune a vehicle...they just want a plug and play solution. If that's you, then so be it...you at least have that choice, which is far better than where we were a few years ago.

Sounds good. When you talk about pulling timing out manually when it gets hot out, I was under the impression the Arrow will run flatout until it senses this temp increase and pull the timing out by itself - although more aggressively than say you would. HP is definitely a useful tool, I've done lots of research on it, and I can see where it is a very beneficial tool for people who will create different tunes depending whether they are going to the track or just street driving. I think Arrow's next step should be the creation of other tunes, basically encompassing the various tunes someone would use - say track, drag racing and all out crazy, and then mate that with driving modes already in the system. That way you could replace each selection with a new one or just simply add extra ones - so instead of having 3 or 5 selections you might have 8. How about it Dick?

[outnumbered]

Ditto. Unfortunately, we see IATs above 80 11 out of 12 months of the year. There's a significant difference in the pull with IATs in the 80s vs IATs in the 70s.

After I left the tuning session, the outside temp was in the mid 80's, so I have to assume the IAT was at least that. It was the strongest the car has ever felt. I do remember making a couple of WOT pulls in second gear, and each time, the car got loose.

[outnumbered]

In the fall, or the next time the temps fall back into the 60's, I will go back and have both tunes dynoed again.

[Steve M]

Sounds good. When you talk about pulling timing out manually when it gets hot out, I was under the impression the Arrow will run flatout until it senses this temp increase and pull the timing out by itself - although more aggressively than say you would. HP is definitely a useful tool, I've done lots of research on it, and I can see where it is a very beneficial tool for people who will create different tunes depending whether they are going to the track or just street driving. I think Arrow's next step should be the creation of other tunes, basically encompassing the various tunes someone would use - say track, drag racing and all out crazy, and then mate that with driving modes already in the system. That way you could replace each selection with a new one or just simply add extra ones - so instead of having 3 or 5 selections you might have 8. How about it Dick?

There are a couple ways to skin that cat...you can either go into the main spark table and simply remove 2° just in the WOT region (leaving part throttle alone), or you can invoke this table that I'm guessing quite a few around here have seen:

http://i305.photobucket.com/albums/nn227/meentss02/HPTuners%20Viper/Gen%205%20IAT%20Timing%20Table_zpswj9kobim.jpg

The key number there is 77° - above that IAT, timing starts getting pulled. Between those discreet points (77°F and 86°F), the PCM uses a linear interpolation...so at 80°, it pulls 1°, at 83° it pulls 2°, and so on. The problem with using that table is that there's another table that adds fuel as the timing is pulled due to IAT, ECT, or knock. I actually did a test last summer to see how much fuel was being added when timing was pulled, and came up with this chart:

http://i305.photobucket.com/albums/nn227/meentss02/HPTuners%20Viper/Gen%205%20Viper%20Spark%20Enrichment_zpsth9q5jak.j pg

The stock Gen 5 calibration with no timing being pulled is already commanding down in the high 11s for AFR, and you can see how much deeper in the 11s it goes as the timing gets pulled by 2° increments. The Gen 4 calibration actually adds even MORE fuel than the Gen 5 does, so the problem can be even worse for us '08-'10 guys.

The net result is that you will notice a significant decrease in power output as those temps start climbing. In my experience, 3-4° of reduced timing is pretty darn noticeable, as is a 0.5 point decrease in AFR (decrease being richer). I can really only speak to what's in a stock Gen 5 calibration, but all indications are that the Arrow PCM retains that functionality. It's not bad...just conservative.

[Steve M]

HP is definitely a useful tool, I've done lots of research on it, and I can see where it is a very beneficial tool for people who will create different tunes depending whether they are going to the track or just street driving.

Oh, and to this point, it is extremely useful not only for tuning, but also for scanning and logging data. I finally got around to adding a full-time wideband O2 sensor into the mix a couple months ago. I was able to get a wideband that outputs the data directly on to the vehicle's CAN BUS system, allowing me to pull the data in as another PID (parameter identifier) on the network. You can log that data at 100Hz, so every hundredth of a second it logs a different point.

Bottom line: you can log that external data source in conjunction with other parameters coming in from the vehicle itself (engine RPM, MAF sensor voltage, etc.), and figure out how much your fueling is off percentage-wise by just doing a couple WOT pulls. I've been able to get the fueling within about one to two tenths of a percent after only a couple adjustments. Not gonna lie - it took some effort to get to that point, but once you are there, tuning becomes quite easy. I'm not sure there are any other companies out there at any price point that come close to the features and functionality offered by HPTuners when it comes to the scanner, something that is often overlooked.

[Dave1968]

Great info. Steve M. Thankyou for your time on this matter.

[outnumbered]

Great info. Steve M. Thankyou for your time on this matter.


Ditto....I have definitely gained some knowledge.

[SRT BILL]

Thanks Steve for all the info, you have a good way of breaking it all down and making some sense for someone like myself. I do have a question though, it seems that controlling the air intake temp is a key factor in controlling the amount of timing that's being pulled. Does the HP tuners allow this table to be adjusted and if so what is consider save? It does seem that the stock ECU pulls a lot of timing at seeming low temps.

[Steve M]

Great info. Steve M. Thankyou for your time on this matter.


Ditto....I have definitely gained some knowledge.

I guess that's what happens when you are short on cash and long on time...HPTuners helps keep my mind occupied while I dream of doing some of the builds you guys are out there doing. I'll get there, but it'll take me a little while.


Thanks Steve for all the info, you have a good way of breaking it all down and making some sense for someone like myself. I do have a question though, it seems that controlling the air intake temp is a key factor in controlling the amount of timing that's being pulled. Does the HP tuners allow this table to be adjusted and if so what is consider save? It does seem that the stock ECU pulls a lot of timing at seeming low temps.

There are guys that have PhDs in this type of stuff, but I'm not one of them...if I can't break it down like that, I won't understand it either.

Managing the IATs is absolutely critical IMO...that's why I was one of the first in line to buy Doug Shelby's heat shield. I can adjust that table so that it doesn't remove any timing whatsoever, but I still realize the big problem is that the intake tract heat soaks like a mofo when you are sitting in traffic.

That said, you absolutely can adjust that table to suit your appetite for risk...here's what I personally run on the street, and feel that it is pretty safe even with the spark advance I've added to the OEM main spark table:

http://i305.photobucket.com/albums/nn227/meentss02/HPTuners%20Viper/Steves%20IAT%20Spark%20Street_zpsyayxokri.jpg

And here's an idea of what it'd look like if I were going to the track just to be safe(r):

http://i305.photobucket.com/albums/nn227/meentss02/HPTuners%20Viper/Steves%20IAT%20Spark%20Track_zpsmduiw8h7.jpg

IMO, the reason why the stock IAT spark modifier table is so aggressive is because at the upper RPM range at WOT, even the stock calibration commands upwards of 28° of timing...that's a pretty decent amount of timing already. I stated earlier in this thread that you can add spark in certain areas to increase your power output...the upper RPM range is not one of those areas I'd add a ton of timing to (like 1-2° max additional at most with 93 octane). The OEM calibrators clearly didn't want people coming in with chunks of pistons missing, so they took certain measures to prevent that from happening. They unfortunately also removed a ton of power in the process of keeping things "safe". I'm not quite as risk averse though.

Hope that helps.

[SRT BILL]

Thanks Steve, So if you were going to the track you start to take out timing earlier to be safe. I would have thought just the opposite, goes to show how little I know. I also have installed Dougs heat shield with Dynaliner attached. This does help but have not seen the effect yet in the hot weather here in NJ. I guess keeping the intake air as cool as possible helps any of the ECU choices perform better. I read that unofficial the Arrow ECU does not alter those tables and the timing pull out is the same as stock. Not sure if this is accurate, but it seems the way your approaching this issue may be best. But for myself with limited knowledge and tech help a one tune system like the Arrow is a good choice with the key being keep the air temps down.

[Dave1968]

So stock and Arrow are pulling timing out as per Intake temp. as a precaution to detonation; I wonder why they wouldn't just let it go until the knock sensors picked up something and retard appropriately. Maybe this is too much living on the edge for them or maybe not a fast enough reaction by the system to prevent any damage. You would think though if the sensors are monitoring everything several times a second it would be enough. Thoughts?

[Steve M]

Thanks Steve, So if you were going to the track you start to take out timing earlier to be safe. I would have thought just the opposite, goes to show how little I know.

Yep...a track would be the more stressing situation, prompting me to be a little more conservative.


So stock and Arrow are pulling timing out as per Intake temp. as a precaution to detonation; I wonder why they wouldn't just let it go until the knock sensors picked up something and retard appropriately. Maybe this is too much living on the edge for them or maybe not a fast enough reaction by the system to prevent any damage. You would think though if the sensors are monitoring everything several times a second it would be enough. Thoughts?

I think you are probably on to something when it comes to relying on the knock sensors...for them to work, the knock actually has to be happening before it starts pulling timing, so the damage would already be occurring. I'm not sure how often the knock sensors are monitored, but knock is monitored by individual cylinder on these cars (two sensors, so there are windows in the crank rotation when knock is monitored for each cylinder).