Modifying ARROW PCM tune possible

[dethred]

Hey guys,

I have the Arrow PCM, and cat-less headers as the two primary mods on my car. I have the DSE heat shield and wrapped both the stock airbox and heat shield in heat reflective foil, and it works great.

The problem is, anything above about 70*F results in >77* intake air temperatures, which in turn begins pulling timing based on IAT temperature. There is a HUGE difference between 85* and 95* IAT's, and it feels like the difference between running stock vs running with the aforementioned mods, and this obviously isn't just air density. I missed out on first place in a few races this summer by one or two mph, but the car was running >95* IAT temps and felt sluggish. Not to mention that the battle against convection in the engine bay will ultimately heat soak the shield and foil so that they are effectively doing very little on very hot days.

Having seen a number of people run a Torrie tuned HP Tuners setup, and knowing they have been reliable even without the IAT timing tables enabled...

I wanted to know whether or not I am going to have to switch back to the OEM ECU, buy the HP Tuners part, reserve and pay for dyno time and Torrie to remotely tune the car. If this is the required course of action, approximately how much $$$ am I looking at spending?

-or-

Can I get HP Tuners, connect it to the Arrow ECU, and simply disable or modify the IAT timing table so I am getting 100% power at reasonable temperatures like 90*F. This would allow me to only incur the cost of HP Tuners and maintain the gains of the Arrow PCM, without having to pay for dyno tuning.

[Martin]

Just a dumb suggestion, but what about moving the IAT sensor to a different location that stays colder?

[texasram]

What about a mild shot of nitrous? ultimate intake charge cooler

[dethred]

Just a dumb suggestion, but what about moving the IAT sensor to a different location that stays colder?

The IAT sensor is built into the MAF sensor, which isn't really able to be relocated...

[v10tt]

$1000 HP tuner Software
$500 Remote Tune
$300-400 Dyno time.

In my particular case HUGE power difference in ANY (cold or hot) weather conditions. Anything below 74 deg. ambient and I can spin the tires in 2nd gear from 60 mph if I go WOT. 1st gear is now useless on street tires at any IAT.

[dethred]

$1000 HP tuner Software
$500 Remote Tune
$300-400 Dyno time.

In my particular case HUGE power difference in ANY (cold or hot) weather conditions. Anything below 74 deg. ambient and I can spin the tires in 2nd gear from 60 mph if I go WOT. 1st gear is now useless on street tires at any IAT.

Thanks for the info! Yeah, unless I can somehow tune the Arrow PCM with HP Tuners or sell the damn thing for a decent amount, I'm going to be stuck only doing race events in early Spring and late Fall.

[v10viperbox]

I just had a friend tap into my gen IV with a HP tuner license. I have the arrow controller and he had access to what looked like everything just like a OEM ecu. I imagine that you can tune a gen V with HP as well even with the arrow being the ECU, i mean its just different turning not a whole new controller.

[FLATOUT]

Or you could leave it alone to help keep detonation at bay the way Dick intended? Not that you have to but a thought none the less.

[dethred]

Or you could leave it alone to help keep detonation at bay the way Dick intended? Not that you have to but a thought none the less.

I understand the logic behind it, and it may be ideal, but wouldn't for example, pdv running in the Florida heat with HP tuners indicate that it's at least a bit conservative? I am at or near sea level much of the time, running 93 octane, and I just want to make full power at reasonably normal temperatures.

At the very least I'd like to modify it to protect the motor at extreme temperatures, but be able to make power when it's still warm enough for my tires to grip.

Do you know if this is possible, having possibly the most experience on the end user side of it?

[Jack B]

The G4 and G5 have way different pcm's. The HPT package is also different for the G4 and G5. The typical HPT package can actually modify the base pcm algorithms, the G5 version seems to act more like a piggy back add-on. To this point, I do not believe any one has posted about being able to change the base values of the arrow pcm.

I just had a friend tap into my gen IV with a HP tuner license. I have the arrow controller and he had access to what looked like everything just like a OEM ecu. I imagine that you can tune a gen V with HP as well even with the arrow being the ECU, i mean its just different turning not a whole new controller.

[FLATOUT]

I know that his car did experience detonation in the heat. Not enough to kill it though.

One thing that still isn't discussed much when these two products come up and timing pull based on IAT's is same day, same track 1/4 mile traps in warmer temps. At the Viper Nationals last year and another separate straight line day where we had very similar cars running both setups actually ended up running repeatable and VERY similar trap speeds with neither aproach yielding an advantage over the other. It wasn't that hot at the Viper Nats (70's) but would have been hot enough after sitting in the staging lanes to see a difference I would think.

I know we've seen differences on the dyno but I haven't seen it translate much to actual trap speeds yet.

I understand the logic behind it, and it may be ideal, but wouldn't for example, pdv running in the Florida heat with HP tuners indicate that it's at least a bit conservative? I am at or near sea level much of the time, running 93 octane, and I just want to make full power at reasonably normal temperatures.

At the very least I'd like to modify it to protect the motor at extreme temperatures, but be able to make power when it's still warm enough for my tires to grip.

Do you know if this is possible, having possibly the most experience on the end user side of it?

[v10tt]

This was from your black TA, back in the day HP tuned. I have not seen an Arrow car (at least the ones I see post on here and I follow on instagram), trap close to that yet.

Year of your Gen V: 2014 TA
Tires: Hoosier 18" Drag Radial
Performance Mods (if any): American Racing Headers, Ipsco Underdrive Pulley, HP Tuners Tune by KP Racing, No Cats
Category submitted for: Boltons without internal engine modifications
60'............. 1.83
330'........... 4.7808
660'........... 7.151
660’ mph... 101.81 mph
1000'.......... 9.1563
1320'.......... 10.8596
1320’ mph… 134.97 mph
Name of the track: Lonestar Motorsports Park
Date of pass: January 4, 2015
Weather conditions: (include Density Altitude, if known): -800'

Image of complete Time Slip:
Time slips by mrandrewwheeler, on Flickr

Link to Video if you have one:

[v10tt]

Fastest (traps) Arrow car That I have seen.

[1.8t]

My Arrow car trapped almost 133mph. I hit the rev limiter twice on the pass in my sig which is probably why it didn't(2-3 and 3-4 shifts). I have never gotten close to 134mph though.

[dethred]

I know that his car did experience detonation in the heat. Not enough to kill it though.

One thing that still isn't discussed much when these two products come up and timing pull based on IAT's is same day, same track 1/4 mile traps in warmer temps. At the Viper Nationals last year and another separate straight line day where we had very similar cars running both setups actually ended up running repeatable and VERY similar trap speeds with neither aproach yielding an advantage over the other. It wasn't that hot at the Viper Nats (70's) but would have been hot enough after sitting in the staging lanes to see a difference I would think.

I know we've seen differences on the dyno but I haven't seen it translate much to actual trap speeds yet.

Part of what I'd like to do is also try a few dyno runs to compare with the IAT protection enabled vs disabled. I know for a fact that the car suffers under warmer temps, as every trap speed I've gotten has worsened as the afternoon heat increased. I just want to know if my PCM will be bricked and need to be sent back to Arrow to be flashed, if I load the tune into HP Tuners. Obviously if my testing yields no real world results, then I'll run everything with the base Arrow tune to be safe.

[Voice of Reason]

Does HPTuners do a real unload of the parameters on our PCM? I thought I read that it acts like it's doing it but in reality it's just pulling in a canned safe starting place that's provided by HPT.

If it's really reading the file why not have it read the Arrow PCM, make all the changes you want, and then load the tune onto the STOCK PCM? Hardware is identical between both PCMs so it should work fine.

[dethred]

Does HPTuners do a real unload of the parameters on our PCM? I thought I read that it acts like it's doing it but in reality it's just pulling in a canned safe starting place that's provided by HPT.

If it's really reading the file why not have it read the Arrow PCM, make all the changes you want, and then load the tune onto the STOCK PCM? Hardware is identical between both PCMs so it should work fine.

That's a good idea, although I worry about not having a stock fail-safe. I am still not 100% sure whether or not using HP Tuners on the Arrow PCM will wipe it back to stock or worse. Only one person has said that it'd ruin the ARROW tune, but I would like to have more input if anyone knows.

[FLATOUT]

This was from your black TA, back in the day HP tuned. I have not seen an Arrow car (at least the ones I see post on here and I follow on instagram), trap close to that yet.

There was an Arrow Gen V at Viper nats that was trapping 134mph and that DA was much higher than the day my old car running on HP Tuners was going 134mph. We had a completely bone stock Viper trap 133mph the same day my old car went 134mph. Yes I was frustrated.

Alex's bolton Gen IV holds the bolton record trapping 134mph on his Mopar ECU in the same positive DA that my 9.9 run was done in. I'm not saying the HPTuner cars won't be quicker I am just saying that I have a lot of 1/4 mile passes in and around a bunch of different Vipers and all of the bolton cars run about the same, and all seem to trap within about 1 mph of each other.

I ran both setups on my TA and was happy with both.

[Stealth78]

There was an Arrow Gen V at Viper nats that was trapping 134mph and that DA was much higher than the day my old car running on HP Tuners was going 134mph. We had a completely bone stock Viper trap 133mph the same day my old car went 134mph. Yes I was frustrated.

Alex's bolton Gen IV holds the bolton record trapping 134mph on his Mopar ECU in the same positive DA that my 9.9 run was done in. I'm not saying the HPTuner cars won't be quicker I am just saying that I have a lot of 1/4 mile passes in and around a bunch of different Vipers and all of the bolton cars run about the same, and all seem to trap within about 1 mph of each other.

I ran both setups on my TA and was happy with both.

Wasn't Alex's pass negative DA (-1150 DA)?

[Steve M]

I'll clarify what has already been stated...you do not want to overwrite your Arrow PCM with HPTuners. It isn't that it won't work, it's that you'll overwrite their calibration.

Here's the deal: the people that coded the PCM disabled the ability to read out what's on there. I'm guessing they were trying to protect their proprietary source code...good for them, bad for us. For that reason, you'll never be able to read out ANY Gen 5 PCM...what HPTuners does is generates a stock file, and allows you to overwrite what's on the PCM. You can modify the tune from there as you see fit.

For whatever reason, there's more flexibility with the Gen 4 PCM...I can log more parameters, and now that I have HPTuners loaded, I actually can read out what's on there (not that I really need to). That's just not possible for the Gen 5, but most of the functionality is there.

I busted my ass over the summer to get the tune on mine to give me the timing I was demanding...in order to do that, the engineers at HPT had to add a few more tables for me. Those have only been available since about June/July, and I verified their functionality for the Gen 4. I think they found similar parameters/tables for the Gen 5, but I don't have one of those to mess with. Regardless, I was missing a good bit of power until I was fully able to keep torque management from intervening, and for the Gen 4, decrease the knock sensor sensitivity. Most people that run HPT don't take the time to verify that what they are commanding is what they are getting on the street...it takes logging a lot of data, and poring over that data. In my case, the input wasn't equaling the output, and it took me most of this year to get it right. Don't expect shops that tune vehicles to spend that much time, especially with a low production volume car like a Viper. If you have the desire, you can figure it out yourself, and if you need some pointers, I'm always willing to help share my experience and knowledge gained along the way. I don't tune vehicles for a living, and have no intent to...I just enjoy seeing Vipers run to their true potential.

[FLATOUT]

I'll second Steve M's dedication to getting it right and pushing the software. Steve's done a great job educating others about the tool as well.

[FLATOUT]

Wasn't Alex's pass negative DA (-1150 DA)?

I was running my blue car that same day and even though the DA was negative I don't think it was that low. I do know we had a massive headwind that day and I couldn't get my car to trap higher than 139. When I trapped 141 it was in worse air +70 feet (still good) but NO headwind. I trapped 139-141 all day with ease.

I still think a Bolton car will go 136 in the right conditions regardless of whether it's using an Arrow controller or an HPT setup.

[bluesrt]

Im gonna highjack the thread, is it just me or does it seem to be all the gearheads that have modded a gen v have not had a engine failure?. Is there any known. ?. Seems people that know a working engine have no failure rate.no? Besides ralphs.

[FLATOUT]

Im gonna highjack the thread, is it just me or does it seem to be all the gearheads that have modded a gen v have not had a engine failure?. Is there any known. ?. Seems people that know a working engine have no failure rate.no? Besides ralphs.

I've always believed in running them hard and yes I have noticed the %'s. Some of the modded failures I've noticed have been self inflicted as well.

[Chorps]

Dumb question time...I picked up the HP Tuners at the same time I got my Arrow PCM on my Gen IV. Never got around to doing anything with the HP stuff but I'm thinking I might swap the PCMs just to see what the HP is like.

Can the HP Tuners software (3.1) do a throttle relearn on the Arrow controller without screwing the Arrow PCM up?