slow mph 1/4 and high ET w/ stock 14 gts

[ViperGTS14]

Hi guys, did a lot of searching prior to posting these questions (my apologies if there is other threads on this same subject). Just a little background I had a ton of experience driving stick and many performance cars over the years, always have done well at the 1/4 mile drag's. Currently use the Dragy unit to get an idea of the mph, et, 0-60 and 60-130 mph on may cars as well as testing modifcations which is always is a + for me since its easier than going to the drag strip. From what I've see these things are pretty damn accurate as others would attest to. Anyway, though I've only had her for a week now I'm starting to get a feel of the shifter better so i thought I could get an idea of the speed she's capability of. Sadly after about 6 runs today, I couldn't get any higher mph than 120.85 (average of all runs), and lowest et was a 12.31 (average of all runs) which IMO is pretty sad since she should be doing better than this. I didn't use launch control since it seems like it would just dump the clutch at 5,500 rpm. With bogging in 1st I'm suprised to see a 4.1 0-60 which felt so slow (my average 0-60 was 4.41 which again is slow), its as if you fry the clutch, spin the wheels or bog are my only options. Also I've read its may be better to shift lower in the rpm, is this correct? Currently shifting at 6500 or there abouts, having a difficlut time getting into the next gear quick enough seems harder when higher in the rpm. The intertupt between gear shifts also seems like my problem, I'm a little nervous of power shifting but if I try to shift like normal there is one heck of a buck as if the rpms don't like to go up that quick when shifting. If there is any suggestions at to what I could do differently I'd greatly appreciate it since I do believe she has more in her.

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Updated two weeks later with heat shield installed : ran a 12.07 @ 122.49, 60 FT was 2.12, IAT was 93, Temp 81, Elevation 14 feet, DA 1400

[99RT10]

Where are you located? If you're at a high DA/high temp track, those times might be about right. If at sea level, something is off.

[Steve M]

About the only source I would trust as somewhat authoritative is an actual 1/4 mile drag strip. Even then, you can still get errors, but over enough runs, you'll figure out about where you stand.

First off, if your car is 100% stock, your rev limiter is set at 6,400 RPMs. Shifting as close to that as possible will get you your best times and traps. If you've really done your searching, you probably came across my Gen 4 drag racing results thread here: https://driveviper.com/forums/thread...08+drag+racing

I've tried to document everything I've done to my car. All said and done, I should be at or around what a Gen 5 makes stock in the power department. My car generally traps in the 128-130 range (I'd say 128 on average), but you'll see some slower runs in there as well, on the order of about 1-2 MPH slower - after going back and looking at the footage, they were all caused by short shifting instead of riding out each gear until as close to the rev limiter as possible. I've also missed a few shifts in there as well, which usually kills about 4-6 MPH on the big end.

I don't trust the numbers you are seeing, and you shouldn't either. That said, Gen 4 and 5 Vipers are notorious for pulling a lot of timing when the car gets hot, and that could be affecting what you are seeing. If you are doing these runs in the 80s and 90s, you could easily be killing your MPH just because of that. Since I have the ability to tune that stuff out, I do exactly that when I go to the drag strip, and my car has been very consistent because of it. For stock-ish cars with the stock tune, I've seen a 6-7 MPH difference in the same car with the only difference being the weather.

[ViperGTS14]

Yup at sea level, something is off for sure.

[ViperGTS14]

Yup at sea level, something is off for sure.

Thank you for that response it's very helpful. Though unfortunately do I strongly disagree regarding Dragy results. I've had too many car's and too much tuning and testing with them to prove results. They are a god-sent IMHO, though that have used them and tested accurately will vouch for them as well.

Regarding heat, I'm totally in the belief of this, though mph is so damn off like 5 mph I'm hoping that is is.

[Steve M]

Thank you for that response it's very helpful. Though unfortunately do I strongly disagree regarding Dragy results. I've had too many car's and too much tuning and testing with them to prove results. They are a god-sent IMHO, though that have used them and tested accurately will vouch for them as well.

Regarding heat, I'm totally in the belief of this, though mph is so damn off like 5 mph I'm hoping that is is.

Well, I have no experience with them, so if you trust it, then so be it. I'd still rather see an actual time slip, but getting to a drag strip and making good clean runs can be difficult sometimes. Story of my life.

That 60' seems suspect to me though...I'd expect something along the lines of 2.3-2.4 at worst.

[ViperGTS14]

Well, I have no experience with them, so if you trust it, then so be it. I'd still rather see an actual time slip, but getting to a drag strip and making good clean runs can be difficult sometimes. Story of my life.

That 60' seems suspect to me though...I'd expect something along the lines of 2.3-2.4 at worst.

Yes, my 60' can't be good. Do you use launch control? I almost attempted it but dropping the clutch at 5,500 rpm i'm thinking its going to fry the ever-loving hell out of the tires.

[Steve M]

Yes, my 60' can't be good. Do you use launch control? I almost attempted it but dropping the clutch at 5,500 rpm i'm thinking its going to fry the ever-loving hell out of the tires.

You mean my right foot? My Gen 4 dinosaur has no such thing as launch control unfortunately. I can drop the clutch at 5,500 on drag radials on a prepped track and it will hold sometimes...on street tires, no way in hell, especially on the street.

[ViperGTS14]

Yes LOL, I personally don't like launch control things unless its an AWD Audi hehe.

Not sure how much this helps but the DA is 2073.

[txA&M08]

Dragy is known to be very accurate. Within a few hundredths of a much more expensive VBox.

The only things I can add to the convo are

(1) Hot weather could be pulling over 100hp out of your car vs a sub 75 degree DA. I don't have quarter mile traps available to compare different density altitudes, but I do have 60-130 times in both winter and summer. In good air, I'll get a repeatable 6.9X, while in the summer I'm at 8 seconds flat or sometimes over.
(2) No-lift shifting is worth half a second 60-130 for me. Doesn't mean it would be for you, but it makes a giant difference in my times, and I know others have found the same.

[ViperGTS14]

Dragy is known to be very accurate. Within a few hundredths of a much more expensive VBox.

The only things I can add to the convo are

(1) Hot weather could be pulling over 100hp out of your car vs a sub 75 degree DA. I don't have quarter mile traps available to compare different density altitudes, but I do have 60-130 times in both winter and summer. In good air, I'll get a repeatable 6.9X, while in the summer I'm at 8 seconds flat or sometimes over.
(2) No-lift shifting is worth half a second 60-130 for me. Doesn't mean it would be for you, but it makes a giant difference in my times, and I know others have found the same.

I'm totally following you! I so can feel the heat soak thing going on with her. When I just cruise for a while in 5th I can see the oil temp come down from 204 to 195, if I pull then she feels really quick. I attempted a few 60-130mph and they are embarrassing to say the least. I'm even more imbarison to say my w204 c63 amg is only a few mile's off from her in the 1/4 mph traps LOL. Hopefully its a combination of heat/DA going on. When I transated the DA to the times I come up with 11.927 @ 124.306 MPH adjusted.

[txA&M08]

why-no-lift-shifting-is-not-good_100703867_h.jpg

[ViperGTS14]

F that, I'm not that good lol

[Arizona Vipers]

You left out the most important info here, your tires and the ambient temp. You could be on 7 year old oem tires for all we know, or it could be 110*
Your trap is a low should be at least mid 120's, so your power seems down. What was the ambient temp?

[ViperGTS14]

You left out the most important info here, your tires and the ambient temp. You could be on 7 year old oem tires for all we know, or it could be 110*
Your trap is a low should be at least mid 120's, so your power seems down. What was the ambient temp?

84F, elevation was 18ft and DA was 2073. Surprisingly I think the tires are original at 8,500 miles on her. And I totally agree with you I'd be happy to see mid 120's. When I did the DA calucation it did come out to 124mph

[1.8t]

Something is off, that mph is far too low for the conditions.

[dewilmoth]

What are the IATs showing? 84F is not all that hot, but if you are heat soaking the car before the runs, the IAT could be huge. Also, even without heat soak, the IAT at your ambient is probably in the 100F range. While I am not a drag guy, my car feels WAY down on power when the IATs climb into the 100s. It is probably my biggest gripe with the Viper. During the shoulder seasons it feels like a different car.

[ViperGTS14]

Thanks dwilmoth, honestly I do not know what they were, that was the only gauge I wasn't focused on. I know there is a box shield thing available but still thinking stock she should get heat soak to the point I don't run the average mid 120's. Regardless I just down loaded the DA app and will check the DA next time out as well as the intake temps. Hopefully it was a combination of bad air as well. Fingers crossed.

[ViperGeorge]

I would wrap the IAT sensors on the air tubes with insulation and get Doug Shelby's air box heat shield. The IAT sensors can heat soak and report higher IAT temps to the PCM than the actual air in the tubes causing the PCM to pull timing when it doesn't need to. The radiator fans blow hot air up and on to the air box and tubes carrying air to the intake manifold. I found by wrapping the IATs with insulation (around the tubes) my IATs stay cooler. I've also insulated the Doug Shelby air box shield and the air box itself with self stick insulation for even more protection. Heat soaks kill the power on a Viper as others have said.

One other thing, Erich Heuschele, the SRT vehicle dynamics engineer that worked on the Gen 5 launch control, traction control, and stability control system said not to use launch control on a prepped drag strip. He said times would be slower. Given this I have never tried it. He said the best launch would be to raise RPMs (I think he recommended to start at 3500 and adjust with trial and error) and to slip the clutch to limit tire slip. He said the clutch would smoke and smell but it can take the punishment. I've often wanted to try Launch Control on the strip but based on his advice I haven't. Has anyone else compared a drag strip run with and without the use of Launch Control? What were the results.

[98intrigue]

What’s your 60-130 time with this air? I haven’t tested mine yet, but would be a fun comparison - I just bought Draggy to try out. I have the IAT displayed on the center gauge, as it’s a good identifier of how much timing is being pulled.

As an FYI, a previous Viper of mine (with the DSE heatshield) and my friend’s Viper (without the heatshield) sat in stop and go traffic for about 30 mins. My IATs were at 100, meanwhile my friend’s was at 130. That heatshield makes a world of difference!

As another FYI, a previous bolt on Viper of mine went 11.3 @ 127 in horrible weather and 10.9 @ 134 in good air. As mentioned above, IATs can make or break this car.

[ViperGTS14]

I would wrap the IAT sensors on the air tubes with insulation and get Doug Shelby's air box heat shield. The IAT sensors can heat soak and report higher IAT temps to the PCM than the actual air in the tubes causing the PCM to pull timing when it doesn't need to. The radiator fans blow hot air up and on to the air box and tubes carrying air to the intake manifold. I found by wrapping the IATs with insulation (around the tubes) my IATs stay cooler. I've also insulated the Doug Shelby air box shield and the air box itself with self stick insulation for even more protection. Heat soaks kill the power on a Viper as others have said.

One other thing, Erich Heuschele, the SRT vehicle dynamics engineer that worked on the Gen 5 launch control, traction control, and stability control system said not to use launch control on a prepped drag strip. He said times would be slower. Given this I have never tried it. He said the best launch would be to raise RPMs (I think he recommended to start at 3500 and adjust with trial and error) and to slip the clutch to limit tire slip. He said the clutch would smoke and smell but it can take the punishment. I've often wanted to try Launch Control on the strip but based on his advice I haven't. Has anyone else compared a drag strip run with and without the use of Launch Control? What were the results.

Have a feeling you are correct it has to do with IAC and current weather conditions, though I don't understand all of the nasty stock times posted with box stock gen 5 viper's. Looks like guys are running low 11's and 127's with not the best shifting. Would be surprised this car run's that night and day different with better air alone but anything is possible. Is there a thread on wrapping the IATs?

[ViperGTS14]

What’s your 60-130 time with this air? I haven’t tested mine yet, but would be a fun comparison - I just bought Draggy to try out. I have the IAT displayed on the center gauge, as it’s a good identifier of how much timing is being pulled.

As an FYI, a previous Viper of mine (with the DSE heatshield) and my friend’s Viper (without the heatshield) sat in stop and go traffic for about 30 mins. My IATs were at 100, meanwhile my friend’s was at 130. That heatshield makes a world of difference!

As another FYI, a previous bolt on Viper of mine went 11.3 @ 127 in horrible weather and 10.9 @ 134 in good air. As mentioned above, IATs can make or break this car.

That's a big difference! Did some searching and found this thread, looks like this thread was prior the heat shield being created. There are a few guys running similar mph's as me and wondering why theirs is slow too. Seems everyone is focusing on the IAT temps issue/solution. Still blown away at the great times of all the testing reviews and youtube videos of guys running 11.2 at 128's bone stock.

https://driveviper.com/forums/thread...ull=1#post5812

Seeing videos like this blow me away that a stock gen 5 can run in the 10's, granded its on drag radials but still.

[ViperGeorge]

Have a feeling you are correct it has to do with IAC and current weather conditions, though I don't understand all of the nasty stock times posted with box stock gen 5 viper's. Looks like guys are running low 11's and 127's with not the best shifting. Would be surprised this car run's that night and day different with better air alone but anything is possible. Is there a thread on wrapping the IATs?

I think there have been threads on the heat shield, wrapping the IAT sensors, and the like. You might want to search threads with Doug Shelby in them. On my car, I got Doug's heat shield used self stick silver insulation from Summit Racing to further insulate it. I then bough this non-stick silver insulation at Autozone or O'Reily's wrapped it around the air tubes and zipped tied it in place. I used self stick insulation on the bottom of the plastic air box as well. Not real pretty but it works. Some folks on here have gone to more extremes using carbon fiber wrap to make it all real pretty after insulating.

I think this has dropped the IATs by quite a bit. However, if you sit in the staging lanes with your hood closed and engine running they are still going to rise. Popping the hood vents (although not as easy on a non ACR) helps extract heat from under the hood. I would also wrap any other lines like the coolant lines that run along passenger side engine to oil cooler. The car uses coolant to cool the oil cooler but if the coolant gets warm this becomes less effective. The lines can absorb heat from the engine which further heats the lines. I also used reflective self adhesive insulation on the plastic coolant tank on the passenger side engine for the same reason.

I don't drag race often, my ACR is used mostly on road courses where IATs don't usually rise too much above ambient due to all the air movement.

Good luck and please keep us posted.

[Rare Snake]

My fastest ET was also my slowest speed for the day, on the last drag I did. I believe I'm still holding 3rd place on the fast list for stock Vipers in here, but it hasn't been updated for some time.

I ran 11.57 at 121mph up in the Canadian Prairies, on PZeros, with a pretty good 60' for a Viper. I was mainly having trouble with bouncing off the rev limiter, and I think that's why we figured the speed was low. Is it possible you're having the same issue? If you're used to an older one, the new ones pick up rpm a heck of a lot faster, and it takes a bit of getting used to.

Dason

[v10tt]

Viper GTS, what rpm are you shifting at?
Can you post a video?