2008 Viper Acceleration - "like pullling an old man out of his chair" . . .

[lcandelaria]

I can't remember which car magazine made this analogy, about pulling the old man out of his chair, but I think it's perfect. Might have been in reference to the lighter flywheel in the 2013 Viper or something like that. I love the power of my Viper, but it just seems to take a little bit of time before it gets up and roars in first gear. I'm talking about a launch from a stop light where you're not spinning the tires but floor it to get to the speed limit as quickly as possible once you're moving. I noticed a big difference when driving my son's 2013 Mustang GT, that chirps the tires in the first 3 gears without going too nuts - it just seems quicker at lower RPM. Are there any suggested mods that could help make my car feel quicker? I'd like to spend less than $10,000 and would ask if you have any recommendations to include expected HP gains. The only mods to my 2008 Viper are Hennessey cat-back exhaust and K&N air filter. thx

 

[Getnlwr]

3.55 gears seem to be the one I keep hearing. It may end up being something I try. The 60MPH redline in first gear just seems a bit high to me compared to other cars I have driven.

 

[lcandelaria]

Let me know if you do make any gear changes and what the effect is.

 

[Getnlwr]

There's quite a few guys here that have done it, and recommend it.

http://www.viperclub.org/howto/faqs/what-are-the-benefits-of-a-rear-gear-swap.php

 

[NO HEMI]

Changing to 3.55's will cure that, also the difference you feel is because 2008 and newer cars have the peak torque higher up the rpm band thus feeling
Less " torquey " at lower rpm's , (kinda like the rush you feel when driving a turbo car ), compared to older models where most of the torque was available at lower rpm's. just my 0.02.

 

[lcandelaria]

That's exactly what I'm talking about - feels like a turbo spinning up. Thanks for the info!

 

[lcandelaria]

Great link - thanks. Are most people going with the 3.73 or 3.54 rear end? This sounds like the cure for my problem. Most of my driving is short trips, quick dashes between stop lights, and never getting anywhere close to the top-end speed limit.

 

[Paul Hawker]

V-8 Mustangs chirp their tires in lower gears because they do not have much weight on the rear, and have much skinner tires than Vipers.

 

[Boxer12]

For under $10k, 3.55 rear gears are perfect along with 2010 5th gear change..

 

[viper vince]

I saw something about changing the drive by wire. You can get a kit to make it respond faster more like a cable.

 

[NO HEMI]

The 3.55 will be Just what the Dr. ordered then!!

 

[Dan Cragin]

If you want to improve just the low rpm response, a lower gear, throttle pedal signal modifier and the Mopar PCM will do the job.

 

[Getnlwr]

If you want to improve just the low rpm response, a lower gear, throttle pedal signal modifier and the Mopar PCM will do the job.

I have not ever found this. Can you elaborate?

 

[ACRsnake]

I have not ever found this. Can you elaborate?

+1 ......

 

[ohlarikd]

I am sure someone will post the pedal modifier, but I saw a video of it - looks great. There is some kind of delay when you mash the pedal to when the engine responds. But with this modifier, the reaction is immediate.

 

[TrackAire]

I'm not sure but I'm guessing Dan is talking about he Sprint Booster.

http://forums.viperclub.org/threads......Sort-Of?highlight=sprint+booster+trackaire

I've done a review of it. It does NOT get rid of the drive by wire throttle lag/dead spot, but it does make it feel less noticeable since the booster just makes your TPS more responsive by giving your 100% throttle with 75% throttle input. The advantage is that it has three settings, off, mild and aggressive. On the race track, it doesn't really seem to matter as much since your are always on the throttle past the dead spot. If on the most aggressive setting, a bumpy track can move your foot enough to cause unwanted throttle inputs which, on a high horsepower car can cause issues with too much throttle and spinning the rear tires in a longer corner. I like the mild or aggressive setting for street use.

I do like the IPSCO gas pedal extender for street use. It makes heel toe downshifting better for me. But once on the track and under track braking conditions, I notice that I tend to over blip the throttle since the brake pedal is that much further down when stepping on the brake pedal at track speeds. I would be going bonkers speed on the street to try and replicate the amount of brake pedal force that I use on the track. Since it is a 5 minute install, it is very easy to swap the gas pedal extender for street or track use.

With a Gen 4, I would probably do engine mods last and start with gearing (I have 3.55's) and a modified transmission that has lowered 5th and 6th gears. I love this mod the most. A lot of Gen 4's can do a compete track lap in 3rd gear since the car has enough power and rpms to do this. But, when caught in traffic, it is much nicer to have the gearing options to pass other relatively fast cars (like a 440 hp mustang) by having the best ratio that puts you in your powerband very quickly. The stock rear end just doesn't allow the higher revving (and lower torque) Gen 4 motor to really pull until it's over 4800 rpm. My current setup allows 70 mph @ 2000 rpm in 6th gear. The car just pulls and pulls with this combination.

I also have a lightweight BBG clutch upgrade that allows the for faster revs and much better shifting over the stock system.

George

 

[chorps]

Mopar PCM seems to have helped my 2008 ACR. Seemed to take a while to re-learn, or maybe my right foot has been re-learned.

Still, it doesn't seem as immediate as it could be. Hoping that the PCM could be unlocked/tuned or even refitted with a Gen V PCM since I've read that the lag has been much improved.

 

[ohlarikd]

I know I saw a comparison video of someone stomping on the pedal before and after some update. Very clear difference in response time.

 

[MtnBiker]

Mopar PCM seems to have helped my 2008 ACR. Seemed to take a while to re-learn, or maybe my right foot has been re-learned.

Still, it doesn't seem as immediate as it could be. Hoping that the PCM could be unlocked/tuned or even refitted with a Gen V PCM since I've read that the lag has been much improved.

+1. I have the Mopar PCM and the lag is way better, but still not responsive like my C6 Z06. I like what George said about mods.

 

[lcandelaria]

I'm not sure but I'm guessing Dan is talking about he Sprint Booster.

http://forums.viperclub.org/threads......Sort-Of?highlight=sprint+booster+trackaire

I've done a review of it. It does NOT get rid of the drive by wire throttle lag/dead spot, but it does make it feel less noticeable since the booster just makes your TPS more responsive by giving your 100% throttle with 75% throttle input. The advantage is that it has three settings, off, mild and aggressive. On the race track, it doesn't really seem to matter as much since your are always on the throttle past the dead spot. If on the most aggressive setting, a bumpy track can move your foot enough to cause unwanted throttle inputs which, on a high horsepower car can cause issues with too much throttle and spinning the rear tires in a longer corner. I like the mild or aggressive setting for street use.

I do like the IPSCO gas pedal extender for street use. It makes heel toe downshifting better for me. But once on the track and under track braking conditions, I notice that I tend to over blip the throttle since the brake pedal is that much further down when stepping on the brake pedal at track speeds. I would be going bonkers speed on the street to try and replicate the amount of brake pedal force that I use on the track. Since it is a 5 minute install, it is very easy to swap the gas pedal extender for street or track use.

With a Gen 4, I would probably do engine mods last and start with gearing (I have 3.55's) and a modified transmission that has lowered 5th and 6th gears. I love this mod the most. A lot of Gen 4's can do a compete track lap in 3rd gear since the car has enough power and rpms to do this. But, when caught in traffic, it is much nicer to have the gearing options to pass other relatively fast cars (like a 440 hp mustang) by having the best ratio that puts you in your powerband very quickly. The stock rear end just doesn't allow the higher revving (and lower torque) Gen 4 motor to really pull until it's over 4800 rpm. My current setup allows 70 mph @ 2000 rpm in 6th gear. The car just pulls and pulls with this combination.

I also have a lightweight BBG clutch upgrade that allows the for faster revs and much better shifting over the stock system.

George

Great advice - thank you! Where did you order your 3.55 gear?

 

[Getnlwr]

Can anyone confirm or deny if the throttle blades will open when pressing the accelerator, with the ignition on with the engine NOT running?

 

[TrackAire]

Great advice - thank you! Where did you order your 3.55 gear?

I had Bad Boyzz Garage do the gears, OS Giken Diff and built transmission with lowered 5th and 6th gear. Call Toddy to give you the complete list of mods, but IIRC, the gears were cryo'd and micro polished, bolts safety tied and some other upgrades he can tell you about.

George

 

[Lespauldude]

V-8 Mustangs chirp their tires in lower gears because they do not have much weight on the rear, and have much skinner tires than Vipers.

^^^THIS ^^^^^

 

[cashcorn]

I always refer to the wheels on a mustang as "PIZZA SLICERS". lol

 

[lcandelaria]

If you want to improve just the low rpm response, a lower gear, throttle pedal signal modifier and the Mopar PCM will do the job.

Are there different versions of the Mopar PCM I can get for the 2008 Viper? Can you send me the link?

 

[1stSgt Viper]

I just traded in a 2013 Mustang GT with the track package and there is NO COMPARISON to my 2005 Viper I just picked up. I did not like the way the Mustang was geared (373s) as when I was in 5th, it felt like I was in 3rd. Also the car could not handle the power and would spin quite a bit. Don't get me wrong, it was fast but not even in the same category. Also, I wasn't even hitting 60 in 2nd gear in the mustang.