Any help here would be appreciated....Dyno results

[Vipernator]

I have a 2001 Viper GTS (creampuff I believe is the nickname for the year but I have a question regarding my dyno results that have me a bit baffled and hopefully someone can shed light on the following:

I bought my Viper in 2001 and purchased Sean Roe's smooth tubes and filter took it to Morgan Motorsports in North Hollywood and dyno'd the car which returned with SAE corrected peak real wheel HP of 399.8 (sorry don't have the sheet handy and don't remember the Torque). I then changed to the new filter/smooth tube kit and dyno'd once again which returned with SAE corrected peak rear wheel HP of 419. Needless to say I was pleased with the results. My car had approx 1500 miles on it at the time.

Fast forward to 2005 and with 3900 miles on my Viper I purchase Belanger headers, exhaust and HF cats. I get them installed. I read that I should drive the car 500 miles or so, so that the computer can recalibrate and drove 480 miles hauling ass around town . I go to Dynamic Racing Solutions in La Habra and get my car dyno'd expecting at least a modest HP/Torque gain after spending $3000 plus. My peak SAE corrected numbers were 414.5 HP/ 448 Torque. Found it weird cause the exhaust/headers are clearly less restrictive. What could account for the power loss/lack of gain.

I'm not too knowledgeable so any comments would be helpful thanks guys.

BTW it sounds awesome.

 

[Daniel Cragin/DC Performance Inc]

Dyno numbers vary from one dyno to another. The conditions which the test is done is also very important. A cooler engine will always make more power. The amount of air (fans) will also change the numbers. Make sure you use the same dyno every time and make sure the conditions in which the test is done are the same. Look at the numbers under the curve, you may pick up power at lower rpm levels.

Hope this helps.

 

[Joseph Dell]

Also, the creampuffs don't benefit from exhaust mods as much as the pre-2000 cars. your numbers aren't that low, believe it or not. A VEC2 and some tuning time would probably benefit you a bit more than just bolting on some stuff. BTW - if you kept the 2.5" pipe that goes to the HF cats then you still have a restriction... 3" from the headers back is the way to go, but cant tell if you have that or not.

good luck!

JD

 

[Dave T (BADVENM)]

Vipernator, check out my numbers in my sig, similar add ons. Hope this helps.

 

[Casey]

Dynos vary, that's for sure. And there can be other circumstances. But I think JD hit it on the head.
I might go as far to say that "2001" may be the year that benefits the LEAST from exhuast upgrades. That's only based on a few cars "01s" that I have seen, and others that I have heard about with full exhaust and NO gain in power.
VEC2 could be what you need to get that hidden power out of her!
The sound of Headers/exhaust on a Viper is Awesome. I know you are liking that!

Let us know your plans and outcome in future mods. Especially if you go with the VEC2. I would think many would love to see if it brings the power out.

Good luck!

 

[Vipernator]

Thanks for the replies guys....in answer to JD the cats are 3" from when I checked them out.

Casey: I'll definetly post my results....I have decided to dyno after every individual mod to see whats working and whats not.....so the VEC 2 might help? I'll look into it...what's it do?

What bothers me is that I know the pre 2001s had the 50 HP guarantee for the exhaust/header mod....all I was expecting was more than what I had...I got 5 less HP dammit

 

[Vipernator]

Oh by the way...I wanted to use the same dyno place but they are no longer in business....it was a Chevy tuner....the new place I went to works on VW's and Porsches I think.

 

[PRVT JET]

If you lost 5 hp, it is not right. I gained close to 30rwhp with the same mods as you but no cats. Try changing your plugs and see if that makes a difference.

 

[C O D Y]

If it's not the same dyno, then it doesn't mean much.

 

[Snakester]

Sometimes there are power spikes at the end of a dyno run if it's not done right, which can skew the numbers.
Frankly I don't see the original 19RWHP gain from just smooth tubes and filters. Maybe half that is closer to average. Add to that switching dynos and that would easily explain the difference.

On the otherhand, you should probably be making 425RWHP with your mods with a good dyno pull (fans, cool air, engine not heat soaked). The VEC2 does allow nice fine tuning to get the A/F dialed in.

Did you install high flow cats? They are relatively cheap, still pass smog, free up the exhaust, and cool down the side sills quite a bit.

 

[KenH]

Biggest question in my mind is what type of dyno these were. If the first was a DynoJet and the second one a Mustang, then your results would make sense since Mustang dynos tend to give a lower HP reading than DynoJets.

Something else to check would be your A/F ratio if that was recorded on the 2nd dyno. Perhaps you are running overly rich. Do you have a check engine light on from the headers by chance?

 

[STUGOTS]

Biggest question in my mind is what type of dyno these were. If the first was a DynoJet and the second one a Mustang, then your results would make sense since Mustang dynos tend to give a lower HP reading than DynoJets.

yeaha good 13% - 15% lower

 

[Vipernator]

Snakester: In 2001 I did 3 consecutive dyno runs stock and 3 consecutive after filter/smooth tube install and in 2005 3 consecutive pulls after the belanger header, belanger exhaust and belanger high flow cats install.

In every case the number were consistent (with 4 HP).

I scanned my latest dyno sheet but cant figure out how to post it :-(

KenH: the dyno used in the latest pull was a Dynojet (they had "Nascar approved Dynojet" banners all over the freaking place )

I believe the other place was a dynojet also but don't recall....will find the sheet.

Air/Fuel is as follows on the run in question starts at 16.5, at 2500rpm is at 13.7, at 4000rpm 12.3 at 5000rpm 12, at 6000rpm 11.85 (giving the numbers from my strongest pull which was the third and final one).

Thanks for the replies guys!

 

[ACELLR8]

I agree different dyno's will give different numbers, even if it is the same brand.

I would try another dyno to see what you get, your car should of have still picked up some HP with the headers.

My wife's 01 GTS just dynoed 429 RWHP and 459 RWTQ with only 1.7 Ratio Roller Rockers and a muffler rear delete.

 

[Russ M]

I have a 2001 Viper GTS (creampuff I believe is the nickname for the year but I have a question regarding my dyno results that have me a bit baffled and hopefully someone can shed light on the following:

I bought my Viper in 2001 and purchased Sean Roe's smooth tubes and filter took it to Morgan Motorsports in North Hollywood and dyno'd the car which returned with SAE corrected peak real wheel HP of 399.8 (sorry don't have the sheet handy and don't remember the Torque). I then changed to the new filter/smooth tube kit and dyno'd once again which returned with SAE corrected peak rear wheel HP of 419. Needless to say I was pleased with the results. My car had approx 1500 miles on it at the time.

Fast forward to 2005 and with 3900 miles on my Viper I purchase Belanger headers, exhaust and HF cats. I get them installed. I read that I should drive the car 500 miles or so, so that the computer can recalibrate and drove 480 miles hauling ass around town . I go to Dynamic Racing Solutions in La Habra and get my car dyno'd expecting at least a modest HP/Torque gain after spending $3000 plus. My peak SAE corrected numbers were 414.5 HP/ 448 Torque. Found it weird cause the exhaust/headers are clearly less restrictive. What could account for the power loss/lack of gain.

I'm not too knowledgeable so any comments would be helpful thanks guys.

BTW it sounds awesome.

Your initial results at Morgans are not unusual for that facility. I have seen cars come back several days later and loose 40rwhp with no mods done.

Your latest power is exactly what 2000+ vipers will pull with your mods, enjoy it.