Dyno results, can anyone explain please?

[Nadine UK GTS]

Went on the dyno this week, (my first time).

I've been trying to learn from other postings about readings, but was a little puzzled over my results and how to understand them.

Firstly, the dyno guy had to do the run in 5th, apparently he was having traction problems in 4th. He also only ran up to 5000rpm. There is no air temperature on the print out, but, it was a warm day! He also said there was "a torque jump" when he dipped the clutch in, and so I could probably add another 10 bhp for this??

Here's the figures I got:

P-eng 475.5 bhp
P-wheel 375 bhp
P-drag 100.5 bhp

Torque 526 lbf-ft
max torque 144mph 4240 rpm

max speed 172, max rpm 5060.

My rwhp seems lower than what others post here? But engine bhp is probably about right?...although I was hopping for about 500.

I have smooth hoses, K&N's, air box without rain baffle, B&B headers (like 'Belangers' tri-y) ceramic coated & 3" stainless system without cats. UK gas is 95 octane.

Any comments would be most welcome...thanks.
(ps sorry, unable to post graph)

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[KenricGTS]

I just finished dynoing my Viper '96 GTS. I have simliar Mods I have the Belanger headers and 3 inch pipes and Hennessey air box my car did 452hp and 512 torque to the rear wheels. The DYNOJET that they use is the same one that Nascar uses. I think you should go else where to dyno your car. Kenric

 

[Bill 96 GTS]

Kenric, did you do a second set of pulls with cooler temps? Which computer were you running?

 

[BWoodbury]

Nadine,

Here is your chart. Sorry about the poor quality folks, but it looks like the original was poor, then it was faxed overseas to me, scanned, and, well you get the idea.

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John,

You're right about the Dyno. It was made by SUN Electric, a company that I worked for for over 7 years. I am pretty sure it simply can not handle that kind of HP. I'm getting more specifics from folks I know that still work there...

 

[KenricGTS]

Bill the car was a lot cooler than last time we dynoed the car. I had the stock computer on the car. I will do a pull with the Mopar computer on. I am thinking of getting an adjustable ECM.


John Hennenesy, my HMS carbonfiber airbox hits the crossmember and, that has caused two big rub holes on this very expensive airbox. Please send me a bolt kit or something for this problem. By the way nice write up in Motor Trend on your Venom 800! What a car! Kenric

 

[Nadine UK GTS]

Thanks for all the help and advice. I knew I was right about running in 4th, but the dyno guy wouldn't have it! I did also question him about tie-down...I can't begin to tell you how anxious I was to be stood besides my Viper running at over 170 mph, I was cringing waiting for him to fly off into orbit. I am very protective over my beloved GTS, it was a stressful moment! I went there as they claimed to have dyno set the GT vipers there!

Thanks Bob for offering, and posting the dyno sheet. I will go to one of the Dynojets John kindly posted, and hopefully the next sheet will be a better one! I'll try not to be too disappointed about the incorrect run, and just be thankful my Viper is still with me, and not in orbit!

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[Kid97GTS]

Hmmmmm, maybe things are different on the other side of the pond, but I have always been advised (and I have actually taken that advice) to make my dyno runs in 4th gear, since that is the 1:1 ratio in the transmission. 5th is overdrive, and I think the reduction may effect power numbers. Also, there is no way the guy should have cut at 5000 - my peak numbers came closer to 5500 (422 rwhp; 456 rwtq in a '97 GTS with smooth tubes and filters). I think you should find another dyno place or tech to help you out. BTW, I noticed no tie-downs on the rear of the Viper in your pic with it at speed - that, coupled with the "couldn't get traction in 4th" comment, wouldn't make me think the shop knew what they were doing. With your mods I would expect closer to 450 rwhp, similar to Venom Lover's.

 

[BWoodbury]

Nadine,

I am no expect on dynos, but that thing your boy was on is NOTHING like the dyno we run on for our IL region event a few weeks ago. I don't even see any tie down straps @ 172 MPH, Yikes! I'll post some pictures of our dyno tonight...

About your numbers... Ignore the "P-eng" figure. Your drive line loss is nowhere near that high. It should be about 12% or 13%. 375 at the wheels would then be about 426 at the flywheel. Stick to what the shop can measure rather than numbers that they calculate... Still you should be much higher (see my numbers and mods below).

I have no idea what "P-drag" is so I will ignore it also. 526 ftlbs at the wheels is a lot of torque. If that number is correct, which I doubt, your HP would have to be much higher.

If you fax me the dyno sheet I'll post it for you. US number, 847-270-4475.

Bob Woodbury