Dyno Chart Question

[98viperGTS]

I dynoed my 98 Viper GTS today. The numbers were 389RWHP and 436RWTQ. I have smooth tubes, K&N Filters and rear muffler delete. Are these numbers about right?

Thanks

 

[plumcrazy]

ive seen lower on other cars in the same year range. but most i think are 400 rwhp or higher

also depends on the dyno

 

[Russ M]

I would say about 15-20rwhp and 30lb's torque low for a 98.

Was this a dynojet?

When was the last time you changed plugs? And reset your computer?

 

[Bratatatat]

My '01, pure stock (BEFORE my mods below) dyno'd at 420rwhp and 446rwtq.

Cheers,

 

[98viperGTS]

I have had the plugs changed but have not reset the computer, How do I do that? The dyno that I was on is notorious for low numbers. It's usually around 15-30Hp off, at least that’s what some of the people were saying.

 

[Russ M]

You have still not answered my question, is it a dyno jet? Or something else?

A properly calibrated dynojet should produce about 395-405 or so on a stock gen 2 viper. That should give you an idea of what your car should be making. The whole low numbers on that dynojet thing is usualy what people say about dyno's that give you real numbers, not 420rwhp for stock creampuffs.

To reset the computer you need to unplug the power for a few days, or remove the cover protecting the computer and unplug it for 30 mins or so.

Are you running stock spark plugs as well?

 

[EllowViper]

Here are my 2001 creampuff #'s. Right in line with previous posts...

 

[98viperGTS]

Sorry, Yes it's a dyno jet and I am running stock plugs. Will reseting my computer matter?

Thanks again for all the input.

 

[Russ M]

Sorry, Yes it's a dyno jet and I am running stock plugs. Will reseting my computer matter?

Thanks again for all the input.

It is just one of the normal diagnostic things you can do to see if its the problem.

Perhaps giving us some details on your dyno pull, or maybe even posting a scan of the printout can get some answers.

Some info on your car as well, how many miles, any previous mods like nitrous that could affect the motor.

 

[98viperGTS]

Here is what they gave me. It was about 90 degrees out and it was in GA so we have alot of humidity.

You must be registered for see images

 

[98viperGTS]

Oh, it has almost 15K on it and it has not had NOS.

 

[Jack B]

A couple of observations:

1. The a/f at peak hp is about 11.5 (graphed), way too rich to achieve peak power. That is costing you plenty. Due to the way the dynojet calculates a/f (massive smoothing) your a/f is probably more like 10.5 -11.0 at peak hp, once again making it difficult to make max power.

2. At peak torque, something happens and overall power drops (stumbles), probably making it impossible to achieve possible peak power as the trace progresses.

You will get a lot input, but, a/f has to be fixed. Try a new set of plugs/plug wires prior to addressing the a/f.

 

[98viperGTS]

Good info, Thanks

 

[Russ M]

Is it just me or does the dyno graph have no correction factor? If so then that is why you are low on power 90 degrees and alot of humidity are bad for making power, and with no correction to compensate your numbers will be very low.

Try reseting the computer, and check the wires/plugs but at 15k your wires should be fine. Then go to another dyno facility and make sure they use cf.

 

[Russ M]

Here are my 2001 creampuff #'s. Right in line with previous posts...

Just looked at your dyno graph, and your car is right where it should be.

The high numbers are because your first pull was done when the car was too cold, and so was your second. This would give you the extra hp that you are seeing. But you can also see that by the 3rd and 4th pull your numbers are right inline with what I said they should be.

All dyno pulls need to start at the same temp on a viper I would say 180-190 engine temp. If your car sitts for a long time you can achieve as much as 15rwhp higher numbers without really trying all too hard. Unfortunatly they are not the numbers you are looking for unless you just want them for internet bragging rights.

 

[Jack B]

No matter what advice you take, the a/f is way too rich, there is more hp available.

 

[2001 GTS]

I dynoed my 98 Viper GTS today. The numbers were 389RWHP and 436RWTQ. I have smooth tubes, K&N Filters and rear muffler delete. Are these numbers about right?

Thanks

Hey JE,

My car with tubes/filters and muffler delete put down almost the exact same numbers, being discouraged I got a VEC1 and leaned it out...and picked up 20rwhp/26rwtq

-Steve

 

[98viperGTS]

Hey Steven,

Thanks for the words of encouragement. Where in Columbia are you located?