Stock LS3 Dyno Results...boo! :(
 

Well car pulls great and I knew going to a Mustang dyno it was going to be low but 338rwhp (with similar torque...I don't have the sheets in front of me)????

I'm "assuming" it's a 15% loss on those versus a dynojet and that would then put me closer to 390rwhp. Thoughts?

Here's the video...

Seems a tad on the low side, what does you Vette do stock in the 1/4 is the real test.

Does your Vette run okay? Does it feel like it did when it was new? Use oil? My bet is an out-of-sync dyno; out of calibration. You know that they can play with the numbers on the dyno, right? The '07 LS2 manual trans I used to have did 356 stock.

I'd rule a good part of the difference out to being a Mustang dyno. It might be a little bit on the low side but I really don't think it's anything to be overly concerned about.

A bone stock LS3 / M6 with the NPP (436 HP) will loose about 12% on the DynoJet. So the average SAE Corrected RWHP will be right at 385.

The OP got 338 RWHP on the Mustang dyno. Although the Mustang dyno will show less RWHP than the DynoJet, I think 338 is just too low.

I am betting that there's nothing wrong with the OPs Corvette ... However, the Mustang dyno he was using had an error.
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From everything I have read, a Mustang dyno will show RWHP numbers about 10% lower than the DynoJet.

If the OP was to get 385 RWHP on the DynoJet, and the Mustang dyno normally gives a 10% lower number, he should be getting about 347 RWHP on the Mustang dyno.

What was the weather? High ambient temperature and low atmospheric pressure will effect your engine performance quite a bit. 10% low could be a possibility. I think rated power is calculated on a standard day (15 C = 58F and 1013.2 MB = 29.92 inches)

I haven't tracked the car yet. It runs healthy and pulls hard (see video below). Car I bought used so I don't know what was done beyond a simple M2W switch and tinting. There's no performance modifications.

I'm hoping to just chuck it up to dyno error. There was a rather decently modified Evo X only putting down 288awhp so I started feeling better once I saw everyone else getting somewhat low numbers. I don't have the dyno sheet yet (guy is emailing me it). Here's a screen shot off the computer monitor on my lower numbered pull. The guy said it may have hurt that traction control was kept on which may limit power on the pulls if it sees slipping. True?

https://fbcdn-sphotos-b-a.akamaihd.n...59907244_n.jpg

It was in the 80s with high humidity. This is how the car pulls in 3rd (dyno was done in 4th for 1:1).

A dyno is simply a tool to tune the car. People who have no other means to compare their cars use the HP numbers from a dyno sheet.

When I took my bone stock 430 rated HP A6 LS3 to get it's first tune, the baseline pull on a Mustang dyno was 306. The final pull was 320. I was comfortable getting a 5% increase. When I returned to the track, my timeslips also averaged .2 seconds quicker. At the track, I was on equal basis with other cars who had much higher dyno numbers.

:iagree: People are WAY to stuck on dyno numbers. Dyno numbers can and will be all over the place when using different dynos in different locations on different days.

I was a little disappointed with my 369 #'s.. but as stated you can't get caught up on them, they will vary from dyno to dyno. As long as the car runs well, that's all that matters. You could always take it somewhere else to compare, or the best way to judge is the track. Good luck with it.

:iagree:......and a great one it is but just as there are variables to dyno tunes (conditions, etc.,.) there are variables to track times also (conditions, etc.,.). No one tool should be the definitive test.

:cheers:

That's a lot of the problem. High temperature a humidity = low power. I bet the density altitude was about 2,000 ft above the area's height above sea level. Oh I failed to mention standard conditions are also based on being at sea level. From what you indicate I think your engine is making correct power for the conditions. Check it again when weather conditions are more favorable. Enjoy!

Are those SAE corrected numbers?

Perhaps I'm in the minority here, but the only "dyno" that matters to me is the one in the seat of my pants. And it's a pretty simple test...
Put the car in gear. Stomp on the right pedal, Hang on for dear life. If the car either scars the crap out of you, or brings a grin to your face, or both, your "numbers" are excellent. :)
Glen

People tend to forget that a dyno is a tool to measure gains. Getting baseline numbers is a good thing, but dont measure your car's performance from them. Now hitting the 1/4mile and seeing what your mph at the end is would be a good measure of performance.

go find a dyno jet and see what it does on there if you are concerned with it.

I agree as long as you take into consideration all variables in making a pass at the track ie driver, prep, and DA.:thumbs:

Just like you keep track of changes on dyno sheets, you need to record 1/4 mile times along with the conditions. No two days on a dyno will be the same nor at the track. Differences of mods/power will show up when averages are taken for comparison.

okay thanks for the input guys. I'm just going to take them with a grain of salt I know the car pulls. Anyways, does traction control hurt on a dyno (especially a mustang dyno since it starts with an initial slip). My friend's Evo ran later and it sounded like the clutch was slipping but then we realized after the fact it was just pulling power to get traction. The dyno graph on mine does a nice little drop after initially getting on it.

Traction control has to be off when you dyno the car, the drop is probably the initial tire spin you described if that's what happened.