Kind of a rant but read on....Car is a 2008 Z-51 MN6 with NPP. Bone stock on a dynojet in 99F weather the car put down 381HP/362TQ. I added the Vararam (which install on z-51 is bad due to oil cooler, PM for more info) I then had a local top end corvette shop/tuner install LG street headers with hi-flow cats and dyno tune. The end result was 411HP and 411TQ. I am very pleased.
A stock 2011 Shelby GT500 convertible from a 30 roll with a great roll start (on a rented track) would not be happy as he would lose by 2 cars. I believe if he shifted faster it would be 1 car. They weigh 3900lbs and I weigh 3350 with a 3LT. The GT500 mustang typically puts down 475HP/460TQ and the motor is rated at 550HP/510TQ.

I feel the vararam is not taken into account on a dyno tune and does add HP, but consider the fact that with my stock tune and simply adding a vararam my A/F ratio dropped below 10 and flatlined on the dyno chart. I am happy there were very few miles put on before the tune as that lean of a condition could spell trouble. Overall the LS3 seems to really like to breathe better and with its reliability history I hope to own this car forever!
Does anyone have similar mods to compare numbers even though dynos vary a crap-ton? I am told that this shop's dyno reads low according to national customers who have work done at the same shop and others, but either way I feel 411HP/411TQ is about right.

 

FYI, Lower the number, like 10 is RICH. real rich.

 

thank you. It would seem odd it ran soooo rich when adding a ton of air though right? I would think that would cause a lean issue.
But I know nothing of tuning cars so...

 

I would say that's close.. I dyno'd 417/426.. car is still a tad rich though. I'm hoping I can pull out a few more HP's by leaning it out. The track will be the best indication of power.

Also, was your stock dyno done on the same one as your modded #'s? I gained somewhere around 50whp from my stock dyno to my modded dyno. All done on the same dyno, SAE corrected.

2008 Z51, 6MN.. Vararam, Ported TB, 1 3/4 Stainless Works headers to NPP exhaust.

 

Kooks 1 7/8, honker, my street tune was 415/400 on a dynojet.
Finished dialing in tune an got 426/410 out of it.

Mine liked 12.6 afr and about 24* up top. Any leaner or more timing and it only picked up a hp or so. Left it on the safe side.

 

I believe my tune was left slightly rich to compensate for the vararam/ram air at speed. The dynos were on 2 different dynos so no they are not exact gain numbers. BUT the pre-dyno of the car stock with the vararam installed was only 368hp/365tq so to get to 411/411 on the same dyno shows actual gains of 43hp/46tq from the headers and tune.

 

I saw 47 rwhp and 41 rwtq gains with same modes on a 08 LS3 MN6. 422/422.