Running too rich!
 

It took 9 dyno pulls to finally get a 370hp number, but every pull showed the same problem.

My car is definitely running too rich!

Same car on the same day ran almost perfect fuel numbers. But mine is running at 12:1. Its very frustrating.

Any theories? Bad O2 sensor maybe???

http://members.cox.net/rednave/cssdyno2.jpg

Here is the same type of car (LS3) with same mods (muffler delete) on the same dyno, same day!

http://www.camaro5.com/forums/pictur...ictureid=17621

I had 3 pulls on a Dyno jet , Bone stock and my first pull was 10.8:1 AFR and the second two picked up to 11.2:1 ! I think its just the random factory settings??? I made 380rwhp and 383 rwtq. Same dyno another stock LS-3 had 12.5:1 with 6 less hp and 8 less on the tq.

I am not so concerned about the power difference as I am the AFR values. It sounds like your car is pretty similar...

I think your AFR is fine. It's the other car I would worry about - leaner than 12.8 is dangerous.

I don't like it when shops use the STD horsepower correction factor. That method artificially inflates measurements when temp is above 60 F. They did give you the ambient conditions. So, I would use the SAE HP correction method to get a more accurate indication of power produced.

wOW, YOU GUYS/GALS ARE TECHies!

If the dyno was using a tail pipe sniffer, then I wouldn't believe anything the AFR shows at all.

Your factory O2 sensors won't really control wide open throttle fueling (however, there's a caveat to that).

Beyond all of that, though... if you're flogging the crap out of a car, it's going to start using Cat Overtemp Protection, dumping fuel to try and keep the cats from melting and breaking apart.

Factory FWHP is rate at 426, you made 370 RWHP like most LS3 Camaro's do. With roughly 15% driveline loss that puts you right where you should be.

Yes it was a tailpipe wideband. I am still running richer than any Camaro tested at this facility. I would trust the reading on a purely comparative basis.

I know my HP numbers are where they should be. Thank you for pointing that out. I would like to keep this thread OT and limit comments to people's experience with AFR on the V8s.

Thanks!

Sorry bro, but FWHP?! Really? It's rated 426 HP at the 'Crank' aka the engine. There is no power being distributed to the front wheels as you said.

I believe DSteck has already answered your question, I would put the cat over temp as my suspect as well.

FWHP = Flywheel Horse Power

Hmn, flywheel horsepower I figured everyone knew that, Opps, I will explain it better next time.

I also have plenty of tuning experience, if 12:1 is the richest they have ever seen on that dyno, they haven't tuned many new Camaro's or that wideband is way off.