Question about dyno and SAE correction Factors
 

Well, :wallbash:
after a 75mm TB and plenum, and an offroad H-pipe, and 4.10 gears I've LOST 1.5 PEAK HP and 15 Lb-ft of TQ. this time with an SAE of 1.14 . The first dyno with all the mods in the sig minus the above mentioned. I was at 264 and 302 with a SAE of 1.10. The dyno guys said that the gears is what's throwing everything off. He said all things being equal, the gears will cause the dynojet to read lower. I've never heard of such a thing and I'm hoping I've misunderstood him.. Can anyone here shed some light on this. My A/f ratio is VERY Lean yet the same for both runs.. it's hovering around 15.5. Yes, the diablo and dyno tune are coming next week. The temp was actually better for the underpowered run with less Humidity,temp, and Baro Pressure.

Any help or atleast a link to somewhere I can get some help would be fantabulous.

4.10's usually show a loss of at least 10 rwhp from what Ive read. Thats where it is. That is a VERY dangerous a/f ratio though. Get it tuned.

definetly richen your a:f. and yes higher gears can show a lower HP reading. thats why i dont put much consideration in dyno nuumbers. all dynos read differently. what matters is who your in front of at the finish line

Ok I Feel better knowing someone else has heard of this happening before. The car is definately getting tuned. Hopefully the coming week. I got a Diablo coming and the dyno guy can get me a custom program with about an hour of dyno time. Hopefully I'll see another 10rwhp, but more importantly, I can finally go to the track. Thanks for those quick responses and I'll keep everyone posted.

well..
i would use sct, but since your jsut bolt on its not a big deal

so get a richer a:f

and dont bother keeping us posted we dont care about you




just kiddin :)

lets fix a myth.... sct diablo wutever they all do the same sh!t the difference being the setting s/ tune... its just a name!!!!!

The loss in hp from 4.10's is not real loss, it is the result of a calculation error from the car not having a 1:1 ratio in 4th gear anymore. Don't panic.

Also, I kinda doubt the 15+ a/f ratio. I wonder if you have a little exhaust leak pulling in air. That is pretty high, though not extreme. If it is that high, you might even loose a little hp with a dyno tune. But, best thing is to get that a/f right and safe.