LS3 vette reduced horsepower,, any help?

[Super Shop]

got a A6 LS3 vette with L/T headers , VR intake, 102Fast, (242,246) Custom grind comp cam, and the car was 498 hp and now got 442 hp and checked for DTC there's nothing wrong and the AFR looks the same with approx 13.

changed the spark plugs, cleaned the air filter and checked the injecters and got the same result.

this is the tune guys, any issues ?

[IDRIVEAG8GT]

got a A6 LS3 vette with L/T headers , VR intake, 102Fast, (242,246) Custom grind comp cam, and the car was 498 hp and now got 442 hp and checked for DTC there's nothing wrong and the AFR looks the same with approx 13.

changed the spark plugs, cleaned the air filter and checked the injecters and got the same result.

this is the tune guys, any issues ?

Tune for 12.5AFR. Did you change dyno's?

[G8-4-speed]

Put more fuel in it.....13AFR is too lean for a high overlap cam. Loosing too much fuel out the exhaust valve during overlap.

As for the loss, it is possible it "was" locking the converter before and now won't. That would account for the difference. You would have to compare a scan log from before an after. Do you have both scan logs of the pulls?

[Super Shop]

i tried tunning it for 12.7 but there was a diffrence of few Hp ( less then 7 hp),, i changed dynos but still the car doesnt seem the same on the street so this is why i decided to put it on the dyno again ( still using dyno jet )

[Super Shop]

no i dont have the log before but so i ant compare the log

how can i check if the convertor is locking now and if not how can i make it ?

[Super Shop]

how can i check if the converter lock ,, any help guyz?

[vette_c6]

use the scanner
that will till u if the everything is okkay or not ,

shot a scan log for the car

if you dont like to post it in here ,, i dont mind helping u ,, Come to me today ,, i will be from 5 to 8:30 pm


Abdullah Alnajdi

[Mep_q8]

Try richening up the AFr and dropping the commanded spark by 4 degrees. Are you not hearing any audible knock? The settings for the Knock attack and decay are a little scary, were you getting alot of false knock to begin with?

[IDRIVEAG8GT]

Double check your Wideband and make sure it's accurate.

[HoP]

got a A6 LS3 vette with L/T headers , VR intake, 102Fast, (242,246) Custom grind comp cam, and the car was 498 hp and now got 442 hp and checked for DTC there's nothing wrong and the AFR looks the same with approx 13.

changed the spark plugs, cleaned the air filter and checked the injecters and got the same result.

this is the tune guys, any issues ?

Yes there are issues.... Is this tune your work?

[Braciole]

Tune for 12.5AFR. Did you change dyno's?

Whyis everyone saying to tune 12.5 afr? Is that for ethenol?

[Super Shop]

Guyz i found out that the best AFR for this cam is 12.8 and changed which got the best smooth curve with it,, but still 452 Hp so decided to take out each spark plug and check each cylinder pressure by installing a gauge and cranking.,, found out that cylinder 3 is not giving out the same reading than others ( less ) so took out the head, found out that the intake valve isnt staright wich there was leak in it. Valve is changed and the engine gained its horsepower again. Got 496 Hp again with the same tune.,,, FINALLY OKKKK
THANK YOU GUYZ for your help and time appreciate it

[Super Shop]

Trailblazi,, there is no knock sound and after founding the problem i dyno run it with the same tune and every thing is runing ok with just modifying the AFR,, thanks a lot,,,

i only habe an issue guyz of why r u guyz want to tune it on 12.5?