CAMAROZ28AQUINO

Hey guys, i need your help. Got my car dyno tuned on a DynoJet today by a reputable shop and tuner. Tune was dialed in good but it kept detecting knock and going to the low octane table. We copied the high octane table to low and still knocking, thats when we went from 234whp to 255. When he gets on it the car knocks and retards timing still, but not much since the high/low tables are the same. Last run the car was at 24 deg timing but we wanted 28. Air/Fuel was around 13.2 and the temperature was about 62 degrees out. I dont know whats wrong guys, its not the tune, were thinking the cam wasnt installed properly. Heres my mods:

1998 Camaro Z28
33 000 miles
228/232 .588/.595 110+4 LSA 106ICL
7.425 Hardened Pushrods
Automatic trans w/ TCI 3000 stall
3.73 gears
NGK TR55 plugs gapped at .55
SLP Lid
Pacesetter Coated Longtubes
Off Road Y pipe (2.5")
3" Magnaflow Catback
SLP Lid

Everything else is stock, stock LS1 intake, throttlebody, oil pump, timing chain, etc. I didnt even take a graph i was so emberassed. Torque peaked around 3500 which was way early and should peak around 4-4.5k and the hp peaked at 5700 rpm and then fell. We were all stumped, something mechanicals gotta be wrong. No way a tune could be out more than 100whp. The tune was spot on. What do you guys think?

whytryz28

iTrader: (28)

My car put down close to 300 rwhp with just a lid an cut-out...somethings really wrong.

1Bad00SS

iTrader: (2)

Sounds like you have the cam advanced... which would cause the early peak in #'s. However I'd imagine with the size of the camshaft any significant advance in timing would cause some serious ptv issues.

I'd do a compression test and see what's going on there as well.

onecamaro1

Did you install the cam at zero or advance it more physically?

CAMAROZ28AQUINO

the cam was lined up dot to dot, since i dont have an adjustable timing chain, but there was 4 degrees of advance ground into the cam

Sweetred95ta

iTrader: (2)

I take it the person that installed the cam didn't degree it first? ALWAYS degree the cam to ensure it was ground to the proper specs.

RAGENZ28

iTrader: (5)

Advancing or retarding the cam some isn't going to make that much difference in power, you are pretty much over 100 hp short of what it should make. I wouldn't suggest driving it or starting it at all sounds like serious problems.

Take it to some one who knows what they are doing and have them fix it.

CAMAROZ28AQUINO

Well turns out there was a small problem with the dyno causing one of the rollers to slightly stick, so im taking it back soon and getting a retune and ill let you guys know!

Slowhawk

iTrader: (12)

I was thinking the same exact thing.I would expect that cam to be extremely tight on P/V plus I would think it's advanced too much.

Also,some 98's are known to have knock sensor problems. If the tuner is confident on his skills he should be able to delete them and see how the power changes.

99FormulaM6

iTrader: (21)

i was thinking more of a dyno problem...

i wouldnt think a car would be down over 100hp without some serious indications popping up from the motor...only other variable is the dyno, whether a roller is sticking or just an improper setup. there is no way a ls1 is making 255hp with a cam, not even a stock ls1 makes 255hp on a mustang dyno.lol