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NoDOHC · 04-03-2011, 10:01 PM

Ok, so I have an unfortunate update:

I made 185 WHP at 5,400 rpm.

Peak torque was 182 W Lb-Ft at 5,300 rpm.

The reason that I list the peak WHp at 5,400 rpm is that I lost compression on the front rotor at 5,400 rpm.

The failure is a classic spark plug boss growth failure (chips off apex seals).

There was almost no marking on the rotor at all (all grooves are still in spec) but the housing is damaged.

I will post pictures later.

The reason that I posted this here is because it appears that the housing growth issue is much worse with higher spark energy (I ran for 4 hours, about 20 runs with the factory ignition with no issues).

I think that I should try turning the pulse width down and run cooler Iridium Spark plugs as dudemaaan suggested.

I never got a chance to see what the plug would do for very high rev testing. I only got to 9,000 rpm once, blew the front rotor on the second run of the day. (first run was with 11.2:1 AFR and netted 176 WHP @ 8,800 RPM, second run was with 13.2:1 AFR).

04-03-2011, 10:01 PM	#2
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	Ok, so I have an unfortunate update: I made 185 WHP at 5,400 rpm. Peak torque was 182 W Lb-Ft at 5,300 rpm. The reason that I list the peak WHp at 5,400 rpm is that I lost compression on the front rotor at 5,400 rpm. The failure is a classic spark plug boss growth failure (chips off apex seals). There was almost no marking on the rotor at all (all grooves are still in spec) but the housing is damaged. I will post pictures later. The reason that I posted this here is because it appears that the housing growth issue is much worse with higher spark energy (I ran for 4 hours, about 20 runs with the factory ignition with no issues). I think that I should try turning the pulse width down and run cooler Iridium Spark plugs as dudemaaan suggested. I never got a chance to see what the plug would do for very high rev testing. I only got to 9,000 rpm once, blew the front rotor on the second run of the day. (first run was with 11.2:1 AFR and netted 176 WHP @ 8,800 RPM, second run was with 13.2:1 AFR). __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)