Intake manifold modifications

NoDOHC · 07-31-2009, 07:55 PM

C. Ludwig - You are my new hero. I think I can safely run in fourth gear. I ran the numbers and you are right. I guess my speedometer is wrong then (I timed it between milemarkers... I thought it was right). Maybe the curve will be more accurate in fourth, plus my transmission will not take as much of a beating.

Thanks for pointing that out. I should have done the math (especially since I looked at the VSS input to the Haltech and it indicates 55 mph at 3000 rpm, not 60 as I thought). I guess this is good, I don't need to worry about a speeding ticket...

With my new knowledge, my power numbers shifted.

It is now 186 WHp @ 7600 rpm
and 170 lb-ft @ 5100 rpm

(we had calibrated the dyno to the speedometer for rpm).

You are right about the efficiency too, I doubt that my highly polished rotors and runners do much for my fuel mix.

I did drive it hard a little today with a wideband on it and I found that it seems to pull just fine at 13.5:1 (Which is what I am currently tuned for). I am running lean of that between 5000 and 7500) just because the VE is higher in that range and I copied and pasted the fueling from 3500 rpm. The tune is identical to what I ran on the Dyno. I only got an average AFR from the dyno, as the rpm signal was wacky. Apparently I was running a bit rich down low (11:1 at 1200 rpm). Leaning the low end out helped with the load up issues at idle.

We will see tomorrow (assuming that my new-found vibration doesn't disqualify the car from the dyno).

07-31-2009, 07:55 PM	#20
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 18	C. Ludwig - You are my new hero. I think I can safely run in fourth gear. I ran the numbers and you are right. I guess my speedometer is wrong then (I timed it between milemarkers... I thought it was right). Maybe the curve will be more accurate in fourth, plus my transmission will not take as much of a beating. Thanks for pointing that out. I should have done the math (especially since I looked at the VSS input to the Haltech and it indicates 55 mph at 3000 rpm, not 60 as I thought). I guess this is good, I don't need to worry about a speeding ticket... With my new knowledge, my power numbers shifted. It is now 186 WHp @ 7600 rpm and 170 lb-ft @ 5100 rpm (we had calibrated the dyno to the speedometer for rpm). You are right about the efficiency too, I doubt that my highly polished rotors and runners do much for my fuel mix. I did drive it hard a little today with a wideband on it and I found that it seems to pull just fine at 13.5:1 (Which is what I am currently tuned for). I am running lean of that between 5000 and 7500) just because the VE is higher in that range and I copied and pasted the fueling from 3500 rpm. The tune is identical to what I ran on the Dyno. I only got an average AFR from the dyno, as the rpm signal was wacky. Apparently I was running a bit rich down low (11:1 at 1200 rpm). Leaning the low end out helped with the load up issues at idle. We will see tomorrow (assuming that my new-found vibration doesn't disqualify the car from the dyno). __________________ 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)