Intake manifold modifications

NoDOHC · 07-30-2009, 10:13 PM

On my tired 6-port, I made peak power at 6200 (155 WHp) this was at 13.5:1

It made 140 Wlb-ft at 3200 rpm.

I am impressed with the 4-port power.

My 6-port experience was what led me to tune around the 13.5:1 region. However, I can believe that my polished intake runners, smoothed ports and polished rotors will require a little more fuel.

I appreciate the advice everyone, I certainly hope that the transmission holds together for this pull.

I should be able to get dyno plots this time. Last time the rpm trace blinked out at about 5200 rpm (I computed horsepower rpm from wheel speed).

Believe it or not, at 9,000 rpm in 4th gear, the rear wheels are actually going 180 mph - not that I have gone that fast, but the engine is running exactly 4,000 rpm at 80 mph (I have checked the speedometer and the rpm is from the Haltech).

The Dyno guy wouldn't run it in fourth.

I know I may lose something to bad bearings in fourth, but the friction must be higher when the bearing is experiencing a side load as the power is transferred through the input gears in 3rd gear (thus 4th gear would be better).

I did check the transmission temperature between runs and it was not touchable, but not smoking yet either.

07-30-2009, 10:13 PM	#18
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	On my tired 6-port, I made peak power at 6200 (155 WHp) this was at 13.5:1 It made 140 Wlb-ft at 3200 rpm. I am impressed with the 4-port power. My 6-port experience was what led me to tune around the 13.5:1 region. However, I can believe that my polished intake runners, smoothed ports and polished rotors will require a little more fuel. I appreciate the advice everyone, I certainly hope that the transmission holds together for this pull. I should be able to get dyno plots this time. Last time the rpm trace blinked out at about 5200 rpm (I computed horsepower rpm from wheel speed). Believe it or not, at 9,000 rpm in 4th gear, the rear wheels are actually going 180 mph - not that I have gone that fast, but the engine is running exactly 4,000 rpm at 80 mph (I have checked the speedometer and the rpm is from the Haltech). The Dyno guy wouldn't run it in fourth. I know I may lose something to bad bearings in fourth, but the friction must be higher when the bearing is experiencing a side load as the power is transferred through the input gears in 3rd gear (thus 4th gear would be better). I did check the transmission temperature between runs and it was not touchable, but not smoking yet either. __________________ 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)