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NoDOHC · 08-01-2011, 10:59 PM

Thanks Logan! I thought that the stainless would be ok. Header wrap kills headers because it holds moisture against them. I doubt that any 3 series stainless will corrode significantly from simple moisture.

As the pictures show, the only thing that separates these headers from a true art form is the usefulness of the headers.

I really need to take more backpressure readings now that I have my exhaust completed, I have been super busy and haven't had the time to update this thread, maybe later this week. I used dual Gibson Superflow mufflers with dual Flowmaster dBx mufflers behind them. Exhaust tone is pretty good (not raspy), but not as quiet as I was hoping.

For what the butt dyno is worth, this car pulls very hard. Unfortunately, I can't give tirespin comparisons for anyone, as I have a set of 215/65R15s off a minivan on the car right now and they spin effortlessly. I wore my 245/40R17s out and my Bridgestone Ecopias are on my '91 (I don't spin them anyway).

I picked up some low end torque, but the real gains were above 4,000 RPM (after I installed 4 real mufflers in place of the tractor muffler).

With my tune which previously ran 13.2 on the dyno I was running 17.2:1 AFR at 7200 RPM. The largest VE gain over the racing beat headers was about 5,500 rpm, where the engine actually lean misfired at WOT (lean of 18:1). I can't explain this, as the headers are not tuned for 5,500.

With the minimal overlap this engine has, I am surprised that there was that much VE on the table.

Strangely, my 6,500 map point was correct (no changes required).

My cruising MAP has decreased, as has my idle MAP (although it is still very low vacuum, I am running a MAP of 45 kPA at idle due to my 5 degree ATDC idle timing and 14:1 AFR).

I was able to go 0.5 AFR leaner at idle without misfiring. The cruising vacuum increase is a pain because I am running too much vacuum to run lean of stoic. (My cruising MAP at 60 mph is about 50 kPA, which is very close to my idle MAP).

Above 9,000 RPM I was also lean misfiring, but I never got this tuned on the dyno, as I always let up on the car about 8500 RPM as the coolant temp was above 110 C.

I really need to go to the dyno again, but I am finding it hard to part with another $80.00.

08-01-2011, 10:59 PM	#27
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	Thanks Logan! I thought that the stainless would be ok. Header wrap kills headers because it holds moisture against them. I doubt that any 3 series stainless will corrode significantly from simple moisture. As the pictures show, the only thing that separates these headers from a true art form is the usefulness of the headers. I really need to take more backpressure readings now that I have my exhaust completed, I have been super busy and haven't had the time to update this thread, maybe later this week. I used dual Gibson Superflow mufflers with dual Flowmaster dBx mufflers behind them. Exhaust tone is pretty good (not raspy), but not as quiet as I was hoping. For what the butt dyno is worth, this car pulls very hard. Unfortunately, I can't give tirespin comparisons for anyone, as I have a set of 215/65R15s off a minivan on the car right now and they spin effortlessly. I wore my 245/40R17s out and my Bridgestone Ecopias are on my '91 (I don't spin them anyway). I picked up some low end torque, but the real gains were above 4,000 RPM (after I installed 4 real mufflers in place of the tractor muffler). With my tune which previously ran 13.2 on the dyno I was running 17.2:1 AFR at 7200 RPM. The largest VE gain over the racing beat headers was about 5,500 rpm, where the engine actually lean misfired at WOT (lean of 18:1). I can't explain this, as the headers are not tuned for 5,500. With the minimal overlap this engine has, I am surprised that there was that much VE on the table. Strangely, my 6,500 map point was correct (no changes required). My cruising MAP has decreased, as has my idle MAP (although it is still very low vacuum, I am running a MAP of 45 kPA at idle due to my 5 degree ATDC idle timing and 14:1 AFR). I was able to go 0.5 AFR leaner at idle without misfiring. The cruising vacuum increase is a pain because I am running too much vacuum to run lean of stoic. (My cruising MAP at 60 mph is about 50 kPA, which is very close to my idle MAP). Above 9,000 RPM I was also lean misfiring, but I never got this tuned on the dyno, as I always let up on the car about 8500 RPM as the coolant temp was above 110 C. I really need to go to the dyno again, but I am finding it hard to part with another $80.00. __________________ 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)