Loves302Chevy
"One test is worth a thousand expert opinions."
I was reading the Frank the Tank thread (pages 13-14) about Brian's good advice pertaining
to header and exhaust choices to achieve his HP & TQ goals. Then I started reading Grumpy's
links and now I am questioning my own exhaust system on the 84 TransAm.
Unfortunately, I can't find any images of these headers or exhaust system.
The headers are 1 5/8", basically a shorty or tubular exhaust manifold design. The rest of the exhaust is 2.5" pipe after the headers Y'd together to the cat converter, and then a single 3" pipe back to the SLP muffler with dual 2.5" outlets. I plan on fabricating a fake cat converter. Inside an oval converter case will be a 4" pipe with a spiral insert. The pipe will have holes drilled on the sides with stainless steel scrubber pads packed around it. This should hopefully eliminate any drone and make the car quieter without restricting flow.
Spark plug clearance is already tight, and the 1 3/4" versions would make it even worse. The complete system is 409 Stainless Steel and cost $1200. 17 years ago. Except for adding a 3" cutout at a 45 degree bend right before the "converter", I'm not modifying this system and there is no clearance for bigger pipe. And I will most likely have the headers and Y-Pipe ceramic coated. So in reality, I have a single 3" open pipe.
The charts below show that will support 339 HP. All cars must compromise in places; is this going to be a huge bottleneck?
In the past (with actual cat converter), using a G-Tech, I ran 112 mph in the QTR, but the ET sucked because I had so many tuning issues and unknown problems to work out. The car could not spin the wheels off the line, but once it hit about 3000 rpm, it took off like a rocket.
to header and exhaust choices to achieve his HP & TQ goals. Then I started reading Grumpy's
links and now I am questioning my own exhaust system on the 84 TransAm.
Unfortunately, I can't find any images of these headers or exhaust system.
The headers are 1 5/8", basically a shorty or tubular exhaust manifold design. The rest of the exhaust is 2.5" pipe after the headers Y'd together to the cat converter, and then a single 3" pipe back to the SLP muffler with dual 2.5" outlets. I plan on fabricating a fake cat converter. Inside an oval converter case will be a 4" pipe with a spiral insert. The pipe will have holes drilled on the sides with stainless steel scrubber pads packed around it. This should hopefully eliminate any drone and make the car quieter without restricting flow.
Spark plug clearance is already tight, and the 1 3/4" versions would make it even worse. The complete system is 409 Stainless Steel and cost $1200. 17 years ago. Except for adding a 3" cutout at a 45 degree bend right before the "converter", I'm not modifying this system and there is no clearance for bigger pipe. And I will most likely have the headers and Y-Pipe ceramic coated. So in reality, I have a single 3" open pipe.
The charts below show that will support 339 HP. All cars must compromise in places; is this going to be a huge bottleneck?
In the past (with actual cat converter), using a G-Tech, I ran 112 mph in the QTR, but the ET sucked because I had so many tuning issues and unknown problems to work out. The car could not spin the wheels off the line, but once it hit about 3000 rpm, it took off like a rocket.
