has anyone ever made any modifications to a stock header? possibly removing the baffling inside them? anything?
is there a baffle in the OEM exhaust manifold???
whats the point of this more power you think???
i got a NIB ebay header for cheap if you need one.
A while back in Sport Compact Car mag they were doing a Header test with couple different brands. One company took a stock header, smoothed out the ports, polished the insides a bit, and gain like 2-3 hp from it.
i wouldnt consider 2-3 hp a gain really unless it was backed by multiple pulls. under 5whp differance between any two pulls i would consider too small to form an opinion.
i’d be up for the ebay header but smog laws here are a pain in the arse. i kinda want to keep it legal. if you look inside the stock downpipe, you will see that there is some sort of heat shield inside of the tubing. either it cuts down on noise, serves as some sort of heat barrier??? or stops turbulence inside the exhaust. i dunno.
But it’s interesting to hear about the porting. 3 hp is better than nothing.
I thought of possibly gutting the inside of the downpipe to see what happens. i think i’ll try the header port too… nothing to lose, eh? I may try this stuff after i get BAR’ed tho
I have heard of smoothing out the transitions, port matching, and modifying the collector outlet size.
i no longer have the stock manifold, ALTHOUGH I AM LOOKING FOR ONE AT THE MOMENT to replace my dented megan header (reason i bought the egay one, but decided to go OEM instead).
machining exhaust manifolds is definitely an option, make sure you port-match the head too for x-tra funny fun!
You could always switch to a 92-93 stock 4-2-1 header instead of the 90-91 4-1.
Dont know if you’ll see any performance gains though.
i actually have a stock 4-2-1 right now. i had no idea that the 90-91’s were 4-1. oddly enough, i have a 91 and i never noticed…