A friend of mine used to have a racecar that kept losing exhaust valves untill he put a cheap turbo muffler on each header. The valves would have pits in them and would not seal to the head. After the muffler went on the valves would not get pits any more. This was a Hobby stock Monte Carlo with a 350 in it, long headers and pipes running out before the rear wheels. He typically raced on 3/8th mile and 1/2 mile tracks. on mid grade pump gas (which was the stuff that the track provided that we had to use for the class we were running)

Massey

Makes you wonder how they handled back pressure on fighter plane engines. Notice the 4" open pipes.
http://upload.wikimedia.org/wikipedi...aft_engine.jpg

I would guess it had something to do with the slower burning and higher lead content. Also an aircraft does not have constant throttle adjustments like a car does.

I love the sound of those big engines. I remember when I was a kid hearing the Hydroplanes when we went to Lake Washington for SeaFair. Now those were thunderboats!

Massey

there is the answer to your friends issue. If we still had leaded fuel he would not have seen the valve issues. Of course you can always change to a different alloy to combat the unleaded.

It always comes down to cash with these things, doesn't it ???????????

I installed a B&B tri-flow cat back on my 95 and then did a off-road thru pipe.. didnt seem to have any problems with it .. but I would def. fix all of your problems first, and keep a muffler on it, just get a good performance muffler for sound

That class has a $500 rule for the engine. Any other driver in the same class can purchase your engine for $500. This keeps the field even and the guys with the big $$$ will move up into the faster classes. So with that being said he didn't want to dump $500 into the heads and put some stainless valves in the car that would not pit bad. He instead spent $30 for a pair of cheap muffs and fixed the engine!

Massey

ok first off i found this link in a thread on here.
. so just look at and read it, it dispells the backpressure myth. heres the link
exhaust myths:
http://www.popularhotrodding.com/eng...xh/index1.html




heres the tread it was linked in on here
https://camaroforums.com/forum/showt...ght=no+muffler


these 2 other links were in there as well and worth reading for sure
http://www.carcraft.com/techarticles...ion/index.html

http://www.mustangforums.com/forum/2005-2011-mustangs/96138-cross-over-exhaust-pipe-explained.html


and i removed the muffler. personally i think it sounds great. its quiet at an idle and if anything im spinning tires more now on accident. it is a bit too loud but my mustang with a offroad h pipe and 40 series flows dumped at the axle was as loud or louder. my stock muffler tips were all retarded from someone hitting some thing so that kinda why i wanted it off for now , so i could see how they were so crooked. so far all my friends like how it sounds. and we are all in our 30s or older so its not kids going "dude thats bad ***".
ive always gotten horrible gas milage in this car. its never felt slow, exhaust smells like gas, and i can scan it with a obd1 gm code reader the kind the have at schucks/orielly its a innova brand can obd1 & 2. i checked several times, removed the hypertech piggyback still cant scan it. check the connector for loose wires nothing. im not fixing the exhaust leak till i install long tubes, its just not that bad or worth it. it goes away when the cars warmed up. but anyways i need to scan the ecu. and i cant. im sure something is bad here, either both o2s, mass air, map or something but im not going to just throw parts at it. my idle once warm drops to around 600 or so, tach may be off some but its no where near 1000 when cold. so that and issue. but i can smell fuel in the exhaust for sure when i rev it and usally at idle too.

so according to the linked thread back pressure is kinda a myth, if someone wants to show proof it isnt im listening. as far as emissions my cars registered in gold bar so i have no emissions. and unless my cat plugs up i have no problem with it being on the car.

Looking forward to hearing my exhaust sound better than my stock one. I'll be adding some new pipes after replacement engine and headers. As long as I'm doing the switch I might as well do that too. Look @ my page an shoot me some tips to get me scootin. Need a cam too I guess?

replacement engine?? what motor do you have?

Does your car have the OBDII scanner plug or the old school OBDI plug? On some 94 LT1 cars (like Corvette) they moved up to the OBD1.5, and cannot be scanned with an OBDII or I scanner with out an adaptor. I will post an image of it in a little while once I move to my normal computer at my office here. It is just 2 jumper wires so the OBDI scanner can read from the OBDII port.

Massey