Exhaust Systems...researched

[mrnickleye]

A bit about me (not for my ego, but for your open mindedness and ponderance of the info I will give from time to time). I am an ASE Certified Master Auto Tech for 20 years. (No, I don't know everything, and I DO enjoy learning something every day). I manage a very successful smog repair and performance shop here in the Mojave Desert of California. (Heavy pollution control laws here!!)

For a decade I was (retired now) a repair analyst and technical training instructor on the American Space Shuttle program. When I am interested in something, I analyze the hell out of it before I do anything or spend $$$ on it.

Now, with the internet so handy, I do even MORE research to get the MOST performance from my cars. I get alot of info from other enthusiasts, and race performance magazines, too.

I have built, tuned, and raced cars, carts, and motorcycles.

I am living on a performance budget, too, like most MKIII owners.

SO.......First Supra tip.....Exhaust Systems.......

I read on this forum recently that a 3" (75mm) exhaust is the way to go. That is only true for the turbo version.... Wide open breathing.... Quick spoolup of the turbo. ...Higher RPMs.

But...for a naturally aspirated motor, (and NOT a track only car) you want 'some' back pressure to give you higher torque at the lower RPM's. (You know, 0 to 60 MPH). And remember, these cars are very heavy (mine is 3800 lbs).

Much research led me to run a 2.5" (62mm) pipe from the Cat Converter all the way out. I went with a Magnaflow straight thru muffler (packing inside). It was too loud for me because it is at the end of the pipe, and it created an awful drony deep tone at cruising of 2k RPMs. So...I ADDED a 24" straight thru glass packed, 4" diameter muffler in the middle of the system (middle of car). Now it has a great sound, with an unresticted flow, and just enough back pressure to keep my torque high at lower RPMs.

Next Post I'll fill you in on the air intake system research I've done, and why MOST after market ones need modifying for street use. TTFN (remember Tigger)

[Leeky]

No offence meant, but you are teaching a granny to suck eggs here

We are all very aware of the need for backpressure on an normally aspirated car.

[Karma Supra]

normally aspir -what?? ;)

[Martin F]

No offence meant, but you are teaching a granny to suck eggs here

Well put, more diplomatic than i was going to be.

:D

[Karma Supra]

At least its factual, and a usefull post!!!