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 performance mod.....Exhaust Systems....

I read on this forum recently (like 2005)that a 3" (75mm) exhaust is the way to go. My experience indicates that is only true for the turbo motor....
Wide open breathing....
Quicker spoolup of the turbo....
Higher RPMs.

But...for a naturally aspirated motor, (and NOT a track only car running high rpms all the time), you want 'some' back pressure to give you more torque at the lower RPM's. (You know, 0 to 60 MPH, daily driving).

And remember, these cars are very heavy (mine is 3600 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. It is at the end of the pipe, and it created an awful drony, deep tone at cruising of 2k RPMs. I could not even listen to the stereo.

So...I ADDED a 24" long straight thru glass packed muffler, same 2.5" inside dia., and 4" diameter outside, in the middle of the system (middle of car).

Now it has a GREAT sound, with an UNRESTRICTED flow, and just enough back pressure to keep my torque high at lower RPMs.

Before this exhaust mod, the car would max out at 125mph.

After this mod, I can easily go 145mph any time I want.

[monkihead]

actually 2.5 with a glass pack is still considered overkill(too free flowing). 2.25 with a single chamber no cat is equivalent to what you used. to gain the best compremise of torque; its a header without cat straight back 2.25in pipe with a 2 chamber or equivalent muffler. if you want a clean crisp sound, try a flowmaster delta series. if you want a deep sound, go with a MAC muffler.

[mrnickleye]

Here in Calif. we must have a cat converter to be street legal. That is why I went with the 2.5" pipe, the cat causes some restriction. Even without a cat, I'd still run 2.5".

[hangsupra]

well... yeah thats true 3" down pipe for the turbo. thats true. n me thats what i were having on my mk2 right now. i got a 5mgte singo turbo n just about to upgrade my turbo into t4 turbo. now i were using 3" down pipe without converter. straight pipe 3" from the turbo elbem all the way to the 3" exhaust to. but i were using this one thing it call something like a flare or something like that tho. and i were using a silencer on my exhaust to. n it sounds like a stock muffler now. its not loud at all. well let me know how you setup on your mk3 alright.

[suprra_girl]

awesome info there mrnickleye... when you've got some luvly research like this post it in the faq's

i may have neglected to mention that 3" was not suitable for na LOL.. oops.. i guess i automatically assume everyone's is turbo.. my bad haha

moved to faq's

[ddmcse]

i hit FULL boost @ 2700 ish rpm (i get boost before that mark but not full until around there)

2.75 elbow
http://www.alamomotorsports.com/AMS/ams_suprao2.html
3" downpipe
http://www.alamomotorsports.com/AMS/amsex.htm

"F" the cat !
i use a striaght through 2.5 ish custom (there's your back pressure) hehehe

3" exhaust
http://www.alamomotorsports.com/prodndxman.html#Blitz
mostly using a silencer on the end of it


it sounds nice and tuned as i pull away or so i've been told .
just my 2 cents on the subject

[KingDiamond]

Your thoughts aren't worth more then two cents?

[ddmcse]

lol thats funny
Hey Diamond you ever go to the NESupra group on yahoo ?

there reason i ask ...
Request to join NEsupras denied
Hello,

Your request to join the NEsupras group was not approved.
The moderator of each Yahoo! group chooses whether to restrict
membership in the group. Moderators who choose to restrict
membership also choose whom to admit.

Please note that this decision is final and that Yahoo! Groups
does not control group membership.

DENIED

[KingDiamond]

Mine was also denied , thats why i'm started my own group and club for new jersey supra owners. I still decide wether people get to join or not, i'm just not such a dick about it.

[Matrix]

Mine has a stock pipe on. I was thinking about putting a 3.5" on, is this too big?