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Hello all,

I'm trying to get some thoughts on horsepower, exhaust gas flow, and exhaust piping diameter.

On a 2JZGTE, what do you think the maximum horsepower is for a 3" exhaust? At what point is a 2JZ flowing more exhaust gas than a 3" exhaust can flow? I have heard that you can flow 1000hp with a 3" exhaust and I've heard that between 600-700hp you are creating a restriction with a 3" exhaust.

Anyone thoughts on this? Has anyone achieved this level with a 3", removed it for a larger exhaust, and picked up hp?

Thanks,

-m
 

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Dude no one has thoughts on this?
Its been 9 yrs! I've read all ovr the forums & all i can find is he ssid she said bs. I hope ufound ur answer bro, cause i havnt....
 

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Dude no one has thoughts on this?
Its been 9 yrs! I've read all ovr the forums & all i can find is he ssid she said bs. I hope ufound ur answer bro, cause i havnt....
Because if you have to ask, your car isn't making enough horsepower for a 3" exhaust to be an issue...
 

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Dude no one has thoughts on this?
Its been 9 yrs! I've read all ovr the forums & all i can find is he ssid she said bs. I hope ufound ur answer bro, cause i havnt....
Just so I can say I responded to a 9 year old thread, I know of a few people making over 1k through a 3 inch on 4 cylinder cars, shouldn't be any different with ours, but with so many easily attainable exhausts bigger that why would you go 3in?
 

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My guess is at 500rwhp a 3" exhaust is already starting to be a restriction. Not a lot but some. That doesn't mean you can't push 1,000hp through a 3" exhaust, it just means it's not effecient.

My contribution to a 9 year old thread. :)

Later, Steve
 

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adammackintosh.net
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weird because ive read some threads that lay it out pretty clear.

ive even seen visual diagrams of the volume changes by moving from 3 to 4" (which is quite a significant cross sectional gain in surface area, aka flow potential)

basically it doesnt matter, youll just lose or gain some power but you can still produce some huge power with 3"
and 4" is louder.

just get straight 2" and a 4" downpipe with a boost actuated cutout and call it a day, and put 9 mufflers in it.

if you dont care about noise, get 4"
if you do... you prolly dont want that. mine is 4" and ive had 2 neighbours come to my house and complain that it wakes them up if i start the supra in the early morning.
and the bass rips through walls. my friends and cops hear it boosting from like 2 blocks away.

there are some great options out there involving cutouts. check those out, you get the best of everything depending how you set it up.
 

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It comes down to back pressure. Sure you can make good power with a 3 inch exhaust, but at some point it becomes a restriction and starts to cost hp. Where is that point? It depends on so many things-head flow, cams, turbo exhaust size, etc. Based off of many threads I would say a 3 inch starts to become a restriction at 500whp. When you go from 3 inch to 4 inch you actually increase the cross section from 7.065 sq/inches to 12.54 sq/inches so you are nearly doubling the cross section area.

Steve K.
 

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Agreeded

weird because ive read some threads that lay it out pretty clear.

ive even seen visual diagrams of the volume changes by moving from 3 to 4" (which is quite a significant cross sectional gain in surface area, aka flow potential)

basically it doesnt matter, youll just lose or gain some power but you can still produce some huge power with 3"
and 4" is louder.

just get straight 2" and a 4" downpipe with a boost actuated cutout and call it a day, and put 9 mufflers in it.

if you dont care about noise, get 4"
if you do... you prolly dont want that. mine is 4" and ive had 2 neighbours come to my house and complain that it wakes them up if i start the supra in the early morning.
and the bass rips through walls. my friends and cops hear it boosting from like 2 blocks away.

there are some great options out there involving cutouts. check those out, you get the best of everything depending how you set it up.
 
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