Guest Supra_dude1987 Posted April 9, 2008 Share Posted April 9, 2008 Hi there, I have a 1994 Toyota Supra N/A. I've been having problems with my exhaust system. I put a 3 inch pipe from the headers all the way to the exhaust, but i didn't get the right exhaust to go with the 3" pipe. The exhaust is 2.5 inch and we had to connect it with the 3 inch pipe. I was planning to buy a bigger exhaust but now i'm wondering if the pipe is to big for my N/A supra. Would you suggest a 2.5 inch pipe all the way to the exhaust? please comment. Quote Link to comment Share on other sites More sharing options...
Matt _Aero top_ Posted April 9, 2008 Share Posted April 9, 2008 don't think the diameter of the pipe will be a problem as my HKS super dragger has a 3" diameter from the cat back if i remember correct . Quote Link to comment Share on other sites More sharing options...
Nic Posted April 10, 2008 Share Posted April 10, 2008 NA exhausts are usually around 2.5". You need a certain amount of back pressure on an NA to give good low down torque, if you fit a larger diameter exhaust you will reduce the back pressure and subsequently the torque at lower rpms. For the same reason NA pipes tend to have more silencing. Quote Link to comment Share on other sites More sharing options...
imi Posted April 10, 2008 Share Posted April 10, 2008 2.25" to be precise......certainly was from my Honda days (2.2ltr). perhaps for a 3ltr engine its 2.5". Quote Link to comment Share on other sites More sharing options...
Thorin Posted April 10, 2008 Share Posted April 10, 2008 You need a certain amount of back pressure on an NA to give good low down torque, if you fit a larger diameter exhaust you will reduce the back pressure and subsequently the torque at lower rpms. Not true, the exhaust back pressure thing is a myth (certainly with modern fuel controlled engines). Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 10, 2008 Share Posted April 10, 2008 Not true, the exhaust back pressure thing is a myth (certainly with modern fuel controlled engines). Yes, it's tuned wave length that counts, same as with the tuned and variable intake length on the N/A. pipe diameter alters the resonant frequency. 3 inch is overkill, save your money and ground clearance, even 2.5 inch is more than enough. Quote Link to comment Share on other sites More sharing options...
paul mac Posted April 10, 2008 Share Posted April 10, 2008 re exhaust size ~ i am with Nic on this, yes i have read the books but when i had my cat on recently for MOT the torque shifted dramatically down the rev range it was like driving a stock car again, i also had the same reverse experience when fitting a BL 4" from a superdragger it absolutely killed low down torque it was awefull and came off within a day and the dragger went back on, 3" on an NA is totall overkill, my car makes 500hp with a superdragger which everyone presume as being big pipework but in fact have a 2 1/2" section right where it joins the mid pipe Quote Link to comment Share on other sites More sharing options...
Guest Supra_dude1987 Posted April 11, 2008 Share Posted April 11, 2008 I asked a few people on the island about the 3" pipe and they didn't think it was a big problem if i connected a good muffler to it. They also said that I needed a resonator for the back pressure. I'm still not sure what i'm going to do. If somebody has another opinion, please let me know. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Guest Supra_dude1987 Posted April 11, 2008 Share Posted April 11, 2008 I asked a few people on the island about the 3" pipe and they didn't think it was a big problem if i connected a good muffler to it. They also said that I needed a resonator for the back pressure. I'm still not sure what i'm going to do. If somebody has another opinion, please let me know. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
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