KiD-ViD Posted February 27, 2003 Share Posted February 27, 2003 I am helping a friend install a CA18DET engine in his '89 240sx and we went to the local muffler shop to see what they could do for us. The biggest pipe they can do is 2.5". I am thinking that should be fine for this turbo 4cyl engine. Any one think we should find another shop that will do 3"? thanks in advance. Quote Link to comment Share on other sites More sharing options...
fl327 Posted February 27, 2003 Share Posted February 27, 2003 2.5" inch is fine i think. 3" is pretty expensive. im happy to hear someone actually woke up and went with the ca18det, its tougher at the high hp. Quote Link to comment Share on other sites More sharing options...
KiD-ViD Posted February 27, 2003 Author Share Posted February 27, 2003 thanks len. he is looking at pushing around 300 hp till he upgrades his turbo and goes for 500. will a 2.5" support 300 maybe even 500 hp? chevy guys who push tons of hp still run 2.5 or 3" and their motors are 3 or 4 times bigger than his. Quote Link to comment Share on other sites More sharing options...
jeffp Posted February 28, 2003 Share Posted February 28, 2003 the 2 1/2" system will be good for 300 hp and run well, but if you are going to go for 500 then I would use the 3" You really cant compare the V8 engines to the 6 and 4 cylinder engines. The V8 has two exhaust manifolds and they will flow well at 2 1/2" each side, but with the 6 and 4 cylinder engines you are building more power per cylinder and running through one exhaust pipe. Also you are going with a turbo so 3" is a better flowing exhaust for that application. Quote Link to comment Share on other sites More sharing options...
KiD-ViD Posted February 28, 2003 Author Share Posted February 28, 2003 ah I see. thanks alot man. I guess he will go for 2 1/2 cause he is a bit cheap. thanks again. Quote Link to comment Share on other sites More sharing options...
Clifton Posted March 5, 2003 Share Posted March 5, 2003 2.5" is large enough for 300, but if your goal is more I would go with the 3" now. You don't want or need any backpressure after the turbo. On a stock 4 cyl turbo @ 7 psi 3" might be overkill but if you are after every last hp and don't want anything it interfere with it spooling as quickly as it can then get 3".I would also find a shop that can mandrel bend the tube, or use pre bent mandrel tube. Quote Link to comment Share on other sites More sharing options...
fl327 Posted March 6, 2003 Share Posted March 6, 2003 2.5 will be fine, 3" usually is only mandrel bent and not every shop carries pipe that big, if youre worried that much about flow dont run a muffler. i got my 3" system prefabbed as part of a trade, or i would have went 2.5" with a cutout. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 18, 2003 Share Posted May 18, 2003 Here are some numbers I copied from a website.....They didn't say how they got these numbers but they do seem a little large to me? Exhaust Tubing Size Chart HORSERPOWER DIAMETER 650-800 - 4" (duals). 550-650 - 3 1/2" (duals). 450-550 - 3 1/2" (duals). 375-450 - 3" (duals). Scavenging and tuning aside, I would say it's a matter of CFM in getting that stuff out the back end, whether it be 4, 6, 8 , or 12. single or dual? Quote Link to comment Share on other sites More sharing options...
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