checkle91 Posted July 9, 2020 Share Posted July 9, 2020 (edited) Looking for some knowledge and opinions please. My 350z DE currently has the following exhaust setup... HFC, cobra sport y pipe, fujitsubo legalis r axle back. Can anyone tell me if I stand to gain anything by fitting the fujitsubo y pipe which has a much shorter exhaust gas collector compared to the cobra pipe? Does the design of the cobra, where the exhaust gases merge much sooner have any negative impact on performance? Edited July 9, 2020 by checkle91 Cropped images Quote Link to comment Share on other sites More sharing options...
Jack94 Posted July 9, 2020 Share Posted July 9, 2020 I seriously doubt there would be any difference whatsoever, let alone one you'd actually notice. If there's nothing wrong with your current Y pipe I wouldn't waste the money. Quote Link to comment Share on other sites More sharing options...
davey_83 Posted July 9, 2020 Share Posted July 9, 2020 I have no idea about performance, but I've read that the 2nd y pipe design gives a deeper tone to the exhaust. Below is the Motordyne XYZ pipe with HFC which is 3' throughout. Quote Link to comment Share on other sites More sharing options...
checkle91 Posted July 10, 2020 Author Share Posted July 10, 2020 Thanks for your feedback I think I will leave it alone and save the cash then. 1 Quote Link to comment Share on other sites More sharing options...
msitpro Posted July 12, 2020 Share Posted July 12, 2020 If you can work out what rpm you want to optimise then you could use a specific length at the collector point. I'd say on a VQ you could optimise 6-6100rpm, as that's where there's a dip before it starts to rise in power again as long as you have the right breathing mods. Look up quarter wave resonators and you'll find the maths you need. Make sure you use one that includes differences for exhaust temp. Think typical exhaust temps are 350-400°c at that point of the pipe. The same principles apply as when designing exhaust headers, except headers have a bigger effect as they're closer to the exhaust valves. (Bigger pressure wave back to exhaust valves to suck out/in gases) Any difference while still N/A is likely to be 5bhp/5lb-ft tops at a particular rpm range. Or.... Maybe save the money. 1 Quote Link to comment Share on other sites More sharing options...
msitpro Posted July 12, 2020 Share Posted July 12, 2020 On 09/07/2020 at 21:48, davey_83 said: I have no idea about performance, but I've read that the 2nd y pipe design gives a deeper tone to the exhaust. Below is the Motordyne XYZ pipe with HFC which is 3' throughout. Is that your car Dave? Did I ask whether you've done a decibel check? Can't remember what your 'cat back' is. Specdroid is also pretty cool to look at if on an Android device. Shows you which frequencies are dominant/louder at different rpm. Ideal for designing Helmholtz/quarter wave chambers to cancel out particular drones. Quote Link to comment Share on other sites More sharing options...
davey_83 Posted July 12, 2020 Share Posted July 12, 2020 Yeah that's my old set-up, ive since swapped out the Toyosport system for a custom exhaust by Thorney Motorsport. Not don't a dB check, keep forgetting to eek Quote Link to comment Share on other sites More sharing options...
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