Jump to content

Y Pipe design


checkle91

Recommended Posts

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?

 

 

 

20200709_213506.jpg

20200709_213518.jpg

Edited by checkle91
Cropped images
Link to comment
Share on other sites

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.

  • Thanks 1
Link to comment
Share on other sites

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.

 

250685307_IMG_20190817_1054272872.jpg.755c7765f109cf370ea1a69cae9f230b.jpg

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.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...