y-pipe revised 2.0
 

first mod was to put flanges instead of the coupling.
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/modified-y-pipe-562651/

second mod was to add a divider in the middle of the y-pipe to help with flow.

the results is that the second turbo kicks a little harder and transition is a lot more quiet, just posting this in case someone else was interested about this mod that was seen in a old RX-7 magazine.
https://www.rx7club.com/attachment.p...d=204040&stc=1
https://www.rx7club.com/attachment.p...d=204041&stc=1
https://www.rx7club.com/attachment.p...d=204042&stc=1
https://www.rx7club.com/attachment.p...d=204044&stc=1
https://www.rx7club.com/attachment.p...d=204043&stc=1

daaamn that's wild. nice work!

I see lately at yahoo auctions jp modified y-pipes with the divider and i was thinking of doing the same.Can you give more detailed results?

Nice welding, but why do you think a divider would improve flow? I'm not saying it doesn't, I would just like to hear your logic.

https://www.rx7club.com/attachment.p...d=204061&stc=1
https://www.rx7club.com/attachment.p...d=204062&stc=1

makes sense, but only for sequential turbo's right...

yup.

Interesting idea :) Maybe I'll think about it while the engine is out and the turbos are off.

Great fab work, but doesn't air take the path of least resistance? If this is true what is stopping it from flowing right over the top of the divider and going toward the secondary just like before? Just wondering, and like I said GREAT work.

thanks,
-josh :)

thanks^

"what is stopping it from flowing right over the top of the divider and going toward the secondary just like before?"

^ the only time that would happen is when you let off the gas and the TB closes.

^ and then it really isn't a problem!!! Got ya buddy. Congrats on your great work and props on your welding work. Wish I could do that.

-josh :)

haha nice illustrations. I suspect that what you are showing above is a nearly instantaneous transient effect and once the pressure builds up slightly the difference is negligible, but it's an interesting idea. Cool that you seem to be getting better secondary response, but isn't the goal by what your showing above to improve primary response?

recon fd - with aluminum i just fabricate tack weld and take to my friends shop the power at my house sucks the power breaker goes out when i use my mig welder on high power.

Maximum - its for both but primary response was not that noticeable and i got lazy on the animation.

Nice work, it's great to see people doing custom fabrication on these cars. By the way, your car was one of the only FD's at Sevenstock9 with the AST at the proper height.

-s-

thanks, wich car was yours.

Understand the idea, but have spent to much time working on a flow bench not to ask. Have you flowed the pipe before and after?

Very nice clean work. Clearly you know your way around a GTAW welder.

you do realize your going to have to let me send my pipe to you now so you can do mine. :D pretty please with a cherry on top HA HA

personally thinking... that's a good idea. but think of it this way.. if the turbo start kicking in... the air will need to fill up the 1st chamber.. once they got to the top pipe... the air needs to be filled backwards toward to 2nd chamber and also the main pipe towards the IC.
due to the air travel, it need longer time to get to full boost...

if the Y pipe was not partitioned, it will immediately filled up the 1st chamber + 2nd chamber then the air flows toward the IC pipe and toward the IC....

between these 2, theorotically, partitioning it might delay the full boost by a few milli seconds... not noticeble. if you have a one way valve to block it from flowing towards the 2nd chamber... then it'll be faster... when the 2nd boost comes in.. it'll be instantaneous quick response...

just my 2 cents.

I'd like to know if anybody has anything they'd like to say about this modification.

Personal experience.

I understand it is for sequential setups.

Has anybody used this with BNR's?

Any flow sheets or dyno sheets to show results?

I'd have to agree with NAN777 on this one. The secondary area still has to be compressed to make boost, so how can a partition like that make a positive difference?

the only way for that to work is if the secondary area is completely sealed off from primary boost.

It is great to see however, I like to think that the original engineers would have done similar had it really been necessary or beneficial.

Regardless, nice fab work. Next step should be testing it against a stock piece to prove the efforts' worth. :)

I also put a flange on stock y pipes and I mod the late model ones.I put five bolts in them instead of two .No warping or leaks .I also remove the blowoff nipple and reshape that area .

Since primary boost only happens at low rpm's, and no one expects to get any real performance there anyway, I don't really see how this modification improves performance.

Since we are both in SD, I have a local friend who has a flow bench if you want to test and compare your mod.