Just recently purchased a used Efini Y-pipe from member airEpic (https://www.rx7club.com/ne-sale-want...-more-1109189/). Friendly seller, but he did not disclose that the Y-pipe had been modded (not trying to throw shade btw).

Just getting around to installing it and on inspection the bung and vacuum line nipples for the charge control valve on the turbo control arm are all crimped and sealed. Also, the two nipples on the y-pipe for the vacuum lines that go to the LIM and the pressure tank are also crimped and welded shut.

I just asked the seller about this, and he said he said, "most efini y-pipes being sold among the community have been slightly modified, and no way will it affect installs. The nipples on the pipe itself regarded as 'not needed' to run twins. Sometimes BOW flange is also welded to provide better airflow. In Japan they mod their Y pipes with an air divider to correctly move the air into the respective sides for people running twins, The one that got sold to you was modified by the previous owner also and it's pretty much a known thing among the forums, but no so much to newcomers..."

I did some searches before posting it seems the "Y-pipe splitter mod" originated out of Japan, but there isn't any hard data to support the performance or drawbacks. Also, I am immediately suspect of mods that are intended upgrade a part designed by professional engineers.
https://www.rx7club.com/3rd-generati...pe-mod-115222/
https://www.rx7club.com/3rd-generati...er-mod-704329/
https://www.rx7club.com/3rd-generati...-2-0-a-592634/

I don't recall their being any splitter in the Y-pipe, but I will double check once I get home. To me the Efini Y-pipe I have looks like it's modded for a non-sequential setup, and is just free flow piping at this point. I assume I can just use the stock turbo control arm from my FD, but the Efini Y-pipe is still an issue as the two nipples are welded shut. Regardless, what purpose, if any, would there be to crimping and welding the nipples for the LIM and pressure tank vacuum lines?

 

"Good condition and working perfectly."

Well, thats a molested Y-pipe. And its the first time i see anything about such mods. I would send it back and request a refund since the part is not working as intended, and seller gave contrary description.

 

Looks like it is set up to run non-sequential. I'd get your money back.

 

Yup, I would send it back.

 

Thanks for the feedback. The seller and I worked out the refund and it sounds like it might have just been an honesty mistake on his part. No harm no foul, so it's all good in the end. Renewed faith yet again in this forum!

 

What the others said. He's full of crap. Get your money back if you can.

 

For FYI, i believe that piece is interchangeable with USDM y-pipes

 

The front (primary) section won't be. On my phone but it looks like it's that part that's screwed up.

 

Yep, I stand corrected. It's the other piece

 

Got a full refund and shipped the used pipes back today.

Yeah, I figured the USDM turbo control arm was compatible with the Efini Y-pipe. Thanks guys!