I finally got around to installing the Efini Y-pipe I purchased from CCarlisi about a month ago. Below is a review that I haven't seen in searching or reading posts regarding the subject:

There are a lot of questions regarding the installation of the Efini Y-pipe. I don't intend to do a write up. However, I simply removed my strut bar, pettit intake (rear turbo), rear turbo intake pipe (2 10mm nuts accesible from underneath). I then disconnected all vacuum lines and hoses, remove the 2 10mm nuts for the front half of the stock y pipe, and Loosened the 2 10mm nuts (accesible from under the car) on the rear half of the y-pipe. This allowed me enough room to go ahead and take out the stock y pipe and insert the new.

Upon reinstalling everything I noted that I had a hard time mating the Crossover pipe to my Pettit SMIC. The pipe was a little lower than the inlet pipe to the intercooler, so the coupler at the jointtook a little extra coersion, and an extra clamp. This may be able to be fixed by either A> bending the IC inlet pipe to fit or B> Lossening the turbos and rotating them so the y-pipe comes up 5-10 degrees. This install REALLY wasn't that difficult. My only suggestion is take it step by step and pay attention to detail.

This is what I have noticed after the install:

- I achieve my target boost, 1 bar, at much lower RPM's after transition.
-my transition is now extremely smooth, almost unnoticeable, resulting in more useable power
-I don't make more boost. I'm using the PFC to control boost and 1 bar appears to be about the limit of my turbos under 6K RPM's witih my other mods
-The secondary seems to kick slightly harder, much more fun to drive
-my engine temps seem to stay 1 to 2 degrees celcius cooler on the PFC.
-My boost pattern is more consistent. I used to spike slightly above my target boost, then drop 1-1.5 psi, then recover. This no longer happens. Again, this gives me more useable power.

I'd be interested in putting the car on a dyno now and will post results when I do. I previously dyno'd at 323 rwhp (2 small boost leaks also), prior to efini y-pipe and pulleys, at 7100 RPM. I'm guessing I'm closer to 335-340 now, with less hesitation and more torque and horsepower closer to the transition.

 

Awesome, i was curious what results were from the Efini y pipe. Now i really want one

 

You make me want one too! I purchased one off of "RTTExtreme" off the forum. He stiffed me the $210!

 

Sorry to hear your bad luck.

On a lighter note: that is a monstrous gain if you are correct.

 

I have one for sale, see this thread

https://www.rx7club.com/showthread.p...28#post3279128

 

I've also recently added one, I didnt notice everything FD newb noticed, besides quicker spool.
I also wasnt looking for any of the others, just the faster spool.

 

"-my engine temps seem to stay 1 to 2 degrees celcius cooler on the PFC."


I think that's wishful thinking

 

Not to burst your bubble, but I think most of what you noticed is a result of the "I replaced my wiper blades now the car feels faster" syndrome. The Efini y-pipe is better than the stock mostly because it eliminates a coupler and a potential boost leak. It probably flows a little better but it isnt that much.

 

yeah, a lot of those variables can change with weather, humidity, duration of drive, avg speed, etc

i agree with TOM93R1, unless you previously had an undiagnosed issue you happened to fix with reinstalling everything you unhooked

 

Mazda Motorsports claims an additional 10 HP with the installation of the efini pipe. It isn't just a reliability mod.

 

I could see 10 hp. The y-pipe *looks* like it just plain flows more efficiently.

 

I'm certain of the changes, I noted. I'm NOT certain of what caused the change. In other words, The efini Y-pipe is most likely not the cause of the temp reduction. However, I definately noticed a drop in temps. 2-3 degrees Celcius on Average. I've been daily driving the FD, 16 miles each way, round trip, to and from work since January. I guess we all agree on this point, as much as I would like to think it's just my turbos not working near as hard

In terms of performance, I consistently hit my target boost much earlier in the RPM range across all ambient temps. The transition is also MUCH more smooth. I also don't experience a problem with a drop in boost pressure shortly after reaching my target boost any longer.

The car feels faster, not due to more raw HP, but where I "feel" the power in daily driver.