I installed the Efini Ypipe and noticed a loud Wiiiiiiiiii sound that was not present before when the secondary turbo comes online. Boost pattern 10-8-10.... I have absolutely no problem making and holding boost pressure. Car appears to pull strong, but I am concerned by the loud Wiiiiii noise that comes when the secondary turbo comes online. So far all of the intake piping to the 2ndary turbo and the Ypipe seem to be tightly connected. My PFC recorded a peak injector duty of approx. 86%... which is a couple percentage points higher than the norm, so it appears that the mod is yielding more power than before.

One hiccup with the Efini Y-pipe install: I was not able to put one of the clamps around the discharge air pipe from the air pump. The Efini Ypipe has such a tight clearance around this pipe that it was impossible to squeeze the OEM clamp around the tube. I'm not sure if this could be the cause of the noise, but if it is, what is the consequence of allowing this to go on? Could exhaust flow back through this pipe and into the engine bay? (doubtful with the static pressure drop, but maybe possible)

Thoughts? Is this an issue?

 

Sounds like one of the metal gaskets is failing or you dont have one of the ypipe connection points secured correctly.

 

Or maybe the 'O' ring was pinched during installation.

 

Driving to work today, I remembered that the flexible hose connection between the Ypipe and the bpv for the 2nd turbo seemed kind of loose when I installed it. I put the hose clamp on both ends of it, but I noticed that I could actually swivel/rotate the hose around the connection point to the ypipe. I thought that as long as the hose clamp was on, it would be tight enough to hold boost. Maybe this is the culprit? Time to crack out a worm-drive clamp and tighten down?

 

Went into the garage and made sure that the clamps on the air pump discharge and the charge relief valve were tight and secure. Checked connection of intake pipe to 2ndary turbo inlet (from under the car). Checked Ypipe connections.

Went out and test drove the car.... still makes the same "wiii" noise after the 2nd turbo comes on and makes some pressure. I boost 10-8-10... if anything, I used to have some spikes to 11 or 12 PSI that seem to have gone away after installing all of these parts. Car pulls hard, it does not seem like a case of boost leak and the intake seems to be very secure.

At this point, I'm going to throw my hands up and put up with it. The Wiii noise isn't annoying, just suprisingly loud (louder than before anyways). From my understanding of fluid mechanics, louder noise usually means that there is some sort of increase in turbulence, which I hope is not the case here...

 

I had a similar problem a few weeks ago. I was hoping for the worst but this might help you and check on the turbos.

https://www.rx7club.com/showthread.p...urbo+loose+nut

Just take it all apart and get to that nut. Mine was finger loose and all I did was tighten it back up and the sound was gone. While your at it you can look for any shiny spots for rubbing and to check shaft play. I hope this helps you out.

 

Thanks for the link Drifter288!

I did check that exact nut tonight, and its on there TIGHT.... I may take off the intake pipe and take a look at the nut on the other side over the weekend though. Good catch.

 

If the short rubber hoses to the BOV's are loose even with a hose clamp, they're likely rock hard and not sealing well any more. If that's the case, time to get a new one from Mazda.

Sounds like your boost pattern is still good, but you're likely losing just a little air.

It can also be from the flange between the top and bottom of the y-pipe. There should be a fresh gasket in there with no RTV and should easily sit flat.

Dale

 

have you tried a pressure test? http://www.fighters-garage.com/rx7.html

scroll to bottom. you can make that yourself as well. it looks like they are capping off one of the turbo inlets and then pressurizing the other

 

Was a solution ever found for this problem? I've got that exact same Wiii noise with no loss of power. Except I have it happening with my primary turbo as well.

 

One of the nuts on my Y-pipe was found to be loose. If you are getting this, I am sad to say, you will need to re-check/verify ALL points of connection for the Y-pipe.

Now things are great!