Sequential system FIXED! Guess the problem...
 

So it has been many months of trying to fix my sequential system. I have bought two racks worth of solenoids, the turbo control solenoid on the ACV, silicone lines, check valves, and did the vacuum hose job. I have probably taken off the UIM 5 or 6 times in the last 4 months replacing and checking solenoids. I always performed the solenoid tests; cool and warmed in the oven, and energized and un-energized. Nothing fixed my low primary boost. Well I finally pulled the turbos, and this is what I found:
http://i288.photobucket.com/albums/l...0710111943.jpg
No amount of solenoids or checking hose routing would have fixed that... I got a low mileage set of turbos, ported the wastegate, and installed them. Needless to say the car is a blast to drive! I think this will be the first time I have had 10 lbs at 3000 rpm in like 3 years. I just wanted to share my joy with you guys. Maybe someone else out there has the same problem.

WOW! That is some severe manifold cracking. Glad to see you found the problem.

How many miles are on those turbos?



John

Yeah I've seen that before. Once the twins get high mileage the turbos on the exhaust manifolds can develop big cracks.

Running lean? The cracks is not my worry, how rounded and "clogged" the ports and cracks look. That looks to me like high EGTs.

I think those turbos have about 110k on them. It might have been running lean in the past, but I'm pretty it doesn't now. Whenever I have it smog checked I have a lot of HC, so I would think it runs rich. Plus I use water injection now, so hopefully my EGTs are in check.

Arghx it's not the high mileage that does that. It's the constant boosting all the time which creates those high temps. My turbos on my original engine with 108k only has a smallish hair line crack and hardly any shaft play. Looking at this carnage, it's amazing the beating some of these engine take over time.

The motor was replaced in the car shortly before I bought it at about 70k miles. I think the turbos were the original. Surprisingly though, they had very little shaft play, but the rear turbo was leaking oil.

is there any kind of coating on that manifold or is it just the lighting?

It looks like a Rhyno's butthole on a bad day

While those are hands down the WORST turbine housings I've seen, have you looked at what your turbine wheels look like? I can't see the bad housings causing THAT big of a problem.

I had a chipped turbine wheel from a previous owner's blown engine that resulted in lower secondary boost.

Dale

There is no coating, it is just the shop light and my cell phone camera that make it appear like that. Dale, I was still able to get about 5 psi on the primary, but yes the primary turbo's turbine wheel was damaged. I will take a picture when I have time, and you can see if it would have caused that much of a problem too.

damn that is some major cracking!

Here was mine at 100k running 12psi to 13 psi the whole time.

https://www.rx7club.com/forum/attach...postid=1986627

Here was the replacement turbo with 40K running at 13psi.
https://i793.photobucket.com/albums/...g?t=1254291513