I've been all over this and other RX7 sites and have tried to learn all I can about potential causes for a boost problem, and since my turbos are parallel I'm assuming I can cut out about half the potential problems. But that doesn't mean I don't need help!

I have a 93 with parallel stock turbos. When I first bought it it was making a good 11-12psi, and a few months after I bought the car I started noticing my boost would level off at about 7psi. I can hear a loud whooshing under the hood so I'm assuming boost leak, since the control valves and things like that are now out of the picture. Is that pretty safe to assume? Plus, I just did the Efini y-pipe thinking that'd be the source of the leak and it made no difference except a little quicker spool.

So my big question is, is there any method to troubleshooting a parallel turbo system that's suddenly only peaking at 7psi, preferably one that doesn't include sinking money into new piping, intercooler, etc?

 

You need to do a boost pressure test to find your leak. A hose clamp that's loose, a Y-pipe gasket that's not there or bad, the hoses to the blowoff valves that are cracked....any of these can cause a boost leak and a loss of boost.

Fighter's Garage makes a nice boost pressure tester. Scroll down for it -

http://fighters-garage.com/rx7.html

Dale

 

Lol I bought one of those yesterday. I wish this was posted earlier it would have save me a few minutes while I googled