Hi guys,

bought an rx7 a few months back, and threw it in the shop to get the basic maintenance done, fluids, tubes under intake, etc. the car has an aftermarket custom made exhaust which is pushing the psi a little too high (around 13psi) but I'm hoping the japanese fuel will compensate a little for this before i get the exhaust changed. the motors got 110xxx km on it but just been rebuilt with over 9k on each rotor so its in great shape.

problem: in the first 20-30 minutes the boost goes up to the max 13psi, but after driving for 30min-1hr it seems to suddenly max out at 8psi for some reason? what could be the causes? just want to check whether its a simple fix before I take it into the jpn shop. doesnt matter if I drive it like a grandma or drive it hard for that first 30-1hr period either.

thanks for any advice!

 

no ideas?

 

here is a great website for seq turbo troubleshooting.

http://www.autosportracetech.com/RX-7/rx7stuff.htm

i'm no expert on this but a leaky vacuum chamber or bad check valve to it can cause variable boost. The symptoms IIRC is more like after letting off and reapplying throttle boost comes back.

 

I would check the lower turbo inlet hose (goes to the airbox). It gets soft after it's warmed up and it compresses at higher boost.

 

If you're just losing a few psi, it's possible that you have a boost leak that only opens up when the rubber coupler gets warm and flexible. I'd start with a full inspection of the couplers for leaks.

Dave

 

Thanks blokes!

that webpage is great, seems to be exactly the prob im having. will have to check em out on the weekend

 

I would suspect one of your couplings as they will tend to hold boost when the car is cold, and tend to leak more once the rubber warms up and gets softer. I'll have to guess you are still running the stock couplers and not silicone.

 

I have the same issue that im gettnig a max of 8psi but i went non sequential and have aluminum intake piping. if there were a lets say 3/4 inch gap between 2 pieces of piping that was covered with the coupler could teh coupler collapse into that space and casue restriction? i got the Cheapo BOMZ or w/e ebay intake lol and i dont know if the couplers are sillicone considering the set was 40 bucks