bldme2

My 93 RX-7 runs great with normal boost patterns out on the street. When I get on the track, after a couple of heated laps, the boost gets cut in half down to 5-6 psi. Is this a heat related problem? Does anyone have any clue as to where the culprit might be? The car does heat up a little on the track, but in the range of the stock gauge. Upgrades are dp, k&n drop in filter,cat back exhaust. Any suggestions would be appreciated!

Toadman

Hmmm... clogged cat when heated up?

ZoomZoom

iTrader: (2)

My drive to work is similar. I get great boost the first few times i get into it after it warms up and then the boost seems to drop off. I think its a few issues. One is heat soak in the intercooler and second the heat tends to cause alot of expansion of all the tubing and y-pipe. I think you will find a leak around there as well. Also if your car idles like crap when that starts happening you may have a bad intake plenum gasket. Maybe still have the old paper gasket. This happens when the plenum starts to expand and contract and any gasket sealing issue is compounded. So may possible problems. Also heat does funny things to solinoids and such. intermittent problems are the hardest to find and diagnos. I imagine there as many single turbo owners out there who just hated trouble shooting boost problems as much as guys trying to make more power by the swap. The stock system is a maintinance nightmare.

Tobal

One reason would why this is happening is the car taking precaution of detonation of running hard and hot. The computer tends to retard timing and boost to prevent detonation. Thats why on certain days (cold days) you'll get more and on hotter days the car runs slightly less.

Dan

The accordian type intake hose on the primary is probly getting soft when it heats up, and that causes it to collaps under big boost. The only way to find out is to remove it and drive it. Just dont drive lots of miles or go down a dirt road, because your turbo is exposed and could suck somthing thru it

aReX-7

iTrader: (3)

bldme2,

Keep in mind that the stock temp gauge sucks. It will not move above the normal temp. reading until the engine has overheated, which is too late to save it! I suggest getting an aftermarket temp gauge to monitor temps on the track. I have a Mazda Competition radiator and Greddy Temp gauge. I have seen my temps as high as 115 degrees C (239 F.) and the stock gauge did not even wiggle. I know some guys have to shift at 7k on the track to prevent waterpump cavitation too.

Not sure if this is causing your problem, but it is still a good idea to think about heat management on the track!

Good luck

Jeff

bldme2

The car seems to idle fine during all of this. Once the car cools down again the boost returns for the frst couple laps for the next track session and then the boost falls off again. I will be going down a straight away and I will see the boost all of a sudden just drop from 10 down to 5-6 psi. Then the mustangs and corvettes catch up and start to pass me! Please help, I can't stand that!