doduong11

iTrader: (4)

Hey guys just wanted to ask if you guys might have had encounter with this problem at all?

Well when i went to tune my car the first time i didn't have a boost controller hook up so KDR said he could only tune it to 11psi and it was making 340whp. So i went back there the 2nd time to get it tune with the boost controller they hooked up for me. So this time when he's tuning it the wastegate got stuck and overboost so he stop tunning it. But he said before it overboost it was making 375whp @ 5500rpm and went crazy like 23psi after that so he stop tunning and told me that i needed a new wastegate before he could tune it again.

Ok so here's what happened after that. I ordered a new wastegate, installed it myself and hooked it up just like how he did with the old one. Whichever vaccum line goes where i put it back just like it was. So when i went to test drive it, it only boost up to 8psi and no more. I've tried low and high boost but only 8psi. So what do you guys think the problem is?

arghx

iTrader: (3)

What is your wastegate and boost controller combination? The first thing you need to do is verify that your plumbing is perfect and your boost controller is properly configured.

If this is an external wastegate, I think most people with stable boost setups first find a pressure source near the TB (not the compressor housing), often by drilling and tapping a 1/8 NPT fitting with a hose barb. Then they take the line from that pressure source and install a T. One end of the T of course comes from the pressure source.

One of the other two ends of the T goes to the bottom/side port of the wastegate. The 3rd end goes to the inlet of your boost control solenoid/stepper/whatever . Then a line comes from the boost controller solenoid to the TOP port on the external wastegate. See the installation instructions for your boost controller.

Then you must make sure the boost controller is configured for an external wastegate. On the Greddy and Apexi boost controllers, they use a Denso solenoid that requires that you remove the fitting from the port labelled "NO" and install that fitting in the port labelled "NC" . The pressure source goes into the "NC" port and comes out on the "COM" port, which then goes to the top port of the wastegate. There may be dip switches or other things you have to set. Consult your manual.

doduong11

iTrader: (4)

Well i had an OBX wastegate on it before and it was connected to a greddy boost controller. Before i switch the wastegate it was working fine. Boost to 14psi like it was supposed to, but since i've change to this HKS it doesn't boost over 8psi (.45 par) for some reason.

I bought my car to KDR here in PA which is a very respectable shop for RX7 and they were the one who hooked up the boost controller and wastegate for me, so i supposed that it was hooked up correctly. So i think the problem is with this new wastegate. This new wastegate comes with a 10psi spring but according to my PFC it only boost up to about .45 so not even 8psi so it can't be the spring, but what else could it be?

MichaelB145

I would first do a leak down test to make sure your not losing boost there. One of those vacume caps probably blew off when you went up to 23lbs. I would make sure your system is capable of holding twice the boost then your running because some leaks are so small you won't find unless pressurizing it that much.