Custard Posted November 18, 2016 Share Posted November 18, 2016 R33 boost spike issue Hi all, I need to find a solution to fix a boost spike issue that my car has. It's a 1997 manual GTST, only mods are YJ coils, return flow FMIC, MBC and 3 inch turbo back exhaust. Since I installed my front mount and dialled my boost up to 10/11 PSI I have noticed that when I punch it from 3.5 grand upwards the boost will spike to 12 or 13 PSI for a moment and then taper back to my set pressure. Just last night I installed a JJR bellmouth 3 inch dump pipe and now when I punch it, it will spike to 15 PSI! Would prefer not to launch my exhaust wheel out my exhaust, so I need to get this under control. Do I need an electronic boost controller or what? Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/ Share on other sites More sharing options...
Custard Posted November 18, 2016 Author Share Posted November 18, 2016 I have a cheap 'Drift' brand MBC - would be I correct in believing that this is a bleed type MBC? Would I benefit from changing to a ball type MBC such as this? http://www.ebay.com.au/itm/Turbotech-manual-turbo-boost-controller-THE-ORIGINAL-and-still-the-BEST-/321155544509?hash=item4ac65cb5bd:m:mJ5Yk12EnMVqXBuR8UxKxhQ Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7792480 Share on other sites More sharing options...
jhjones Posted November 18, 2016 Share Posted November 18, 2016 (edited) connect the wastegate actuator hose directly to the intercooler pipe and see what happens Edited November 18, 2016 by jhjones Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7792485 Share on other sites More sharing options...
djvoodoo Posted November 18, 2016 Share Posted November 18, 2016 Why don't you just turn the boost down via the MBC?? Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7792503 Share on other sites More sharing options...
Custard Posted November 18, 2016 Author Share Posted November 18, 2016 1 hour ago, jhjones said: connect the wastegate actuator hose directly to the intercooler pipe and see what happens Okay, I did this. I saw 5 PSI when easing into boost and around 6-7 when stomping it from higher revs. I had a thought: perhaps with the addition of my front mount intercooler, the extra volume that has to be pressurised before results in the opening of the wastegate being delayed? If this was the case, would relocating the barb from the cold side to the hot side fix this? 13 minutes ago, djvoodoo said: Why don't you just turn the boost down via the MBC?? Probably would have achieved the same result what as post above suggested, but it's done now. Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7792507 Share on other sites More sharing options...
Sklyn Posted November 18, 2016 Share Posted November 18, 2016 Just to be sure, the stock solenoid has been disconnected and the other hose blocked properly right? Getting 5 and 7 suggests the stock solenoid is still in use. Are your psi readings from an aftermarket gauge? Stock one is not psi. Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7792568 Share on other sites More sharing options...
Custard Posted November 18, 2016 Author Share Posted November 18, 2016 (edited) 35 minutes ago, Sklyn said: Just to be sure, the stock solenoid has been disconnected and the other hose blocked properly right? Getting 5 and 7 suggests the stock solenoid is still in use. Are your psi readings from an aftermarket gauge? Stock one is not psi. Yes, actuator is connected straight to the nipple on the cold side of the intercooler piping, no stock solenoid. Readings are taken from an aftermarket boost gauge in PSI. The higher boost level that I'm getting isn't dependant on my RPM but rather how hard and fast the boost is coming on. Edited November 18, 2016 by Custard Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7792570 Share on other sites More sharing options...
Custard Posted November 21, 2016 Author Share Posted November 21, 2016 (edited) Because I'm getting boost spiking on just wastegate pressure, would this suggest my wastegate actuator is no good? Edited November 21, 2016 by Custard Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7793093 Share on other sites More sharing options...
Sklyn Posted November 21, 2016 Share Posted November 21, 2016 Very well could be that. When i started to get 7 on that set up i replaced it and went back to normal. I then put in an r32 one for an easy 10 psi with no need of defectable boost control. Link to comment https://www.sau.com.au/forums/topic/467794-r33-boost-spike-issue/#findComment-7793152 Share on other sites More sharing options...
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