Guest yoshi_v300 Posted July 22, 2008 Share Posted July 22, 2008 Setup : 2jz-gte turbo / blitz air filter / 3" downpipe / TOMS ecu or factory ECU / Blitz DSBC / BTN rebuilt turbos I had a boost spike problem previously. It would spike on stock engine/turbos to 1.5bar. Crazy. Later I found that I removed the spike by tightening up the collars going to the Blitz DSBC solenoid. This seemed to stop the spikes and I was running around 1.05bar up to 80mph. The car still had boost creep and the fuel cut hit about 1.15bar at 100mph+. Fine I thought, that's the 'downpipe'. So last night I figured I fitted my TOMS ecu (set to 0.9bar boost) which removes the fuel cut and find out how big a problem is my boost creep. I've ran the TOMS ecu on a previous car and it makes 0.9bar @ 6500rpm typically. Instead I find that I'm boosting to 1.5bar from 80mph+ on full throttle. In fact I can hit 1.37bar from 30mph+ and I did a 0-30mph launch @ 7000rpm which gave a readout of 1.2bar. As you all know it should be somewhere 0.8-1.0bar on my setup. Meanwhile my AFR ratio meter shows 11.8-12.3 during all this. Could it be the boost controller? Well, I've tried a brand new DSBC unit and it gave the same wacky readings. So my questions are : - should I go out and buy 2 brand new actuators and fit? - should I buy new hoses? Is a pressure test of hoses accurate? - any other ideas WTF is the problem? Quote Link to comment Share on other sites More sharing options...
Guest yoshi_v300 Posted July 22, 2008 Share Posted July 22, 2008 Just a note, I can't buy actuators seperate to Toyota twin turbos. Therefore, can I dissaemble/repair/analyse the actuators? Quote Link to comment Share on other sites More sharing options...
Guest yoshi_v300 Posted July 22, 2008 Share Posted July 22, 2008 Further point - would the wastegate spring being incorrectly setup cause my spike? Previous owner of the car re-fitted the turbo DIY style.... Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 22, 2008 Share Posted July 22, 2008 Revert the wastegate system back to stock. If it still spikes, your wastegate is too small to deal with the free-flowing exhaust system, which is cured by putting a restrictor ring in the exhaust system. This doesn't cause any EGT or loss of power issues and is very cheap -Ian Quote Link to comment Share on other sites More sharing options...
Guest yoshi_v300 Posted July 22, 2008 Share Posted July 22, 2008 Well I was thinking of changing back to stock downpipe and seeing how the boost goes then... When BTN rebuilt the turbos (with garret parts), do they put a new wastegate on the turbos or not? I am not sure what the standard procedure is. Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 22, 2008 Share Posted July 22, 2008 They certainly won't try to enlarge it, that's for sure. Sounds like your basic boost creep/overboost issues from any decatted j-spec car. -Ian Quote Link to comment Share on other sites More sharing options...
Guest yoshi_v300 Posted July 22, 2008 Share Posted July 22, 2008 I thought that de-catted/downpipe Supra would give boost creep only? And not boost spike? Or when you de-restrict the exhaust, do you get spikes also? It also has a SARD racing cat which is prob.more free flowing. Oddly, I didn't have any boost spikes on my old car, same setup. It did however have ceramic Toyota turbos instead of the BTN turbos. Old car did not give boost spike, but it still had boost creep issues. Quote Link to comment Share on other sites More sharing options...
Guest yoshi_v300 Posted July 24, 2008 Share Posted July 24, 2008 Well, I swapped factory ecu back in today...and the boost settled down to .95 bar. But get this : My old TT mkiv - standard boost 0.8bar. TOMS ecu 0.9bar Spec : Toyota ceramic twin turbo, large front mount intercooler My new TT mkiv - standard boost 0.95bar. TOMS ecu 1.5bar. Spec : Garrett BTN rebuilt turbo, standard Toyota Intercooler Ideas????? Quote Link to comment Share on other sites More sharing options...
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