How to Gain Extra Boost from Ct-26 Turbo

[Robert Smithers]

AFter Fitting new dump pipe to my ST-165 GT-4 Took the car for a test drive
when reaching 12 lb boost the engine went pop then it wouldn't let me go over 5lb
shut the car down, re started but worried about getting up in boost and the car shutting down on the track. The engine will run to 11lb no worries now but worried that if I push it
it will shut me down again. Do not want this....... Is there a simple fix to stop the car shutting down like this please let me know......
Robert.

[Roundy]

the ST165 will hit a fuel cut if it reaches ~12psi.

obviously your dump-pipe if flowing a lot better and it is easier for the exhaust gases to go out the turbine then through the waste-gate.

i think the only way to fix it would be to alter the fuel cut point, but that is a bit dangerous as it could boost to something a lil bit higher then 12.

maybe disable the TVSV and see if that helps?

on the waste-gate actuator there should be 2 hoses, one goes to the turbo, the other one heads towards the block. Un-plug the one heading towards the block from the pipe near the block (lol hope that made sense) then block of the hose.

What this will do is run a lower wastegate spring pressure (~7psi), i would imagine it will climb to 7psi quickly then slowly build up over that.

[Squid]

Have you checked the error codes? more than likely you will get a report of overboost problem and it has gone into limp home mode...

[Squid]

As for stopping it in the future, you could look into a fuel cut defender, which can either be an $50 aftermarket part, or a 5 cent zener diode (do a search there is a write up somewhere).

Generally you are better to go for better managment to handle the extra boost, but a FCD could be a good interim measure...

[Robert Smithers]

thanks Guys I will try to find the other thread , just need to stop it from going into
limp mode. Not a good thing to happen on the race track.

[Squid]

Try this - his point on it being better than the zener mod is valid, this just delays the Fuel cut (adjustable through pot) rather than disables it.

http://www.gtfours.co.uk/default.htm...to/fcd/fcd.htm

[spectral]

thanks Guys I will try to find the other thread , just need to stop it from going into
limp mode. Not a good thing to happen on the race track.

Be very careful becaue the 3SGTE ECU doesn't have mapping for beyond 12psi, so pushing it that far will be a bit questionable. It does go fully rich, not lean... but you certainly won't make more power.

The zenor diode mod is good to stop the cut that you describe, but don't use it as an opportunity to screw a bit more boost from the turbo (ie.. 13-14psi+).

If you want to run 13+psi, then you'll need a piggyback computer at the minimum to get the mixtures right.

[jonra23]

Get an electronic boost controller to control boost more accurately, will have the added benefit of spooling quicker.

regards
jon

[Robert Smithers]

Thanks guys . What is the best boost controller for the job with out going over board.

[e30-323ti]

If it is over boosting because of the new downpipe (as roundy suggests), you will find the wastegate port is too small to control the exhaust gases.
Some fancing EBC won't solve this problem, you need to get the wastegate ported so if flows more & better.
Don't mess with FCD's or oneday it will be bye bye engine.

[Robert Smithers]

My mechanic is starting to think that the guy I got the car off might have bent the accuator on the wastegate to try and get extra boost originally. so we are pulling it off to check it out.