Ct20 Turbo Compatibility

[flyingtele]

Hi there, i have just discovered that the oil seals in my ct26 turbo have gone as white oily smoke pours out of the exhaust pipe. The car is a st185. Would it be a good idea to replace it with a ct20 turbo? would it bolt straight in? I am planning to replace the headgasket with a steel one. What would be a safe level to turn the boost up to? The engine will be stock other than a metal head gasket, ct20 turbo, straight intake and a dump valve?

[dawesy]

hi mate, the CT20 will bolt straight on although the lower manifold heat shield bolt wont fit nor will the lower turbo support bracket bolt but this will not affect it.

whilst doing the head gasket fit a set of ARP head bolts then you should be safe running around 0.9-1.0 bar with an electronic boost controller.

ist worth fitting a FMIC or carlos sainz chargegooler as well if yours is the ATA 185

[flyingtele]

hi mate, the CT20 will bolt straight on although the lower manifold heat shield bolt wont fit nor will the lower turbo support bracket bolt but this will not affect it.

whilst doing the head gasket fit a set of ARP head bolts then you should be safe running around 0.9-1.0 bar with an electronic boost controller.

ist worth fitting a FMIC or carlos sainz chargegooler as well if yours is the ATA 185

Yeah, i know the the fmic is generally the best, but i dont want to go down that route as its expensive, and the turbo and throttle body being where they are means very long pipework and considerably more lag. And the CS chargecoolers are too hard to come by second hand in NZ, only guaranteed option is toyota dealer, but it would cost the earth for that and pump and radiator etc. If i can get a second hand one then great.

Out of curiosity, who here has a fmic on their gt4? How much more power do you get and how much lag is there typically under hard boosting?

[dawesy]

you will find quite a few on www.gt4ec.net and www.gt4oc.com, power gains will depend on other mods but it will help by giving lower charge temps.

if you keep the core size and pipe diameter down to 50-60mm lag wont be much of an issue.

you may even benifit by moving the original cooler to the front and having pipes made up for it