Need a new CT-26

Choir Infantry

New member
My original turbo has more than likely kicked the bucket. A few days ago I was out driving and I lost all boost pressure at any throttle position (read off an aftermarket gauge reading .6 bar normally) and it felt like it became N/A. I pulled off the intercooler to get to the wastegate actuator to see if it was stuck and found quite a bit of oil in the compressor side outlet. I’m currently trying to find an oem replacement without buying a Garrett replacement or used but can’t really seem to find anything as I’m not yet comfortable with rebuilding it myself. I’m wondering if anyone has any experience/recommendations for finding one?
 
You have a 1992 Celica GT-Four? If so, don't you have a ceramic rotor on your CT26 turbo?

There are plenty of rebuild kits out there for your turbo, and rebuild videos.

I'm thinking some of the folks in this forum know of turbo rebuild shops too, if you prefer not to do the rebuild yourself.
 

Choir Infantry

New member
Correct, it is ceramic and dual entry (so I know the 7M isn’t exactly a replacement) at that too, I wanted to ask even if just to see for the normal us spec steel wheel considering the MR2 turbo isn’t all that rare or forgotten about.
 
FC Zach":11u2n4nu said:
I'm considering a rebuilt/modified CT from ATS Racing, check their page: http://www.atsracing.net/Parts/Index/TURBOS
The one I think you are looking at gets you an additional 20-30 WHP at 16 psi - are there other changes needed to be made to accomplish this beyond just installing this rebuilt/modified turbo? I'm not an expect on this at all - hopefully others in this forum who've done this can chime in.

My concerns are:
- MAP on an ST185 (tops out on VDC output at 17.4 psi - 5VDC)
- fuel cut pressure I think is in the 12-13 psi range - you have to figure out how to raise that cut pressure to take advantage of the turbo
- waste-gate valve pressure (when it opens to bypass) - I think is ECU controlled also so as to prevent fuel cut pressure from being attained

Something to at least be aware of.
 

FC Zach

Active member
93celicaconv":25muhj8t said:
The one I think you are looking at gets you an additional 20-30 WHP at 16 psi - are there other changes needed to be made to accomplish this beyond just installing this rebuilt/modified turbo? I'm not an expect on this at all - hopefully others in this forum who've done this can chime in.

My concerns are:
- MAP on an ST185 (tops out on VDC output at 17.4 psi - 5VDC)
- fuel cut pressure I think is in the 12-13 psi range - you have to figure out how to raise that cut pressure to take advantage of the turbo
- waste-gate valve pressure (when it opens to bypass) - I think is ECU controlled also so as to prevent fuel cut pressure from being attained

Something to at least be aware of.

I'd like to have the CT27. . with that I am still staying below fuel cut (which is 14.7 I believe) till I replace the head gasket with a multi layer steel type and head bolts with studs. Anymore than stock pressures and you'll want supporting mods like those, as well as fuel upgrades and management depending on how much power you're looking for. I have an adjustable wastegate that works independently from the turbo vsv which I have capped off.
 
I'm pretty sure fuel cut occurs when the MAP output 4.3VDC. The MAP curve equation for an ST185 is:
- V = 0.1319*psi + 2.7000 up to a maximum of 5V
so at 4.3VDC fuel cut threshold, the resulting manifold pressure is 12.13 psig

Again, I'm not the expert - but I see several references to 12 psig fuel cut for an ST185 with MAP outputs at 4.3VDC (some say 4.4VDC).
 

FC Zach

Active member
Not sure, I thought I saw that somewhere before. . . I'm probably getting it mixed with pressure at sea level.
 

Magroo

New member
I'll send you my old one if you pay for shipping.

It came off a jdm with around 55k miles. Was still working fine when I pulled it off when I upgraded. Wasnt leaking or burning oil. I'll take some pics tomorrow if you want it.
 

Gert

Active member
I have a CT27 since short time.
My car is having 264 cams, free exhaust and Autronic.
T-vis destroyed my old CT26, so bought an CT27.

Pfff, probably me, but disaster. First, there was a sticky wastegate resulting in too much boost.
Fixed the wastegate.
Than had massive boostcreep after 6.000 rpm.
So we ported the turbine housing. Unfortunately, too much porting resulted in an leak in the housing.
Let it weld at an professional weld shop.
But now, I cannot get boost over 0.8 bar.... sigh. So the actuator is not strong enough. Had no time to fix this, due to other priorities and the car is running fine.
Resumé: I am tired with this CT27.

If I must do it again: I should rebuild my (upgraded) CT26. My CT26 was upgraded somewhere in 2000 and ran without any problems.
Turbo was upgraded here: http://www.turbocharged.com/main.htm
They make the intake from the compressor bigger and add an other (balanced) wheel.
 
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