Stock CT26 efficiency?

[Mikek3]

Hi im new here just bought my first mkIII a few weeks ago with a bad turbo its actually being rebuilt right now by a local shop with no upgrade (they didnt offer an upgrade) and i was wondering how many PSI the stock CT26 is efficient to.

If it help my mods are:

Lexus V8 AFM
Custom 3inch downpipe (no exhuast, No CAT)
Cometic 2mm MHG
ARP head bolts (or studs not sure)
Fidanza lightweight flywheel

Any advice would be appreciated, thanks

 

[sneakypete]

well i wouldnt drive the car until you get some bigger injectors and a wideband.
as far as the turbo, as long as its rebuilt properly, they max out at around 18-20 psi.

 

[Mikek3]

Wideband meaning? is that the same thing as a air/fuel meter? and i think my injectors will be fine as long as i keep the boost low(correct me if im wrong). i am planning on getting some 550s but dont have the cash right now just bought this car for 1200 and spent 371 on the turbo rebuild, and any cash i got now is for insurance tax, tag, title ect...

 

[sneakypete]

a wideband o2 sensor is used to monitor exact air/fuel ratios. its a good idea to use one since you are running a lexus afm (25% more fuel) and arent using 550cc injectors (25% more fuel). so basically there isnt enough fuel being burn and your likely going to run lean and cause damage to your engine.
do some more research about the lex afm/550cc injector upgrade before you decide to drive your car again.

 

[Mikek3]

I bought the car like that and the previous owner was driving it on stock boost like that, maybe it has 550s how can I check? Also I have an air/fuel ratio meter in my dash the wiring for it is spliced into my O2 sensor, is this normal?

 

[carter]

From what I remember, the CT26 efficientcy, is 14-16psi without a rebuilt, because the turbo because heat socked.

But I would be wrong its been forever since i've looked up what was the highest on the stock CT26.
Carter, J.

 

[LilMissMkIII]

http://wiki.supramania.com/tiki-index.php?page=CT-26

 

[sneakypete]

I bought the car like that and the previous owner was driving it on stock boost like that, maybe it has 550s how can I check? Also I have an air/fuel ratio meter in my dash the wiring for it is spliced into my O2 sensor, is this normal?

the a/f meter you have is a narrowband monitor.... its basically useless. you can tell what injectors you have by looking at the brand and part number, then look it up.

 

[Mikek3]

yeah the air/fuel meter seems useless to me it never stops moving, i will check the injectors as soon as i get a chance and thanks for the info

 

[rawmk3]

yeah the air/fuel meter seems useless to me it never stops moving, i will check the injectors as soon as i get a chance and thanks for the info

Try the AEM UEGO wideband controller and gauge setup. I think u can find them for as cheap as 250 or so (depending on where u go or who u know). It has the full wideband setup, and the adjustments are made right there on the gauge, so no external boxes are needed to tune it out. Just and idea. And u said your current a/f gauge is always moving around, could mean u have a cloged injector somewhere, and your A/F ratio is jumping all over the place as well. Pull your fuel rail, and send your injectors to be cleaned, and flow tested, so you really know what you have. But stock injectors are yellow, and all the aftermarket ones i have seen really arent. So maybe that will help you out a lil as well.

 

[bountykilla0118]

umm stock turbo injectors arent yellow they are black ..... those would be NA injectors but they are more of a green then yellow

 

[CATarga]

yeah the air/fuel meter seems useless to me it never stops moving,......

This is how the narrow band ones are supposed to work when driving under normal conditions. If you floor it, it should peg in the yellow(top of band), and at idle it should be in the red(bottom of band). It is more helpful for fuel economy than anything else, however if you had it floored and it was in the red(or yellow at idle) you would know you had a problem.

 

[antman]

as far as the turbo, as long as its rebuilt properly, they max out at around 18-20 psi.

LOL, I almost lost my drink on this one!

This thread is FULL of some interesting information.

 

[Mikek3]

So 13.5psi max is more acuarate right?

 

[antman]

Yeah, thats probably the most I would run on a stock ct.

 

[7MGTEsup]

The truth is no one actually knows when the CT26 becomes in efficent as there is no compressor map for it. The best guess compairing turbos of a similer size is between 13 - 15psi about the limit.

 

[antman]

If your car is up to par. A dyno works pretty well.

 

[bountykilla0118]

I am going to say its 15psi ...... but there are so many variables to consider… a simple one is pressure drop caused by the stock setup.

 

[figgie]

yeah the air/fuel meter seems useless to me it never stops moving, i will check the injectors as soon as i get a chance and thanks for the info

Well more of a clarification

useless as an AFR.

The moving you are seeing is a good indication as that is how it is supposed to be working. If it was not moving, then you would definetly have issues

 

[figgie]

Nope

not 15 psi. As the CT26 will come down to about 12 psi at the upper portion of the RPM range.

anyway.

Without someone doing temprature logging of the turbo (both Pre-intercooler and post). It will be a best guess of where the turbo is doing more than it is meant to.