st 204 turbo Options

[thorshammer]

Hi I have a st204 Celica with 5fse engine and am wanting o turbo it. I have read 1bwilson's and Shid's posts on turboing a 5sfe and list of components needed and this seems to be the best way to go. In my neck of the woods CT26 turbos are hard to come by, T3/T4 turbo is easier to sourc.e My question is what T3/T4 do I need and other than a CT26-T3/T4 adaptor is there anything else I need. I live in Australia so Mustangs and other American cars are not common here but plenty of Japanese sources. Thanks

[lagos]

the stock ECU is setup for n/a, and has alot of timing, especially in the low load areas, too much for a boosted application, and that will cause issues, no matter the piggyback.

I can't stress enough how important this fact posted by presure2 is!

After tuning my megasquirt for the past few months and learning a lot about ignition timing maps, I am amazed that the 5sfTe setups running any type of piggy back manage to hold up as long as they do. In fact Id guess that the only reason they do is that the factory knock sensor is very good and stepping in and constantly pulling timing (and robbing you of power) in an attempt to save the motor.

To give you an example of what I mean, a none turbo motor runs around 30 degrees of ignition timing at high load (100kpa is high load for an NA motor).

*Not a real toyota map, just an example of the idea.

So these will pretty much be your timing values with something like an Emanage. With an SAFC, this will be even worse as the safc will fool the ecu into thinking its at a lower load in some cases giving you even more timing (the posted map is not a great example of this, but the factory ecu could run as much as 40 degrees in this range.

On a factory turbo ecu these timing values need to be tuned to decrease as boost increases (the area from 100kpa to 200+) to account for the extra heat/power produced by the turbo, and in the case of a 5sfTe, would probably need to be dropped down to the 10-14 degree range.


Because of this I believe the factory ecu is the next weak link in the 5sfTe setup.

This post has been edited by lagos: Jul 4, 2013 - 12:28 PM