I blew my turbo. It has 70 a/r compressor with .63 a/r T3 journal bearing.
I replaced it with the same .70 a/r compressor but .82 A/r turbine ball bearing.

Do I need to remap my ecu? Its K20z3 using flashpro.

Thank you

 

The graduating scale for fuel/timing vs boost should be pretty close still. Data-logging it would be the only way to know.

 

i think so. ball bearing will spool faster which means more air at a lower rpm than your current tune is set for and possibly a lean condition. the larger exhaust housing may slow the spool down a little but i wouldnt chance it with an engine a nice as a k20z3.

 

Depending on your turbo manifold and really your setup as a whole, you may have less back pressure with the bigger turbine housing then before. It’s likely your tune will need some small changes. Definitely not a whole new tune. Like I said depending on your setup and if back pressure dropped you may pick up some good power up top from ignition timing changes as well. On my old ls hatch I switched from a .48ar hotside to a .63ar and it definitely required changes to the tune, also picked up a good bit of power on the top end.

 

Thank you guys !!
Ok, so I should bring it to the dyno and talk to the tuner?
Or maybe dyno it and see how the AFR performing?

I'm figuring it out if I have to pay him in full tuning or just dynoing just to see the afr (which is cheaper).

 

What the ****. U got money for an Ariel atom, u got money ey for a retune lol. Nice car man, major goals right there.

 

there will be no need for a full retune based upon what you've just changed. You probably won't be on there but for less than an hour after a few wide open throttle runs on the dyno itself. No need to worry.

 

IMO I would get it tuned you should be able to make more power possibly down low(BB turbo) and definitely up top, which will require more fuel also as stated timing may also come into play which simply watching an AFR gauge wont tell you. should be well worth a retune. Other then that you should be pretty safe on your current tune I dont think the turbo swap would change things too drastically

 

Also I forgot to ask:
I live in a hot weather, brutal on summer. Winter is nice (for 4 months) here so I don't use my methanol. I only use the meth during summer & track time --- starting at 8 psi of boost to avoid detonation.
I'm only boosting maximum of 11 psi. The internal is stock ( I don't want to gut it out since not too many miles on the engine). How much boost can stock K20z3 handle?
The car is light 1200lbs -- easy on brake, easy in clutch, easy in acceleration almost easy on everything. I don't need torque but I want hi-reviving.

 

Boost pressure has nothing to do with what any engine will take. Going by PSI is not the way one tries to work out the limits of the engine. Remember, a turbocharger is basically an air-conversion pump and is determined by its maximum efficient airflow capability.
So, that means that 25psi on a GT2871R is going to have a different airflow rate than 25psi on a GT35R. Same boost pressure, different airflow rate at that same boost pressure. With the the bigger one, you'll blow the engine, the smaller turbo, might not be as likely to go.

You want to go based upon the "projected" HP limitations of the engine itself. That means the right question to ask is "how much power to the wheels can a stock K20Z3 engine handle, based upon people's experience?".
The answer to that is around 400whp-450whp (to the wheels) or so, but that engine isn't commonly used to boost that often. Considering how light the car is and your purpose, you don't need more than 400whp anyway.

The actual boost pressure used to make that power will be determined by your tuner (or yourself if you are the tuner) when it's time to go get everything tested and mapped out.