turbo tuning
 

I'm autocrossing a 1.6 M45/E85 and decided to step up the power.

So I found a turbo'd 1.8, drove it and bought the motor. I'll be reusing my Megasquirt and staying on E85. When I drove it, I found it to be soft 4000-down and hot 5000-higher.

And that looks a lot like a few dyno curves for similar engines I've found around here. Torque building 3000 to 4000 then peaks and stays pretty high.

I want to stay down around 210 max whp and they say that should be easy. But can I flatten the torque curve to make up the missing power between 3000 to 4000, then keep the higher revs more docile? Looking for smooth even power from 3000 to 7000 which matches rpm band I've seen during my runs.

Need specifics on exactly :

What turbo,
What manifold,
Method of Boost control
Pretty much the whole damn turbo setup / design.
Wouldn't hurt to show us the tune as well.

Also wouldn't hurt to have this moved to the DIY turbo discussion, not engine performance.
Further wouldn't hurt to search. The Sticky"I want your spool data" thread comes to memory.

This is my first aftermarket turbo and I don't know all that stuff. I'm buying, not building this engine. I'll be leaving the tuning to a professional. I'm just interested if others have been able to arrive at a flat torque curve when you don't need all the top end a system is capable of.

I do know it's a T2860R, running a fairly large IC. But I don't know many details beyond that. I was told it was once tuned for 265 whp, but has been detuned since then for street use. I'm low on the learning curve here. I'll go find that thread you referenced, thanks.

No, you cannot push the powerband down 1000rpm with tuning. You need to decrease the size of the turbocharger to do that.

That's the info I was looking for. Thanks.