Hi, I recently bought a 2005 impreza 1.6l with an ihi rhb5 turbo (about 150 hp) and I noticed that the real boost starts over 3800-4000 rpm (100+ octane gasoline). The thing is that I dont want (for now...) more power I just want a little bit more torque at lower rpm (lets say 1000 rpm less). I checked over the internet and I saw 2 or 3 propable solutions. 1) wider exhaust pipe for lower back pressure in order to help turbo spool up faster 2) stiffer spring in wastegate actuator 3) remap ecu

What is the best to start with and because stock ecu isnt a good choice for remapping I would like a suggestion for an aftermarket one.

Thank you in advance.

I'm sure that it's like any turbo, and that a good tune will help with what you're after. And there's a good chance that a better flowing exhaust would help as well. Just make sure you have it tuned after any modifications. But a good tune, even at stock level will help alone.

You're not alone with the tuning thing, that is the problem. How do you tune it short of 2 K dollars in stand alone? A pro tune here in the states could cost $350.00 up. A small twin scroll turbo and tune is probably what you would look into but I have no idea of the cost of that, or availability.

 

A twin scroll on a 2.0 hits boost around 2400 rpm, something like that.

 

First question, what is your budget for this? All important question.

 

Heard of Mega Squirt?

Thanks for the quick response!

I just googled MegaSquirt and it seems very promising but unfortunately I dont have that kind of knowledge (yet...!!!)  I will search for a local tuner or subaru mechanic to tell me exactly whats up with my ecu because as far as I know the local dealership made the turbo convertion and they added a piggyback to the stock ecu to handle the extra boost. About the budget I will try to get the best with the current parts and if there is no real difference I ll consider getting new ecu and wider exhaust and maybe a twin scroll turbo (max 2.500 - 3000 euros)

Does anyone know how to reset ts ecu because there are several choices depending on the age of the car (1 unplug car battery  2 connect the green and black plugs under steering column  3 take the ecu battery out and 4 by OBD port)

that's actually the best choice for now, to get a mechanic. Since you don't have enough knowledge yet to do on your own

 

Edited December 20, 201312 yr by berthamcVicker