STI Conversion for Baja

General talk about the Subaru Baja.

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Bugjelly
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STI Conversion for Baja

Post by Bugjelly »

Hello,

I have a 2005 Subaru Baja Turbo DOHC , automatic Transmission...
Unfortunately, I have had a failure on a head gasket.. Since I have to pull the engine to repair my Baja, I may as well do some upgrades. My goal is to get about 300 to 350 WHP. I have been looking all over to see what it would take to do a STI conversion. This would include upgrading my Turbo to something that is more reliable than the stock turbo..
Is there someone out here that can get me pointed in the right direction to get a list of parts required for this type of conversion?
Do I need to modify my transmission?
ECU?
Brakes?

Thanks for any help,
bobjr94
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Re: STI Conversion for Baja

Post by bobjr94 »

That is alot of power and not an easy or cheap swap. The automatics will take an increase in power but to make 350whp your putting out 400hp+, or about double the 210hp it has now and even 100hp more than an STI. The auto trans won't take it that much and it will pretty much mean changing everything on the motor plus you will need a 6 speed sti trans, maybe a 5 speed if you don't launch or drop the clutch.

Upgrading the turbo won't be more reliable than the stock one, they last 100,000 miles or more already, to make 350-400HP at the motor you will need a good size turbo, starting around $1500-$2000 but the trade off is lots of lag and not great to drive everyday. You don't need a new ecu, but it's easier if you use one from an STI, since tuners are knowledgeable with accessports, keep your old ECU and you will have to find someone good with opensource tuning.

In short, big turbo, downpipe & exhaust, up-pipe, big TMIC, TVG deletes, 800-1000+ cc injectors, fuel pump, manual transmission swap with stage 2-3 clutch, head port & polish, sti ecu & accessport & pro tune or old ecu & opensource protune. Probably get a new build shortblock if you want it to last, putting 350-400hp on an old motor with like 130,000 might not end well.

Your best bet, catless uppipe, downpipe, wrx or sti intercooler and a tune, it will get you from 210 to about 240-250hp.
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