I am running a stock 13b-re with stock twins, water injection and a microtech efi. I have been trying to boost to 14psi with the AEM water injection spraying before the throttle butterfly 50/50 denatured alcohol and water mix. My question is, will the stock twins handle 14psi or should I back down to say 12psi? Is there a major hp change between 14 and 12?

It is daily driven and I want somewhere between 250 and 350 horse reliably.

Thanks!

 

twins can handle it.
the stock solenoids start to crap themselves around 15 psi though...

 

also, is your ful setup matched for 14 psi? what about ECU? Stock ecu doesnt like this boostlevel.

 

I understand that the stock twins will be producing quite alot more heat at those levels but the Aux. Injection should help. Seems like you'd be close to your hp goals at 12 psi though, and the harder they work the shorter their life-span.
You might want to do some searching/reading in the Auxillary Injection section and I'm pretty sure you want to be careful NOT to go any higher than 50/50 as the mix w/o fire supression.

 

What year and how many miles are in it? I think the older and more miles you have, the less your should be pushing the limits, something to consider

 

Bearing in mind they were designed for pushing 10 psi, 14 is going to be the sensible limit on *new* turbos with AI.

With my new Efinis I was running 14 psi, then decided to experiment for a while at 17.5 psi. The extra 3.5 pounds probably gave me an additional 5% extra torque, enough for me to notice a power increase, but I knew I was overdriving them, and there's a mechanical and aerodynamic limit to how much these little guys can flow.

Again this was with *new* Efinis that I bought and personally installed in 2007. Nevertheless, they're still poorly-designed bushing Hitachis circa 1991. If you're running older turbos, I'd suggest keeping it at 12 psi with the AI. It's doubtful you're likely to squeeze much more out of your twins trying to push anything above that.

 

I ran 14psi on my stock twins with an aftermarket ecu, the standard injectors start to max out at 14psi as well.

 

stay at 12lbs. For the little extra, its not worth the potential problems.