Ok i know this gets asked alot and there is no straight forward answer. Or at least that's what i found when using the search function. What is the maximum boost one can run on a completely STOCK motor. When i say stock, i mean all the way from the air filter to the exhaust tips. The only non stock part is the K&N air filter and Saab BOV; even the brake pads, oil, and oil filter are toyota parts.
Maximum boost?
- Thread starter bentandbroken
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You probably didn't get a straight answer because you're talking about doing things out of order. If your car is bone stock, I wouldn't bother turning up the boost at all. Do exhaust first.
But if you must know, you can turn it up around 12-13(or just under fuel cub) but I wouldn't advise doing so on a bone stock car.
But if you must know, you can turn it up around 12-13(or just under fuel cub) but I wouldn't advise doing so on a bone stock car.
I know what the worst is that could happen. But why not turn the boost up? I'm not trying to be an idiot(read:ass), I just don't know.
some cars are different for fuel cut.. depending on basic mods. My car hits fuel cut at 11psi, my friends hits cut at 13.. etc etc.
if i were you i'd shoot for 7 or 8 psi.
if i were you i'd shoot for 7 or 8 psi.
You can accelerate the MHG symptom the 7M's are prone to. Since you've said your stock, a good thing to do right now is to retorque your head bolts per tsrm patterns to the newer rate torque amount (not sure exacly what it is, but around 70-76 ft/lbs area) to prevent the BHG. A BHG = a down supra, and not done correctly when fixing a BHG = rod knock.
Start by freeing up your exhaust restrictions, the most bang for your buck is there.
Start by freeing up your exhaust restrictions, the most bang for your buck is there.
the new toyota head gasket has less than 30k miles on it and the studs are torqed to ~85lbs. I think what i'll do is install it on a low setting just to improve boost response. I just wanted to know what i could turn the boost up to.
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~12 psi with stock fuel and and AFM, but you're not going to see much of a difference at all until you get that stock turbo elbow/down pipe off there and replaced with a full flowing 3" piece.
Backpressure is the reason why exhaust and intake mods are done first. To create boost, the turbo has to overcome whatever backpressure is in the system first, hot or cold side. Making 10lb boost on stock equipment is not the same as 10lb on a low backpressure system, the turbo will actually have to do substantially more work. Going up from stock pressure without addressing this issue quickly puts you out of the CT26s efficiency range, and gives you hot (read:detonation prone) air out of the turbo.
Oh, and raising boost won't help the response...
Oh, and raising boost won't help the response...
It'll raise on it's own once you put a full turbo back exhaust on it and larger hardpipes and a better IC 
. I have all of that and just running off of my wastegate I'm pegging the stock boost gauge.
. I have all of that and just running off of my wastegate I'm pegging the stock boost gauge.