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Highest PSi

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2 psi. j/k
How high do you want to go? Remember you'll need more fuel with more air. If you use stock injectors, I wouldn't go above 15-16.

With larger injectors, pump, turbo (of course), fpr, proper logging/controlling methods (wideband 02, logger, afc/ecu mods), proper fuel/knock suppressant (high octane/race gas/methanol/water), then you can get much higher without really causing too many problems.
 
You could have found this in the Tech Articles by one of our Wiseman, kpt4321

"Engine Limits - Psi, CFM, or horsepower?

A lot of people like to define an engine's limitations in terms of the maximum boost pressure it can sustain, but that's really not the right way to do it.

What happens in most of the cases when these limits are exceeded, is you either blow up bottom end stuff (ringlangs, for example) or you lift the head and/or blow up the head gasket. All of these problems are directly caused by too much pressure during combustion. However, maximum cylinder pressure is NOT determined solely by boost pressure, so we shouldn't use boost pressure to define the limits of a motor.

Another popular way to define the limits of a motor, are with a horsepower limit. While this is closer to being related to the true cause of motor problem, cylinder pressure, it still is not perfect. Horsepower is the net result of cylinder pressure over time, meaning that 300 horsepower at 5000 rpm is NOT the same peak cylinder pressure as 300 horsepower at 9000 rpm. Because of this, you can increase power by increasing top-end breathing capacity, without getting any closer to the limitations of the bottom end.

Cylinder pressure is actually most directly related to torque, because torque comes from the push on the top of the piston. In terms of what we can measure, torque is the most representative of cylinder pressure. Also, rpm is not an influence in the relation between torque and cylinder pressure. In general, if torque goes up, cylinder pressure goes up. (Interesting tidbit: thus, cylinder pressure, motor stress and load, and knock propensity are highest at the torque peak, which is also the VE peak).

In the end, I think that defining a motor's limits in general terms of horsepower, or maximum MASS flow, is the way to go. Torque is a better measurement, but nobody ever has payed much attention to it so switching over would be difficult.

Also, everyone knows that tuning plays a big part in all of this, because the quality of the tune plays a VERY big role in determining not only the maximum cylinder pressure, and also how it happens. Very sharp spikes in pressure can be more harmful to the motor than a nice smooth curve up to the same pressure. Also, knock/detonation is one of the primary killers of motors, because it causes excessive cylinder pressure oscillations.
"

http://www.dsmtuners.com/forums/showthread.php?t=96677
 
It's not about the highest boost. Its about the amount of air you are flowing. 20PSI on a 18G is a whole heck of a lot different then 20PSI on a 14b or a T25 (partly because the T25 can't hold that kind of boost).

But if you have all the things you need to go for a high boost setup (as the others have mentioned above me), then I know of someone who ran a pure stock bottom end with a GT2871R to around 25PSI. But before you go and take this information and go blow up your engine, you need to make sure your engine is in tip top shape to handle this kind of power. Or else things will go bad...and they will go bad fast.
 
Yah with my big 16g i don't boost past 12 psi, and at 12 psi my exhaust temps are getting pretty close to 1400 deg. f so i don't suggest anything over that w/o fuel upgrades. With a re-wire you can push to 15 but after that start thinking about some seriouse fuel and tuning.
 
well right now i have a ported and polished turbo mani, t3 turbo(68 trimm)
so just with the turbo upgrade i should keep it between 13-15?

Judging by this, it seems that this is all you have. So I have to ask, why would your first mod be a turbo upgrade? With no engine/fuel mods/ECU monitoring mods, I would not even make a 1 psi increase. If you haven't installed these parts, I honestly wouldn't do so yet.

In short, DGajre777 led you in the right direction. :thumb:
 
http://www.dsmtuners.com/forums/showthread.php?t=269031

No one can say XXXPSI is safe on a motor because no one knows, with that being said look at the link and notice that he is running 28PSI on a stock 7-bolt. I wouldn't be concerned about how much boost you can run but more about how safe is your tune. If your knocking like crazy 15PSI can blow a motor. If you have a nice safe tune with all supporting mods you can run as much boost as you want, granted after you make too much power eventually you will need to upgrade parts in the motor.
 
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