Would This Be A Safe Tune?

[swanny180]

I have a theory that boost pressure is probably relative to turbocharger life in an exponential relationship.

Obviously this belief would allow for some turbos surviving on 12psi, some not, some surviving on 14psi+ and some not.

Basically, your turbo will last for X amount of time running 7/8 psi (ie stock boost). X is unknown obviously, but we can safely assume that X probably represents quite a long time, maybe 10 years?

At say 10 psi, you might find your turbo will now only last for X/2. But if your turbo is going to last for 10 years at 7/8 psi, its still going to last for another 5 at 10psi. So still a long time.

At 12psi, you might then find that turbo life has shortened to X/4, in other words, 2.5 years. Starting to shorten now.

Bump boost up to 14psi and you may find turbo life reduces further to X/8, or just over a year before failure.

16psi, a bit over 6 months... you get the picture.

If this theory of mine is correct, it obviously allows for other factors influencing the unknown X value. Newer car (and therefore newer turbo), better maintained, better condition turbos might have an initial X value far higher than a car that has been neglected, has already been run at a higher boost, is older, etc etc.

The problem is with imports, you never really can expect to know the *exact* and entire history of the car, and even still you are only making an educated guess as to the turbos lifespan.

I personally run mine at 10psi. I do not believe that this will severly limit the lifespan of the turbo.

12psi would be reasonably safe too in my opinion. There becomes a real risk of failure, but in most cases an acceptable one.

If your turbocharger *is* in good condition, I dont think there would be any reason for premature failure, as the turbo is still operating efficiently (and so temperatures are under control)

At 14psi, things become more iffy. Basically it becomes much more luck oriented. I know of people personally who have run 14psi on an RB25 with no problem. I also have read of plenty who have had failure at this level.

To run 14psi you need to be willing and able to replace your turbo as there is a significant level of risk of failure at this stage, due to higher shaft speed and increased temperatures.

Anything above 14psi in my opinion is pretty stupid. You would not do this without being very much ready to replace your turbo, in which case you might as well just go ahead with replacing it and sell the stock one to recover some cost?

A few hundered $$ off the cost of the replacement is stupid to throw away for nothing more than running above 14psi simply for the sake of it?

Obviously this all may or may not be correct, its just an educated estimation of how things could likely work that Ive come to by observation.

Biggest problem is that its still a bit of a dark art once boost pressures are raised.

We know 100% is that there is NO magic number.

We know 100% that turbo life is reduced at some level as boost pressures rise

Its then just a case of making an informed decision and trying out a number for yourself and hoping its not one that is too high for your turbo to handle

[Fletch]

phhhh

all wrong!

i'm gettin 320rwkw at 22psi outa my stock turbo.

musta got a "good one" hey?

[jase-r34]

lol

[simpletool]

High exhaust temp also hurts turbos. So leaner a/F ratios or excessively retarded ignition would cause turbo failure, more so at high boost.

There's more than one way to kill yourself and more than one way to kill a turbo. Combinations just increase the risk.

Running 14psi and a lean A/F ratio is like being a basejumper who loves to carry knives in his parachute bag. Sure someone always knows somebody who has done it since he was a kid, but we are all waiting to see the "freak accident" on Today Tonight.

[cankas]

well i just put in a ebc and my low boost is on 6 and high on 14 on a stock turbo r34gtt its been like that for 5 months now and no problems (YET)

Why would u put low setting at 6psi when its standard at 7psi?

Depends on tune and most times alot of luck. Ran my std 34gtt turbo at 12 for a yr then got bored and uped it to 14.7 and that lasted a yr b4 it went bang but i was prepared to buy a new one. Somewhere round the 12 mark seems about right b4 putting more stress on the shaft.