I don't understand.

Is it just the more hp the more unreliable my 1jz would be or the more psi the more unreliable it would be?

I'm trying to decide on a 60-1 turbo setup for my 1jz, or an hx35 setup (If I go hx35 I would like to know what the max psi I could go with stock bottom end)?

Cant find questions.

Or is psi unrelated to the bottom end, just horsepower?

not really a "max psi" per se, just max that your internals can hold before you need to get forged or stronger forged.

5 psi on a small turbo is much different than 5psi on a big turbo

Depends entirely on the tune. It always does.

we need a turbo discussion thread... There is alot about them that I don't know, and I'd like to.


How so? Is it just the rate at which it spools up?
Does the size of the turbo limit the maximum amount of air it can push?
Do you have to modify the intake manifold from stock to be able to stand up to the pressure?
Is there a way to maintain fuel economy with forced induction?
Simple and vague questions, I know... but without some sort of direction, it is difficult to find information on the subject. I'm all about learning though.

It all has to do with temperature, for the most part. Forgive any errors as im posting via my droid.

Youve probably heard that boost pressure is actually a measurement to the resistance of the engine.

A turbochargers performance is non linear. And depending on the compressor, each turbo has a specific range of volume output. (this is why you hear many people say I have a stage blah blah compressor)

The problem is...only so much air will move through a given tube (intake runners, intercooler piping and the valve ports in the head, both intake and exhaust. Exhaust size and restriction plays a large roll as well.)

So as we increase power by forcing air (limited by the factors listed above) into the motor, it becomes harder and harder to move that same volume of air as as rpms increase. But as i mentioned first, all of this pressure causes added temperature, and hotter air creates less power. So on that principle, if youre using a smaller turbo it will have to work harder (and hotter) than a larger turbo; which since its not working as hard (or as hot) as the smaller, it is easier to compress the cooler air and subsequently you have the POTENTIAL (important) to make more power.

This is one of the reasons why larger turbos are used.

I will probably edit this when im at a desk and see all my wonderful autp correct errors.



(Im just BARELY getting started! )

This post was edited by OldAndyAndTheSea on Apr 23 2013 07:18am

Boost is simple a reference to how much pressure is being built up.

How much power the engine actually makes combined with tons of other variables decide when things will break. Of course there are always random things that can happen to a perfectly fine engine like detonation which can destroy shit.

Do some research on your specific car and I am sure people have experimented and found when things will start to break and what the weak links are.

I wouldn't consider detonation to be something random. Detonation never occurs without a reason. A properly set up system with a correct tune will not detonate period. If youre detonating at all, something is not quite right.

As I said in my first post tune means more than anything else....for the most part.

my car runs 20 psi stock turbo i making 300~ hp people with gt30's or holsets are running 20 psi making over 400+ hp, a smaller turbo can push 20psi but its running out of breath and getting really hot at 20 psi vs a bigger turbo which can make 20 psi without braking a sweat and still being efficient.

I think we need a turbo thread. I'm thinking about going turbo lq4 but I'm almost clueless on a lot of it. I have the general idea and how everything works and is put together . But I still feel lost when talking about it. E85 is more forgiving the 93 octane right ?? For detenoation

There is always a possibility for something to break or malfunction.. that would be a random variable you cannot account for. And of course you can always set something up wrong, etc.



Yes E85 has a octane rating of like 102 or something

This post was edited by Killerme99 on Apr 23 2013 12:01pm