12psi on a t3/to4e -> 1.6 style. Add ~20-30hp for a 1.8.
http://lh3.ggpht.com/_tMYIeupe-9Q/S8...jeff_c_235.jpg

12psi isn't always created equal :). On that turbo 12psi is plenty enough to bend the piss out of the rods if your tune isn't spot on.

thanks for the input guys and sorry about sucking. guess I should have stated it wouldn't be tuned on a dyno and that's why I was going by psi...in my mind I made sense. How many psi will get me to a hp level that will break things and then stay under that.

I will be staying at 10psi until this winter when I can build the engine and get a 6 speed and I am going to work on finding how many lbs/min I will be putting into the cylinders.

The gt2560 is barely capable of moving 30lb/min of air at a PR of 2.0 but the T04E compressor in a 57 trim (which the ebay t3/t4 claims to have, but doesn't) is capable of moving over 40lb/min of air at a PR of 2.0. This, by my off the cuff calculation, is greater than one third more air at the same PR.

If I had to stress but one point to you it would be that psi of boost is not, and has never been, the measure of how much air is being forced into your engine. Boost pressure in the intake manifold is the measure of resistance or backpressure in your engine. It is not how much air is getting in, but how much restriction there is to letting it in. It is a measure of how much your engine is fighting not to let air in, or more succinctly its inefficiency at a certain lb/min of flow rate. Am I explaining this well?

Some light reading for some basics:
http://www.rx7club.com/printthread.php?t=345518

http://www.moddedmustangs.com/forums...ze-r-trim.html

Fun with compressor maps:
http://www.squirrelpf.com/turbocalc/index.php

But you are going to need to search outside our forum and dig a little on your own to grasp the big picture of how all of this works together to keep your stock motor functional. Or not. Trial and error can be a cruel playmate.

So.... (wait for it)






how many psi can I run? :makeout:

lol, thanks guys.

I'd say, for anyone tuning on the street, for their 1st time, on a stock internals car, etc etc etc. I'd stay in the 8psi range and start off with conservative timing and bump it up after numerous logs on a bigger turbo, and about 10psi on a smaller turbo.

I went 12psi on my gt28 equivelant in the past, my engine lasted a few months. I don't think boost pressure alone killed it, but it is what it is.

Urgh

Do you have a wideband at least?

You can run both of them most of the time, just not all of the time, as long as it isn't the wrong time, or your time will be up. That's as clear as I wish to be.

I ran between 5psi and 16psi on the 1.6, depending on how soon I wanted to yank the engine. It even hit 21+ pounds when the wastegate vacuum hose broke. Ran fine the day I pulled the engine, and is probably running great in the new owners car.

Yes dear, my first post says I am using an lc1