so confused on AR, trim, etc...

[Loochy88]

it seems to me that the AR ratios on one turbo are different on a model to model basis, or am i wrong?

1.) is a t3/t4 turbo with a .60 compressor and .83 exhaust about the same as a t4 turbo with the same AR ratings

2.) on a t3/t4 turbo, which side is wich, is the t3 the compressor or the exhaust?

3.) what the heck is trim? i see a lot of P trim, some O trim. does trim differ from one turbo model to another, or is it a universal measurement

4.) finally, what is the best way to go about finding the right turbo. i hear people say there are a lot of calculations you need to figure out, but what the heck are those calculations. im looking for a turbo that will give me boost in the mid to high rpm range. im not looking for huge boost numbers... something in the 5 psi range should give you the idea.

any help is appreciated. thanks.

and while im at it, what do you guys think of this one: http://cgi.ebay.com/ebaymotors/ws/eB...MakeTrack=true

or this one: http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWA%3AIT compressor trim on this is .60, i emailed him. exhaust is .69

[ September 29, 2005, 12:39 AM: Message edited by: Loochy88 ]

[asdf1234]

I doubt any of the active posters in this forum will be able to answer all of that. I know I can't. As you can tell by posts like this:

http://www.camarov6.com/ubb/ultimate...c;f=4;t=002438

We don't exactly have the most respectable turbo crowd.

However if Tuefel or GN were to drop by, or nocutt maybe, you might get a nice answer, which should probably join our massive list of stickies that nobody reads.

[T-Punk]

1.) is a t3/t4 turbo with a .60 compressor and .83 exhaust about the same as a t4 turbo with the same AR ratings

No, because the turbine section on the hybrid is that of a t3 it will have pretty different characteristics.

2.) on a t3/t4 turbo, which side is wich, is the t3 the compressor or the exhaust?

The t3 on the hybrid is the turbine and the t4 is the compressor.

3.) what the heck is trim? i see a lot of P trim, some O trim. does trim differ from one turbo model to another, or is it a universal measurement

first you need to know what the inducer and exducer are on the compressor wheel. If you take a look at the compressor wheel you will notice it looks somewhat like a trunkated cone. The smaller circle on the top of the cone is the inducer, the larger circle at the base is the exducer. The trim is equal to the (inducer/exducer)^2*100. some companies like to use letters to express this information instead of an acutual number making it all that much more confusing. hopefully i made that make some sort of sense to you.

4.) finally, what is the best way to go about finding the right turbo. i hear people say there are a lot of calculations you need to figure out, but what the heck are those calculations. im looking for a turbo that will give me boost in the mid to high rpm range. im not looking for huge boost numbers... something in the 5 psi range should give you the idea.

Well, that is the hardest question to answer, even if i give a suggestion there could be another turbo that would better suit your application. The best suggestion i can give you is to look at what other people have used and see what they say about spool, power, and times and try to sift through it all to find the one you think fits your application. That said, i feel a properly sized T4 (like Tuefel has) is a better choice than a hybrid.

[Loochy88]

thank you sir!

now for another question: what is the difference between the t04e and a t4? im very seriously considering a garret t04e with a .60 compressor ar and a .84 exhaust (O trim exhaust wheel... just like you said, no number so it makes it complicated) the compressor trim is 57. if anyone could throw out an opinion on this one i would appreciate it.

[RedFrk13]

Read these two links, they have lots of good info. [img]smile.gif[/img]

http://www.turbominivan.com/tech/turbo101.htm

http://www.turbominivan.com/tech/turbo201.htm

From what I see, most companies rate the compressor trim solely by the inducer size. Example, the T70 has a 70mm inducer and like a 90mm enducer, but they considered its trim as 70.

[T-Punk]

Yup, very good resources. In fact i have those bookmarked and I think that is where i went and learned about trims a few years back. There are a few of us left that still know a thing or two about turbo's but we are missing the gurus like GN, Tuefel, and Tiago. I still have a lot to learn before i will have the knowlege any one of those guys have.

Oh and i forgot to answer your question, the To4e and To4b are different housings you can choose from.

[ September 29, 2005, 09:20 PM: Message edited by: T-Punk ]

[asdf1234]

Very useful information, we need to make a sticky containing this information.