just out of curiosity what a/r are you people running on the compressor housing? i have a to4e with a .70 turbine housing and a .50 compressor housing and was just wondering what everyone else runs around here. i found the link that subs1000w put up and found it very interesting http://www.racetep.com/turbomatrix.pdf
but im not as worried about peak horsepower as i am the characteristics of the turbo itself. any input would be appreciated. i should be able to start installing all the parts sitting in my garage in about a 1 1/2 months and i cant wait.

 

i think 50 on compressor side is a little too small, i think the norm around here compressor side is .63

 

Yeah a .50 is kindof small. Try it and if it doesnt work you can buy a new compressor housing for like $100. I've got a .70

 

so do you think that its gonna choke out in the upper rpms, what about the exhaust side do you think that is a good size?

 

really? I heard a .5 / .7 is a good size. Thats what Ive got coming in the mail. I hope Ill be boosting quicker with the smaller turbo.

 

Yes I think it will start to choke a bit up top. That's what too small A/Rs do.

 

what about the a/r on the exhaust side too big or alright size? i thought that the pfi kit was using a .8? somwhere around there is that correct?

 

whats the compressor trim

 

.70 is not bad on the turbine side. Some have bigger, a few have smaller. .70 is what I30tMikeD has.

 

the compressor is a .50 a/r it is a "O" trim

 

"o" trim is the turbine trim

to find out the compressor trim remove the compresor cover "silver snail looking thing"

then measure the inducer "small" and major "big" diameters of the wheel "round thing with a bunch of fins"

then go here http://64.225.76.178/catalog/comp_wheels.html and compare measurments to find what trim you have

(the trim is more important than the A/R)

 

the measurements arent on that site to compare to, but the measurements are 2.23" and 3.31"

 

here is a link to the exact same turbo that i ordered http://cgi.ebay.com/ebaymotors/ws/eB...tem=7985267029. i still need to find out the trim of the compressor wheel before i can really plot the points on a compressor map. i managed to find some threads that subs1000w and nealoc187 posted in november about plotting on compressor maps. very informative, probably the most useul info i have found yet. but i still cant seem to figure out how to calculate the trim (if there is a way) or where to find a chart with the same numbers as the measurements i have taken to compare it to.

 

in hindsight i wish i would have looked into it a little more before just jumping into this headfirst and possibly getting a horribly sized turbo. now that i have a little more education on turbos i cant seem to get enough of it, i just want to keep learning.

 

You shouldn't use that at all.

http://forums.coloradoracing.net/ind...howtopic=89168

I looked into one of those but appearently they have very shotty quality, which is why they are so cheap. Look around you can get a quality turbo, for a little bit more on ebay.

 

wow........that is all i can say......im amazed. now im really scared to put that thing on my car. is it only the compressor housings that are crapping out on the turbos or what?

 

Compressor specs:

TO4E .60 a/r

your choice of 50, 57 or 60 trim compressor wheel

Turbine specs:

T4

.58 a/r, .70 a/r, .84 a/r, .96 a/r, 1.00 a/r, 1.15 a/r available

P-trim turbine wheel standard


This is the turbo I have in my car. I choose the .70a/r just like I30tMikeD and it is a P-trim. Here is the website to good priced turbos:


www.phoenixturbo.com

 

thanks for the info and the link just to prove myself wrong again though i found the formula to figure out trim on the compressor wheel it is [(inducer x inducer)/(exducer x exducer)] x 100 = trim which would mean that the trim of the compressor wheel in my turbo is 45. not the 50 trim that they said it was anyways. now im just frustrated i think im just gonna have to put the kit together using this turbo while im waiting for another one to get shipped in the mail. oh well i would rather get it done right than to try to shave here and there and end up screwing myself in the end anyways. according to where i plotted my points on the compressor map for the 46 trim the turbo would be at maximum efficiency at like 3250 rpms at 10 psi boost anyways, by the time i get all the way to redline i think that it is somewhere around like 60 percent. if i did my math correctly at 10 psi boost i should be somewhere in the range of 520 cfm at redline and around 260cfm at 3250rpm for the flow using 1.68 as the pressure ratio. i think that i finally got the hang of compressor maps although i know there is always more to learn, especially as long as there are people in this forum willing to share their experiences.

 

(Inducer squared)/(exducer squared) x 100 = the trim. So according to the measurements they give it's a 45 trim, as opposed to what it says 50 trim.

You can try the turbo, they definately aren't very good turbos, but it might be ok. The chances of it doing something to hurt your car (besides the turbo itself) are pretty low. Just be aware it will probably go bad sooner rather than later, and be saving for another one.

 

Oh I just noticed you already figured out how to calculate the trim

You can get Turbocalculator, it is a program that enables you to plot points on maps very quickly and switch from one map to another to another to see whats best for what you want to run.

The problem with compressor maps is, you don't really know if what you are plotting is possible. What I mean is, technically you can say "ok I want to make 20psi at 2000rpm on a T88" and you can plot that on a T88 turbo (surge city lol) but in reality you would never be able to spool a T88 so soon as to make 20psi at 2000rpm. So you have to make sure your goals are realistic or else you might think you are going to be at XX efficiency but really you might only be able to attain YY efficiency.

 

Also the other thing that should tip you off about that turbo is the terms they use. They don't even know how to express certain things. They say .50 trim instead of 50 trim (not to mention the fact that they are lying and its a 45 trim if the dimensions they give are correct). They say "Mayor" instead of "major" (or exducer which is really the term they should have used). Wet floating ball bearing... heh, cheapest ball bearing turbo I've ever seen by a long shot. The flange... it's divided like a T4 divided flange is, but the bolt spacing shows it's T3, which is weird. Etc.

 

yeah i regret having bought it now

 

ill just sell to some unsuspecting ricer and tell him that it is a new quick spooling titanium roller bearing turb..........muah ha ha ha

 

i really think that im just going to have to use this turbo for a little while, although i really dont want to since im running an almost definite risk of failure. there are a few things that i would like to consider after looking at that picture though as to why the compressor housing blew up like that. 1) very high boost 2)intake backfire or finally a stuck wastegate these are not excuses for crappy build just ideas as to why that compressor housing failed like that.

 

is there such thing as a turbine map? i would like to learn how to use one if at all possible that way i could combo the turbine and compressor housings that i wanted to get the characteristics that i want. does anyone have a link to show the turbine trims? what trim and a/r turbine are most of you using? royal t said that the p trim is standard, my current turbine is an "o" trim .70 a/r. ive got to get this down before i even attempt to buy another turbo!

 

geez i feel like ive been posting for myself for the last few, but it is a forum so i figure that the information is useful. so this is the way that i understand it, the trim of the compressor wheel and the turbine wheel are actually what determine for the most part the spool characteristics of the turbo where as the a/r is basically there to determine air flow itself, ie a 57 trim compressor wheel with a .60 a/r will flow less air than a .70 a/r (duh) but the .70 a/r will still have approximately the same response as a .60 a/r within reason. only thing to worry about is the fact that you add weight when you enlarge both the inducer and the major?

 

Yes there are turbine maps, turbines are just compressors backwards basically, but your choices are much more limited with turbines than compressors. I've seen a couple turbine maps before but given a certain type of turbo you usually don't have much of a choice. You choose the compressor you want, and in most cases that compressor is mated to only 1 turbine option, and that's it. Sometimes you can choose but not often.

A/R and trim are intertwined. But for the most part I'd say that trim determines how efficiently X amount of air flows through the turbo, and A/R determines the rate at which it spools, and the maximum amount of air that can be flowed through it.

Citing your above example, the 57trim with the .70 vs .60 A/R, the compressor A/R won't really affect your boost response, it's the turbine A/R which does that (as far as the turbo goes, there are other things which can have a drastic effect on your boost response, exhaust piping being the main one besides the A/R). The compressor size will mostly affect the maximum amount of air that the turbo can flow (A 57 trim with a .60 A/R will have a lower peak horsepower potential than a 57 trim with a .70 A/R).

In the FAQs, one of the two compressor map pages I posted has a couple turbine maps for the GT series turbos if I recall correctly.

 

Oh and for turbine trims, I don't have much knowledge on O trims but the largest turbo I found with an O trim seems to max out at about 500whp worth of air, P trims dominate between 500whp and 700whp, and above 700whp most are Q trims, or trims specific to that turbo, such as a turbine wheel which is just referred to as a T88 for example, or a numerical trim (84 is a common one, but you can have different SIZE 84 trims, further complicating matters lol. The 84 trim turbine wheel on a GT42 is MUCH larger than the 84 trim on a GT40 for example)

 

wow, very informative i must admit. ive gotta start looking into this turbo stuff more so i can start to work up my own kit design. for financial purposes im thinking about buying the emanage first, getting it in and learning how to work it at my liesure, then getting together some of the turbo parts and eventually putting them in without an ic on really low boost like 4 psi for a while, then getting the ic and piping all that up to it and then ittle be done. and wow that was one long run on....ohh well. anyway, great thread. keep it up.

 

thanks to Nealoc187 i think that the light bulb is finally coming on inside my head......also thanks to subs1000w for his input.

 

between the t4/t04e with a 60 trim and .70a/r and the t3/t04e 60 trim with a .82 a/r. what is the difference in performance if any? I'm assuming that the t4/t04e would see quicker spool due to smaller a/r, am I right? also would I see lower hp output going with the t3/t04e rather than the t4/t04e?

 

i would go with the straight T4

 

wat specs for a t4?

 

also compressors with big a/r affect the efficiency negatively with low boost level and vice versa small a/r affect high boost efficiency negatively