David Floyd

Can someone explain the performance difference in two identical TO4E's except, one with a .50 a/r compressor and the other with a .60 a/r compressor?

Edman951

A smaller A/R will spool fast in simple term. In a smaller A/R housing the volume in the housing is smaller in a .50 A/R then a .60a/r. So just like the A/R in a turbine housing the .50a/r will compress the air faster end great more low end grunt but loss efficiency faster then a .60a/r especially at higher rpm. But the A/R in the compressor housing has less effect on boost response then on the turbine side. I think the trim is the most important. But you can use the A/R to maximize a certain trim .
**This is from my understanding of A/R that i have read and remember, and i might be wrong.**

I will scan some pages of maximum boost tomorrow about A/R on the turbine housing. He does not mention compressor housing A/R in the book.

David Floyd

Thanks Edman951,

I have the Maximum Boost book, but like you say it does not talk about compressor a/r

Edman951

I thought you probably had it
I saw in an other post that you wanted to know if your t04e-60 was a good choose for your set up. Well if you post some info on you setup i can use my turbocalc to see if its good or not.
need this info: - max boost.-low boost -max rpm.
-Any head work(incress in VE)
I`ll be happy to look it for you.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Jeff Lamb

I think you guys are getting a bit confused with how Turbonetics labels their compressors. The "50" and "60" that you are referring to are the TRIM numbers for the compressor WHEELS. They are not the A/R ratios of the compressor HOUSINGS. Basically, you start with either a T04B or T04E compressor housing and then you can install different compressor wheels with different TRIM ratings. The T04E compressor housing is listed as being able to use 40,46, 50, 54, 57 and 60 trim compressor wheels.

As the TRIM number gets bigger, generally the inducer size of the compressor wheel gets bigger. Some examples: a 46 trim compressor wheels has a 1.87 inch inducer diameter and 2.95 inch major size diameter, whereas, a 60 trim wheel has a 2.29 inch inducer and the same major size.

It is interesting to note that all of the different trims used in the T04E use the same MAJOR size for the wheels except for the 50 trim wheel. The MAJOR size for the 50 trim wheel is 3.00 inches as opposed to the 2.95 inches used by the five other T04E trims.

Jeff

Russ Murphy

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva"> The "50" and "60" that you are referring to are the TRIM numbers for the compressor WHEELS. They are not the A/R ratios of the compressor HOUSINGS. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Pardon my ignorance, but what the hell is the ".60 A/R " cast into my T04E compressor housing?

Edman951

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva"> I think you guys are getting a bit confused with how Turbonetics labels their compressors. The "50" and "60" that you are referring to are the TRIM numbers for the compressor WHEELS. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">I think you should read the complet post again.
We all know what trim means and what a/r means.
We where talking about the difference in a T04E w/.50A/R and a T04E w/.60A/R.
NOT THE TRIM&gt;..
Look at the 2 pictures in the first page. You will notice 1 has .60a/r and the other has .50a/r.

<img border="0" alt="[byebye]" title="" src="graemlins/wave.gif" />

jimbo1111

Pardon my ignorance, but what the hell is the ".60 A/R " cast into my T04E compressor housing?

Even though your turbo opening starts at 2.75" it tapers down to the size of the induser measurment witch in you case is 2.29". but the taper is a little larger the the induser measurment about 2.37". 2.37" = .00060198 radian. thats why your turbo is stamped 60 area/radian

Jeff Lamb

Jimbo1111 has pointed out that if you are using a T04E compressor housing with different trim wheels that turbonetics is matching the inside diameter of the intake flange on the housing to properly mate up to the inducer diameter of the wheel. Makes sense.

This is interesting because NOWHERE in the turbonetics catalog does it refer to A/R when describing their compressor (cold side) housings. They clearly only describe their compressor housings as being in different TRIM families. They only refer to A/R when describing their turbine (hot side) housings. Hmmmm . . . A bit confusing I must say.

So, what do we do with the T04B housings where their TRIMs are listed as S, SUPER S, T5/6, V, SUPER-V, H, SUPER H??? I guess we would have to manually calculate the A/R??

Moral of the story -&gt; I hoping to clear up some confusion between TRIM and A/R since they were seemingly being used interchangably and perhaps incorrectly.

Jeff

rage2

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Jeff Lamb:
<strong>Jimbo1111 has pointed out that if you are using a T04E compressor housing with different trim wheels that turbonetics is matching the inside diameter of the intake flange on the housing to properly mate up to the inducer diameter of the wheel. Makes sense.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">That's what I thought too, until someone pointed me to here :

<a href="http://store.yahoo.com/cheapturbo/gart3to450tr.html" target="_blank">http://store.yahoo.com/cheapturbo/gart3to450tr.html</a>
<a href="http://store.yahoo.com/cheapturbo/gart3to457tr1.html" target="_blank">http://store.yahoo.com/cheapturbo/gart3to457tr1.html</a>
<a href="http://store.yahoo.com/cheapturbo/gart3to460tr.html" target="_blank">http://store.yahoo.com/cheapturbo/gart3to460tr.html</a>

Notice that the detailed specs for the turbos, all 3 trims (50,57,60) all use 0.60 A/R compressor housings. I think the reason why the compressor A/R is never mentioned is because it's ASSUMED that if you have a T04E with a 50,57 or 60 trim wheel, that the A/R is 0.60... I think anyways .

Someone also mentioned that all T04E's compressor housings have .60 A/R, and 0.50 A/R housings are called T04B (or something). Can anyone comment on that?

Edman951

This is what A/R means. ( In this case turbine but is the same for the compressor.)

A/R =The Area / Radius ratio
A = Area of throat at intake
R = radius of scroll in the housing of either the compressor or exhaust turbine

TRIM -turbine wheel trim can effect an increase or decrease in turbine pressure for a given housing A/R

<img src="http://wwwrsphysse.anu.edu.au/~amh110/all_gifs/Turbo%20page%20gifs/trim%20ratio" alt=" - " /> This diagram of an exhaust housing conveys the general idea.

David Floyd

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva"> it's ASSUMED that if you have a T04E with a 50,57 or 60 trim wheel, that the A/R is 0.60... I think anyways .

Someone also mentioned that all T04E's compressor housings have .60 A/R, and 0.50 A/R housings are called T04B (or something). Can anyone comment on that?
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Well... my TO4E is a 60trim with .50 A/R, this turbo replaced a T04B which is quite a bit smaller, no A/R markings on that turbo.

David Floyd

Pic is TO4E 60trim .50 a/r
TO4B 50trim
stock K26



Well, I tried to post a pic ????

Jeff Lamb

Okay, now I am getting even more confused. Edman951's reply contained some very good information about calculating A/R ratio for a scroll type housing (both the hot side and cold side use the scroll shape), however, I don't see how the size of the compressor inlet (or turbine exit) affects the A/R ratio?? The A is the area of the biggest circumference of the scroll (aka compressor EXIT OR turbine INLET) and the R is the distance from the center of the housing to the center of the scroll where the A is being measured. Nowhere does the size of the other hole (aka compressor INLET or turbine EXIT) figure into the equation.

I can see how Turbonetics could easily vary the size of the inlet on the compressor housing, however, I don't see how they could vary the size of the exit scroll of the housing. To really change the size of the scroll, they would have to use a different casting for every different A/R ratio (to change the R) OR do some sort of boring out the scroll part of the housing (to change the A)??

In other words, it is beginning to look to me like the T04E is one size scroll with a given A/R ratio that really can't be changed. As different wheels with different inducer measurements (aka "trims") are installed in the housing, they probably machine the compressor inlet to match the inducer size of the wheel. However, this process of installing different wheels and matching the compressor inlet has NOTHING to do with the A/R of the housing itself. Am I on track here??

Jeff

David Floyd

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">I saw in an other post that you wanted to know if your t04e-60 was a good choose for your set up. Well if you post some info on you setup i can use my turbocalc to see if its good or not.
need this info: - max boost.-low boost -max rpm.
-Any head work(incress in VE)
I`ll be happy to look it for you </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Edman,

You have a PM with my specs

Thanks