GR40RCapri

i'm looking at a turbo for my Cummins, and the guy knows little about
the turbo... how/where do i measure the wheels, exhaust housing etc,
to find out what size they are...

i have measurements as the turbo sits ready to bolt on (not
disassembled...)

are the wheels measured from what is seen in the housings from the
exterior of the turbo? how do i measure the exh housing size?

thanks guys!!

RowJ

Any brand name/serial # on the turbo?

Holset measures turbine housings in cm2. All others at dia in mm.
I have measured some turbos I've used in the past. If you want to PM me what you have I'll try and help... by comparing.

# of blades on both sides and diameter of each might help? Compare those to yours.
Tough to help much without more info. How about some pics? I would possible drive his to see how it spools and what boost it makes.

Best would involve some work. Make sale contingent on trying it on your truck!

Sorry... not much help.

RJ

signature600

See if you can find us some names/markings on the charger, then I'll bet we can help a little more!!

Chris

GR40RCapri

i know it's a schwitzer (sp?)

s-300 ...but i'm wondering if it's stock or upgraded...

calling HTT didn't get me too far, although i'm planning on sending it there perhaps for a freshening..

intake side:

7 blades
3 1/2" ID
62mm where the opening to the wheel is

exhaust side:
11 blades
3 1/2" ID
65mm where the opening to the wheel is (approx...might be closer to 64)

i know a 58mm wheel is stock...but i don't know where the measure it from..

thanks again!

JAY

signature600

There are stock 62mm versions...I have one on my 95

That sounds like what you need to me. What A/R is the exhaust housing?

Chris

GR40RCapri

Chris,

HTT told me 58's are stock... are there 62mm versions also?

what's the difference between this and a htb2-62?

where would i find the A/R size? on the exhaust housing somewhere?

i would like to run a set of 435 injectors or something..

J

linetrash75

What does the A/R ratio stand for? I noticed the Garret turbo on work truck 250hp DT466 is .58?. What would something like that do on a mildly bombed 5.9? Thanks and sorry about the hi-jacked thread.


Jed

signature600

That Garret from a DT466 is probably about the same as on 7.3L Powerstroke...good for flow, bad for high boost like our Cummins need! Max of 35psi on a Garrett like that! Also, that sounds like the Intake Side A/R!

Now, to find the A/R on the Schwitzer...look in the ports where it would bolt up the the manifold! It should be stamped inside one or both of them! Probably a 0.70 or .080 A/R!

As far as I know, there are 62mm versions stock...I know there are 57mm and 59mm versions (CAT uses some of them on the 3126's)! Now HTT might be telling you that just so they don't confuse you...some performance turbos are based from that 57mm version. It has a smaller compressor HOUSING that it's bigger brothers.

Maybe I have a pic on my computer somewhere showing the difference...I'll look!

Chris

Mike D

I don't think a/r stands for anything other the measurements in the exhaust housings. Basically the smaller the a/r ratio the quicker the turbo will spool.
If it's too small the drive pressures will go sky high and become restrictive.

NoSeeUm

The Garret Website has some pretty good info. Go to "Turbo Tech" and read through the Turbo 101-103 sections. I am not sure how much this applies to your question though. Take it for what its worth...

http://www.turbobygarrett.com/

Jim

RowJ

A/R is a size ratio of the Area of the turbine housing (A) to the Radius (R) of the turbine inlet (distance from shaft to the center of the inlet cone).
This ratio must be constant throughout the entire turbine cone and is important because it controls the velocity of exhaust gases hitting the turbine blades.
Higher A/R indicates slower exhaust velocity and in general better high end power. Lower A/R numbers indicate faster velocity of exhaust gas hitting the turbine blades... and better low speed response.
Note-A/R is a critical measurement because this ratio, at the discharge shute (where the gas hits the turbine blades), is what determines possible back pressures and reversion into the combustion chambers.

EDIT: Just re-read this and wonder if I've been reading too many of "HOHN's" threads?
This is just a technical explanation of what MikeD said more simply and clearly above.

RJ

GR40RCapri

Thanks for the crash course in a bit of turbo-tech guys!! i've been out of the turbo world for a while (was planning a twin setup for my road-course car...hence the username griggs racing, 85 Merc Capri)

the garrett page was good reading, and i will keep 102 and 103 for my records...some good info...

i guess the only way to tell what's what is to disassemble a unit...if it's not marked..

thanks again guys!!

J