Turbo Sizing Experts Please

mdr40z

mdr40z

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I posted over on SF too....

I trashed my turbo last weekend and I wanted to know what it was capable of and what to replace it with or rebuild it, need some opinions please.......

Garrett name is cast in the cold side along with A/R .60 BCC, the intake is 2.75" o.d., 2.375" i.d., the impeller o.d. measures 2.9375", the shaft measures 0.25" diameter

the hot side is stamped A/R .70 M 3 G 1, the impeller o.d. measures 2.9375" also, standard T4 flange, and it has a 3" v-band connection

Any idea how much hp this turbo is good for and what would be a comparable or slightly larger or smaller turbo in Garrett or Turbonetics. and what do you think of Turbonetics turbos? any good? and lets talk about shaft sizes a little, it seems like this shaft is very small........

1005.jpg


As you can see, the shaft bent and the impeller crashed into the housing

1003.jpg


Like I say, I've loved this turbo and I'd probably like to replace it with something similar maybe with a slightly earlier spool, it was maybe 3600-3700 rpm or so.... How bout a GT40 or GT42, or GT35?
Thanks in advance for all your help and support,
Mark
 
mdr40z

mdr40z

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IJ. said:
3540R is just about the perfect match for a 7M if you're shooting for the mid 500's.
Click to expand...

Where do you think it would spool? I'm happy with a little less hp and earlier spool
 
I

IJ.

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Depends on supporting mods state of tune and quite a few variables but for what it's worth I run a 1.06ar turbine and am seeing 1 psi at 1900 rpm.

With it going totally berserk by 3500 and breaking traction.
 
mdr40z

mdr40z

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whats the difference in a/r hot or cold side...... does a smaller # a/r hot side spool faster? and a larger a/r cold side push more air?
 
mdr40z

mdr40z

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and since a/r simply means area over radius ideally you would want to have the smallest a/r possible hot side and larger cold side for greatest air movement... within the confines of diminished return of course
 
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IJ.

Grumpy Old Man
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It's not that simple the Hot side and Cold side need to be somewhat matched to each other or you'll build a Surge Monster.
(this is why I chose the 1.06 to allow the motor to breath at high rpm)

The 3540R is a hybrid based on the large 40 compressor and the smaller 35 turbine section, it's now become the norm and was a great effort by who ever thought of it :)
 
mdr40z

mdr40z

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I know it's great but the least I've seen it is about $1200USD, do you know what is comparable to it without the ball bearing design? Have you heard anything good about Turbonetics?
 
mdr40z

mdr40z

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well I've been real happy with the one I had, I've run about 1.4 for about two years but I've never dyno'd so I have no idea what hp. I rebuilt it w/forged internals, still running 550's/lex/afr/exh/walbro/mbc, etc
 
Nick M

Nick M

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I am having a hard time saying no to the GT35R myself. I would run the smaller .82 a/r through a T4 housing through PTE. Because some of us still use the stock A340e upshift of about 5500 rpm.

I don't want to buy a new manifold, downpipe, wastegate, etc. etc., just to make it run.
 
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IJ.

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Mdr: Any idea what the old one was?

Nick: They do an internal gate 3540R with the smaller AR housings now so it's a viable option, downpipe and an adaptor is a small price to pay for the goodness ;)
 
Nick M

Nick M

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IJ; interesting. I don't want to hijack hard, but this could apply to the original poster as well. I think the LIPP/ITS turbo sold through Suprasport as the Boss 4 will do well also. It even has a fancy shroud over the turbine wheel to deflect some of the turbulence from the wastegate. And it bolts to my manifold.

Oh well, I have until next spring to decide.
 
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