XR6 Garrett GT40 Turbocharger

[Guest BennyXRT]

  Benny said:

Not many pics available I don't think.

Hey..... what donk is in the pic???

Is that a blue rocker cover I see??

Was that taken at the MotorShow??

Benny........

[Benny]

  BennyXRT said:

  Benny said:

Not many pics available I don't think.

Hey..... what donk is in the pic???

Is that a blue rocker cover I see??

Was that taken at the MotorShow??

Benny........

It's the Typhoon engine which uses the same turbo. Picture taken by someone on this forum.

[Guest discopotato03]

Thanks for the pic . It does look like a GT3540 with integral waste gate . The GT35 Turbine makes sense for high flow/low restriction on 250 cubic inches . The GT40 compressor side would also have enough mass flow at low boost to keep charge temps down and reduce the chance of detonation . In a race application no doubt a GT40 would have been used to reduce back pressure and reversion for constant high rpm and boost . For a production car desired performance and cost dictated the smaller turbine side for an engine in a very mild state of tune .

Cheers DP03 .

[ExAreSix]

Well, sounds like he knows what he's talking about...

This one a keeper... Ken? Can we keep him? PLeeeeease?

DPO3.

What I'm trying to say is...

Before you say anything Ken, just shutup! Don't want you scaring him off.

:lol:

[Guest discopotato03]

When this engine option was released there were some pics floating round on the net of this turbocharger but from the compressor side . Also there should be a cast number like eg AR .82 or AR 1.06 on the turbine (exhaust ) housing . Does anyone know what it is , or where the pics are located .

Also no one seems to be in a hurry to change the std unit so it must have plenty of reserve capacity , or the bottom end can't stand high boost . Nispro were very quick to change the rods and pistons .

Cheers DPO3 .

[bcl]

We use a GT3540, which is a hybrid turbo with an internal wastegate, and not part of the standard Garrett turbo catalog. It uses a GT40 compressor, and GT35 turbine.

A GT40 is recommended for a displacement of 3.5 to 5 litres.

A GT35 is recommended for a displacement of 2.5 to 3.2 litres.

The largest version of a stock GT40 is rated by Garrett to 650HP.

The largest version of a stock GT35 is rated by Garrett to 510HP.

I was told the compressor trim is 50. The Garret catalog lists the GT40 compressor as .58 A/R (not .5), with compressor wheel of 82mm, and maximum corrected air flow of around 57 lb/min. A larger compressor is available, with 88mm wheel, .72 A/R and 54 trim.

Turbine wheel is 68mm, trim is 84, exhaust housing is 1.05 A/R (based on Garret catalog, but I’ve seen it as quoted elsewhere as 1.06).

The relatively larger compressor supports larger air flow, the relatively smaller turbine is good for good turbo spool-up at lower revs; so the turbo is good for a low-boost / strong mid range torque situation.

The stock turbo works very well until you try to crank up the boost, at which time the smaller exhaust presents a flow problem. Once you get over 300rwkw it’s best to modify the wastegate and use a larger swing valve, and maybe make a few other mods to the exhaust housing to improve flow.

I expect to be able to use this turbo (in modified form) up to around 450rwkw.

The above information has been obtained from various sources, as I’ve yet to look at the housings and wheels in detail, so I welcome any further clarification.

Brian