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Garrett G Series


LaurelPWR

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A new line of turbo. They unveiled the flow and turbine map for these and they seems bloody good.
Very high compressor efficiency on a very broad range of flow and pressure and new turbine wheel apparently. It seems to be based off the gt28 wheel because the diameter are really close but this new turbine flows a shit ton more.
All in all they seems extremely potent turbo for their inertia.
Avalaible in 3 A/R in vband form and 1 in t25.
Twin guy should look into these.

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Wait to see what real world results look like.

Could be good, though the new turbine material isn't much less dense than the existing type, and not like the ERFs



Yeh... every time Garrett bring something new you the table, I little voice in my head says "it still looks nothing like an FP or EFR" haha
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First time Garrett has released something which has given me a flicker of excitement in a long time, at least based on the information they've given so far and the clear effort that they've put in.  Those maps look awesome, the work they've done on packaging and reliability is very promising, and the flow for the wheel sizes basically is insane.  

Mar-M doesn't seem any lighter for size than the EFR range but at a quick quick glance at the flow maps etc, if you were considering a turbo upgrade and EFR and Garrett turbos are options - you have all the data for these so you can actually compare.  The G25 fits between an EFR7064 and an EFR7670, so I'll pick a point which is in between (really RB25s would like a turbo between those two sizes) so I'm going to compare a .92 EFR7670 and a .92 G25-660.

With a mega-rushed attempt at working how well matched they'd be at 6500rpm on 20psi on a stock RB25 (I'm using ~51lb/min as a target)

.92 TS EFR7670:

Compressor inducer: 57mm
Compressor exducer: 76mm
Compressor efficiency: 67%

Turbine wheel OD: 70mm
Turbine inlet pressure: 3psi above boost pressure
Turbine speed: 103,000rpm (74% of max)

.92 open scroll G25-660

Compressor inducer: 54mm
Compressor exducer: 67mm
Compressor efficiency: 67%

Turbine wheel OD: 54mm
Turbine inlet pressure: 3psi above boost pressure
Turbine speed: 137,000rpm (83% of max)

 

So, the G25 is working slightly harder than the EFR to achieve what it's doing - however doesn't have a fragile Ti-AL turbine wheel to deal with, has a much smaller compressor and more importantly a WAY smaller turbine wheel... like way way smaller.   It doesn't have the fancy light Ti-AL material the EFRs have, but moment-of-inertia has a huge amount to do with how much of the mass is how far from the rotational centre.   I don't know how the materials compare weight wise but this turbo has a significantly smaller turbine wheel than ANYTHING in the EFR range, if they ended up weighing the same as the comparatively giant EFR7670 turbine wheel then they'd still have a much lower moment-of-inertia... which is where your response comes from.

Going by the turbine flow map this doesn't mean you are going to choke your engine, in fact - at the hypothetical 20psi & 51lb/min point that I picked, the turbine flow is very comparable with the .92a/r EFR7670.

The trick is there is much more to it than just the wheel sizes, it depends on how they've managed to get such huge flow from such small turbine and compressor wheels - they could be coming at some other cost but I am VERY interested to see the real world performance of these things.  I wouldn't count out the possibility of these being something that put the BW EFR range on notice performance wise, but with better reliability than the previous Garretts - let alone having to worry about turbine overspeeding as a thing.

 

 

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11 hours ago, Lithium said:

 but moment-of-inertia has a huge amount to do with how much of the mass is how far from the rotational centre.   I don't know how the materials compare weight wise but this turbo has a significantly smaller turbine wheel than ANYTHING in the EFR range, if they ended up weighing the same as the comparatively giant EFR7670 turbine wheel then they'd still have a much lower moment-of-inertia... which is where your response comes from.

:thumbsup:

Inertia = mass x radius^2 

Because the radius is squared, even if the larger wheel is lighter, it only takes a small increase in size (radius) for the larger turbine to have a higher moment of inertia.

cheers

Mike

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11 hours ago, Mick_o said:

Interesting attack plan by Garrett.... lets make em smaller! 

Pretty keen on some results! 

I know the engineers will have done their homework to achieve flow efficiency, but the size of the holes in the housings are a factor in how much air can realistically pass into/out of the engine.

Lithium's calculations suggest a speed increase of ~30% to achieve the same flow.

Makes me wonder about longer term durability for severe duty use, and whether they have done due diligence for the bearing arrangement.  Turned out not to be the case with the early GT series with plastic bearing cages.

But yes, it's sure going to be interesting to see how these things perform!

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40 minutes ago, Dale FZ1 said:

I know the engineers will have done their homework to achieve flow efficiency, but the size of the holes in the housings are a factor in how much air can realistically pass into/out of the engine.

Lithium's calculations suggest a speed increase of ~30% to achieve the same flow.

Makes me wonder about longer term durability for severe duty use, and whether they have done due diligence for the bearing arrangement.  Turned out not to be the case with the early GT series with plastic bearing cages.

But yes, it's sure going to be interesting to see how these things perform!

The compressor and turbine maps will be taking those into account, given that they have different turbine flow maps for the different housings.   The max wheel speeds are no greater than the old plastic bearing cage -5s which have been running around for ages, and they have definitely done development on toughening up the core construction on these - though even the GTX series (for interest, the Gen1 GTX2860R's max rpm is 185,000!!!) all had steel bearing cages etc.  I doubt there will be an issue there, the rpm sound crazy but it's not unusual for smaller OD compressors to go even faster.

I am really interested to see the real world performance, however.  I'm not going to count any eggs before they are hatched - but if my arm was twisted behind my back and I were forced to say they're going to be good or not... I'd say they're looking pretty promising.  

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I think wait and see what other examples Garrett comes out with .

For us same old as when the T3 IW GT3076Rs came out . NEED A T3 mount flange and that integral waste gate to make it a bolt on proposition .

Like Mr Lith  said need something that's about in between the capacities/capabilities of EFRs 7064 and 7670 .

I thought I smelt a rat when the GT3584RS came out because mobs like Garrett have to spend big to develop new turbines so I reckon there's a few more sizes to come .

Hopefully soon RIP the old GT28 NS111  GT30 and GT35 turbine families . Gut feeling new designs with less hub mass fewer blades with wide tips and big trims . 

Edited by discopotato03
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Its because Garrett have really not had any drastic changes since the GT series of turbos were released a long time ago (~15 years?) and this is looking promising. If you know nothing about turbos think of it as hopefully now you are able to run a smaller turbo (helping response) and make the same power. 

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