New line of Garrett turbos - G series

[zeppelin101]

Which could be quite impressive!

There's only two so far: the 550 and the 660 which, as you might guess, mean 550hp and 660hp capable compressors.

https://www.turbobygarrett.com/turbo...series-g25-550

https://www.turbobygarrett.com/turbo...series-g25-660

80% peak compressor efficiency on the 60mm wheel is good going, 75%+ for a good portion of the map on both. The current GTX 60mm runs out to ~42lb/min versus ~50lb/min on the newer G series, more than the the current 67mm GTX even. The higher flowing wheel is a 67mm wheel. If you think that Garrett current offerings are 71mm for ~600hp it's a good improvement and has better surge margin as a result.

What's really interesting though is they've done some work on the turbine wheels too which are now 1050°C capable and have some pretty high flow for their size. They are the same inducer size as a GT28 but with a nice increase in trim / flow capacity which should mean inertia is similar to a GT28 wheel (decent response) with the flow capacity of a ~1.01 GT30 on the largest housing.

V-band only turbine entry and outlet on the bigger housings (the smallest 0.49 A/R is a T25 inlet) so will need a new manifold to go with it. Wonder what they will sell for - the turbine materials for 1050°C aren't cheap!

[Jezz_S13]

Interesting.
Now if they did a g30-700 and g30-800...

The GTX's (certainly the newest GTX3584RS) use inconel turbines, is this MAR-M alloy better/worse or just a specific type of inconel?

[Jezz_S13]

Oh, more details...
http://www.atpturbo.com/gseries/garrettgseries.html

better than inconel, 200degrees better allegedly.

[zeppelin101]

So far as I know MAR-M is less dense primarily with more stability at higher temperatures. Need to check on composition differences. Less weight is good for spool and boost threshold so it should outperform an equivalent GT28. These have only been on the website for less than a week so I imagine there are more to come.

I think the small housing version of these will probably top out in the late 300s / early 400s depending on cams maybe but should be more responsive than a 2871 - sounds like a good combo to me!

[green_rs13]

I bet the price is going to by eye watering though.

[zeppelin101]

Circa 2000 USD by the looks of it, although ATP haven't put all the prices up yet.

http://www.atpturbo.com/mm5/merchant...ategory_Code=G

Imagine that someone like Owens will have them in soon to find out what a UK price is.

Given the cost delta to a 2871 or even a GTX2867 they best be shit hot

-edit- $500 more than a GTX2867 with turbine housing, $800 more than a GT2871.

[Jezz_S13]

From that link...
MORE G SERIES MODELS COMING SOON!!!
Bigger ones hopefully.

Too good to be true? Hopefully not, GTX3582R power with GT30 response would be dandy on my 2.3l 4G63.
The BW EFRs seem to have issues with their turbines exploding from over spinning, and these G25 ones spin fast looking at the compressor maps.

[zeppelin101]

Don't know about EFR but the speed limits quoted in the comp maps are well within standard speed limits in terms of blade speed. Typical max is ~560m/s, on the 550 the turbine would be around 525m/s at 185k rpm and the 660 will be slower because the larger compressor spins slower anyway.

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[Jezz_S13]

The EFRs use Gamma-Ti turbnes, which has high burst speed. Maybe they don't like the temps, or maybe the reports I read of them failing is bollards. These are on big turbos/turbines though, the 9180 and the 8374

[zeppelin101]

I bet the people who have blown them up haven't been running speed sensors and are running serious boost. The speed climbs really fast on the larger wheels at high mass flow and probably doesn't take much greed to exceed the speed limit.

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[zeppelin101]

Comparing these to EFRs, the 550 outflows the 62mm EFR wheel (and nearly catches up to the 67mm EFR) and the 67mm 660 wheel makes a mockery of the 70mm EFR compressor for the same mass flow. The smaller wheel size for the additional flow capability means there is loads of surge margin too.

What won't be clear until they get thrown on an engine is how the turbines behave.

[R3K1355]

At least there's some decent development coming, and not at a totally stupid price to the end user.

[zeppelin101]

What's probably a bit irritating is that this is stuff the OEMs have had access to for a while now. Honeywell don't filter new stuff through to the aftermarket very quickly at all.

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[R3K1355]

It will only end up on really special stuff though, as the performance increase is negligible for the extra money.
Will have to wait a while to see if the claims match real world performance, like you said one of the main competitors is BW's EFR series, which has been on the market a while now.

IMO the GTX series was really late to the party, and while they are good Turbo's they didn't prove to be any better than what was currently out there.