NEW Garrett G-series turbos...

[Bleakley]

I just ran the numbers on these things.
Would like to hear your guys' feedback...

G25-550
Turbine: 54mm x 49mm = 82.34 trim
Compressor: 48mm x 60mm
The numbers:
260whp @ ~14.5 psi
300whp @ ~18 psi
320whp @ ~21.5 psi
335whp @ ~23.5 psi
350whp @ ~25 psi
380whp @ ~29 psi
G25-660
Turbine: 54mm x 49mm = 82.34 trim
Compressor : 54mm x 67mm
The numbers:
~335whp @ ~14.5 psi
~375whp @ ~18 psi
~415whp @ ~21.5 psi
~435whp @ ~23.5 psi
~460whp @ ~25 psi
~500whp @ ~29 psi
Now lemme break this down as I'm interpreting / comparing it.

Outta the G25-550.
We're looking at basically a turbine wheel similar in size to a td05h, inside a similar housing (with options for bigger sized housings). And a compressor wheel roughly the same size inlet (but little smaller exducer) as the 16G.
And flowing about the same as an EVO III 16G (until 25-30 psi, then we get same hp as 20G) Okay, that's not bad. But we're not gonna shell out all that money for just a little more performance than a 16G.

The G25-660 on the other hand.
We got the same abovementioned turbine wheel with housing options. Combined with a compressor roughly, similar in size to an 18G --> but we're flowing about 75 more hp than a 20G across the board! COMBINED with the ability to crank up the boost (25-30+ psi) for even more hp. At those higher boost levels you're flowing GTX29R/GTX30R territory....
Plus - you've got new tech packed all throughout this thing, AND ball bearings!

The 20G is the route I planned on going with the car, But this G25-660 has me thinking.....

 

[FIBA M - EC17PSE]

There is nothing little about it on the performance! It blasts the 16G right out of the water! The 550 and 660 are the end HP figures so a 16g and 20g will struggle to get to these numbers plus are not BB.

So while its on the 2k side it seems decent compared to a GTX turbo but smaller form and alot more powerful! But i would never mate it to a T25 flange though, so the FP manifold wont work as its too big for a T25 flange, and if you want the most out of this then you have to go V band or at least T4 at a minium

 

[Canadian_CD9A]

Are these tested numbers, or theoretical numbers? I have no doubt that it's a great turbo line, but I would wait for some testing first.

 

[Bleakley]

I just looked at compressor maps. Strictly theory from reading the maps posted on garrett's site.

 

[Bleakley]

There is nothing little about it on the performance! It blasts the 16G right out of the water! The 550 and 660 are the end HP figures so a 16g and 20g will struggle to get to these numbers plus are not BB.

So while its on the 2k side it seems decent compared to a GTX turbo but smaller form and alot more powerful! But i would never mate it to a T25 flange though, so the FP manifold wont work as its too big for a T25 flange, and if you want the most out of this then you have to go V band or at least T4 at a minium

Thanks. Still researching. Comparing flanges and whatnot. Yeah, def don't think a t25 flange would be ideal. T3 minimum. I like the idea of v-band, but I'm trying to retain the FP manifold. Lol. (Possible to machine it into v-band? Or maybe just buy an adapter?)

Edit: just made some rough sketches comparing dsm flange to v-band. I think it's possible to machine FP's manifold into a 3" OD v-band (G25-660 uses same v-band as GTX30/GTX35). Next time I have my turbo off the car (or manifold) I'll take measurements and probably load everything into CAD. This could prove useful. Has anyone tried this yet? --> machining the FP manifold to 3" OD v-band?