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Have you considered the 0.72 A/R? The 0.92A/R flows like the GT30 turbine wheel in the 1.01 A/R. In the GT30, most people go for the 0.82/0.83 A/R on 2.0-2.5L builds.
The higher saturation flow of the hot side is mostly due to the new housing and the new turbine wheel blade design, which are completely different with respect to the gtx series. Roughly speaking we don't have to expect a similar response of gt30 with 1.01 A/R but only the same maximum flow. In fact housing itself and turbine wheel size are much smaller compared to gtx30. In any case, this turbo kit is designed for high rmp applications, so that's the real reason of the 0.92 choise.
I hope to share first impressions as soon as possible
The higher saturation flow of the hot side is mostly due to the new housing and the new turbine wheel blade design, which are completely different with respect to the gtx series. Roughly speaking we don't have to expect a similar response of gt30 with 1.01 A/R but only the same maximum flow. In fact housing itself and turbine wheel size are much smaller compared to gtx30. In any case, this turbo kit is designed for high rmp applications, so that's the real reason of the 0.92 choise.
I hope to share first impressions as soon as possible
Very exciting. Yes, the G-series turbine wheel is more efficient, so it should spool sooner even given the same exhaust flow as the GT30 equivalent flow turbine stage. And the smaller diameter and lower mass will drastically improve transient. 0.92 does make a good match for high rpm use.
Side note, Tuscany, Italy? I was in Siena, Italy almost exactly a year ago. Very beautiful place, but I think the drivers are a bit crazy!
23% correction factor...
385WHP uncorrected at 26+psi...
Just FWIW, local air pressure around here is 84kPa and I made 360WHP uncorrected on an IX turbo with less boost and faster spool on a 2.0L. In fairness though, those boxer do have terrible lag on the dyno.
23% correction factor...
385WHP uncorrected at 26+psi...
Just FWIW, local air pressure around here is 84kPa and I made 360WHP uncorrected on an IX turbo with less boost and faster spool on a 2.0L. In fairness though, those boxer do have terrible lag on the dyno.
Yeah, I really had to pick my words when I found and commented on that post. It isn't an overwhelmingly impressive result on a 2.5litre. I've yet to see a result which I'd celebrate about for those turbos, but I'm hoping it's just early days yet as it'd be nice to see Garrett make some waves.
Yeah, also worth keeping in mind is this has been compared to the GT30 on the turbine side. Basically saying it's a smaller wheel that flows like a GT30. Anybody that's been paying attention knows the GT30 turbine isn't particularly impressive though on the power side and usually requires A LOT of boost to make power.
It fits with what appears to be Garrett's approach though...making the same power but with a smaller package, when comparing to the GT30.
OR
You could see it as making more power with the same package and this should be compared more with the GT25/GT28s (as the name suggests). But the Evo world would never resort to caring about the GT25/GT28 so I get why it's being compared to the GT30 in this community.
Yeah, also worth keeping in mind is this has been compared to the GT30 on the turbine side. Basically saying it's a smaller wheel that flows like a GT30. Anybody that's been paying attention knows the GT30 turbine isn't particularly impressive though on the power side and usually requires A LOT of boost to make power.
It fits with what appears to be Garrett's approach though...making the same power but with a smaller package, when comparing to the GT30.
OR
You could see it as making more power with the same package and this should be compared more with the GT25/GT28s (as the name suggests). But the Evo world would never resort to caring about the GT25/GT28 so I get why it's being compared to the GT30 in this community.
Yeah, I fully appreciate all that - however in saying that, the spool on that car is worse than what the EFR7670 gave from the EJ25/EFR testing done years ago by Perrin when the EFR range first came out. At this stage that spool doesn't look significant (if at all) better than a typical GT30, so basically it is like having a GT30 which comes with GT25 housing and wheel sizes. The advantage would purely be to do with packaging.
BTW, just to be clear - I am not saying I believe that is what the final outcome is going to be, but so far the results have added up in a way which one could conclude that. I was, and still am holding hope that the results that would justify them is spool/transients somewhere between GT28 and GT30 turbos with GT30 type flow.
Going off of what some of you have mentioned about getting more power out of a smaller package. These turbo may be geared more towards motors using a hot-v turbo setups where space is at a premium. So where they cannot fit a pair of GT30 series turbos in, there they could potentially fit a pair of G-series turbos and get similar performance but a smaller package.
updates?!?!?!?
Thinking about running these on my Supra as twins.
but the talk of efficiency and mismatched wheels might make me choose the 550 vs the 660.
I found this over on a Subaru forum. Blue line is a Gen1 GTX3076R in the 0.64 A/R. Red is the G25-660 in the 0.92 A/R. I'm actually a bit surprised how quickly the 0.92 A/R spools. I'm personally going with a 0.72 on my S2000 as it will be predominately a street car, so I'm looking for maximum response and street-ability. I believe this is a 2.0L EJ205. I figure the 0.72 will improve spool by ~300-500rpm. Give or take, on a ~2.0L engine.
Dont know what Garrett done wrong with the Gen 1 GTX3076R but its kind of "the flop" in that range of turbos. SURE it was capable of making alot more power than its older GT series brother but it was WAY laggier in comparison. So Hardly a good comparison especially with the .64 rear on it. Its a horrible mismatch.
Dont think the 660 has earnt any bragging rights unfortunately. Though rexies are a terrible plaform to judge a turbo off as everything is laggy on them haha!
Looking forward to seeing some evo results though. So good luck to the guys who have dropped their hard earnt on a G series as id like to hear just how they drive as the dynosheet only tells part of the story.
