More turbo newbie-ness for you all Assuming you had two cars both pushing out a solid 180rwhp; one is running a Greddy setup, the other a GT2554. I'm guessing the GT25 would spool sooner, but what would the difference in driveability be between the two cars? Thanks John

Garrett turbo would be ball bearing and water cooled, so it should last much longer than the GReddy/Mitsu turbo.

Because the T25 would spool sooner, you'd likely have quite a bit more torque in the 2000-3500 RPM range, making around-the-town driving more pleasant.

I don't think the turbo cartridge would "last much longer" than the Mitsubishi's, though. If taken care of properly, the difference should be near negligible.

I have driven both. The GT2554r in almost instant boost were as the Greddy kicks in around 3000rpm which isn't bad. Both feel comparable in the upper rpm range. You probably have to run a higher boost level with the Greddy to achieve 180 compared to the gt25r depending on your setup. I give the edge to the gt25r, but I own one

While I agree with you....we'll see soon enough....

To actually add something useful here is a merged dyno graph of a GT25R vs. a Greddy both at 8 psi. Both on dynojets. Both relatively not well tuned. Both with 2.5" exhausts. GReddy with stock 1.75" DP and GT25R with 2.5" DP. (Yes, I am making excuses) Not done on the same dyno, nor the same day, but good for a general comparison.

Look at that early spool! So jealous....

Almost forgot two more excuses...below dynos GT25R was on a 1.8L and GReddy on a 1.6 and who drives under 3K rpm in a miata anyway? :gay:

Attached Images

dyno.jpg (94.9 KB, 74 views)

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91 widebody brg - built 1.63L engine, worked head (MS solid lifters/shim under bucket/Supertech valvetrain/Integral cams), Flipside custom GT2871 turbo setup, Flipside custom IM w/65mm TB, 6-speed trans, 3.63 Rx7 diff, FM front sway, Tein Flex 9/7

i'll know in a little while.

We'll to make Greddy owners feel a bit better....the sleeve bearing turbo's are rebuildable (rebuild kits available), where as ball bearing are cheaper to replace than repair (alot more $). Also since your not in boost in the lower rpms, your saving some gas. I kind of like the dual personality of my Miata with the Greddy.

Is that my dyno chart?

Wow, great info, thanks!

That Dyno chart was interesting, a 2.5" DP on the greddy would help narrow the spoolup gap wouldn't it?

I see this isn't going to be an easy decision. Once I've decided on the GT25 the Greddy's low price tempts me...and when I've decided on the Greddy someone says they wished they had thrown a GT25 in to start with.

Hopefully getting a ride in a Greddy next week so I'm hoping that will help me decide.

Thanks!

Stay tuned...Brgracer is installing a 2.5 inch downpipe and new intercooler system. I just installed a link so we will both have similar setups and will be pushing 12+psi. I'm look forward to seeing what these cars will do side by side.

I realise the dyno graph isn't a super-accurate comparison, but it's surprising how similar the two turbos are once they're up and running.

I can't wait to hear about the 12psi battle

An extra 200cc and a 2.5" downpipe went a long way toward decreasing spool-up on that setup. Add that to the fact the Mitsu. is a slightly bigger turbo...

Yes it is. I hope you don't mine. The other graph was when I was running 8psi awhile back.

No, not at all. It just looked familiar.

Well if you keep changing your screen name we will think you're in the witness protection program

i had a highly customized greddy. for a little more, i'll have the equivalent to an fm2. i also have the flexibility of moving to a full fm3 with the manifold i have. the installion will be a helluva lot more clean, too.

:gay: You noticed. I never liked my screen name. I still don't like this one, but it's the best I can come up with until I have to relocate