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I read this three times Lith and I am no closer to understanding the first sentence.

Oops, I ment to say the .63 only showed advantage over the .82 below 3000rpm.... above that it started waking up pretty similar from memory and generally feels nicer to me. I reckon the .63 GT30 hot side is too tight for something that flows 50+lb/min.

I shouldn't post techy stuff when I have the flu :(

Its been a long year thats gone really fast, if that makes sense. Just to clarify, I've gone from .63 to .82 and I'd never go back to the .63 - the .82 is smoother and imho generally more fun - results in a much more knock resistant setup and boost control is noticeably easier, makes it seem like its the right match to me.

A .82a/r GTX3071R would be really really fun I reckon.

Oops, I ment to say the .63 only showed advantage over the .82 below 3000rpm.... above that it started waking up pretty similar from memory and generally feels nicer to me. I reckon the .63 GT30 hot side is too tight for something that flows 50+lb/min.

I shouldn't post techy stuff when I have the flu :(

Are you saying the 0.82 made similar power to the 0.63 even between 3-4000rpm? I would have thought while the 0.82 is building boost through this rev range the 0.63 would be going hard.

I do agree with all the other advantages of the 0.82 I just would have thought the 0.63 would be ahead to around 4000rpm.

When loaded up against a dyno you might be able to tell the difference, but in the real world IN MY OPINION the difference starts becoming a case of you'd have to go from a car running the .63 and then jump back into one running .82, and back and forth and have a big think about it to try and work out which is which if you hadn't been told which was running what... assuming they were both otherwise identical. The way I remember it there was a slightly lazy feeling sensation from 2500-3000rpm when going to the .82 which went away once above 3000rpm.

Lets put it this way, if you have a healthy stock turbo car next to mine at anything 3000rpm+ and stand on the throttle in both the difference in response negligable enough that anything that may be gained in that instant is negated almost immediately afterwards. Full boost at 3500-4000rpm doesn't mean that its dead until then.

Last question, I promise!

What do you guys think a GTX3071 with a 0.82 housing will cost when they are available in Australia? I'm trying to decide if I should get one from the US now, or be patient. If it doesn't save me any money going local, I might place this order today.

I won't be getting the manifold to suit until mid January, so I guess I could wait and see, but given that there isn't high availability of GTX3071 overseas yet (ATP has no stock, RSP has 1 left), i don't know what australian supplies will be like, or if there will be the limited-supply overcharges :P

IMHO the .63 showed its major advantage over the .82 below .63, I have had both and there is no way I'd go with the .63 again. With an old GT3071R I'd consider .63 possibly, but with the extra compressor flow of the GTX3071R I'd go .82.

I know what you mean and i mostly agree. I previously ran the gt3071 .63 on an rb25 and would do so again (with an ex gate this time). It didn't seem to give away anything up top over the .82 graphs i saw but was all in 500-750 sooner with mountains of torque from 3k. If i were to go a gtx3071 i would definitely do the .82 housing as there were already manifold pressure issues showing with the gt.

I know what you mean and i mostly agree. I previously ran the gt3071 .63 on an rb25 and would do so again (with an ex gate this time). It didn't seem to give away anything up top over the .82 graphs i saw but was all in 500-750 sooner with mountains of torque from 3k. If i were to go a gtx3071 i would definitely do the .82 housing as there were already manifold pressure issues showing with the gt.

Yeah that's what I'd have expected, and yeah if I went a GT3071R I would actually definitely use the .63. The trick is the 76mm compressor is heavier and its going to be a bit laggier, no point half committing and getting the extra lag without the full extra flow.

I would LOVE to actually drive an R33 with a .63 GT3071R actually, it was my first choice - though I don't regret the option I have it'll still be nice to know what the grass is like on the other side. If I rebuild my RB25 I'd probably go to a GTX3071R, 6lb/min more flow with less lag definitely has me intrigued.

  • 2 weeks later...

U need an apples-to-apples comparison with the turbo as the only variable on exactly the same setup to make an accurate comparison. Too many other thing can cause lag (intercooler piping and size, cams, cam timing, compression ratio, exhaust, blow-by, tune)

Saw results for a GTX3076R, so far unimpressed - if I had been told it was a GT3082R I would have believed it... more power than a normal 3076 but also quite a bit more lag.

If that was the one that was run on the WRX, then apparently the turbo is bogus. It's a rebuilt turbo that the user (OP) had delivered 4 months before Garrett had released the GTX wheels. Read post #60 on page 3.

http://forums.nasioc.com/forums/showthread.php?t=2034214

Edited by D_Stirls

U need an apples-to-apples comparison with the turbo as the only variable on exactly the same setup to make an accurate comparison. Too many other thing can cause lag (intercooler piping and size, cams, cam timing, compression ratio, exhaust, blow-by, tune)

Sounds like... backpeddling ;)

Ah my bad, I hadn't seen the last post by Geoff. The GTX3071R post looks interesting though, 521hp is pretty epic- thats pretty intense. People who are familiar with Dyno Dynamics dynos, is the mode that is done in some kind of flywheel estimation? I normally take 521hp on a DD dyno to be pretty big power for a GT30 turbo.

gtx3076r with the skyline .73 AR exhaust housing (avoturbo.com) might be very interesting.....

currently using this housing with gt3076r bb core, lag in awd auto stagea until just over 2000rpm then it takes off! easy 250awkw with 450cc S15 injectors

better than stock automatic torque converter would change this again tho....

throw in 550cc injectors and the gtx3076r turbo and there's an easy 300awkw on pump gas with remap

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