Single Turbo RX-7's Questions about all aspects of single turbo setups.

Which GT40 to get?

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Old 04-01-04, 10:41 PM
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Which GT40 to get?

OK, I spoke to A-Spec and Davinci today about non-BB GT40s. I'm not positive which one I should go with, so I'm asking for input.

My setup is a 13B-RE with a 1/2 BP on it. I'll be running a divided tubular manifold with 15" equal length runners. I'm looking for the best spool-up possible without losing too much on the top end. The car will be used for autocross, some drift, and the occasional dragstrip runs.

I'm was using a Garrett 60-1 with .70 comp side and 1.15 hotside and an HKS manifold. It's nice, but I want something a little better. I just sold those, so my car is currently sitting.

Currently, the GT40 with the 88 wheel won't be available until May. (Not wanting to wait that long). That pretty much leaves my choices as:

GT40 with 82mm wheel .94 hot side

GT40 82mm wheel 1.15 hotside

Yet another 60-1, but this time with a .96 hotside.

Like I said, I'd like the setup to be fairly respnsive, but I don't want my power curve to look like most dyno queen Supras. I'm looking for something that will have a fairly broad power band. I know that Michel has this turbo with a .94, and he said he gets 17psi by 4000 RPMs. I'm hoping that my 1/2 bridge can drop that by a couple hundred RPMs.

Thanks for the input, guys!

Reese
Old 04-01-04, 11:29 PM
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the 60-1 with a .96 is going to hit full boost at around 5000rpm (15-16psi). Maybe 4750 if you're lucky. It probably hits full boost right about where the 1.15 did, but it's a softer 'hit'. I have a .96 on my car... it sucks . All this is on stock ports...

If you want 17psi at 4000rpm, a divided .94 housing is as big as I think you can go.

-Manolis
Old 04-01-04, 11:49 PM
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Reese, since you know I have been looking over the GT40's since they got brought up on this board. Go with the GT40 82mm comp and 1.15A/R hotside. The GT wheels are supposed to have incredible spool time vs. A/R. You'll get better response than you do with your turbo now and much better power with the GT40 compressor. If you don't like it, use it for a year and sell it to me after that. Then you'll have to money to buy whatever you want!! Just my .02 though.

Zach
Old 04-02-04, 06:54 AM
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Originally posted by Manolis_D
the 60-1 with a .96 is going to hit full boost at around 5000rpm (15-16psi). Maybe 4750 if you're lucky. It probably hits full boost right about where the 1.15 did, but it's a softer 'hit'. I have a .96 on my car... it sucks . All this is on stock ports...

If you want 17psi at 4000rpm, a divided .94 housing is as big as I think you can go.

-Manolis
hmm sorry but a proper tuned ported Rex with a 60-1 should see full boost in the early 4K rpam range
(The log style turbo manifolds add several hundred RPM to the lag factor)

I got full boost by 4200-4300 RPM with Turbonetics T-66 non-bb (tubuler manifold)

In fact I realized The T-66 came on so soon(too soon/less top end) that I can afford to go much bigger turbo and hence I have sold it
in favor of a T51 hybrid

Lag is really only a major factor if your road racing where you have spool down and up on a reguler basis

In drag Load takes over in making it almost a non issue
That is why you do not see any road racing mustangs with Y2K turbos but in Drag they run upto T100 turbos with no problems (2 step rev limiters also help)

Lisa Kubo in her "4 cycl" saturn runs a Y2K
yet she has a very long tubuler manifold

I do not the exact science behind it but the longer the turbo manifold the bigger the turbo you can run it seems

I have been to dozens of NHRA Import events and everyone uses very long tubuler manifolds with HUGE turbos or large twin turbos with mid-sized turbo manifolds

But each to there own
I dont street race any more making "light to light" lag issue a Non-issue with me


Last edited by kabooski; 04-02-04 at 07:14 AM.
Old 04-02-04, 07:13 AM
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Dang Reese I didn't know there was a wait. I still stand by what I said earlier about the a/r not being big enough on the .94. I just think that it's going to limit your top end. Have you tried seeing if you can get an 88mm wheel from Sean? He might be able to, and he seems to always want to give us the best price. I would suggest the 1.15 it may not spool as quick but with your manifold I think it will compensate for it. Good luck buddy.

- Steiner
Old 04-02-04, 07:16 AM
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Thanks for the input guys! Kabooksi, where did the 66 start to fall off? I know that with my 60-1, my last dyno run showed that it was still pulling fine when I let off at 7000 RPMs. Well, it wasn't pulling as hard, but it wasn't losing anything. . .

Reese
Old 04-02-04, 07:38 AM
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according to my data logs I shifted around 7600 rpm at the track

11.72@118

I think the T66 is one of the best street/strip turbos out there

I would of kept the T66 had it not started to smoke
It came out better selling it and taking the money I would of spent rebuilding it and putting it towards a larger custom turbo
Old 04-02-04, 08:59 AM
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Hey buddy Sorry I didn't call you back.

I say Gt4082 with a .94. As you are aware I made nearly 470 RWHP on my .84 turbine housing... so you will make PLENTY of power with the .94... no reason to go bigger IMO. Especially for the applications that you're looking for.

You should see 17 before 4000 no problem.
Old 04-02-04, 10:01 AM
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nm

Last edited by allrotor93; 04-02-04 at 10:10 AM.
Old 04-02-04, 10:39 AM
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If the car is going to be used for autocross I wouldn't use 1.15 as a first choice, I would go with the .94, If you want more after that I would be willing to work something with you on a 1.15 later. But from the sound of your desription above the smaller housing seems closer to what you need.

-Sean
Old 04-02-04, 01:01 PM
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Chris, no problem.

Sean, thanks. I believe you said you had the 4082 with .94 in stock? If so, I think you might be getting an order from me pretty damned quick. LOL.

I did have a couple of questions about it. I found out from another source that the footprint IS a true TO4, so there won't be any mounting issues as long as I'm not using a GReddy manifold, correct?

Secondly, Chris might be able to offer input as to how the manifold flange is oriented. I understand that the GT40 can only be clocked in 90 degree increments, correct? Will that give me any issues in your opinion? Also, what kind of fittings are needed for the oil lines on that turbo?

Other than that, I think I'm pretty much ready to order. How long to get it out and to me?

Reese
Old 04-02-04, 01:31 PM
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{QUOTE}: Manolis_D
the 60-1 with a .96 is going to hit full boost at around 5000rpm (15-16psi). Maybe 4750 if you're lucky. It probably hits full boost right about where the 1.15 did, but it's a softer 'hit'. I have a .96 on my car... it sucks . All this is on stock ports...

If you want 17psi at 4000rpm, a divided .94 housing is as big as I think you can go.

-Manolis {END QUOTE}



WTF?!?! Your talking about a 60-1 (aka T04S) hitting 15-16 psi by 5k rpms?? Dude, your set up has major freakin problems. Most people are getting full boost (15-17 psi) from any were of 3200 rpm's to 3800 rpms on stock and street ported 13b's. I'd expect a half bridge to be sooner if not the same. And these are typically done with a 1.00 A/R divided with divided manifold and also on the .96 non divided with the crappy log manifold. Stock ports and log manifold or not, your boosting really really REALLY late.

~Mike..............
Old 04-02-04, 01:43 PM
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Originally posted by NOTA944

Secondly, Chris might be able to offer input as to how the manifold flange is oriented. I understand that the GT40 can only be clocked in 90 degree increments, correct?
Reese
Strange if that's true... But the manifold flange is angled so that it is slightly higher on the drivers side... maybe a 10-15 degree angle.

TiAl does make a sweet products

-C
Old 04-02-04, 02:46 PM
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http://www.atpturbo.com/Merchant2/me...egory_Code=GRT


i may go with this when i upgrade mine. (i have a half bridge as well)
Old 04-02-04, 03:36 PM
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I can match that price
Old 04-02-04, 03:40 PM
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can you beat that price? if so i may jus go with that when the times comes.
Old 04-02-04, 03:43 PM
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Originally posted by NOTA944
Chris, no problem.

Sean, thanks. I believe you said you had the 4082 with .94 in stock? If so, I think you might be getting an order from me pretty damned quick. LOL.

I did have a couple of questions about it. I found out from another source that the footprint IS a true TO4, so there won't be any mounting issues as long as I'm not using a GReddy manifold, correct?

Secondly, Chris might be able to offer input as to how the manifold flange is oriented. I understand that the GT40 can only be clocked in 90 degree increments, correct? Will that give me any issues in your opinion? Also, what kind of fittings are needed for the oil lines on that turbo?

Other than that, I think I'm pretty much ready to order. How long to get it out and to me?

Reese
I can tell you it will clock on more than 90 degree increments and it is a straight T4 footprint the greddy mani. was the problem on Michels car. Just make sure you will have enough room for the size difference it will be larger than Chris's turbo.

-Sean
Old 04-05-04, 08:35 PM
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Hmmm, big turbo time for Reese!!!! Sean, you rock! Reese, what whp numbers are you looking for bro??

Zach
Old 04-06-04, 02:46 PM
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Originally posted by razorback
can you beat that price? if so i may jus go with that when the times comes.
And if I can't beat it but only match it, is it no good then? Just curious what the difference would be at that point.


-Sean
Old 04-06-04, 03:37 PM
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Originally posted by Zero R
And if I can't beat it but only match it, is it no good then? Just curious what the difference would be at that point.


-Sean
I guess it's just a popularity contest after that Sean.

Zach
Old 04-06-04, 04:22 PM
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Hey he's got my vote, after all the explaining and and helping me decide what I need. I will definately recommend Sean to anyone. It's good to finally see someone who actually cares and helps people in the community instead of just avoiding calls and not answering anything until you make a fit about it. Thanks Man.

- Steiner
Old 04-06-04, 04:35 PM
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Couldn't have said it better myself Steiner.

Zach
Old 04-06-04, 07:39 PM
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Originally posted by SnowmanSteiner
Hey he's got my vote, after all the explaining and and helping me decide what I need. I will definately recommend Sean to anyone. It's good to finally see someone who actually cares and helps people in the community instead of just avoiding calls and not answering anything until you make a fit about it. Thanks Man.

- Steiner

this has to be best post on the forum!

supporting the rotary specific shops over shops that dont give a damn about us rotary guys is the smart thing to do... even especially if Sean is matching prices!
Old 04-09-04, 12:29 PM
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Originally posted by razorback
can you beat that price? if so i may jus go with that when the times comes.
My friend Mike bought a 3540 turbo kit from Sean about a year ago. Since then he has had a string of engine failures that are not related to the turbo kit. Despite this Sean has spent considerable time trying to help Mike diagnose the problem.

That kind of service is worth paying a premium for IMO. The fact that Sean is willing to match the other shop's price makes the decision a no brainer.
Old 04-09-04, 04:51 PM
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Absolutely Carlisi. I just feel bad that he can't advertise prices or basically much because of the monopoly being run off of this forum. Sorry to have hi-jacked this thread. So back on topic. What's the word Reese? Have you ordered the turbo yet. You know I am anxious to find out what you can do with it, and I'm sure a lot of other people with 1/2 bp's are wondering as well.

- Steiner


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