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Discussion Starter #1
I am having a hard time deciding which turbo I want to use for my 2v. Maybe someone here can help. I am stuck between a Garrett GT4294R dual ball bearing/water cooled or a Precision 7675CEA with the single ball bearing and billet compressor wheel. Garrett does offer a GTX4294R with their billet wheel also but I believe it's alot more $$$. I've got a 4.6 2v that will be used mainly for race. The sad thing is that my hotside I just had built is for a standard t4 housing and the Garrett uses a divided t4. I had it built with the plans to use a precision turbo but now am thinking about possibly using a Garrett. Also the Garrett uses a 4" exhaust outlet and the precision uses a 3" outlet. I had my downpipe made to fit the precision. So if I plan to use the Garrett I'll need to send my hotside back to the fabricator to have it modified for different flanges. Would it really be a substantial difference using the Garrett turbo with divided housing? If it's worth it then I might end up going that route. The intake, heads, and cams I'm using are all for high rpm, possibly 8500rpm or more. So I need something that will be comfortable with that. I'm not worried about street characteristics too much and low rpm driving. Just looking for ideas here. I won't be picking up a turbo for a little while
 

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Formerly eades5.0
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Imop the ball bearing stuff isnt worth the extra coin, for a few hundred rpm better spool. The billet wheel stuff from precision spools better they claim, so that in a journal bearing would be my choice. I had a hiccup with mine, but got it replaced and has been great since. The spool time on a 331 with a .96 is 3000ish rpm.
I thought t4's were 3" in 4" out, unless I am still half asleep (early here) my 7675 cea is 4" out.
 

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Discussion Starter #3
No the 7675CEA uses a 3 5/8" discharge on the exhaust. It has a 4" inlet on the compressor. The problem with that turbo is that they only offer up to a .96 a/r. That is a good size for the street and under 7000rpm, but after that I see people running out of steam with the .96 a/r. Im thinking I will need something bigger on the exhaust. I dont mind waiting until 4000-4500rpm to spool. You may be right about the journal bearing, well just have to see about what I can do when the time comes
 

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Mmmmm, I'd talk to PTE about it. At 8500 you might be over spinning both of them. Especially if you are looking at900 hp or the upper end of either turbo.
 

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No the 7675CEA uses a 3 5/8" discharge on the exhaust. It has a 4" inlet on the compressor. The problem with that turbo is that they only offer up to a .96 a/r. That is a good size for the street and under 7000rpm, but after that I see people running out of steam with the .96 a/r. Im thinking I will need something bigger on the exhaust. I dont mind waiting until 4000-4500rpm to spool. You may be right about the journal bearing, well just have to see about what I can do when the time comes
Yeah you are 100% right, now that I'm awake your post made me feel like an idiot. Note to self, drink coffee and wake up before trying to give tech

LMAO
 

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I buzz mine to 7200ish and it was still making power, but my cam/valvetrain is setup for that. 8500 i cant even imagine and for me it isnt needed to do what I am after, but any of these t4 turbos will have hella backpressure at higher boost levels, another battle you will have.

A t6 may be better suited for your goals. After a certain hp #, or ET?

You can make 800rw on that 76 thru an auto, thats enuff to sneak into the 8s on the right car.
 

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Discussion Starter #7
Well I have seen a few cars that have hit 1000whp with the precision billet 7675. I am only looking for around 800 which like you said should give it the capability to run 8's. I dont feel like the PI heads are going to do that under 7000rpm. Maybe I should call precision and see what they say about it. I am planning to use pistons that give me about 10.5:1 compression and will be running E85, so I dont feel like I will need a ton of boost. Thats why I have been leaning more towards the T4 turbo rather than going with a T6 setup. Plus I know people have gone 160+mph in the 1/4 with a T4
 

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Who did 1000rw, Supra/Import? Thats insane for that turbo!!
Precision rated it at 1200 but told me 900whp on a V8/maunal trans would be best case senerio.
I said who cares about dyno #'s, haha he laughed and said ok high 8s on the right car.
 

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Discussion Starter #10
Who did 1000rw, Supra/Import? Thats insane for that turbo!!
Precision rated it at 1200 but told me 900whp on a V8/maunal trans would be best case senerio.
I said who cares about dyno #'s, haha he laughed and said ok high 8s on the right car.
it was a 4v cobra, ill try to remember or find out who it was. either here or on modularfords. lol thats funny though
 

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You look into the bullseye turbos too? They have billet wheels now and the cast wheels made good power before.
 

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Discussion Starter #12
Yea people have been pm'ing me trying push them and sell me one. That kind of scares me away from them. I'm pretty set on a precision or Garrett at this point
 

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The precision billet 76 is a tried and true unit, although I am not sure how it will respond to the kind of RPMs you are talking. Might want to even think about a t4 GT4788. What trans are you running?
 

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Discussion Starter #14
I'm going with a t56 right now. I didn't really think I would need an 88 to make the power I'm looking for but there aren't that many guys out there with a setup like this to compare it to
 

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Sounds like you have everything setup for the billet 76, so I would go with that.

However, I will bring up the billet bullseye 76mm unit (B376 is the designation) has a/r's of .90, 1.0, 1.1, and 1.25 with an 83mm turbine wheel, which may give you the room you need for the high rpm. However, it would require a 4 inch DP.
 

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Discussion Starter #16
Well I'll look more into the bullseye turbos. I'm not completely closed off to other options. I have a 4" downpipe, but it's got a 3" flange. So all I would need to do is have a new flange welded onto it. I just wish precision offered a larger exhaust housing. I wonder if I could find a different brand housing that would fit on it and I could just swap them out. Kind of like a hybrid turbo
 

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In my searching I think I saw a GT4294r with a precision billet compressor wheel, which may be what you are looking for. I saw the downpipe that was made and it was VERY well done. I am almost positive I will be going with CG Fab when my time comes to go fast.

I believe I also saw that the GT4294R needs a water line too?
 

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Discussion Starter #18
Yea all the GT-R series turbos need a water line I believe, but that's not a big deal. The only problem with a GT is that it uses a divided T4 flange and my current setup has a standard T4 flange. The CG Fab stuff is sick. Only thing is the 2v kit won't work with a/c but I haven't had that stuff hooked up in awhile anyways. I don't plan on making any trips to the grocery store lol. I would go with them if I were you and especially if you plan on doing some real racing
 

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Sounds like it would be a lot of work to switch over to the GT series turbo, and I don't know if the gains over the billet 76 are worth it. I would stick with the billet 76 for now, and see how that shakes out.

When I get back from deployment, I am stationed in central texas. Ill probably get an 03/04, and just send it to CG to get the hotside and coldside done by them.
 

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Discussion Starter #20
I think that would be a good idea to see what happens with the 76mm. Now that I think of it the bullseye turbo might be worth a closer look. Ill see if I can get some more information on them or talk to some people who have used them. If you get the car down there to have the cold side done let me know because I want to get my cold side done by them as well. Only problem is that he said they didnt have a car at the shop right now to design it from. So that would be a good thing because im all the way in tennessee and cant bring mine down there. He did alot of work for Chip Havemann, Mike Murillo, and alot of other top names out there. You wouldnt regret it
 
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