# Vr6 turbo questions for VRT guys/gals



## gti vr6er (Oct 8, 2010)

I posted a thread a while back regarding the following but didn't get much response(probably because my goals werent clear). 

Well I've done extensive research and decided to use a stg 3 kinetic kit as a foundation for my first turbo build. Although, I'm stuck on a few things and need some guidance. 

Whp goal is 400 and I'll be intercooler and have a head spacer.... 42lb injectors and inline fuel pump. My bottom end is stock for now and gonna be throwing in Autotech 262's and new lightweight lifters. Tranny is being rebuilt and prepped as we speak with a Peloquin LSD and stg 3 clutch net clutch and yellow pressure plate. 

Now my confusion starts here: I have the option of a) precision t3/t4 60 trim and b) garret t3/t4 60-1. Both with either 63 ar or 82 ar. I also have the option($700 more yikes) to upgrade to a gt35r, 30r or precision 6262 all with either 63 ar or 82 ar. Now considering I don't want to pony up the extra $700 on top of everything to upgrade to a gt35r, what t3/t4 turbo should I go with as well as what ar? I suppose it's useful to say that this is my daily driver that gets me to work and I don't rev(nor do I plan to) my engine to 7500+ rpm. Some say on a t3/t4 the best ar for a vr6 is 81 since the with the 63 it boosts too soon and runs out of breath. That's understandable but with the 81 ar, would I be as daily driver/street friendly as the 63 and where would I start to see boost and where would I see full boost? 

Sorry for the long post but I know the turbo gurus and more versed like to have as much info on goals and such so they can give the best/most accurate advise. 

Thanks in advance for any and all help. It's much appreciated.


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## AlexiGTIVR6 (Jul 21, 2000)

the t3/t4 .63 ar feels real good on a Kinetic stage 1. With the boost turned up any more it hits way to hard and you just get a lot of wheel spin. Not a good option for your HP goal 

The .82ar is a far better choice then the .63 in a t3t4. I have driven and put together countless VRt's and most had this set up. It gets the job done but deff there are better turbos out there. 

My car for the longest time had Gt3076 .82 ar. Back in 2005 when i installed it my goal was a nice daily Vrt with a round 350 hp. The car easily made that and more.. Of coarse after a while i always wanted the more Up untill around the 350 to 360 whp mark the turbo felt good. Its just when i turned it up more the turbo spooled up so fast after that the HP just went strait up. It was gaining 250+ whp in a 1000rpm. 

Felt awesome for 3rd /4th gear highway pulls but pretty useless powerband when i took it to the track. The car would run the same et's at the track on less boost just with a lower mph then a high boost run. 

I had enough so i had to change it out. My car now has a t4 flanged PT6262 and im loving it. My car was the development car for the new CTS pt6262 T4 , v-band dp set up. 

The power is so much more usefull. For example with my old set up i was struggling for by best et of a [email protected] at the track. Very hard to put the power down on street tires. With the new turbo running less boost i was running consistent 12's at a min of 120mph. best of [email protected] Cant wait to put it on the dyno to see what i can safely turn the boost up to


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## V-dubbulyuh (Nov 13, 2005)

*T3* anything less than *.82 a/r* on a VR is garbage. 


Given your fueling choice (42lb) and some of the turbos that you have listed you probably will be doing more than ~6 psi (how will you see 400 whp on low boost). Very low/tame boost numbers is the only justification I can see for considering a T3 .63 (which you would not need cams or the injectiors that you have selected). 
If you must run a T3, .82 is where you should start. It is also counterintutive to be installing cams (even if mild - 262's) and not be able to utilize the increased range because of a T3 .63 turbine housing. 

FWIW, I personally do not like T3 turbos on a VR, period.  

The 6262 best matches the other components of you build better (cams, injectors, chip, 400 whp). That being said, if finances are an issue though you might want to consider the Garrett 60-1 as an alternative. If this is your introduction to the FI world I would not start out with a Precision t3/t4 due to your unfamiliarity with suitable oil pressures etc potentially leading you to destroying those turbos in particular. Nothing against Precision as I personally do run them on my cars however the supporting oil setup is a lot more critical/unforgiving than a comparable Garrett. Do research on oil drain, oil feed and oil pressure with respect to Precision journal turbos and you will see what I am hinting at. You don't want this added complexity unless you are very familiar with FI.


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## gti vr6er (Oct 8, 2010)

AlexiGTIVR6 said:


> the t3/t4 .63 ar feels real good on a Kinetic stage 1. With the boost turned up any more it hits way to hard and you just get a lot of wheel spin. Not a good option for your HP goal
> 
> The .82ar is a far better choice then the .63 in a t3t4. I have driven and put together countless VRt's and most had this set up. It gets the job done but deff there are better turbos out there.
> 
> ...


 Funny u mentioned the 3076 .81 ar because I was kind of considering that too. But gaining 250whp at 1000rpm doesn't sound like much fun lol. Plus u say u were really pushing it with 350-360 and that would be right for my goals. I'm shooting for 400-420 with room to grow. What ar are u running on your 6262? Where do u start seeing boost and where are u at full boost?


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## gti vr6er (Oct 8, 2010)

V-dubbulyuh said:


> *T3* anything less than *.82 a/r* on a VR is garbage.
> 
> 
> Given your fueling choice (42lb) and some of the turbos that you have listed you probably will be doing more than ~6 psi (how will you see 400 whp on low boost). Very low/tame boost numbers is the only justification I can see for considering a T3 .63 (which you would not need cams or the injectiors that you have selected).
> ...


 A huge thank u for the headsup with the oil issues with the precision turbo. I'm sure I'll be wrapping my head around alot as is so not having a problem like that would really make life a bit easier. 

I think you are the 3rd person who's mentioned the 6262(not including the above post) so I'm seriously considering it(what ar would u recommend for my needs on the 6262?) Although, there is one problem: both the precision 6262 and Garrett gt35r both seem to be +$700 according to the cts website...and people rave about the gt35r that it's the holy grail for a vr6...so if price was the same, would u still(with my needs and goals) choose the 6262 and why?


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## gti vr6er (Oct 8, 2010)

Sorry for so many questions, I just don't want to make the mistake of the wrong turbo and have to rebuild. So far precision t3/t4 option is out. So Garrett t3/t4 60-1 for budget conscious 400hp(is it even capable of 400whp on the vr6?) or pony up $700 extra and get the 6262 or gt35. Damn, I'm really tapped out financially on this build but if that $700 more means I'll have room to grow as well as more reliability it might be worth holding off and saving a bit more.


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## V-dubbulyuh (Nov 13, 2005)

You will gain a slight spool advantage and power advantage with the Precision. The Precision powerband is very aggressive (ie comes on harsh/less linear) compared to the Gt35. 

The Gt35 is the standard because of how long it has been around and the robustness. My Gt35 has been on 3 different cars (lost count of how many engines) in the 7 yrs I've owned it, seen I don't know how many miles and I still daily it 70 miles. It has also never been rebuilt - zero issues. If extracting every last bit of power is not your thing and you want to play it safe, as many times as a Vrt Gt35 has been done you can't go wrong. 

The Precisions are great but not as consistent in terms of being forgiving (again see oiling issues), unless you pony up more money and get a BB version. If you want the most aggressive setup get a 6262 BB. I have yet to smoke one of their BB turbos... but then again I don't put many miles on them either. 

Hotside comes back to preference but looking at the other components in your setup like I said in the previous post t3 .83 would be adequate. _My preference for anything over 15 psi is t4 .81._ "Slow" spool is a myth if you have an appropriate exhaust setup. 

In summary: 
60-1 - if you are on a tight budget 
Gt35 - if you are unsure/want to play it safe 
6262/6266 - if you are power hungry and have a budget to account for either a JB rebuild or just start with a BB.


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## PjS860ct (Dec 22, 2002)

6266 with T4 .81 (journal bearing) is my choice.. ive always put a custom drilled restrictor on it (.080) instead of the normal .065 restrictor... never failed on me yet... ive had Precision Pt-61 on 3 engines for 3.5 years and it was still good when.i upgraded my setup last year... now i have the 6766 w/ .96 T4 on a better setup and i couldn't be happier... ill roast my 225/50 Mickey Thompson drag radials in 4th gear at low boost  lol not really fun as it suck still not having traction ll :/


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## V-dubbulyuh (Nov 13, 2005)

PjS860ct said:


> 6266 with T4 .81 (journal bearing) is my choice..


 I second your choice of hotside, that is what I run on my street/daily setups. 




PjS860ct said:


> ive always put a custom drilled restrictor on it (.080) instead of the normal .065 restrictor... never failed on me yet/


 
That is my point... the lattitude is not there for the variety of oil setups that people use. I've got a Precision t3/t4 off a 1.8T here that is somking and was used with the vendor-supplied restrictor from day one (ran perfect on the previous Garrett). You basically have to experiment to determine the appropriate restrictor & oil routing/sizing to avoid issues. If this is the OP's first dive into this kind of arena I would not suggest complicating things. 

I still love my Precision turbos and honestly they are the only thing that I buy new for my personal cars anymore but then again I have quite a bit of experience setting them up and if they blow up I am not too concerned. I've personally had good "luck" with them but I know how tempermental they are in general as I have had personal experience with *several* Precision failures (even though they were not owned by me). I've pulled quite a few of them that were bleeding at the turbine wheel. FWIW, they just released a 6466 so that might be something interesting to play with in future.


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## PjS860ct (Dec 22, 2002)

the new 6466 is suppose to be greater/better than the 6766 turbo but I think the 6466 only comes with BB center section... 

yea Precision is more aggressive with its power band and any of my friends Garrett turbos...

I dont know though if they are any worst than the Garrett jb turbos, ive seen them smoke on some of the cars here with less than 1000miles on them and they were new when installed... 

:beer:


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## V-dubbulyuh (Nov 13, 2005)

Yes, only BB but it is rated at a lower hp than the 6766 as you would expect. The spool is probably something crazy on the 64 though.


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## Norwegian-VR6 (Feb 6, 2002)

6466 billett bb T4 would have been fun to see on a 20+psi 12V :beer:


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## V-dubbulyuh (Nov 13, 2005)

^ It is actually very tempting.


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