# Precision 67/66



## joshisapunk (Oct 1, 2004)

Okay, hypothetical question time. 

Stock vr6 longblock with 8.5:1 headspacer, full 3.0" exhaust and an SRI. 

What approximate rpm would i see full boost (20-25 psi) with the .68 ar T4 turbine housing?


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## cabzilla (Jan 3, 2000)

lateish. like 4500 or a bit more


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## MiamiVr6T (Jul 24, 2004)

6765 T4 .81 a/r. 24 psi. 2nd and 3rd gear pull on M&H 235/60/15


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## PjS860ct (Dec 22, 2002)

^ sounds awesome!


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## V-dubbulyuh (Nov 13, 2005)

cabzilla said:


> lateish. like 4500 or a bit more


That turbo spools a lot quicker despite its size. On the T4 .81 I can hit 20 psi by 4K no problem.


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## 2DR16VT (Mar 16, 2006)

What power are you guys seeing on this turbo at 25psi ?


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## MiamiVr6T (Jul 24, 2004)

2DR16VT said:


> What power are you guys seeing on this turbo at 25psi ?


with a 6765 I've made [email protected] on a 26" tire. I make around 550-560whp now that I put a headspacer with the same tire and goes 140mph in the 1/4.


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## Yareka (Mar 5, 2002)

V-dubbulyuh said:


> That turbo spools a lot quicker despite its size. On the T4 .81 I can hit 20 psi by 4K no problem.


Holy ****, wouldnt have thought that. What compression and exhaust manifold?


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## V-dubbulyuh (Nov 13, 2005)

MiamiVr6T said:


> with a 6765 I've made [email protected] on a 26" tire. I make around 550-560whp now that I put a headspacer.


What was the compression ratio before and after (making 575 then 550)?


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## V-dubbulyuh (Nov 13, 2005)

Yareka said:


> Holy ****, wouldnt have thought that. What compression and exhaust manifold?


It will be interesting to see what MiamiVRT sees for PRM and spool.

The numbers I gave are on a modified Kinetic manifold (porting and wastegate relocated to on top of the collector), 8.5:1 CR and a BB turbo. From my experience on that turbo the JB will delay you a good 300 RPM. That 6765 BB spools up rapidly especially once you get above 10 psi or so.


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## joshisapunk (Oct 1, 2004)

wow, a lot of very encouraging numbers in this thread. I unfortunately ended up going with a garret T67 with an on-center 0.69ar turbine housing for this season to save some cash (allowed me to keep my gutted stock intake mani and atp exhaust manifold).....Still hoping to see 500whp at 25psi with the T67 and C2 pro maf setup


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## 05JettaGLXVR6 (Jan 25, 2006)

Ive gone 150-152mph on 35-40 Psi 8:5:1 comp. 67 65 .96 makes 30+psi at 5k.


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## M.P (Mar 7, 2009)

05JettaGLXVR6 said:


> Ive gone 150-152mph on 35-40 Psi 8:5:1 comp. 67 65 .96 makes 30+psi at 5k.



do you have any problems with 6765 ?? 
in this video your turbo smoking terrible  http://www.youtube.com/watch?v=1OqAQZTRCSk&feature=channel_video_title


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## MiamiVr6T (Jul 24, 2004)

V-dubbulyuh said:


> What was the compression ratio before and after (making 575 then 550)?


went from around 10:1 to 8.5:1


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## V-dubbulyuh (Nov 13, 2005)

MiamiVr6T said:


> went from around 10:1 to 8.5:1


Mmm, so the comp drop cost you ~25hp. Thanks for the update. :thumbup:


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## MiamiVr6T (Jul 24, 2004)

V-dubbulyuh said:


> Mmm, so the comp drop cost you ~25hp. Thanks for the update. :thumbup:


 
I just remembered I put a cam in during the change and this is how it went:

10:1 stock cams @ 25psi = 575whp
10:1 268 cams @ 22psi = 570whp
8.5:1 268 cams @ 24psi = 550whp (Current Setup)

So the higher compression looks to be around ~40-50whp

*Remember these dynos are on 26" tires*


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## V-dubbulyuh (Nov 13, 2005)

MiamiVr6T said:


> I just remembered I put a cam in during the change and this is how it went:
> 
> 10:1 stock cams @ 25psi = 575whp
> 10:1 268 cams @ 22psi = 570whp
> ...


I know you run stand-alone so why the severe compression drop? Were you having detonation/lean issues at 10:1? Or just pouring more boost at it, > 25?


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## MiamiVr6T (Jul 24, 2004)

V-dubbulyuh said:


> I know you run stand-alone so why the severe compression drop? Were you having detonation/lean issues at 10:1? Or just pouring more boost at it, > 25?


Headgasket blew twice. I gave it one last chance and put in a 8.5:1 spacer. So far, so good :thumbup:


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## V-dubbulyuh (Nov 13, 2005)

MiamiVr6T said:


> Headgasket blew twice. I gave it one last chance and put in a 8.5:1 spacer. So far, so good :thumbup:


I use 8.5:1 too but only if around the upper 20's to 30 mark. 25 psi or less the 9:1 seems to suffice, even on a chip tune.

You made nice numbers regardless. :thumbup:


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## PjS860ct (Dec 22, 2002)

M.P said:


> do you have any problems with 6765 ??
> in this video your turbo smoking terrible  http://www.youtube.com/watch?v=1OqAQZTRCSk&feature=channel_video_title


I think thats when he had a low compression on 1 of his cylinders... which when he ran his best mph at 152:thumbup: Lugtronic ftw


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## 05JettaGLXVR6 (Jan 25, 2006)

M.P said:


> do you have any problems with 6765 ??
> in this video your turbo smoking terrible  http://www.youtube.com/watch?v=1OqAQZTRCSk&feature=channel_video_title


Usually try to keep the car cool. But had to let the thermostat open that day cause my battery was shot. I think the valve seals leaked when they got hot. I replaced them so well see if that fixes it


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## MiamiVr6T (Jul 24, 2004)

V-dubbulyuh said:


> I use 8.5:1 too but only if around the upper 20's to 30 mark. 25 psi or less the 9:1 seems to suffice, even on a chip tune.
> 
> You made nice numbers regardless. :thumbup:


Thanks :thumbup:

But remember, psi and whp are different animals. Above 600whp I'd go to 8.5:1


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## M.P (Mar 7, 2009)

05JettaGLXVR6 said:


> Usually try to keep the car cool. But had to let the thermostat open that day cause my battery was shot. I think the valve seals leaked when they got hot. I replaced them so well see if that fixes it


we have 2 broken 6765 billet Journal bearing / for that I asked


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