6870 Turbo

[TTA976]

Cant think about like that. Turbos have what is called a compressor map. At your boost level the 68 compressor is no where near where it needs to be for it to be efficient at 22#.

You have remember the T66 is a (6665) with a .63 exhaust housing which is a true stock style exhaust housing. You are making a HUGE change.

Also, a 6870 does not belong in a buick 3 bolt housing. That doesn't make any sense to me. That turbo is capable of 1100+ HP which could never be made in the 3 bolt Buick housing you are receiving.

There should be a particular match between a compressor wheel and A/R housing. That set up is no where near a close match.

Your car is barely going to be able to build any boost at the line if any. It's gonna spool like it's tied to a tree.

 

[Double-L]

Well there is a lot of opinion but like I said with the fast system on we can have more control over the tune and I will let everyone know how it boost and how it runs, If worse comes to worst I will just stick a smaller turbo on, I do want to do some dyno pulls with both turbos, It took a 70 off when I put the 66 on

 

[BEATAV8]

Post #86 has some boost / back data:
http://www.turbobuick.com/threads/precision-6870-gen2-cea.407363/page-5

This illustrates how aggressive the compressor is relative to the turbine. It could benefit from having a larger turbine than what it has.

 

[Ed Valvo]

If you're not afraid to turn up the boost, run more boost with the turbo you have now and see what it does. With the 6870, you'll go slower with the same boost level until you turn it up to the moon. I'm tinkering with a 7168 which the 6870 replaces so I've had very similar issues to what everyone here is trying to help you avoid.

 

[forcefed3.8's]

I replaced a TE63e .63 with a 6766 .85, and it spools faster on a 9:1 233"

 

[Mr.Spool]

If worse comes to worst I will just stick a smaller turbo on,

if your a street guy you will be surprised how much time a bigger turbo will cost you,there are better/cheaper turbo options for a 10sec car.oversizing the ex side at that power level kills the combo as any 65/66 turbine wheel with a decent size comp wheel can run 9s with much better turbo response.

 

[ttypewhite]

You will be just fine with this turbo. Spooling won't be a issue. Your converter on the other hand.... remains to be seen. A turbo of this magnitude with a lock up converter is eventually going to cause you a issue. From reading your post, I would definitely concentrate more on your suspension. There is no reason your car should be blowing away the tires from 24 to 26 psi ( no offense, it doesn't make that much power to do that). Something is wrong here. When my car was running high 9's in 2005 I would leave at 20psi off of the transbrake and hook 1.37 sixty foots consistently with only Lakewood shocks all around on a completely factory set up and no electronic boost controller (just a manual bleeder valve). Just keep in mind, that "IF" you figure out your suspension issue and turn up the boost, your injector duty cycle is something you want to keep a eye on. Your under injected with that turbo. With a set of 95lb injectors and a Dusty spec'd PTC 9.5" converter..... this car will be like nothing you have seen before. Good luck.

 

[sackracing]

The 68/70 will perform at 22 pounds. I've been 5s in the 1/8 on 22 and 5.76 on 28 pounds. It makes crazy power at lower boost.
It's not what I would have chosen for that combo tho.
I would recommend a PTC converter matched to the combo tho.

 

[turbocamino1]

I replaced a TE63e .63 with a 6766 .85, and it spools faster on a 9:1 233"

interesting..is this because the te-63 is an old cast wheel?

 

[sackracing]

The new turbine wheels perform much better than the old ones. They are all cast.

 

[TTA976]

I'm confused .. Tmk, Jason White went 8.80s with a 67/66 three bolt. Bison went high 9's with a MFS 6265. Why would OP need anything bigger than a 6266? A 6266BB w/ .85 3 bolt will make plenty of power and he wouldn't have to change a thing.

Why would someone put a 3 bolt on a 70 turbine? A 6780 is rated 1100hp. Why choke it off to 750-760hp, pushing it, with a 3 bolt .85? A .82 T4 or bigger makes a lot more sense on a 6870.

I'd do a PTE 6266BB .85 3 bolt on his setup and be done with it.

 

[BEATAV8]

I'm confused .. Tmk, Jason White went 8.80s with a 67/66 three bolt. Bison went high 9's with a MFS 6265. Why would OP need anything bigger than a 6266? A 6266BB w/ .85 3 bolt will make plenty of power and he wouldn't have to change a thing.

Why would someone put a 3 bolt on a 70 turbine? A 6780 is rated 1100hp. Why choke it off to 750-760hp, pushing it, with a 3 bolt .85? A .82 T4 or bigger makes a lot more sense on a 6870.

I'd do a PTE 6266BB .85 3 bolt on his setup and be done with it.

I think your spot on.
6266, 6766, 6870. All can work here. The 6870 is just excessively big.... not ideal.

I for one would like to take a look at using the 67 CEA compressor with that 70 turbine, even if in a 3 bolt. Curious if there would be any back pressure reduction or if it wouldn't matter (relative to a 6766). I sorta doubt precision would build such a turbo though, even if custom ordered.

 

[sackracing]

I'm confused .. Tmk, Jason White went 8.80s with a 67/66 three bolt. Bison went high 9's with a MFS 6265. Why would OP need anything bigger than a 6266? A 6266BB w/ .85 3 bolt will make plenty of power and he wouldn't have to change a thing.

Why would someone put a 3 bolt on a 70 turbine? A 6780 is rated 1100hp. Why choke it off to 750-760hp, pushing it, with a 3 bolt .85? A .82 T4 or bigger makes a lot more sense on a 6870.

I'd do a PTE 6266BB .85 3 bolt on his setup and be done with it.

I'm pretty sure I'm making more than 750 with a 3 bolt 68/70. I know Richie is making more. He's been low 8.70s in TSM trim with his.

 

[ttypewhite]

I'm confused .. Tmk, Jason White went 8.80s with a 67/66 three bolt. Bison went high 9's with a MFS 6265. Why would OP need anything bigger than a 6266? A 6266BB w/ .85 3 bolt will make plenty of power and he wouldn't have to change a thing.

Why would someone put a 3 bolt on a 70 turbine? A 6780 is rated 1100hp. Why choke it off to 750-760hp, pushing it, with a 3 bolt .85? A .82 T4 or bigger makes a lot more sense on a 6870.

I'd do a PTE 6266BB .85 3 bolt on his setup and be done with it.

He could have ran 9's with his current turbo and more boost if his turbo wasn't blowing smoke. The choice was already made, the 6780 is on route from what he said, so there's no point in discussing anything outside of this seeing how he is going to run it. You'll be shocked to see how quick this turbo comes on boost. A lot of people have a false impression of the 6780. Most people look at the rating of 1,100hp and think it's a big lazy slow spooling turbo. That couldn't be anymore false. With the right converter and a good tune, this turbo can come on boost extremely quick. I have seen it first hand. I also don't understand the logic your speaking of about why someone would put a 3 bolt on a 70 turbine. This turbo in a 3 bolt configuration has broken TSM records and is more then capable of exceeding the OP's goals.

 

[kandc7]

Richie has run 8.68 @154.23 with 6870 .85 3bolt.

 

[V6sleeper]

The 5 disc vig converter is the weak link here, although I think its a good converter, I run one in a car and I wouldn't use it with anything bigger then a 62mm imo , had it against 6765bb,T-66 single bb was slower to spool but worked ok, then a 60-1 and a 6262 it spooled like a rocket.

 

[TTA976]

He could have ran 9's with his current turbo and more boost if his turbo wasn't blowing smoke. .

I don't think that's possible with a true Tnetics .63 housing(similar to Garrett .63) That setup MIGHT take you to 10.3X. If he had a PTE exhaust housing then okay.

sack racing, with all respect, have you ever had it on a mustang dyno? Or are you using a racing calculator??? Maybe, 775hp is ABOUT the most I could imagine.

I agree with V6sleeper, a 62 with the tall turbine (6265/66(BB, of course) is the biggest I'd go with that 5 disc on his setup.

 

[GNBRETT]

I don't think that's possible with a true Tnetics .63 housing(similar to Garrett .63) That setup MIGHT take you to 10.3X. If he had a PTE exhaust housing then okay.

sack racing, with all respect, have you ever had it on a mustang dyno? Or are you using a racing calculator??? Maybe, 775hp is ABOUT the most I could imagine.

I agree with V6sleeper, a 62 with the tall turbine (6265/66(BB, of course) is the biggest I'd go with that 5 disc on his setup.

other then you no one uses Mustang dyno's around here so ur point is moot. its already be stated thats its gone 8.68@154. thats about a 1000 hp. on ur Mustang dyno thats 850-900. IDN where u get 775 other then a bad guess.

 

[sackracing]

I've never been on a dyno.
I've been 149 and Richie has been 154.6 in 3350 pound cars.
The math shows thats more than 775 even with margin of error.

I'm presenting actual data, not opinion.

 

[machinegun]

Any chance I could by your 66?