6870 Turbo

Double-L · Jul 23, 2016

Well first this is what I have -
1987 grand national
3.8
JE with total seal filed rings
Champion GT1 aluminum heads
1.65 shaft mount rockers
Comp part # 69-400-8 Cam
Girdle
Egale Crank
Eagle H-Rods
Hemco plenum
Accufab 70mm throttle body
Big front mount Intercooler
83lb injectors
Meth Injection
Walbro twin pumps,
200 4r with the best All billit
PI 5 disk convertor,lockup at 126 mph
3.42 gear
LT1 mass air meter with translator
4" cold air intake
Turbonetics CPT 66 BB turbo
TA performance headers
ATR 3" down pipe
Turbonetics delta gate mark II 6psi
Turbonetics boost controller-
Well A friend took it to change the oil and called me and said we have a problem the bearings are bad in the turbo, We have talked about getting a new turbo so now I guess would be the best time, I was going to get a 6766 but after talking to the guy at Precision and told him our set up and what we do he said we would be better to go with a 6870, We run the car at 22 pounds of boost and it runs 10.40 at 131, The chip is burned for 24-26 but anything close we can't hook the car up, I have a fast system that we are going to put on and that should take care of that, Later going with e85 and bigger injectors, So what do you think, Suggestions, Commits

blklt1z28 · Jul 23, 2016

Well either turbo would be an upgrade...but you haven't stated what you're wanting or goals you have for the car.

Double-L · Jul 23, 2016

Well a lot of my goals have changed health but I have the parts and needed a turbo anyway and like they say is anything fast enough

blklt1z28 · Jul 23, 2016

Well the 6766 has been mid/high 9's with a standard buick exh housing and I would assume....that the 6870 would support more power, like low 9, high 8sec power, but would you still be able to spool it easily with your current converter? If you're running 131 in the 1/4 before then I'd spend some time tunning the suspension too. You're awfully close to a 9.xx as it is. The 6766 will def get you there like I said and still spool very easily with your combo.

Not sure if you posted it, but what's your current exhaust setup? Still running a buick 3 bolt housing? Int or ext gate?

V6sleeper · Jul 23, 2016

Imo I would do an 18 blade ptc nl and a 6766 with that combo, and do the 6870 if I was going 4 bolt.

Double-L · Jul 23, 2016

We have done some and more to do on the suspension and with the fast system we can work on where the boost comes on, The car is a blast to drive and race, If it wasn't so nice it would be easy I even have a LS6 that run 10.92 in my 5200 lb truck with a 122 super charger, That with a good turbo would be fun to but couldn't bring myself to do that

bad V6 · Jul 23, 2016

I would think you will be happier with the 6766. Jason White pushed the 6766 to 8.81 @ 153. The 6870 may have more upside, but at what price down low.

Double-L · Jul 23, 2016

Well already have the 6870 ordered,

Double-L · Jul 23, 2016

bad V6 said:
I would think you will be happier with the 6766. Jason White pushed the 6766 to 8.81 @ 153. The 6870 may have more upside, but at what price down low.

Don't know how that happen I can't post without a picture of my car with it, Can't seem to find a way to delete it either

bad V6 · Jul 24, 2016

Great looking car. Keep us posted as to how it performs.

BEATAV8 · Jul 24, 2016

I would also recommend the 6766 over the 6870.
The 6766 runs a more favorable boost to back pressure ratio than the 6870, especially in a 3 bolt config.

Double-L · Jul 24, 2016

Well I like I said I was going to order the 6766 but after the guy that built my engine talked to the people at Precision they said the 6870 would be the better choice for my car, I can't double guess them or my engine builder, I have run the car for 10 years and never had the heads off it, Wish I could say the same for the transmission, At 22 pounds of boost I can run bracket at 10.40, The car was purchased here in town and only had 5,000 miles on it when I got it, Have all the paper work, Window sticker and the stock wheel that had a few 100 mile when changed and a few other stock parks The car has original paint and still not a mark on it, My wife was the only person I know of that has ever set in the back seat, If it sounds like I am bragging, Just love the car, Will post what it does after the turbo change and the fast system, It is always fun to take someone a ride that has never rode in a turbo Buick

GNBRETT · Jul 24, 2016

I wudnt go 3 bolt with that Turbo. convert to a V band or 4 bolt if 6870

TTA976 · Jul 24, 2016

6780 is gonna spool slow with a PI multi disk...I would go bigger the a 6466BB. At your boost level (22) the 6870 is gonna be way out of its efficiency range.

Double-L · Jul 24, 2016

Well he told Precision everything about the car and the boost we was running and he said both are good but I would go with the 6870, Will have to wait to see if I regret getting it but he says I will love it

BEATAV8 · Jul 25, 2016

If its not too late, I would change the order. That 6870 is an expensive unit and will be difficult to sell.

TTA976 · Jul 25, 2016

I agree with Steve. Cancel it.

Tell them you want the 6262BB. It will spool like lightning with your upgraded bottom end /converter.

The guy you spoke to obviously has no idea what he's talking about. 70 turbine needs wayyyyyyy more converter.

Double-L · Jul 25, 2016

Well like I said will let you know how it does

L8TRH8R · Jul 25, 2016

6766 is a great turbo I've gone 10.50 @ 19 psi with mine on a soft launch and a 255 tire. 6870 is going to spool like a sloth without converter change, but, if you are mainly a track guy that may not be an issue for you.

Double-L · Jul 25, 2016

I know someone that has one on a car close to mine, I will ask him how his spool my car spools good now with the 66 BB and I just don't see how a 10 year old turbo will spool faster. It's 68mm on the inlet side. That's 2mm bigger than what i've got now. It's 70mm on the exhaust. I could be wrong but I can't see it killing the spool time. It's still ball bearing. It's the new gen 2 design. I just don't want to be a scenario where we wishing we had went with the recommendation from Precision

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