Which Turbo?

[INTERCOOLED]

Hey guys-

Just thought that I would get some opinions. I have built a motor with Stock block, Main caps, Eagle Forged Crank, K1 H-Beam rods, Diamond Pistons, Roller Cam, GN1 Heads, Champion Intake and fuel rails, 83 lb. injectors, 70mm TB, Precision Front Mount, etc....all the good stuff.

I was thinking about a 72........whatcha think?

 

[RUQWKNF]

Honestly, the next big thing will more than likely be the PT70 GT-Q with the dual bb internals. This turbo will easily support 850 flywheel hp, and by all reports should only need a 3500 stall converter. It will also support enough hp to physically break a 109 over time. Unfortunately no ETA on when they will start shipping tho.
Question about your combo, what engine management system? Stock ECM, XFI, BS3, FAST?
The 70 GT-Q is a little bit more efficient with a combo like this vs the 72.
What boost do you want to run with your combo? Meaning, do you want to run higher than 25psi? Or do you want to make tons of power with boost levels under 25? If less than 25 and you can live with a 3800-4000 stall converter and gotta have it now, then I would suggest the PT74 GT-Q non ball bearing with a .85 A/R PTE housing. Also, do you plan on running any classes with the car or just having fun? What ET and mph are you aiming for? FWIW, I would choose a 74 GT-Q vs a 72 any day.
Let us know.

Patrick

 

[INTERCOOLED]

Honestly, the next big thing will more than likely be the PT70 GT-Q with the dual bb internals. This turbo will easily support 850 flywheel hp, and by all reports should only need a 3500 stall converter. It will also support enough hp to physically break a 109 over time. Unfortunately no ETA on when they will start shipping tho.
Question about your combo, what engine management system? Stock ECM, XFI, BS3, FAST?
The 70 GT-Q is a little bit more efficient with a combo like this vs the 72.
What boost do you want to run with your combo? Meaning, do you want to run higher than 25psi? Or do you want to make tons of power with boost levels under 25? If less than 25 and you can live with a 3800-4000 stall converter and gotta have it now, then I would suggest the PT74 GT-Q non ball bearing with a .85 A/R PTE housing. Also, do you plan on running any classes with the car or just having fun? What ET and mph are you aiming for? FWIW, I would choose a 74 GT-Q vs a 72 any day.
Let us know.

Patrick

Thanks for the reply. For starters, I am planning on using the FAST system. That way the car can be tuned to its best potential. I haven't really thought about the boost level I want to run. Obviously, I am wanting to run 10s without any problems. I am not running nitrous on the car. I know that some folks like to use it with bigger turbos to make up for the lag, but I will decide that later. I plan on having a lot of fun on the street and will take it to the track occasionally. I am not wanting to put a roll cage in it yet, so I am limiting myself at the strip because of the requirements. Also, I was planning on a non ball-bearing turbo because of longevity issues.

 

[Black Power]

with that setup you could run 10s with a TE45a i believe...if you have a good stall of course.

also, I thought the BB turbo's were more reliable ???

 

[RUQWKNF]

The Garrett ball bearing turbos are more reliable than their journal bearing cousins. Honestly, if you were just wanting to run mid to low 10's and wanted to keep your spool up, then that changes things slightly. If you're dead set against BB turbos, then I would recommend the PT6776S, this is a non bb turbo with a 67mm inducer compressor wheel and the P-trim turbine wheel. This turbo is rated to support up to 750 flywheel hp and would spool just fine with a 3500 stall converter. I have had numerous customers run this turbo on full weight Buicks with great success. Easy mid to low 10's on 25-27psi. It is also available with the Garrett dual BB chra.
HTH

Patrick

 

[INTERCOOLED]

The Garrett ball bearing turbos are more reliable than their journal bearing cousins. Honestly, if you were just wanting to run mid to low 10's and wanted to keep your spool up, then that changes things slightly. If you're dead set against BB turbos, then I would recommend the PT6776S, this is a non bb turbo with a 67mm inducer compressor wheel and the P-trim turbine wheel. This turbo is rated to support up to 750 flywheel hp and would spool just fine with a 3500 stall converter. I have had numerous customers run this turbo on full weight Buicks with great success. Easy mid to low 10's on 25-27psi. It is also available with the Garrett dual BB chra.
HTH

Patrick

Patrick-

Thanks for the responses. I am getting a little more of an education about the BB turbos vs. the non-BB, and I thank you for it.

Here's the thing......what if I wanted the car to run the best that it is capable of...both on and off the street? I other words....make it the baddest car it can be.......what would you recommend in THAT situation?

 

[KENAN_JAMES]

Turbo Choice

Easy question, lots of proven setups to research from to make a choice. My vote would be the same turbo the guy is using in the new GM high Tech Mag. (Pt 67GTQ) great spool up with a 3500 stall capable of pushin the right setup into the 10s.

 

[John Wilde]

Thanks for the great information Patrick!!!

 

[INTERCOOLED]

Patrick-

After being a little more eduacted on the BB and Dual BB turbos, I am not against purchasing one if it will produce the best results for my combo. I had actually thought about the BB turbo first, then decided against it after input from others.

With that said.....which turbo would you recommend?

Would I be selling myself short by getting the 67?

Would I be disappointed in the lag of the larger 72 or 74?

I want to spank some serious ass on the street AND turn the best ET possible at the track.

Also, would the higher stall with the non-BB turbo be ridiculous driving around town?




Sorry for being such a pain......

 

[RUQWKNF]

No problemo.
If bb is ruled out, then you have to ask yourself how much converter are you willing to live with? IMHO, a 4000 stall converter is too much for a street driven Buick. Some do it all the time, I'm even guilty of it with my old S2 Grey car. But if you do more driving that simple cruise ins or hang out spots, 4000 is too much. Now, if you go lower to say a 3800, this limits your turbo choices.
Anything larger than a PT70GTQ will make more power, but will need a 4000 stall converter. Sure a PT74GTQ will make crazy power at lower boost levels, but I would much rather sacrifice maximum top end power, for quicker spool up and less converter slippage. In a perfect world, everyone wants 700 whp and a low stall tight converter that can travel across the country and get high 20's in gas mileage. Unfortunately, this is almost impossible without using a dual ball bearing chra. Remember, one persons take on streetability will always be different than another. If your hp goal is 650-750 reliably, and running a 3600-3800 converter, the PT67GTQ would be a little better as far as spool up goes. You really have to make a personal decision on sacrifices made with regards to streetability. (IE converter stall)
Technically, a PT70GTQ makes enough power to eventually break even a full blown 248ci TSM motor. My personal choices are still this, 235-248ci stop with the PT70GTQ, 252-276ci Stage II with 3-bolt turbo, PT76GTQ, 276 Stage II wanting to make 800-1200 fwhp with a 4-bolt turbo, Then PT76GTS or PT88. All out race car Stage II 276+ci, GT4788R - PT91 F-trim for single, twins would be PT70GTSR dual ball bearing when they come out, or GT4508R featuring 80mm compressor wheel.

Just my O2s worth.

Patrick

 

[John Wilde]

Patrick what about the GT5533R for a single, that should work better than the 91.5 / F trim don't you think? Also how do you feel about the GT4094R for twins???

 

[bison]

If you are running under 6000rpm and under 28 psi boost then i would not go any bigger than a 70GTQ. BB or not. You dont have a girdle listed in your sig, only caps. You cant detoante this thing at all or it will break for sure with the high boost.

 

[RUQWKNF]

Hi John.
To be honest, I don't remember anyone actually trying the GT5533 on a Buick unless it was on the sneak, Top Secret R&D. However, it being the replacement for the older 91.5 F, it technically should work, especially if they offer it in DBB which Garrett claims is in the works. I never laid eyes on one of the R versions while I was there. The GT4094R is their latest GT40R with a larger comp wheel, which from what I've been told will support an honest 800 fwhp without pushing it too hard. Now that would be roughly 1600 fwhp worth of airflow with DBB cartridges when maxed out. If they make them with the same turbine housing options, then I'd say yes, you should have a winner combo for twins. The trick will be determining which housings would work the best with as little lag as you can live with. Meaning, we want the largest A/R housing on them that you could spool up in race conditions. IE Pro .400 tree heads up racing. Garrett offers 4 turbine housing options, .85, .95, 1.06 & 1.19. I would like to see a full on built 276+ ci aluminum motor with two of these and the 1.06 A/R housings and see what kind of power could be made to the tires running 28-30psi. I would suspect somewhere north of 1300-1400 whp would not be too hard to achieve.
Here is the map and link for this turbo.

TurboByGarrett.com - Catalog
You'd probably have to still run a 4000 stall converter with a t-brake, but it would be a blast. Although the 1.19 A/R would be prefered, I seriously doubt even a 276+ ci would be able to spool up quick enough and be able to cut a light with them. The only downside right now is, noone offers a true 3-bolt Buick turbine housing for this turbo at this time. It should however, out perform a 67mm 4-bolt tangential housing equipped turbo.
HTH

Patrick

 

[John Wilde]

Patrick,

Harry offered to make us a GT5533 for Orlando.
Considering the damage we incurred with GT4718 I am glad we did not make
the swap!!!

 

[John Wilde]

Patrick,

Thanks for all your input.
I really like the GT4094 for twins on a stage 2.
If I can finish my junk I may try them!!!

 

[INTERCOOLED]

I would recommend the PT6776S, this is a non bb turbo with a 67mm inducer compressor wheel and the P-trim turbine wheel. This turbo is rated to support up to 750 flywheel hp and would spool just fine with a 3500 stall converter. I have had numerous customers run this turbo on full weight Buicks with great success. Easy mid to low 10's on 25-27psi. It is also available with the Garrett dual BB chra.

Would there be a significant difference by buying the PT6776S with the Garrett dual BB chra over the same turbo without?

Also....in your opinion....which one would be the better purchase with my set-up?.....the PT6776S described above or the next big thing, the PT70 GT-Q with the dual bb internals?

 

[RUQWKNF]

The difference on the 67 from non bb to bb could easily be 600-800 rpm difference in spool up time. Here is the main differences between the 6776RS and the 7080RH that they are developing. The 67 is pretty much done at around 785-790 fwhp, and that would be pushing that rotating assembly very hard. (29-35psi) After 28psi, the charge temps from the 67 wheel start to climb. If you want to push a 6776R past 28psi, I would recommend you equip it with an H cover so the charge temps won't be as high. To this day, I don't know of anyone who has maxed out a PT6776RH, not too mention of anyone actually has one as this turbo is normally equipped with either the standard S cover or the S cover with the ported shroud. If you know for a fact that you want to make over 750 hp to the wheels, then your turbo choice should be the PT70 GT-Q with or without dual ball bearings. It's going to be almost impossible to make 750hp to the tires with the 6776R turbo, unless of course you run nitrous or Alky, but that's a whole other bag of worms. With regards to the 7080RH, (which is PTE terms should be the next logical part number for a PT70 GT-Q with ball bearing) I don't believe anyone in the Buick community has gotten their hands on one of these new turbos yet due to not being on the shelf. Now, this might have changed this past week, but I honestly don't know. I would recommend you call PTE yourself and ask them when they will start shipping them. Until someone gets one for a Buick and does back to back dyno testing or track testing, (PT70 GT-Q non bb, vs PT70 GT-Q ball bearing version) we won't know. But I can say this, in all of the testing results I have seen or heard about, whenever someone would go from non ball bearing to ball bearing with the exact same wheel combo, customers would report 600-800 rpm difference in spool up as a minimum, in some cases up to 1000 rpm difference. This was on everything from Honda 4 cylinders, Mitsubishi 4G63 4 cylinders, Supra I6 turbo, and even some V8 applications.
Hope some of this helps.

Patrick