Ball Bearing Twins Idea

Jim Fulmer

Jim Fulmer

New member
I know some have done it, some have mapped it out but who is actually running them! Was thinking once again how it might workout, not a big set but a decent size set for street use......say under 600 hp!

It seems there are spenty of people running a single but I'm not impressed with there numbers but what about say a 66/88 combo with duel external wastegates, Any thoughts!

Yes this would be an expensive setup!

Jim
 
Well, it's not twins yet, but I'm running a GT4088R Garrett, and have a GT4508R on the shelf waiting for time and money to mate them!

I'm shooting for 700hp on #2...63.5mm top charger, 81.6mm bottom, dual external gates, and the tightest housings I can find for them! Right now I think I have a location on a .80A/R housing for the GT4508R, and a guy is checking to see what he can come up with for a smaller GT4088R housing...the factory .85A/R isn't cutting it on my 12v! On a CR, I'll bet it would be OK, but it likes to surge on mine!

I'm sure someone will beat me to completion with a ball bearing twinset!
Chris
 
now Jim let's not limit it to 600 hp---let's say for 700hp and 800hp and all the way up to say 1200 hp for now--if I had unlimitied funds and a shop I'd have had this figured out a long time ago, but alas I'm in the same boat as you---hopefully someone will chime in......chris
 
Well for the most part a decent 88mm primary would be good for well into the 800hp range (and on a CR motor pushing 1000hp). So if you want 600hp you'll be down in the 70's for inducer sizing. About the only reason a ball bearing turbo spools faster is the lower oil pressure requirements. If you look at Garrett's they use a restricter to limit oil pressure to the bearings. Lower oil pressure equals lower drag thus quicker spool up. Granted ball bearings typically can get away with less oil than thrust bearings.

Shortly I'm going to build a big set up for my '04.5 with a ball bearing secondary but the primary will be a standard thrust bearing. I thought about a ball bearing primary but the one I wanted to use was over 3500.00 so I went for a thrust bearing that was less than half of that. The biggest reason is this wont be my driver set up and I couldn't justify the cost. It's strictly for big hp.

For something that spools well and still makes good hp go with tight housings and external gates. A 62/B2 combo will make 600hp on any year of truck and if you want something faster spooling get a smaller exhaust side for the B2. I'm also building a 62/13SS and a 88mm turbo combo to see how well it drives. The 88mm turbo is a thrust bearing with a extremely tight exhaust housing and it will be externally gated. The 62 is too small in my opinion but I want something that drives nice and is still capable of 7-800hp. I can always go to a 64mm later too.
 
Chris, I was thinking more like a daily driver than a racer, figured they would be cool and operate nicely as long as the housings are small enough. Got to see a T-88 recently that had a .98 housing on it, not to big if you ask me.

No I'm changing my 12V to this, I like as a single on the bottle too much, but it's getting a Silver Bullet upgrade as we speak and will get a big solenoid for the second stage........as long as I can control the boost.

Jim
 
i built a twin set a couple of years ago with tubonetic ball bearing turbos. a 70mm on top of a 91 if i remember right, but i might be wrong. it was for james lucas's daughter. she has been driving it every day at school for the past couple of years. i will dig up some pics.
 
gunracer1
 
Jim Fulmer said:
Chris, I was thinking more like a daily driver than a racer, figured they would be cool and operate nicely as long as the housings are small enough. Got to see a T-88 recently that had a .98 housing on it, not to big if you ask me.

No I'm changing my 12V to this, I like as a single on the bottle too much, but it's getting a Silver Bullet upgrade as we speak and will get a big solenoid for the second stage........as long as I can control the boost.

Jim
Click to expand...

Mine will be daily driven...but I know I'm not the Chris you were referring too:D For a 600-650HP daily driver, I'd go with the Garrett Stage II BB (GT3782R) and a GT4202R. Should spool very fast, and cool like a 62/S400 set, or slightly better, from what I've seen of the Stage II Garrett!

I think if I can get the primary housing on my 4088 down to a .60 or .70A/R, I'd be a lot better off...even with the ball bearing, the big wheel on the turbine side takes a bit to get spinning.

Chris
 
I like the blow off valve on the intake horn. I wish I drove something like that back and forth to school.
 
So let say you used a 66 with a .81 housing and a T-88 with a .96 housing using lets say duel 44 mm wastegates.....one in the manifold, one in the hot pipe.

Nathan, how would these work and is this the setup that Cliff put together for his School paper.

Jim
 
Jim,

It is the set up Cliff did his paper on. It is a good combo for balance and would work well. It might spool slightly slower than you want but I definately dont think it would be undrivable or unable to tow by any means. I would expect it to spool slower than a 62/B2 combo but it has the potential to make way more power. The T-88 flows almost as much as the Big Brother so it can make around 800hp + or - but it will make more drive pressure getting there.

Nathan
 
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