Did a quick search and didn't see anything, Jim Wolf is working on a twin turbo kit with Garrett full ball-bearing turbos and submitting it to CARB:
http://www.jimwolftechnology.com/news.asp


'03 G35 Coupe 6spd, briliant silver, all options. Brembo upgrade all 4 corners, 19" Gunmetal LE3T's, HKS Hipermax LS+, HKS Legamax exhaust, Gialla grill.

 

I've had experience w/ ball-bearing turbos and they like race gas and lots of boost to put down good numbers. And since TS and Signal are blowing up there G/Z's every other week at 9-10 psi on a stock V35 I'd say look else where or build the engine first. Only bb turbo I've personally seen throw down some decent numbers was a HKS 3037S single conversion on a RX-7 but there big money. Personally I'd go w/ a Greddy kit and run 5-6 pounds tops.

 

There was just a thread on this a day or so ago, I forget where it was located in the forum though. it was the coupe, sedan or this section though.
Ball bearing turbos are awesome! They have better response and efficiency and reduced spool up with long life. But they are more expensive by a few hundred dollars, when compared to a non bb turbo. Garrett recently released a new ball bearing turbo that's perfect for the 2.0L SR20 motor, it's the GT28RS (aka disco potato turbo). It starts to spool up pretty much right off idle and holds boost up to redline (7500-8000rpms). The turbos will easily support 300whp+ on that motor. Two of these turbos on a VQ35 would still spool up within a resonable rpm range and provide an insane amount of top end power (2-3x the stock hp?). Probably a little bit of overkill for a street driven car....
JWT's turbos are a little bit smaller, and will probalby only run at 50-75% of their limit, allowing for some additional power upgrades in the future. One of the first probably being lower compression and beefier components in the bottom end of the motor.

Justin McClanahan
Heavily Modified 95 Infiniti G20
Working on a G35 Project Coupe
EverythingG35.com

 

Weather or not a turbo has a ball-bearing center section or not has nothing to do with weather or not it will blow up at 9 or 10 peak psi. Why not run 5-6 psi on the BB turbos and get a better more usable power curve? If you compare similar size turbos at the same boost the BB is the better choice for it's power delivery and longevity. You have to consider the size of the turbo also (9 psi on a small turbo vs 9 psi for a big turbo does not have the same volume of air). The tuning would be different for large vs small turbos at the same boost.

There are a lot of factors. From what I've heard the rings are very high up on the stock pistons reducing the amount of material above them. This makes them more prone to breaking with too much power, not to mention the compression. I will agree with you that building the block would be wise for more serious power. The HP range mentioned on JWT's site seems to be all the stock will hold reliably and what most forced induction tuners are shooting for right now (JWT, Greddy, ATI, Vortec, ect).

Then again, who know's for sure if that's all the pistons can handle when (in my opinion) no one is running "real" engine management here yet. It's all piggy backs and basic stuff tuned by "who knows". Until a reliable tuner with a real computer (like maybe JWT or an AEM EMS plug and play stand alone) tunes a car the right way we won't know for sure. If a good tuner with a real computer tunes a turbo or s/c car and does it right and the motor breaks then we can say "hey, there's the limit", but I don't think we can say that yet when you have guys blowing up on boost dependant fuel pressure regulators ect. Who knows if TS and Signal have the ECU cracked yet. Jim Wolf has good ties to Nissan, maybe he has it cracked. I can only hope, as the ECU is the big bottle neck right now for any level of mods.

There are tons of Supras with the HKS/Garrett GT28 kits making good power here as well as EVO's with the GT3037. There is also a Z32 kit from them. The RX7 isn't the only application where they will work well. Hell, on any application I'd say a BB turbo is better than a bushing turbo if you can afford it.

'03 G35 Coupe 6spd, briliant silver, all options. Brembo upgrade all 4 corners, 19" Gunmetal LE3T's, HKS Hipermax LS+, HKS Legamax exhaust, Gialla grill.

 

Gabe and Justin you both have great points and I totally agree w/ you both. My only point is this. With the garrett wheels on the market at the 9-10 psi on pump gas the bushing turbos will put more power to the wheels than a bb. That's not to say bb are bad I love how they spool. In my personal experience I had a 46 trim garrett turbo w/ a t04b housing and at 20 psi tuned w/ a laptop on 93 pump(8.5:1 compression mind you) I netted 336 whp. Three months later I anted up for a GT30(bb) 52trim(74% eff.) t04e(slightly larger housing) and at 20 pounds on pump I maxed out at 303 whp w/ 1-3 counts of knock up top. The shop than threw in c16, redynoed it about 4-5 times @ 25 psi and I saw 392 whp. This was off a dynojet. The ball-bearing turbos spool several 100 rpm sooner than a bushing, but where you feel it most is inbetween shifts, it's almost like you don't lose boost w/ a bb turbo. I just don't want somebody to go spend all this money on a bb turbo setup and be disappointed. I made a $1500 mistake when I chose a bb turbo, w/ this car it's more like a $7k mistake not counting labor. That's a lot of money to be pi$$ing away. Until they come out w/ much larger rods, stronger pistons, oversized valves, and decent cams or some type of stroker kit I 'd recommend keeping it NA for now.

 

"With the garrett wheels on the market at the 9-10 psi on pump gas the bushing turbos will put more power to the wheels than a bb"

How do you figure that? What turbos/maps are you comparing?

It sorta sounds like you had custom tuned the car to the first turbo, then everything changed when you switched turbos and the old maps were no longer optimal (hence the detonation) and that a good retune (instead of just running higher octane gas) would have gained some power back. Right?


Justin McClanahan
Heavily Modified 95 Infiniti G20
Working on a G35 Project Coupe
EverythingG35.com

 

I will comment when I come back from a busness trip on Tuesday! Have a good weekend.
Later,

'03 G35 Coupe 6spd, briliant silver, all options. Brembo upgrade all 4 corners, 19" Gunmetal LE3T's, HKS Hipermax LS+, HKS Legamax exhaust, Gialla grill.

 

Ok so my trip got cancelled!
1PHATG35, I'm not trying to pick on you but the only thing I'll agree with you on is that for someone who wants a turbo kit for a cheap price then the bushing turbos would offer a better price point. But thinking long term (if you are going to keep it for a while) the BB turbo is a better value as bushings can wear out before bearings. They could cause the wheels to contact the housings and destroy the turbos. The BB versions can handle more load and are more durable, so in the long run that will save you money vs replacing a whole bushing turbo. Then there are the obvious performance benefits.

Again, comparing turbos of the similar wheel sizes and housings the BB would offer better response vs a bushing turbo. If the turbos were identical except for the center section the bushing turbo would not make more power! Which is what you are basically saying. Now if your BB turbo had a much smaller turbine housing/wheel or compressor housing/wheel than your bushing turbo then yes, it is defintely possible that it could not make as much peak power. A lighter wastegate spring or bad tuning could also produce this result. As a matter of fact, a lot of things could have produced this result! I think you just had a bad experience with the tuner or were led to expect something out of that size turbo on your application and where misled.

If those turbos where similar in size then you should have out performed something based off a T04B. Thats an old turbo, and has old wheel designs where as the GT series are much more efficient and the design and technology is much newer.

I made these comments because leading people to believe getting a ball bearing turbo is a waste is totally untrue. They have deffinite value and performance benefits when making apples to apples comparisons especially in the hands of an experience tuner (like JWT). Hope this helps.

'03 G35 Coupe 6spd, briliant silver, all options. Brembo upgrade all 4 corners, 19" Gunmetal LE3T's, HKS Hipermax LS+, HKS Legamax exhaust, Gialla grill.