Precision 6765 journal or ball bearing?

[MNwe4]

Hey guys, after talking to quite a few people I've come to the consensus that my Precision 6780GTQ is just too big for my combo and it's time to purchase a new turbo. The decision I'm having trouble making is...is a ball bearing unit worth the extra cash? Is the difference in spool up that noticable? Is it more sensitive to oil pressure and flow? Other than cost, why would you NOT buy a ball bearing unit? I think I've listed the critical components in my sig, but let me know if I need to provide more info. I realize a 9.5" non l/u would be a nice addition, but whatever turbo I purchase I would like to have work with my current setup.

Thanks, Dave

 

[Mr.Spool]

that depends on how fussy you are about spool time.the bb is worth a couple of hundred rpm.not that i didn't read your post,but i don't understand why you just don't go to a 9 inch converter and complete the combo.i have a bb billet 64/strim and the 10 inch wouldn't spool it either,ptc 9 inch got the job done.however if you still plan to sell the q trim drop down to a ptrim or 65 wheel and keep the comp wheel around the 62mm range.

 

[bison]

What are your power goals? Looks like the 9.5" ptc would give you the most return on investment if everything else is ok. You will still drive over your current converter if you run a 6765.

 

[MNwe4]

The power the car is making now is great, it's just that it takes forever to wind it up and get it moving. Once I get over 4,000 rpm the thing takes off like a rocket. On the 2-3 shift I currently get about 500-600 rpm drop down from 5900 rpm. Best ET is 12.0xx at 120.xx with a 2.1xx 60'. With the older alky kit and pump gas the most boost I could run was 22 psi. At 23 I began picking up small traces of knock. Next time to the track I will use race gas and eventually upgrade to a new alky kit.

Back on topic....From what I've gathered the Q-trim turbine is not really meant for a true street car that goes to the track only 2-3 times a year. To take advantage of this turbo a very large stall is needed and a t-brake is not a bad idea. I never plan on running a t-brake in this car. So, what I'm looking for is a turbo that will make the same power, but spool at a more reasonable rpm so I can consistently creep up on the boost on the foot brake. This is the reason I thought the 6765 would a good choice.

 

[GNVYUS 1]

Ya that turbo is WAY too big for you, your 60ft and ET prove it.

If you can't run a high 10 with the 62/65 and your current combo than you need to tune etc. Without knowing your suspension mods etc you're probably not setup to take advantage of the new PTE64 to it's potential let alone that 67.

Are you brake boosting and to what RPM?
Are you planning on a transbrake?
What rear shocks/springs?
Rear tires?

If you go transbrake, good rear shocks and something like 275/60 MT's than you can dial in the 64 to low 10's with tuning etc. That turbo has high 9 potential so if those are your goals keep that in mind it's a combo, not just a turbo.

 

[bison]

If youre happy with the power then I'd just get a 6262 and call it a day. You wont lose any peak power with it and it will come on way faster. I can't imagine running a gtq under 130mph trap speeds and without a converter that will be driven over hard. It would be a turd out of the hole then when it spooled it would flash too high and the converter would not couple. The 6262 will drive into that 10" converter just as hard too but at least it will spool 3x as fast.

 

[Mr.Spool]

my s-trim combo foot brakes 1.52 60fts on drag radials with dusty's 9.5,pump gas alky,tt 5.6 chip.having good spool is possible with the right converter.ive been 125mph on 22psi at 3800lbs with warped and cracked stock headers shifting at only 5000rpm.

 

[MNwe4]

Thanks for the replies guys. Bison, won't the 6262 make quite a bit less power, at least according to the charts that were previously posted? I'm referring to the sticky comparing "new school" to "old school". I assume those HP ratings are based at the engine. My current setup is making between 500-550 rwhp. Also, to the original question, do any of you think the ball bearing unit is worth the extra $$ or just the newest trend?

 

[bison]

Thanks for the replies guys. Bison, won't the 6262 make quite a bit less power, at least according to the charts that were previously posted? I'm referring to the sticky comparing "new school" to "old school". I assume those HP ratings are based at the engine. My current setup is making between 500-550 rwhp. Also, to the original question, do any of you think the ball bearing unit is worth the extra $$ or just the newest trend?

It will support more power than you're making. We just made over 520whp@22psi on a stock bottom end with one. Your mph indicates roughly 455-460whp. I went 122mph last summer weighing 3600 lbs and the engine made 465whp on that tune about 3 days before I ran it. 550 will be enough for mid 10's. Dont be fooled by those ratings. Those are what the turbo will support roughly not make. Bigger turbos won't make more power unless the engine will flow the air. You have to increase boost/rpm to see the potential of larger turbos. I'd run a journal and put the extra $ toward a ptc 9.5".

 

[MNwe4]

Thanks. Good to know you have first hand experience with one and the results were positive. I know the 9.5" comes highly recommended by many people and I'm sure it's great for cruising around town and performs excellent at the track. Would you still recommend it knowing I drive my car the 2.5 hours it takes to get to the track? No truck and trailer here. Does hwy driving for that long with a high stall non lock converter cause any heat issues? I understand around town and short hwy cruises are fine, just not sure about the occasional long trip. Oh, and my hp comment was based off of previous dyno results. The thing just leaves like a turd. Nothing really happens until the 1-2 shift. I appreciate your help.

 

[turboc87gn]

I just found this and found it interesting what you guys think...YouTube - Demonstration of Precision Dual Ball Bearing vs. Journal Bearing

 

[bison]

Thanks. Good to know you have first hand experience with one and the results were positive. I know the 9.5" comes highly recommended by many people and I'm sure it's great for cruising around town and performs excellent at the track. Would you still recommend it knowing I drive my car the 2.5 hours it takes to get to the track? No truck and trailer here. Does hwy driving for that long with a high stall non lock converter cause any heat issues? I understand around town and short hwy cruises are fine, just not sure about the occasional long trip. Oh, and my hp comment was based off of previous dyno results. The thing just leaves like a turd. Nothing really happens until the 1-2 shift. I appreciate your help.

I have driven my black car to LVD from central CT many times with a 9.5"'ptc. On the way there i drive through the highest elevation on the east coast. The cruise slip is minimal. With the correct 9.5" you won't notice much difference on spoolup with a journal or ball bearing. It will be much faster spooling than what you have now. With a 9.5" and a good tune down low it wil come on in about 1 second.

 

[turboc87gn]

Hey bison has anyone figured out if the ball bearing will outlast the journal bearing say if you ran a turbo saver on both?

 

[bison]

Hey bison has anyone figured out if the ball bearing will outlast the journal bearing say if you ran a turbo saver on both?

Idk. Journal bearing turbos have been used for about 50 years now. Some with almost unbelievable longevity records. I know of a stock gn longblock with over 200k on it and it still has the original turbo. I've heard of a Saab with over a million miles and it reportedly had the factory installed turbo still on it. I know of a ball bearing turbo with over 30k on it. Unfortunately it was spooled without oil pressure. If damaged the backing plate so it had to be opened up. The ball bearing assembly was fine. It would have likely went many more miles if it hadn't been run without oil. There is very little metal to metal cintact in a turbo assembly. An oil film protects it from wear. The ball bearings need minimal oil to function. Journal bearings need a lot of clean oil or they are damaged. Just about every failure out there could have been avoided and is usually caused by operator error.

 

[GNVYUS 1]

FWIW, when I went from the Precision 5 disc to the PTC here is what I noticed.
At 50mph in 4th
Precision locked = 1600rpm
PTC 9.5 = 1750rpm

These are eye balled while driving but the PTC is not going to melt down the trans on the highway and if you run a nice sized cooler and good fluid, Red Line etc, no worries for sure.

62/65 with a 3200/0psi stall is a killer combo, the 62/62 even better for the street.

62/65 has a high 9 potential for us, I'd try to get close to that first and then move into a bigger turbo personally.

 

[JP112_89]

The ball bearings need minimal oil to function.

I noticed when I received a Tnetics BB turbo. Tnetics BB have a oil restrictor.

Joe

 

[MNwe4]

I just found this and found it interesting what you guys think...YouTube - Demonstration of Precision Dual Ball Bearing vs. Journal Bearing

Cool vid, but....is it really a fair comparison since there is no oil floating the journal in this case? I'd be inclined to say no. However, if the parts were pre-lubricated it may be a little closer to reality. Either way it does show how nicely the bb unit spins.

To everyone else, you are really making me consider stepping down in turbo size more than I originally intended. There's a lot more to consider than I initially thought. With regards to the non lock converter, a couple hundred rpm jump doesn't bother me. I could care less about the slight mpg loss and it won't hurt the motor. I was curious if running at hwy rpms for a long time would build too much heat since the converter would be operating well below it's efficiency range. Seems like the consensus is don't worry about it.

Any more people who have the newer style turbos care to comment on what stall at 0psi it actually takes to get them spooling?

 

[DCVING 6]

Any more people who have the newer style turbos care to comment on what stall at 0psi it actually takes to get them spooling?

Way too many variables from combo to combo to get an honest answer on that.

 

[bison]

Cool vid, but....is it really a fair comparison since there is no oil floating the journal in this case? I'd be inclined to say no. However, if the parts were pre-lubricated it may be a little closer to reality. Either way it does show how nicely the bb unit spins.

To everyone else, you are really making me consider stepping down in turbo size more than I originally intended. There's a lot more to consider than I initially thought. With regards to the non lock converter, a couple hundred rpm jump doesn't bother me. I could care less about the slight mpg loss and it won't hurt the motor. I was curious if running at hwy rpms for a long time would build too much heat since the converter would be operating well below it's efficiency range. Seems like the consensus is don't worry about it.

Any more people who have the newer style turbos care to comment on what stall at 0psi it actually takes to get them spooling?

You will need a lot more fuel in the mid range if you go with the 6262 and new converter. You will have boost at a much lower rpm.

 

[northerngn]

Dave... how soon you making the purchase... ill give ya a ride this spring with my new J/B 67/65 if you like...but im sure you don't want to wait that long...
-Dan