Journal VS. Ball bearing..Same combo scenerio inside.

[driven87]

Figuring out if Ball bearing will always be worth the extra money or not so i have a scenerio in my head and im curious as to what you think. Lets say you have a GN that goes 10.5 in the 1/4 with a 70gtq journal bearing and a 3400stall convertor. Lets say you leave off the transbrake at a low RPM of 3500 to achieve those times. Now with the COMPLETE car being the same but switching the turbo for a 70gtq dual ball bearing. If you leave at the same 3500 will the car be faster or run the same? Will a ball bearing only have an advantage at lower RPM launches? Will the MPH be the same but ET be different? Aside for street driving if you have a good 3600 say PTC convertor will the ball bearing vs. journal bearing even matter leaving off the transbrake? If indeed the journal bearing was a little lazy would rasing the leaving RPM to say 4000 make it even? Just picking at some brains here, thanks.

 

[forcefed3.8's]

It will make the same power, just start making power sooner. At the track there will be no difference, you will just have to leave on more boost to achieve the same 60'.

 

[bison]

Figuring out if Ball bearing will always be worth the extra money or not so i have a scenerio in my head and im curious as to what you think. Lets say you have a GN that goes 10.5 in the 1/4 with a 70gtq journal bearing and a 3400stall convertor. Lets say you leave off the transbrake at a low RPM of 3500 to achieve those times. Now with the COMPLETE car being the same but switching the turbo for a 70gtq dual ball bearing. If you leave at the same 3500 will the car be faster or run the same? Will a ball bearing only have an advantage at lower RPM launches? Will the MPH be the same but ET be different? Aside for street driving if you have a good 3600 say PTC convertor will the ball bearing vs. journal bearing even matter leaving off the transbrake? If indeed the journal bearing was a little lazy would rasing the leaving RPM to say 4000 make it even? Just picking at some brains here, thanks.

If you have a properly speced converter it wont matter much at the strip. Fwiw no one leaves off a t-brake at 3500rpm with a GTQ and for that matter no one leaves at 4000 either. Most run at least 3800 stall with zero boost/vacuum for a journal GTQ and 3200 for a ball bearing. Typically launching at 4800+ depending on the engine and suspension. The ball bearing cartridge will come up faster with the same tune and converter but if the converter is selected for a journal with a higher stall(and the rest of the combo) and launched where the it should be there will be no difference in e.t. Its a lot easier racing on a pro tree with a ball bearing turbo and a 2 step. If you can justify spending $800 more than get the ball bearing cartridge. I see a lot of guys run ball bearing turbos but they insist on keeping a POS converter in the car when they could have went journal and got a new 9.5" PTC for about $100 more combined! I know what id be doing if money mattered and i wanted my car to haul a$$ as much as possible with the least amount of cash outlay.

 

[bison]

It will make the same power, just start making power sooner. At the track there will be no difference, you will just have to leave on more boost to achieve the same 60'.

You would not need to leave with more boost if the converter was on target.