7 BOUND

Hey guys i wanted to know if this could be done, i just recently bought a t-78 and i saw another on sale, and the guy said that he made it into a BB turbo, didnt know if this was crazy fake or what! So if you know please let me know, i would love to make mine into a BB turbo. thanks

fastcarfreak

if by some chance somebody did make a bb turbo out of a t78, it really isnt a t78 anymore. Why didnt they just buy a bb turbo to begin with?

Jasil

BB's are way overrated and can die a quick death on a the high temp rotary. For the upcharge to buy a BB the spool difference really is minimal maybe 100-200rpms tops. Many people won't run BB's some people will only run BB's, but I have seen EVO's with standard cartridges and BB's and the spool was negligible you would never notice it with the naked eye only on logs...these were GT35's same A/R etc etc.

Good luck and the answer is no.

7 BOUND

hmmm ok thanks for the info, Well i dont know why the guy didnt just buy a BB turbo, thats what i was thinking. He said that there was no lag at all, most that i have talked to say that the t-78 is not that bad when it comes to lag, then i was told that i could get a lighter flywheel to take care of that problem, is this true?
i was also told in the aol car chat that if i was to get a lighter flywheel it would be counter productive when dealing with lag, is that bogus or what,

Jasil

lighter flywheels will cause the engine to ramp up or rev quicker and ramp down decel quicker. A lighter flywheel will normally hurt you on a launch. Just up the boost.

jamespond24

iTrader: (13)

WOW! Great info on BB turbo. So why does people spend the extra $$ on BB?

Jasil

BB's do spool faster you just have to make sure you have restricters in the oil line to prevent full oil pressure. Then decide if the upcharge is worth it or not.

ROTARYFDTT

iTrader: (4)

I believe there are a lot of misconceptions regarding ball bearing turbos and their spooling characteristics. The conclusions I have drawn from my research/talking to other individuals including my friend with a GT30R Shelby Charger is as follows.

Ball Bearing turbos don't significantly shorten spool time but rather they shorten the time span from when a turbo comes into positive boost and hits full boost. I am sure everyone is familiar with watching a boost gauge "sweep" when you go WOT. With a ball bearing turbo this time is drastically reduced to nearly nothing. However, the time it starts spooling shouldn't be drastically different from a non ball bearing turbo.

jacobcartmill

iTrader: (6)

what?

ROTARYFDTT

iTrader: (4)

Sorry that was worded very poorly, and in the first sentence "shorten" should be replaced with "reduce." But anyway, lets try this again. A ball bearing set up won't necessarily make a turbo initially spool faster, but it will allow the turbo to make full boost faster from the point where it starts spooling ......if that makes any sense.

So to throw my input in regarding a bb T-78, I really wouldn't bother based on the cost.

jacobcartmill

iTrader: (6)

A ball bearing set up won't necessarily make a turbo initially spool faster, but it will allow the turbo to make full boost faster... uhhh i guess we can just drop it then, lol.

ROTARYFDTT

iTrader: (4)

LOL I know, I wish I had a few videos for comparison. Perhaps I just suck at explaining things.

I know on my stock twins when I get into it, they really start going around 3500 and make full boost by about 3800 depending on the gear. There's a 300rpm transition where they are starting to get pissed, and when they are making full boost. With a bb set-up, basically this time is eliminated, its instant full boost.

1sicsol

You can buy a turbo with near idential A/R and compressor housing that would be very close to the T-78. Percision Turbos has a large BB turbo selection, you can custom order your own turbo if needs be. You wont be able to get the same trim compressor blades as greddy, but you could get somthing dam close. Most if not all BB (garret?) turbos can't be replace or fixed when damaged. Also alot of experenced rotary builders wont recomend BB. I dont know the scientific facts.