sb427f-car

That is worth anything when you get right down to it. Though, most of us are on a budget. Ask any restrictor plate racer what they'll say about that, and it's probably the one big thing they would like to have.

KissMySSo1

iTrader: (2)

Actually it's Less friction= Less heat= more moving parts = less reliable.
The biggest turbo with a BB option spools plenty fast enough . A two step for instance wil take car of the 6 speed cars. In the end BB is a waste. For a drag car that is

sb427f-car

Right, you keep qualifying this for drag only cars. Anything with a good turbo setup is already stupid on the street (stupid meaning wild or mean) and having the ability to build boost quick from idle to redline will help out anyone that likes to turn left and right from time to time. Like I said earlier, to each there own.

KissMySSo1

iTrader: (2)

apparently you guys don't realize when the cars at an rpm when the turbo is spooled. After a shift it spools instantly . BB is not going to make **** for a diffrence

sb427f-car

But again...it still depends on your application. If you road race or auto-x...it might be of a help to be able to spool that thing from a low rpm load. Also...I know in a Dodge diesel (97 non-24v cummins motor) that it takes a little bit to get that turbo to spool, so, anything can be a help. Again, you are correct, drag racing doesn't make any difference, especially with a two step but personally, I like to have all the power band covered. Hey, you you're horse, I'll mine.

chuntington101

sorry if i repeat some of the things that have been said already, got on here later than i would have liked. first off, having BB/DBB/whatever is not the only thing to look for when getting a turbo. if the turbo itsself spools as fast as a 90 year old does the 100metres then even with DBB its not going to turn into a instant spooling set! now Garretts GT series (both the DBB and the normal ones) are very good turbos that have (from what i have been told) class leading spool up and operate over a wide range of pressures. so sticking a DBB in one will help reduce spool times even further. but on thing i think some of you have forgot (or get mixed up) is on the road you dont worry about Spool up times that much coz your normaly in the operating band. its lag that causes the real problems. now this is where again DBB are better. as for the bearing life thing. i wouldn't worry. you will find that its is more down to crap instalation or running TOO MUCH oil to the bearings that causes the problem.

but iof you are worried about spool up or lag (and on a 5.7 i dont think thats much of one, try a 2.0 4 pot) then why not just fit anti-lag? ok so the turbo life will be reduced but you just turn the thing down when you dont want it and on again when you are at the track or on a road course. alternativly fit a small shot of N2O, say 50hp, and engage it at WOT. then when you hit the throttle the N2O is there and reduce the effect of lag. also the N2O can cool the intake track realy good leading to more power. and if the second two are a little to harsh for you then its down to set up. run the turbo closer to the ports and try and use nice free flowing headers. also make sure that the turbo/s you are running are sized corectly. some people still think that if they stick the biggest one on they can find they will get the best performance (hehe)! cam set up can also help a lot. you want one with as little overlap (if any) as poss. this reuces the chance of the inlet charge going straight out the open exhaust valve. also the Evo guys generaly recomend high lift as well...............

i could probably go on for a realy long time (s**t i already have). but if you really want to kill lag then try this setup. it was on a Ford RS200 EVO2 + car driven up the side of the Pike Peak by Stig Blomquist (i think). the 2.4 4pot in the back of that ran the compresed inlet into the exhaust mainfold when he changed gear (thus bypassing the engine). this worked realy well. but then when the S**T really hit the fan (ie on the hill) they would run a normal anti-lag system as well. this ment that they pumped neat fuel into the manifold along with the air! BANG no lag at all!

thanks Chris.

sb427f-car

That anti lag sounds HOT! But to much $$ to worry about. So patterned cams make really good turbo cams is what you're saying.

Trent

iTrader: (3)

Having just come from the Supra community and having worked for two of the biggest Supra shops in the country, I think I might be able to help a little bit.

I worked for MVP Motorsports and PowerHouse Racing. They have both turned out some of the best and fastest Supras out there today. PHR built their own turbos and I was able to see how they were built, what worked, what didn't, etc.

Bottom line was BB or DBB made little to ZERO difference even on a 6 cyl Supra. It may have spooled a few hundred RPM faster, but did not make more power and didn't last any longer than the non-BB versions. On several occassions we took a car and put the non-BB on, dyno it, let it cool. Then put the BB or DBB on and dyno to see what the differences were. As said before, they were very little to zero.

BB turbos are also not rebuildable should they blow. You have to replace the entire backing plate to even "rebuild" them which is esentially buying a new turbo to begin with. At least on the non-BB's you can do a 600 rebuild on it if the seals or bearings go.

So if it makes that small of a difference on a 183 cu in. straight 6, it's going to be even less worth while on a 350 V8. I never had a BB turbo and drove around with 600+ hp for several years. After seeing the results and seeing what the differences are first hand, BB isn't a worthwhile option ESPECIALLY considering the cost difference.

My 2 psi.

Zombie

iTrader: (2)

Sup Trent, MKIII owner here as well as a turbo LS1

Not all DBB CHRA are non-rebuildable, garrets are not, but ITS CHRAs ARE REBUILDABLE. Cost is about the same as a std bearing unit.

I will agree with you, there is not much of a difference going std to DBB. Picking the correct turbo for you application seems to have more to do with it.

Grant B

Ditto on what Trent said. A few Supra owners have done camparos with DBB vs. regular turbos and not found any difference. But of course as with all things, take results with a grain of salt unless you know the exact test conditions.

As far as I know, the only ICEs ball bearings are used in are ones without pressurized oiling systems (2-strokes). If they are so great, why not use them in 4-strokes as opposed to the floating bearing found in crankshafts and turbos?

On the other hand, changing exaust housings (say from a .70 to a .81 a/r) can make 300-400 rpms difference in spool and be VERY noticable. In the case of my Supra, the smaller housing made the exhaust same power on pump-gas boost levels and spooled sooner, so experimenting with different housings may be a good idea and is relatively easy to do.