mslovak1

Just a beginner at this stuff.
Posted a thread a couple weeks ago but still need help.

Replacing the Turbo, found this out:
I need to know the spool-up I want and how much Hp I want, then how much $$ do I want to spend.

I've read and received info on the 360 degree thrust bearing turbo types and the double ball bearing type:

Double BB is supposed to give faster spool-up and better top end Hp.
Thrust bearing types can have impeller and housings trimmed to allow them to spool up like a BB type.

Let me know if this is true. The cost of a double BB is 2 times that of the thrust, and is it worth it?

Talked to someone at a Turbo place. Mentioned I wanted a fast spool up and 350HP.
He suggested a #8, Stage 3, 360 degree thrust bearing type, with T04B housing, 3" inlet, 57 trim compressor wheel, lightened and with bullet.

Being new to this, I thought he was speaking a different langauge.

Can you guys that replaced your turbos, give me some insight.

Thanks
M

1988 944T S

Mike S

I'm sorting all this turbo stuff out myself. After talking with turbonetics the other day, I was told that the ball bearing stuff is really usefull for running all out race cars or 20+psi of boost on the to4e type turbos. He felt it was overkill if I wouldn't be seeing over 20psi. It's nice to have, but the cost just isn't worth it to me.

Also....i won't comment on the rest of the setup, but I beleive that the 57 trim is an older (less efficient wheel) setup. A couple of non-porsche sites have recommended using the 50 or 60 wheels and "skip everything in between". That being said there are a few members here that run a 57 and are real happy with it.

4G64 944

From friends I have in the import world we have seen not that great results with dual BB, spool is only helped 100rpm or so, and the failure rate is about double, what IS helped is lag between shifts, once they are spooled, they stay spooled. Many times when shutting a car off after idling you can hear the turbo spinning for 20 seconds. I don't feel the cost is justified for a street car though. We have made over 450hp awhp (all wheep hp) with a 50 trim on a 2.0L eclipse motor on pump gas no less (22psi) I think a 50 trim is a great street turbo, it should spool up qucik enough for you and support the 350hp you're looking for. (of course a DOHC 2.0 is very different from a 2.5-2.8 SOHC porsche motor, you should spool up quicker than we do, but not rev as high). My good friend gary put down 532awhp with a plain garrett 60trim which ran 10.7@132 just to give you an idea of the potential of a 50/60 trim.

Mark Szalaiy

I was talked out of putting a BB turbo on by almost every place I called, I ended up having a TO4B w/60 trim and #8 hot side and it spools up great with alot of top end power. If you look up the compressor maps on this turbo you will see it flows 56lb/min. turbonetics said to add a zero to the end of that number to get the power potential , which in this case is 560 hp.
The compressor maps on the TO4E w/60 trim only flowed around 46lb/min
I was really afraid of a lagy turbo but this one seems to have the best of both worlds, quick spool and good top end.

Good luck on your choice,
Mark

jimbo1111

Turbonetics only offers a bb for the turbine side. A true dual bb turbo center section like the one hks sells is much better.

Posted by Mark Szalaiy:
I ended up having a TO4B w/60 trim and #8 hot side and it spools up great with alot of top end power.

I always thought the 60 trim was only used on the e housing. Is this a custom turbo?

Sam Lin

I believe the HKS unit is a modified Garrett GT BB.

Sam

ewainwright

BB or not - equally sized turbochargers will move equal amounts of air. Merely a question of lag time and not much

porshhhh951

i was wondering this myself.Its another $800.00 to get the turbo i want in a bb.Is the benefit really worth all of this extra money??? I sure dont think so...but, i would be open to opinions on this matter

RajDatta

If anyone is interested in a dual ball bearing GARRETT GT30, I have a brand new one. Not sure if I will be using it so if someone is interested, it might be up for sale.
It came with the 968 turbo RS motor I bought from Technodyne and he was planning on running it in his race car before he gave up on 944 turbo cars and went to a Carrera RS. He had it built to produce 463rwhp @1.3 bar with a milledge spec 2.7 head according to him. I don't plan to run such high boosts so I might have to look at a different solution. I also have all the adapters and brackets required to make it work including a modified engine mount.
I am still researching so I might decide to keep it depending on what I find out. I know what they are worth so if I don't find a good price here, I will throw it on Ebay and let the Supra and Skyline guys bid for it.

Sam Lin

968TurboS, e-mail me some pics, I'm definitely interested.

Sam

RajDatta

Sam, lets take this offline. You can send me a direct email at r_datta@yahoo.com.
Raj

mslovak1

Emailed Tim at SFR about the Turbo & Spec's in original post.
He mentioned this setup would spool-up at about 4000 rpm. Michael, at Majestic Turbo who gave me this info, said this would spool up at 2800 rpm.

" I'm sooo confused!"

Tim also mentioned the BB will always spool-up faster than the thrust, on equally fitted turbo's.

Keep the comments coming.

M

4G64 944

Are they both referring to the eact same combo, are the turbine (exhaust side) housings both the same a/r? this will make a difference in spool up (1200 rpm would take a HUGE housing size difference though).

Kienle

I have had several turbos on my car (stock 26/8, powerhaus KKK 27/6 with fast spool, SFR stage 2, vitesse stage 2 with quick spool), the vitesse stage 2 was the one which spooled up fastest and had the most power too.

Waterguy

On the Garrett website, they claim that the dual ball bearing set up in the new GT turbos will spool up 15% faster than an equivalent non-ball-bearing turbo. I agree, it sounds like a lot of money for a 15% reduction in spool time. (Mind you, they also talk about all the aerodynamic and efficiency improvements on the GT compressors compared to the older T03 and T04 turbos.... To someone serious about power, that might be worth the effort.