I would like to know a bit more about the pro's and con's for BB versus journal bearing turbo's??

And maybe people want to share their experience/oppinion after installing a new/rebuild turbo, journal or ball bearing. What type off turbo and what sort off improvement it gave?

Now I have run the engine in after rebuild and changed the oil etc. I gave it some boost a few times.

Now with the stage 3 kit (BB T34 50trim/ stage 2 0.63 hotside) from Dink. The engine's character is more like a 20VT.

Now the turbo is starting to make some boost below 2000 rpm. And when you floor it a bit you have full boost in the blink off an eye. Really impressive I think, if you compare to the standard unit. And exactly what I wanted. I was scared that it would become to laggy. But it's the opposite.


Best Regards
Michael

Well you've experienced the pros right there : Lower boost threshold and less lag.

Also able to handle greater thrust loading - Garrett's duall BB can supposedly handle up to 10x more than a journal bearing CHRA. Turbonetics old hybrid roller bearing CHRA can supposedly take 50x more, IIRC.

Cons: Considerably more expensive to buy compared to the same turbo with journal bearing CHRA.

Also completely impossible to rebuild; the only way to "rebuild" a BB turbo is to unbolt the old CHRA, buy a brand new one and bolt it in.

I have a BB Garrett GT28R with some flow mods (manifold+turbine inlet) and Flea mapping.
i get full boost at the same revs as std Coupe and positive boost (over 0bar) just over tick-over, ca 1100rpm!

Ok so that is why they sell a BB CHRA. And you can keep using your old housings. BB costs more money, but lives longer too.


Very impressive Per. Spool up like standard but bhp not so standard I think. I like that too.

So how much more expensive are they ?

They are more efficient, robust, faster spooling and more durable...sounds like a no brainer...dependent on price!

Well, apparently they are not more durable under all circumstances.

Advice from Turbo Technics to me was: if you suddenly stop the engine after running at high turbo temperature, or for whatever reason can't allow the turbo to cool down progressively for a relatively long time from max heat, the bearing cage will melt or at least distort due to heat soak. Unless you have non-plastic bearing cages e.g. ceramic (do they do metal ones to?) which adds still further expensive.

I guess with most road cars this won't be an issue, but if you drag or do track days etc.....

Ball bearing T3/4 is about $1500 where as a journal bearing is only about $700. Journal bearing turbos are generally quite robust and easy to fix. If you pop a BB turbo it's usually to total write off.

Your wright, but that is also for a journall bearing. Maybe it won't fail as quick as a BB. But in the end if you turn the engine off after hard driving every turbo will fail. My old original turbo had done 80.000 miles and it still has miles on it. A little play on the shaft but it performed well and didn't smoke even with decat for the last 25000 miles.

When I drive it fast, I always drive the last 5 miles slow to cool everything down. And when I get home I let it idle for a little minute. So no barbeque for my Coupe.

A journal bearing turbo won't fail immediately and beyond repair if the engine is stopped without cooling the turbo, as a BB turbo can. The only damage will be to the oil - not the bearings. If not dealt, with the 'coked' oil in/around the bearings could cause a problem later on. But that can be prevented by simple dismantling and cleaning before the turbo is used again. So, unlike with a BB turbo the CHRA does not become instant junk.

When you on the dyno Turboman?

Nick

That will be end off next year. After my garage has installed new camshafts and timing gear. Then I want the last remap etc. and that includes a RR session. But I'm quite broke now so.....

After the rebuild the garage checked the AFR. And did a full diagnostic off the ECU. Also I have an AEM wideband sensor. And everything looks good. They don't risk a rebuild engine. I have guarantee hehe

That garage who does the work for me are friends from Dink. They have a Delta HPE two wheel drive for racing etc. Haven't got any problems with the car after rebuild etc. not even a small oil leak or stuff like that. I'm really impressed with their work.

So what pressure is full boost set at??
Which size injectors?
When exactly in rev range are you seeing 1 bar & full boost??
I suppose max boost is holding all the way to redline as you have stage 2 turbine??

Nick

to give you some idea of the differences in very similar size turbo's, 1 ball bearing and 1 journal bearing on a 20vt turbo

i went from a journal bearing hybrid turbo 60trim 60mm compressor wheel to a ball bearing 62trim 60mm compressor wheel (both with standard 0.49a/r turbine housing size and standard turbine wheels) so the difference in turbo size was quite small

the ball bearing version spooled about 200rpm earlier in the rev range despite being slightly bigger (not overly impressive but it's still a relatively small turbo, the gains will be greater on a bigger turbo) but the biggest difference was in response once over the engine speed at which the turbo is fully spooled (about 3000rpm), the response from the ball bearing felt much quicker and jumped to full boost noticeably quicker than the journal bearing turbo

as has been said though they are considerably more expensive and if they fail you can't rebuild them

hope the above is of some use

I have stage 3 kit from Dink, that includes a chip and 500cc injectors from Bosch. Full boost is 1.2 bar to redline.

I only drove 250miles after run in period and oil change and I want to be gentle on the engine. It has done around 1000miles in total now.

So I only did a few small tests. One was load the turbo in 4th gear from 1500rpm and then I had 0.3-0.4bar at 2000rpm and I lift the trottle. So I imagine that full boost will be around 2500rpm?! And today full trottle in 2th gear to redline. Was quite fast so I only had the chance to look at AFR a little. And try to keep it on the road.

I do a good test on motorway after it has done some more miles.

Very interesting. This is what I was asking for. To compare the same unit but different bearing. Or what max performance people make on what sort off turbo.

Dink's website calls for a 0.48 A/R turbine with St2 wheel. I assume he is using the OE turbine housing. Can you confirm you are fdefinatly on a 0.63 A/R? 1000 miles is run in, give it some beans and report back

It is definatly a stage 2 0.63 A/R hotside. And the compressor is a TO4E 50 trim (76mm-54mm) and 0.50A/R with double BB. I think the serial number was TB0385 but not sure on that. But the A/R I'm very sure because it's stamped in the housings. And everything off the turbo was definatly brand new.

I had all those parts laying around for a year. Had it a lot in my hands to see the spec. Even measured the compressor wheel, it was 54mm from memory. The hose for turbo inlet was 57mm inner diameter.

I will give it some beans tomorrow if its dry....

I thought a TB0385 was an intergrale evo one turbo ( & possibly escort cossie turbo)?
Your head has been worked on hasn't it?......
If so with that compressor you should piss 400 bhp, with around 1.5-1.6 bar of boosty!!
Would be good to find out Exactly when you're getting 1 BAR and full boost??
Full boost at 2500 sounds a little optimistic to me, I'd guess around 3100-3200, which would still be pretty phenomenal with turbo that size!!

Nick

Nick

No, I have a original head, intake and exhaust manifold. And original ECU. And want to keep it like that.

Only new camshafts from C&B max fast road and live mapping for next year. And then going for an Accusump system and brake, handling parts and stuff like that.

This project has cost me more than enough. And because the rebuild is already done, I'm not planning on opening the engine again and porting or polishing anything. Because if I would it has to be done by GC.

So the specs for now are:

rebuild head (re-cut and cleaned valves and seatings, new valve stem seals etc)

Rebuild bottom end:
wossner pistons
ZRP forged rods ARP2000 bolts
Fully balanced and lightened bottom end
All new bearings crank and big ends
ARP headbolts
Spesso 66212 1.9mm headgasket
3 inch downpipe (Dink)
2.25 inch decat to rear
SIP (75mm) with Green pod filter
FMIC and had to chop half the bumper off so
3bar FPR with 500cc bosch injectors (red)
Garrett BB TO4E 50 trim 0.50 A/R with 0.63 stage 2 hotside
Stage 3 map from Dink
front new wishbones track rod ends etc etc.
Upgrade fast road clutch (original flywheel)
AEM wideband and boost gauge
EBV from Dink
New Forge DMV004
Walbro 255L per hour fuell pump
New coils and spark plug leads
New RVS fuell lines and filter at the rear
New alu radiator and waterpump
Balance belt removed etc. and 22mm cambelt kit
AGIP fully synthetic oil 10W60

Do you know what power level you were at before latest mods?
If so how does the new set up compare??
Think you will have to run some SERIOUS boost then to get near 400 bhp, I know your not interested in max power figures but I still reckon you'll need to run 1.8 bar to get near 375 bhp with no head work...
I run the max fast road cams and they seem to help power climb right to redline, yours may reach peak power right at the top end as your boost will hold better than mine.
With your early spool you should have a great power band and with those cams it will make for a fantastic FAST ROAD car!!

Nick

Just read you spec list..... You should have no problem running higher boost with uprated head gasket and head bolts!! Turn it up.... Turn it up Loud

I just want to max out performance a bit more. So want to run max 1.6 bar. And then we will see what figures it can make. I want usable power and fast road car.

But I know it pulls a lot harder now already with 1.2 bar so 1.6 is more then enough for me. For example it feels like second gear is now first gear. Or first with stage 1 set up I shift exactly at 6000rpm so when I gave it some beans last time with new set up I shift at 4800rpm because it pulled as fast/hard as 6000rpm on the stage 1 set up. Or with stage 1 set up I could always floor it when I wanted on normal dry roads, but now is impossible to do without wheelspin, torque steer, or a crash.

A T04E 50 trim compressor will flow 47lbs/616CFM - which is at least 460BHP and upto 504BHP depending on intercooling.

max p1/p2 is 3.4
max efficiency is 74%.

It's a great compressor wheel (for it's age).... peak boost is higher than any other T04E compressor wheel can manage.

On a 2 litre engine:

full boost at 4500 RPM (not before, but 1.2 bar will come earlier, of course)

and

MAX flow at 7750 RPM before flow/boost will tail off.

Should see some boost from 1500 RPM.

TB0385 compressor wheel is 52.2mm inducer and 68.96mm exducer - 57 trim.

It will flow 42lbs/550CFM, so about 400-420BHP tops.

max p1/p2 3.1
max efficiency 71%

Full boost at around 4000 RPM and will run out of puff around 7000 RPM on a 2 litre engine.

It doesn't matter how good a head is if the turbo can't flow enough air!

And bye the way, I got 387BHP @1.7 bar on an 8 valve head with this turbo... engine dyno, not rolling road.

I 'Think' that the tb 0385 compressor is what I'm running..... My figures sound about right @ 1.55 bar!
I believe 'Saint' was using the same turbo (journal bearing though) as Turboman a while back with 'min' fast road c&b's.... And I tweaked version of my flea map at the time.
His turbo was stage 2 turbine but still .48 ex housing...
Iirc boost peaked at 1.45 and held 1.4 all the way....... Results were around 300 of both bhp and torques!

Nick

A friend of mine just put together an Integrale 16v hybrid. TO4E 60-1 comp with O trim turbine. Makes 180 kw @ 17psi on a chassis dyno. Very responsive, full boost at 3500. Not bad for old tech.

What are your figures? I couldn't find them easily on here, though I did look.

Yes - something wrong there. Peak boost should be much higher. The turbo will flow 35lbs at over 2 bar boost, 38 lbs at 2 bar boost, 41lbs at 1.8 bar boost and 42lbs at 1.6 bar boost, but efficiency has fallen below 60% at that point.

Efficiency is down to 65% at 40lbs/1.9 bar boost. Flow maxed out is at 1.4 bar boost, but that is about 42.5lbs/min and only 55% efficiency. So it's best not to exceed about 40lbs/min and 1.9bar boost - and that's about 400BHP.

I'm 100% sure I have a BB TO4E 50 trim 0.50 A/R compressor with the stage 2 0.63 A/R turbine. For example the comp. housing is that big it clears the gearbox only with 5mm. So to replace clutch or flywheel the turbo has to come off

So a little update: today I drove my Coupe in full wet haha. So in 4th and 5th gear I have 1bar at 3000rpm and full boost (1.2 bar) at 3250rpm. And in higher gears it starts producing boost below 2000rpm. But in lower gears like 2th or 3th full boost (1.2bar) is a little higher at 3500rpm.

But still with this weather, roads and trafic can't do a good test to redline area. But it pulls a lot harder with lower rpm then first.

I think I will do a Dyno session begin off next year. A company does happy hour on monday mornings for like 80 euro. So that's a bargain. They have a new 880E series AWD chassis dyno. One off the best Dyno's in The Netherlands but is it good for a Coupe too?? I think so but....

Thanks for info everybody!