T3 Turbo....

[Roy]

Why the boost drop? would it be because the steel wheels are heavier or something?....

Could be becuase it used the R34 wastegate actuator, simple fix is to use the wastegate actuator of your RB20 turbo

[TrevR32GTS-T]

RBsileighty

you will see a little differents in the turbos. It will be easier to run an after market boost controller. The intake side of the turbo.

[DJ984]

Oh, ok then... that's an easy job then (changing the actuator)... or is it?

[Revhead]

Changing the actuator is a piece of piss... unless you have to modify it. Even then it's not too bad, just annoying

[DJ984]

kool.....

So.... how much should i be putting aside to buy a R34 turbo?...

is there anything else required other than the turbo itself?....

[RBsileighty]

I have a question, this was posted on another forum:

quote:

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Originally posted by rbsileighty  

HKS said that BB turbo's should spool about 500 rpm quicker than a similar sized non BB turbo when I spoke with them on the phone.  

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Sounds to me like they wanted you to buy a ball bearing turbo. Ball Bearings do not spool the turbo at greatly lowered RPM. The exhaust housing A/R and the turbine wheel (stage 3 vs. stage 5) determine the spool characteristics of the turbo.

ball bearings increase the transient response of the turbo. An example would be that if you are already in an rpm range where full boost is reached, from the time you floor it to the time it is at full boost would be sooner on a BB turbo.

A turbo without ball bearings will spool at almost the same rpm as a turbo with ball bearings if the turbine and compressor specifications are identical.

-Jay

Who is right, this guy or HKS?

[DJ984]

just by reading that (NOTE: I am BY FAR, NO EXPERT);

I'd say both are saying the same thing really... just this Jay guy is explaining it more precisely that HKS....

Any other opinions?

[Roy]

I have a question, this was posted on another forum:

Who is right, this guy or HKS?

I tend to agree with this person to a certain extent. Just because a turbo is BB doesnt mean that its going to be responsive. The size and material of the wheel, the pitch of the blades, the A/R of the housings used all play a much bigger part in the characteristics of the turbo.

I started a thread that got erased with the backup a few months ago "BB VS Bush turbos"

My opinion only and many will disagree is that BB add more to the durabilty/reliabilty of a turbo then to its performance. Looking at bearing in general, not just specific to turbos, the two different types behave differently.

Basically any sort of bearing's purpose is to overcome friction. Now there are two kinds of friction, the static (stationary trying to move) and the kinetic (once its moving)

The resistance for something to move is always greater then once it is moving, so the kinetic friction is lower then the static friction. And whilst the use of ball bearings lowers both the static and kinetic friction over a normal bush bearing, its most dramatic effect is on static friction. How many turbos spin at idle...

The BB turbo is superoir as it can withstand higher axial loads, isnt so sensitive to oil pressure/temp/quality, and typically it turbine/compressor uses superior aerodynamics/materials. That said many factory performance cars today still use bush bearings and are covered by warranties, so its safe to say if the reliability aspect of the modern bush bearing turbo was too big a concern then it wouldnt be used by manufacturers like Porsche.

So does a BB turbo lower the boost threshold and lag of a turbo, yes, but i fell its not as pronounced as ppl believe. It would be interesting to see someone build a turbo using the exact same wheel/trim and housings, only to used different cores, one plain bearing one ball bearing. I suspect ppl would be surprised by the result.

[Roy]

Oh and since two turbos invariably use different turbines/compressors, and A/R housings, from a performance aspect, you cant say a given garret turbo is more responsive then a given KKK tubo because its perhaps BB.