Best turbo ?

[Sweeper]

I had this question for a loooong time.

What is the best turbo to replace old K24 one ?

Is it RS2
Is it IMSA
Is it QS
Is it Hybrid ???

Not for a racing purpose but just for an agressive driving and streetracing. I suppose LOW lag and High Torgue.

Please help me out. Detail suggestions welcomed.


And another one :

About thouse blow-off, pop-off , ****-off valves. What is the best ??? I've heard that HKS SVQ or something like this is the best one.

Cheers.

[Pisobiker]

It depends on what performances and range of use you're expecting from your engine.
As far as my technical knowledge over this topic allows, I can say there isn't an answer to this question. I mean that too many aspects influence turbocharger behaviour and usually putting the right turbocharger (which means both hot+cold side right dimensioning) on an engine doesn't leave too many options.
Biggest limit of turbocharging is that you put a "centrifugal" machine into a "volumetric" machine and suppose they must work fine togheter although they heve totally different flowing laws. The result of this is that you ALWAYS will have to make compromises between low lag or high power output.

Only way to get the max performances possible out of a turbocharger for a street, and supposedly relyable engine, (which is what tuners go for) is to make turbine work on theyr upper limit range (of efficiency) and compressor work as near to the surge line as possible in the lower rpm to have the widest range possible and higher output as possible. Still not enaugh to have both anyway

If we could have all the turbo maps (for both cold and hot side) of turbines you mention, it could probably be possible to roughly tell how behaviour is supposed to change.
Mihnea, probably, who proved to have some experience and "friends" in the tuning field, could give some max hp and supposed rpm range for the different choices over our engine.


Marco

[Sweeper]

You mean such maps ? T3/T4 turbocharger.

[Pisobiker]

Yeah, exactly!

That one is of a cold side.
If you can find all the maps for the turbines and compressors for the different options (RS2, K24, SQ, K27, etc. etc.) it could be possible to tell how behaviour is supposed to change compared to stock turbocharger.
There is another info that could be useful. I think the "P1C" and "P2C" of the map are pressures at inleto of compressor impeller and outlet of compressor diffuser. If they are, they of course are different to outside pressure and manifold pressure. If we could mesure those two parameters for our engines compared to pressure in manifold, we could be able to find out exact limit boost curve of cold side.

Marco