The higher the flow rate on the compressor wheel (cold side of turbo) the higher potential power assuming correct tune,fuel, etc. The way I understand is that the 16g wheel will outflow the stock k16 and k24 compressor wheels. 16g wheel is heavier so the billet version was introduced and it is lighter. With the billet version you have the higher flow capacity but not as much weight so spool is still fast.

Also, I believe there are a couple versions of 16g/billet etc. so there is some variation.

 

Compressor wheel sizes:
K16=40,5 mm
K24=42,5 mm
K26=46,15 mm

So the one i want is freaking 49,5 mm big
Lots of punsh for sure.

 

Here is a picture of K24s on the left compared to my K16/997GT2RS on the right. The difference in compressor size is clearly visible. The turbine inlet housing is enlarged and ported to reduce exhaust back pressure and funnel more air to the turbine further improving spool. Zero clearance process (the visible black coating) is used on the compressor housing to create a perfect seal between the compressor wheel and walls of the housing). The compressor wheel basically wears it's own pathway into the walls of the compressor housing coating. As such, a careful break in of around 1000 miles with gradual increase of boost is required. The compressor outlet is also ported and enlarged to reduce back pressure further improving spool and flow on the top end. There is a lot more to it than just sticking a large compressor on a K16 turbo..

Ideally you also want to run 2.75" inlet piping to the turbos to reduce any restriction on the intake. A high flow exhaust is a must.

[url=https://flic.kr/p/pqfEDG]

 

well, they sure are purdy!

so do the older versions of 16/24's that most made available not have the porting/polishing and "backplating" that the "newer" versions tend to have?

as in these pics of "newer" billet 16/24's? ( right pic obviously )

 

They do not. 16/24s do not have a billet wheel either.

 

got it! thx. i knew i had the old lowly little snails but now i feel awful .. just kidding. thx again!

 

Billet wheels are popular in the aftermarket due to their relative easy manufacture. It's much harder to make a cast wheel for obvious reasons. All the OEM wheels are cast including Porsches latest generation 997GT2rs wheel.

 

Are the Porsche ones cast for durability?

 

I would think the billet wheels would be more durable but that's a guess on my part. Either way, if you suck something in you will trash the compressor whether it's billet or cast in my opinion.

 

Interesting article I just read between cast and billet.
http://www.enginebasics.com/Advanced...%20Wheels.html

 

No cast is actually weaker but if being produced in high volume it's much cheaper. Billet wheels came around at first for testing more than anything. Much easier to test a different fin design by 5 axis cnc 1 wheel compared to make a form for casting which is very expensive. Over time now 5 axis cnc machine have become much more affordable and the programming is easier with today technology making billet wheels more of a norm.

 

Has anyone switch to an electric boost controller so you can go boost buy gear? I'm worried about torque with my setup and possibly bending a rod.

 

that was pretty informative. the garrett graph of the two 88mm's cast vs machined was pretty telling also. the conclusion of that read *seemed*?! to be, that while a billet wheel *might* perform *better* it would not be by virtue of the material alone, at all. i mean, the graph alone tells a story, does it not? i'm terrible at reading/comprehending those things, but the words i understand. ( usually )

A Billet Compressor Wheel compared to a Cast Compressor Wheel offers NO GAIN in performance by its material alone. Some have argued that they can be made lighter for better spool, or that they can be made with more aggressive fin designed due to there better sheer strength. While that MIGHT be true, we have seen no conclusive evidence or study that has proven this so we have to rule it out for now and say it’s NOT FACTUAL even though it MIGHT be true.

what IS the takeaway from all that, and are they correct?

 

I'm thinking it would depend on the specific wheels that you're comparing. In the map you posted it is comparing the same wheel with one being cast while the other is billet. In this case then the difference wouldn't be that much.

But...if you compare say a cast stock k16 wheel vs a billet 16g (or similar) wheel it will be a big difference

 

exactly, that makes sense. ok, well that goes along way toward explaining why there IS so little disparity between the two depicted in that graph. or does it. so then if you would explain the terminology for me?

a stock oem k16 "wheel" is "cast" while a billet 16 "wheel" is referred to as a "16"G". and the difference is?.. simply the material? or is there more in the 16g billet wheel, e.g. porting/polishing/backplating etc?

if the "wheel" is the same size, and the only differenitial being the material ( cast vs billet ) then wouldn't that be the way to conclusively determine which one is capable of making "more" power under equal conditions? again, wouldn't an "all else being equal" situation be necessary, and is that not what they compared? i'm not certain i'll ever truly understand this "difference". but thx for explaining.