Billet Vs. Cast Turbo Compressor wheels article

[crashtke]

I found this very interesting and exactly as the turbo engineers I have spoken to over the years have said.

http://www.turbobygarrett.com/turbobygarrett/news/race_updates/Garrett_Fully_Machined.html

[SPOOLIN]

there is a flaw in this whole thing you have posted.

the flaw is Garrett.

Precision is smart. Precision figured out that the billet design makes the blades a whole lot stronger. So, since they are stronger, they cut the wheel in a way that makes the hub a good bit smaller....what happens when you cut a hub smaller?....Magically...the blades gain more surface area. A 67mm compressor wheel becomes a 70ish mm compressor wheel. Precisions Billet 67 flows almost as much as my 72mm compressor wheel on my S372 from Borg Warner. The only possible way for that to happen is by using a Billet design allowing the surface area gains. If you cut a billet compressor wheel to the same specs as its cast counter part, OF COURSE IT WONT HAVE A PERFORMANCE GAIN. You know the ridges that you see cut into a precision wheel? Those are there on purpose....Precision figured out that they actually act as an air buffer allowing air to flow over itself, air flowing over air flows faster than air over an actual material. they CAN cut the wheels to be as smooth as silk if they want. The Precision 67mm is rated for 700ish HP. The Billet 67 is rated for 950hp....and it has repeatedly done just that. The billet design is OBVIOUSLY better.

I cannot figure out for the life of me why Borg warner, bullseye, and Garret will not fucking do as the Romans do and make their wheels comparable to precision.

[stretch]

there is a flaw in this whole thing you have posted.

the flaw is Garrett.

Precision is smart. Precision figured out that the billet design makes the blades a whole lot stronger. So, since they are stronger, they cut the wheel in a way that makes the hub a good bit smaller....what happens when you cut a hub smaller?....Magically...the blades gain more surface area. A 67mm compressor wheel becomes a 70ish mm compressor wheel. Precisions Billet 67 flows almost as much as my 72mm compressor wheel on my S372 from Borg Warner. The only possible way for that to happen is by using a Billet design allowing the surface area gains. If you cut a billet compressor wheel to the same specs as its cast counter part, OF COURSE IT WONT HAVE A PERFORMANCE GAIN. You know the ridges that you see cut into a precision wheel? Those are there on purpose....Precision figured out that they actually act as an air buffer allowing air to flow over itself, air flowing over air flows faster than air over an actual material. they CAN cut the wheels to be as smooth as silk if they want. The Precision 67mm is rated for 700ish HP. The Billet 67 is rated for 950hp....and it has repeatedly done just that. The billet design is OBVIOUSLY better.

I cannot figure out for the life of me why Borg warner, bullseye, and Garret will not fucking do as the Romans do and make their wheels comparable to precision.


I COULDNT HAVE SAID IT BETTER MYSELF MATT

[crashtke]

Borg may have figured it out with their new EFR turbos. There has to be some reason Sierra Sierra picked the EFR to run on their Evo and why it broke a previous time attack record by a whopping 2 seconds. The main point of the article in my opinion is that billet alone does not make the wheel anything more than stronger unless the aero of the wheel is changed.

[EmminoDaGreat]

There is too much going on with the EFR turbos in my opinion, I like the idea, but it makes them too bulky. Also the prices are kinda up there...

[josh green]

I haven't seen any pricing for the EFR turbos, I just can't see them being "affordable" for most people in this region. Ceramic/titanium turbine wheels, stainless steel turbine housings, ball bearing center cartridges, billet compressor wheels, plus all their bolt on "accessories" like boost control solenoids, and recirculating valves. The accessories being optional, but I can imagine that a base unit is $1500+.

[EmminoDaGreat]

Ill show you our price next time you come to the shop joshy poo

[SPOOLIN]

the EFR stuff looks like something that would be in an OEM application....but its got all of the performance edge.

[crashtke]

I am sure they are going to be up there in price. But they also seem pretty amazing. I am personally waiting to see how much better on a variety of cars as I could buy 2 91-79s for the price of one EFR 9180.