e85_4g63
10+ Year Contributor
- 1,492
- 13
- Nov 17, 2008
-
Manheim,
Pennsylvania
Can you post a link to the KTS 11 blade 20g wheel please?
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I'm not so sure.
The 7 blade wheel doesn't surge at all mated with an 05h turbine in an 8cm² housing on my car. I've seen 30psi (Pressure ratio of 3.45 at my elevation) at 3500rpm in 3rd gear briefly with zero hint of surge. Granted, the 7 blade has the advantage of higher blade count (14) over the 11 blade. You can see in the models below the effect that blade count has on slip factor and efficiency (Z= number of blades).
Part of the increase in efficiency means more exhaust is wastegated, which reduces the overall restriction of the smaller wheel. At lower boost, this setup makes the same power figures that my old TD06-20g did, but with significantly faster spool.
There are two things about all these newer wheels that will help prevent surge:
1. Extended tips.
This acts like a wheel with a slightly larger exducer. This reduces the radius ratio (RR) of the wheel, and improves its slip factor:You must be logged in to view this image or video.
The 20g is already one of the largest RR wheels out there at ~0.77, and it's already operating in the region of the model where efficiency is dropping off quickly. Extended tips move the RR to the left on the model. In fact, I think the 20g wheel probably benefits from extended tip technology more than any other wheel out there, for this very reason.
2. Larger blade angle.
The OEM MHI blade angle is around 28° and these new billet wheels about double that. Smaller blade angle helps generate more velocity off the exducer tips, which translates to pressure in the diffuser and scroll more quickly (i.e. quicker spool), but as the linear speed of the exducer increases, it also results in massive shock losses as the air exits the blades.You must be logged in to view this image or video.
The larger blade angle doesn't build pressure as quickly (though I believe these wheels make up for it in volume flow per revolution), but it eases the transition off the exducer and into the diffuser, allowing higher wheel speeds before shock losses begin to choke the compressor. When the 20g spools up too fast, the shock losses result in the pressure breaking down, which starts the surging. You'll notice all the other MHI wheels that use the same blade angle have the same rightward dip of the surge line above 2.0PR.
The less blades there are, the better a certain compressor performs at high boost (generally).
Are you referencing higher or lower boost levels? Higher blade count may have a broader map, but I look at the T04B V-Trim compressor which was a poor high-boost performer....it had (16) blades total- (8) major, (8) minor.I don't think it would be correct to call that a "general" rule, as it's pretty clear from the models (which Busemann derived by observing and cataloging actual compressor behavior) that more blades are, generally speaking, more efficient.
Not saying you're wrong- just trying to get a better understanding from experience as well as what other manufacturers have done in the past. Fluid dynamics was never my area of expertise.
Has anybody given one of these a try:
20g Billet Compressor Wheel "Big Sale US$100 00 Only" | eBay
For $120 shipped it seems to be a great deal.
I have an exteded tip turbine wheel!
People keep misusing that term.
Extended tips refer to the tips of the exducer on the compressor wheel. The term does not refer to the height of the blades.
Some weights of stuff i have tried. I am liking that 185 g #Well I recieved my kinugawa wheel.
Weight Comparison
My Td05h: 196 Grams
Kinugawa 9 Blade Td06sl2: 185 Grams
I wasnt being serious obviously cause I was refering to my turbine wheel. I wil correct myself....
I have an extended exducer blade turbine wheel.
Also I must have a pretty heavy td05h wheel if yours only weighs 183 grams!
I'm running my 11 blade at 26 psi right now. I've never experienced surge before so I don't think I know what it feels like. But at 26psi it runs nice and smooth. I am running an anti surge (holset style) housing and this wheel is paired with a td05h turbine in a 7cm housing.
hey i saw u changed from the billet 6 blade to the billet 11 blade. how do u like it? any difference between those two? im about to get a either a billet 7 blade or billet 11 blade from turbolab but wanted someones imput with experience in them. what u notice as far top end and spool?
I put down 374/369 on the billet 11 blade 20G, TD05H/7cm. Boost was at 25psi on 91 octane.