Thats why there is all this testing being done. What the guy is stating isn't "Incorrect" at all, if the only modification is the wheel, what he states may be entirely true considering the different dimensions of the two wheels. Since we do not know yet what if any modifications are already being made to the compressor cover itself, there's no conclusive data.

I stated in that thread that its likely the compressor cover itself also would need to be modified slightly to not only accomodate the wheel, but also allow the increased "flow" otherwise the bigger wheel's ability to move more air, is being obstructed by the cover. Ok, what does that mean? Well it means that according to the dimensions stated (Not sure if their accurate since I have different data that I'll explain a little later) It means that if the new wheel can "Bite" into more air, but the cover isn't moving any more air, you'll have a turbo that has a bit more lag, but at the upper RPM you end up with similar results as stock, obviously then the limitation is the compressor cover itself. Take into account that the larger wheel may have more "Surface area" and the profile of the blades may be slightly different, but as stated, the hub in the center is a bit larger, you are actually reducing the path INTO the turbo (inlet) slightly.. This is all information I'm 100% certain that David is aware of and what he is likely doing, is using test data to analyze where the restrictions are one point at a time. Plus the "20G" wheel he had already produced, was actually larger than what he had wanted. I'm sure you'll see greater improvements than 15hp, but it comes with more than just the 20G wheel.. Give him the time he needs to develop and find the "glitches" you'll see good results, how much is just hard to say, but he'll get there.

Now, Here's the additional interesting facts that I've discovered after looking at the different variations of the 16G turbo.. the inlets vary in size, even though the wheel itself may be the same on many of them (there are 2 or 3 different wheels used over the years on different EVO <edit: originally I said 16G but meant TD05> applications) also the compressor cover itself has at least 4 different versions on the reverse twin-scroll design. and each one had different inlet and outlet diameters. The Smallest being the first of the turbos offered on the Evo 4 or 5, and Evo GT-A (I'm not talking about the turbine housing, but the actual compressor cover) what is interesting, is the markings on the compressor covers give no indication of any difference other than visible differences in castings and the turbo series and generation data on the ID plate.
The largest being off the JDM Evo 8.5 (Evo MR) which what I was told, should be the same cover as the 05 turbos, but I have not been able to verify. However the inlet on the 03 turbo, and the 05 turbo is the same, the outlet and interior volume is slightly greater on the 05 (as far as I was able to tell, this data isn't exactly conclusive or necessarily accurate since my measuring methods may have been flawed, BTW I used mineral oil and blue dye, not water to CC the interior volume)

All in all, THE ONLY WAY to create this product is either by using computerized models, or trial and error.. Both are expensive, but the computerized models are obviously not really possible unless you have the software and hardware capable of doing it..

So what does all this mean.. Well really, not much, it only generalizes that careful choice and matching of parts will ultimately result in the gains, not just one component (20G wheel only) Of course, this is the reasoning behind any upgrade path, which is matching the components for the intended use.

 

Holy crap, can I nominate Malibu for post of the year with that one? Well said sir. I can vouch for the different versions of our turbos out there, to be completely honest we don't even know what I got :P

 

GVR4kid,
The throttle plate doesn't close on shifts in a automatic but when you lift to slow down it closes all the way.

evo8ltw,

Not having a BOV would hurt you more on slow shifts than having one. Not having the BOV makes the compressor wheel try to stop.

David Buschur
www.buschurracing.com

 

Im interested on how this kit is coming along.. this is my first time reading it..
As this guy i quoted, i have this prob, and bad.. unfortnatly im starting to get a sig. amount of sepage in my intake pipe.. so my bearings are getting worn out... this is a big prob esp. on the highway.. part throttle, say im climbing a hill and i crest the top, when the engine starts to even out, the turbo is still spooling and im getting horrible flutter.. this usally happens over 10 psi.. so say if im really on it it shakes the whole car.. i guess having no resttriction in the intake or exhaust has its downfalls with the factory turbo.. and these prob are not do to the bov. im on my fourth one.. wish i figured this out before.. everyone i talk too, says i have to upgrade to a bigger turbo.. so i was prob going to go with a 30r kit.. im aiming for 425 whp, on 93 octane.. so will going with this 20g amplify my prob, or should i stay with the 30r.. i have the tube header,big o2 housing and 3inch turbo back. full i/c pipes, autronic ecu. all i need for a bigger turbo is cams, injectors, rail and reg., and head studs.. I wish i didnt have to buy new stuff. thats why i like this 20g.. any help.. thanks... sorry for the long thread..


Quick question David, wouldn't you say that this compressor wheel mated to the stock turbine wheel cause some nasty surging? I mean the stock turbo will surge with high boost so I can only imagine that this hybrid will magnify this problem, specially since the compressor housing is stock and really designed to flow just enough air of the stock wheel. Maybe im wrong though, but it would seem that the turbine side should be upgraded as well, and I dont mean just the housing since even the 10.5 housing will cause surging under high boost part throttle operation.

Gil-superz
__________________
Gil-superz
WickedWhite MR- Stock for now.

 

The stock turbo should not compressor surge.

The 20G should also not compressor surge when it is done. They didn't in the past.

We have GT30R kits.

David Buschur
www.buschurracing.com

 

37 pages..... much of it off topic. Time for a trim (including "gee I want one too" posts, "cool dude" posts, "subscribing" posts, "questions already asked on previous pages" posts, and "keep us posted" posts.) to get things back on subject.

Wonder what the page count will be when I am done?

Keith

<edit> What was the first 18 pages have been condensed into 10.... I am taking a break!

 

Which cam setup(hks or otherwise) would best compliment this turbo. I'm most concerned with increasing mid-range power and decreasing spool-up time.

 

stock turbo? (sorry you weren't specific...) i know that STithis ran his stage 4 buschur on 264s it was fine... got him 4th place at evom shoot out. like i said the 272 are not even begun to be exploited with stock turbo. but 264 will choke anything larger than stock.

 

I've read that 264's is better for the stock turbo and 272's are better for a aftermarket turbo. I have 264's and that is how it's gonna stay. My car idles perfect with just a small hic cup everyonce in a while.

 

Hey guys,

I trimmed a lot of junk in a two day editing frenzy(from 37 pages down to 18). I left the "meat" of any off topic subjects until they became repetative, and all on topic posts are still here. If you have a problem with anything I deleted and can actually remember what was in your post that I deleted I may consider restoring it Until then, the thread is much more readable now.

Later,

Keith

 

Thanks Keith for the trim job

Any of the HKS cams will work well with the 20g. I started the dyno testing out, found here on the forums, that I am doing to test all the combinations.

My RS is now up to 355 dyno pulls. The only part I did not test yet that I intended to was the 264 cams. I tested the 272's and gained about 35 whp with tuning. I later added the 280's and gained another 15 whp just dropping them in and 24 whp with tuning. That is a 50 whp gain over the stock cams. I still have the intentions to go back and drop the 264's in the car but honestly don't know if I am going to get to it. There are a lot of questions about which ones to run. From where I am sitting the decision is easy and I say the 272's for now. The 280's are my choice for a serious car running a standalone. The idle is VERY aggressive, meaning the cams lope alot. We are going to try the flash on the car next weekend with the 280's, if we can get it to idle well then that is the cam to run. I don't think the idle is going to be good though.

BTW, I haven't noticed any increase in lag ON THE DYNO with any of the cam swaps.

David Buschur
www.buschurracing.com

 

As usual great work Dave! It would be nice to see what increase over the stock cams the 264's would get on your RS. The 264's were great street cams when I had them in my 94 Talon. The off idle and midrange torque would keep me up with those pesky V-8's from a roll.

 

I won't be putting the stock cams back in the car, that's for sure. I may drop back down to the 264's from the 280's and use some creative math to figure out the difference though.

David Buschur
www.buschurracing.com

 

Dave,

Do you recommend, or have you done any testing, of any of the high lift cams(tomei, revolver, etc. )? Do you think there would be enough of a mid-range gain(or any gain at all for that matter), with the 20g turbo to justify the extra cost?

-thanks

 

I have not tested any other cams than the HKS and the Crower.

Even with the stock turbo on the car the full line up of HKS cams, 264, 272 and 280's have shown significant gains. The turbo size means very little when choosing the cam.

David Buschur
www.buschurracing.com