I have read through the various banter on this thread, some of which I agree with, some of which I dont...its only expected as we all have different opinions.

I for one have the 20G9-6 from tc.com which has a similar wheel than that being sold in Australia. My turbo has a aggressive turbine wheel clip. The clipping is done to alleviate some of the back pressure issue BR spoke of.

I cant compare with the so called 20G-5 (which in fact is a revised 16G - rumoured to simply be the WR wheel). Anyway the 20G9-6 I have is great, it pulls hard and I havent had any problems on my setup. Its pulls faster than any similar setup Evo I have raced with a stock turbo.

I bet the half of you speculating on this thread about the 5 or 6 blade havent even used either. The only way to solve this is to get the opinion from someone who has used both the 20G-6 and 20G-5.

The closest opinion on this site is from Ted B who has results comparing the 20G9-6 against a TME turbo (If Ted B is reading I hope you dont mind the mention). On his setup the 20G9-6 didnt perform any better than the TME. It certainly performed better on my setup but it might be a unique case. In any case until there is a direct comparison between the 5 and 6 blade, speculation is simply going to just that.

 

Buschur has officially compared the 5 Blade to 6 Balde wheel and documented the results...........its the way you interpret the results which leads to the facts about the differences between the two wheels

Eitherway, this thread has turned out to be the be all/end all discussion between these two 20G wheels

 

I've installed and dynoed the EVO8 20G "6" and was able to crack over 300 whp on our local mustang dyno. It spooled later than my stock 05 turbo, but made more hp with a less aggressive tune and less boost.

The car ran an AEM EMS and had no surging issues.

 

Is anyone going to try this?

 

If you guys want I can get the turbine wheel around $200, $150 for the compressor wheel 6-bladed. It's an inconnel wheel but unclipped.

A TD05 turbine wheel with a TD06 compressor wheel with a stock compressor housing and a 10.5 twin-scroll hotside is only a race gas turbo for the EVO largely because it's a band-aide solution made to conform to the limitations of the TD05 turbine wheel and the 10.5 hotside.

Cheers,

Gary
Gruppe-S

 

I have talked to the guy at GTpumps. They have tried a 20G on their turbo dyno which gave poor results in the evo8 turbo. They are about to release an 18G which showed 25% flow increase on the turbo dyno. They machine the compressor housing to make it fit. It can be bought as a complete new turbo or you can have your existing turbo rebuilt with the 18G wheel. If you get a complete turbo it comes with their upgraded turbine (better grade alloy).

 

still so many new developements...

 

does Buschur sell just the 20g-5? or do you have to send him in your housing as well?

 

interesting stuff

 

Just noticed that GTPumps is now selling their TD05HR 18G wheel. Ive asked for some dyno prints comparing the 18G with the 20G. Will post any feedback I get.

 

did you find anything?

 

Yes I did, they dynod the 18G and they got some gains over the 16G - I guess that was expected, but they havent dynod the 20G for comparitive purposes yet. Ill see if I can get any information over night re numbers and graphs.

 

Did anyone else here note that the larger wheels are ONLY larger in the INDUCER?

It takes the trim from .711 to .775.

Most of the time, a larger trim results in more flow at lower boost levels ... and WORSE high-boost performance as well as more problems with surging. Weird how that's exactly what most people saw. The reason is just physics: air comes into the inducer, goes out the exducer and the radial distance between the two acts like a "seal" to resist air going the wrong way. Lower trims also help efficiency in part because the airflow through them is a little smoother. The .5 to .7 region seems to be the "magic number" for most turbochargers. I'd say .775 is pushing it ... but I guess it depends on the design?

I believe this is covered in "Turbochargers" by Hugh MacInnes, if I remember correctly. It could have been "Maximum Boost" by Corky Bell, as I can't recall, but it was one of the two.

Seems pretty consistent with the results as well, if you ask me.

 

Its funny you mention this........if you look at the old T series wheel specs & maps and then compare them to the new GT specs + maps, you'll notice design is more important then magic number regions........for example, the trim doesn't take into account the actual height of the blades/wheel themselves......

Also, if you really know your Mitsi Turbos' then you'ld notice that all the wheels currently available from GTPumps is of the new MHI design where the blades are perpendicular to its axis, rather then at an angle........which means the compressor maps we have around on the web are pretty much useless now......

 

It's a generalization, take it or leave it. More often than not, it holds true, but, like all generalizations, it doesn't apply to every case.

(that it is a generalization also does not mean that the 20G/16G is an exception; indeed it seems to fit the generalization quite nicely with the evidence in hand)

But, since they were BOTH "upgraded" to the newer design, the same generalization probably still rings true. Is it a gurantee? No. But I never said it was.

Anyway, as I said before, it's just "interesting" that many of the results between these two turbos have fit the textbook expectations based on visible compressor wheel differences almost to a T. Veeeeddy interestink indeed.