Okey i will go with proto recomendation

 

100% true !

that's why so difficult with correct turbo tuning.

 

my upgraded gt2 vtgs have 49.8m compressor and am being told it the best you can get in VTG technology (they would say that of course!) and am running over 1.55bar for around 730hp/900+ nm with custom tune with many hours on the dyno. I guess the vanes must be getting fully open in my tune (have also cams/ ported heads).

 

+1 Mike. Thank god someone's on it. And "Killer post".....you're a cruel man .

Here's a link giving a general understanding of VTG technology for those who may be unfamiliar with how a VTG Turbocharger actually works. Its worth a read.

http://www.autozine.org/technical_sc...h_engine_3.htm

Note the exhaust or "hot side" is the one with the variable vaned wheel. Coolside or "compressor" is the wheel that pushes the air into the cylinders.

This next link whilst applicable to non VTG explains the area ratio and also explains how the larger size of the wheel does not necessarily make it more efficient (Bigger is not always better). Its well worth a read.

http://www.turbobygarrett.com/turbob...o_tech102.html

 

champion, be super careful about spreading bad info! -with respect

 

You're absolutely right. However, I will say that it was me personally who made the error, not "Champion" as a whole. After posting, I was corrected by Mike (and Louis here on my end), and acknowledged the mistake.

 

Tom,
We all learn something new on a regular basis.
You don't run and hide.
That tells me a lot about you.
You seem like a stand-up guy, and build some nice machines.
Props to you.

 

Thanks man..much appreciated.

I always say... "I'm no expert...but luckily I work with people who are"

 

+1.

Agree it's best to use the experts as a sounding board first in any marketing excercise or these things are bound to happen . So Tom, moving forward from here and getting back to topic, why is the new 68 better than the next persons 65? And who decided on the 68 wheel and, why 68 and not some other size? Was the turbo developed with or by the VTG turbo manufacturer or was it simply devised by Champion and the spec given to the manufacturer to produce? As Borg Warner designed the stock VTG turbo was there any consultation? Don't mean to offend but so far it does sound like a "bigger is better" marketing exercise.... a size war, when in reality size is apparently not the be all end all here.

PS. Whilst off topic what ever eventuated with the IAT comparison between your new ICS and the .2ttrs you said you had coming in? Did you ever manage to prove your intercoolers can match or better the IAT's of the .2tt coolers?

 

These were developed/tested and produced by Tial

 

Thanks Arone997tt. Looking at Tial's website it appears they are associated to Garret in some way and I'm not clear who ultimately manufactures the item and, who is actually the brains behind the final design. It would still be good to hear from Tom/CMS why the larger size 68 wheel was chosen and what actually dictated the need to go to a larger size, which now appears on the surface to have trumped the competitors wheel size. I guess you could look at it two ways here. Going by Mikes account they, in conjuction with Borg Warner, have achieved the right mix of aerodynamics and wheel size, and appear satisfied they have achieved the "optimum". It kind of makes you wonder who has the better recipe really....is it "brains" or "brawn"(simply size). I know its a natural tendancy for some folk to automatically think bigger must be better but there has to be a reason that stacks up in a way that it can be determined which is "better". We all know how marketing works and it can often get down to who tells the better story and has the shiniest parts and prettiest pics. So, there surely must be a means to be able to properly evaluate/compare the different offerings rather than simply relying upon assurances and say so.

 

I'd like to toss a few pennies into this pot as I have fooled with turbo cars of different makes for a couple of decades. Some cars originally came with turbos and some didn't and the design goals were different on many of them.

Basics: a turbo is nothing more than an air pump and the more air and more fuel you pump through the engine, the more power the engine will produce.

However, the optimum set-up is dictated by all the ancillaries such as fuel feed system, exhaust system, engine/air cooling system, ignition system, etc., etc.

When Mike (whichever Mike, TPC or AWE or AWD) says they have the optimum system, they probably do for the ancillaries that they use. Certainly Porsche thought they had the optimum system for a reliable road car.

You heard the however and now back to the BUT: Everything else being proportionally equal, a bigger turbo is going to make MORE POWER. It may come in later (lag) than you like, but it will be MORE.

The trick (maybe art) is to right size all the supporting systems that make the turbo work properly (no matter what size) in the first place.

Obviously, when you start making more power than the engine is designed for you have to consider a re-design or else. So another consideration for 'OPTIMUM' is your design goal.

 

No offense taken speed21.

Arone997tt is correct, our billet turbochargers were designed in partnership with, and are manufactured by, Tial Sport. Tial also produce turbocharger and turbo components for some of the biggest names in the game as well as the VTG upgrades for most* other companies in the Porsche market.

It all started with out 65mm billet turbos. At the time Tial had been making our 63.5mm upgrades in the standard housings when we approached them about the possibility of going with a 65mm wheel in the factory housing. Although it is possible to use the 65mm wheel in the factory housing, what Tial realized was that doing so pushed the turbo too far out of efficiency. The only way to bring it back into an efficient operating range was to redesign the housing itself for the increase in flow. Once the new housing was designed, we developed the 68mm option with Tial for those looking for even more power. I should add, though....that we don't sell the 68mm turbos without our carbon turbo inlet pipes or intercoolers. They're simply required to get the full potential of the turbos.

There's a definite difference in power from our 65mm and 68mm turbos. For example, on a 997 GT2 with the 65mm turbos we were able to safely get up to 688 RWHP with the 65's. On the current GT2 build we have going on right now using our 68mm turbos, we're up to about 755 RWHP. Once the engine interals are built in that car, we'll REALLY be able to see what the potential of the 68's is.

At the end of the day, our goal with these 65 and 68mm VTG's is not to build the most powerful 997 turbo in the world. Our goal was just to build the most powerful 997 turbo with VTG turbochargers. Drivabiliy, OEM-like installation, reliability....those are paramount for us. We're all HP junkies and enthusiasts here at the shop, so we get excited when we see posts from guys pushing the envelop with GT30's and things like that. It's awesome! But that's the beauty of the market...there's something out there for everyone.

As for the IC's...I did confirm when the GT2RS was here that it does indeed use the same coolers as the 997.2TT. As for any more specific testing other then what we did about a year ago...unfortunately not.

 

Thanks for the reply Tom, but it would be nice to have more technical meat (detail) on the bones of your above statement with regard to IATs (at wot) between the 65 and 68 and, the boost applied to make those whp numbers at wot. Most are aware that boost really needs to be applied with safer IAT's or timing will become an issue. It would be great to hear what IAT's your new IC's deliver(at wot) in comparison to the IAT's the new .2tt coolers produce... which allowed Porsche to deliver 1.6 bar "safely" at wot. If the new 68's can apply more boost torque than the 65's, then im assuming you have achieved the same or lower IAT's as what the new GT2RS has at 1.6 bar wot? When are you able to provide info on the IAT's vs .2tt ICs? I think that one really needs to be cleared up.

 

With both the 65's and the 68's we never run more then 23 psi on any car with stock engine internals. The WHP numbers I gave above for the two GT2's we built we both at 23 psi, the only variable being the turbochargers and turbo inlet pipes.

We've never conducted an actual "real-world" comparison between the .2 IC's and ours, because the reality is that's just impossible for us to do. We'd have to take the same car, go find a stretch of highway to do a high speed run, come back, change the IC's, and go do it again. Street testing is just something we don't endorse. We don't have the roads for it here in South Florida, and we just don't take chances on the street like that.

That being said, I can tell you that we recently completed a build on Arone997TT's tiptronic turbo cab. That car safely makes 670 awhp. During our testing runs on the dyno with his car, the ambient temperature was 25ºC. The highest intake temperature we recorded with the GIAC datalogger was 30.8ºC at 6734 rpm's. That's with absolutely NO knock, and full lambda control. The tunes we use are VERY safe. Granted...as I mentioned above, we were not conducting a comparison test of any kind, this is simply the results we got with his car during our final tuning stages.

The fact is that the .2 IC's are good...very good. They are extremely efficient, thermally. The only issue with them becomes flow in applications where a larger turbocharger is used. Remember, 1.6 bar from a factory VTG and 1.6 bar from one of our 68mm VTG's is very different. The actual volume of air being pushed through the intercooler is much greater. They're a great option....and if I was only planning on running a tune/exhaust on my car, I'd be ALL OVER these for the price.