Originally Posted by TURBODAWG

I can tell you this. I have never heard of a stock clutch going out at ~1000 miles, that has NEVER been launched. The car we tuned in the link above is making some serious torque. We just installed an RPS Carbon Carbon clutch in it, because the stock clutch couldnt hold the torque. When we left the dyno it was slipping in 6th gear. A few hundred miles later and it wont hold in any gear. If you look at the dyno sheet in the link I posted before you can see the nice area under the curve.

https://www.evolutionm.net/forums/sh...torque+monster


Brian

Originally Posted by justchil

I made pretty nice numbers on race gas but the pump gas results weren't much better than my stock 03 turbo. I will dyno again soon to see if I actually had "problems". I'm in the process of getting it converted to the 5 blade/fin whatever you call it... but with the 2-3 week (car has been for 2 weeks already with other issues) wait I may just go with a 50trim/30R.

http://img.photobucket.com/albums/v2...chur/ACarn.jpg

Originally Posted by shiv@vishnu

Not really. A larger compressor is going to have more mass which means more inertia. It take loger to spin up all things equal. Since it is a competely new wheel, we also have to take into account aero design differences which may or may not be improved over the regular TME. As also have to take into account balancing issues (which is most likely the cause of the turbo noise that people talk about) which will also degrade performance. And lastly, the compressor and the turbine are joined by a shaft which means they always spin at the same speed. Because of this, it is important to have a proper match between the compressor and turbine.

A larger compressor will have to spin slower to move the same air. Now the turbine is forced to spin slower which will move it to another place on its turbine map. This place may be better or worse than before. If it's worse, it will result in more exhaust backpressure which would explain why the several extra psi of boost that people are running with these turbos aren't resulting in gobs more power. Just remind yourself how much more power a GT30R makes at the same boost pressure that people are spinning their "20gs" to. It is blessed with a more appropriate speed match between the hot and cold side. The larger turbine hurts spool-up, of course. But it does wonderful things to power at higher engine speeds.

Now if you spin the larger compressor the same speed you spun the TME, it will move more air and create more exhaust flow. Now you are asking the same turbine to move more exhaust flow which will create backpressure. Sure, you can clip the wheel to help get the exhaust gases out. But unfortunately, clipping results in a big reduction in turbine efficiency which hurts spool-up and power.

So no, it's not as easy as just bolting on a bigger compressor wheel, compressor housing and clipping the turbine wheel. All that work just juggles around compromises that may or may not work out in your favor.

Just my 2c,
shiv

Originally Posted by 13-0

Ted I went over your charts and have seen something similar before with a clipped wheeled turbo. Basically it looks like the comp. map is being forced to the right of the powerband (relying on increased exhaust flow) except that there isnt much comp. efficiency left and the system equalizes were the wheel doesnt move enough cold air in turn not supplying enough energy to spin the exhaust side due to the fact that clipped wheel has reached an equalibrium. .

Originally Posted by Ted B

One thing that does come to mind is the fact that I recall David B. making the comment that he had never seen a turbo surge as badly as the TME. FWIW, I was a bit puzzled by this, as I've *never* experienced any surging problems with a TME, nor can I think of anyone I know who has.

From what I understand, the turbine on these 20G-9 units is clipped.

In all fairness, David B. has asked me to be sure the WG actuator is *tight*, so that the initial boost spike comes straight from the turbo and not WG duty settings. Obviously, I can see that any leak at the WG will drive compressor efficiency to the right and skew the results.

Can anyone offer a brief primer on the best way to do this? Obviously, I'm not going to touch it until/unless I can get back to the dyno.

Originally Posted by shiv@vishnu

Just fill the boost map in your xede with 0s. This will make you run mechanical wastegate pressure.

Originally Posted by Sean@Vishnu

I ran into the same problem with the 20G-9 that I tuned 2 weeks ago. It had none of the midrange the *stock* turbo had and only made a few hp up top (6500-7800rpm). Area under the curve, however, was so underwhelming that I honestly wouldn't even consider the turbo to be an upgrade.

Originally Posted by fury656

After the tuning session I found out that my original Forge valve was leaking.

Originally Posted by tigeron

Going to probably get flamed. But which one would be better to buy if you the posters and or new guys wanted to upgrade and not spend $2000. on a turbo upgrade? Just tryong to get info since all these posts and different forums and popping up every where. Thanks.

Originally Posted by Ted B

If I find the incentive to get back to the dyno with this, I'm going to replace the Forge BOV with my JDM MR unit and observe any changes. I definitely don't want to rule out the possibility of the same.

Originally Posted by Ted B

Ok, but once I've obtained that info, I could use a bit of guidance as to what I'm trying to achieve via adjustment of the WG actuator.