I was talking with VTC Civic tonight about clipping my turbo. I have an IHI RHB5 VJ14, and having said turbo, I don't have any choices of turbine housings. I'm stuck with what I have. I can, however, put a larger compressor wheel and housing on it.

Anyway, he said that clipping the turbine wheel will make it spool faster because the wheel is smaller, but won't increase the flow capacity because it's the same housing. I say that it'll spool slower because clipping increases the A/R ratio and will flow more because the A/R is larger.

Also, what are the benefits and disadvantages of clipping? I did a search and most of the replies were along the lines of, "clipping is ghey." I'm looking for some intelligent answers. Thankee.


[Modified by Loco Honkey, 2:05 AM 1/17/2003]

 

I am no expert, but I have the turbo in my supra clipped...
from what I understand is you clip to make a small hotdise turbo flow better but it increases lag... it lets the exhaust get through easier so it will flow better up top

 

I don't see how clipping a wheel can increase a/r? Mine is clipped to aid in high rpm airflow.

For anyone not sure what clipping looks like, here are pics:





[Modified by apexii, 9:01 AM 1/17/2003]

 

You are not changing the geometry of the housing so I know clipping would NOTchange the A/R.

Clipping causes little to no increase in the wheels flow and it lowers the the turbo's efficiency. According to garret this also causes the turbo to come up on boost at a later engine speed and increases turbo lag.

art

 

That is very helpful, thanks so much

 

hey thanks for the pix now i know what it looks like....

 

No problem fellas...

 

It even kills your efficiency under boost.

 

I was under the impression that you clipped the outer edges of the vanes, and not the trailing edges.

So, general concensus is that clipping is not a good way to increase high RPM flow because it will reduce high RPM efficiency, right?

 

Clipping seems stupid to me. Seems the DSM guys are really into clipped wheels. YOu would think if the manufacturer could improve there turbos by clipping, they would be clipped brand new from them!

 

Gee, that sounds wonderful

 

So if it increases flow a little, yet decreases efficiency and increases turbo lag, why would people pay for it to be done? Is this to trade off low end power for top end?

 

I have a t3/t4ob with a stage 3 wheel that has been clipped and balanced for max performance and efficiency from turbo performance and they have been doing this for a while they reccomended this for my app. and I couldn't be happier.

 

In my opinion clipping would be beneficial when using a smaller turbo on a larger engine because it would take more exhaust flow to turn the turbine because there is less surface area to push the turbine. I was debating doing this to my t3 .60 ar compressor turbo because I thought it was too small. I haven't done it yet, but I'll see how my h22a truly takes to the turbo. I've read a lot of dsm guys clipping their turbos and they have been very happy, so I 've heard both good and bad things about clipping.

 

Yes, that's the whole idea, IMO.