Mad Cow

As you can see, my wheel is clipped. There are various posts on this in the archives with various people saying "clipped wheel will make performance suffer", "bad bad bad", etc. but nobody has examples and/or reasons.

I'm just looking for a bit further explanation from people who have witnessed it or experienced it themselves.

Art, Vapor? C'mon, I wan't some experienced opinions here.

falcongsr

i believe a clipped turbine wheel will effectively raise the a/r of the turbine, which means it will spool up later but flow better (less restrictive on the top end. ) dsm guys do it alot for higher peak hp...someone correct me if i am wrong.

rudebwoy

iTrader: (1)

it makes the turbo off balance, therefore the biiger chance for bearing failure.

Mad Cow

Off balance how? It was rebuilt (including balancing, I assume).

ImAcracker

What does it mean for a wheel to be clipped?

falcongsr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rudebwoy &raquo;</TD></TR><TR><TD CLASS="quote">it makes the turbo off balance, therefore the biiger chance for bearing failure.</TD></TR></TABLE>

while i see the potential for messing with the turbine wheel causing it to get off-balance, the intention of clipping a turbine wheel isnt to throw it off balance.

from a DSM website: "Turbine wheel is clipped to increase exhaust flow in upper RPM ranges.
Clipping does increase spool up time and reduce turbine efficiency slightly. Recommended for continuous high-RPM cars (drag racing, fast road courses)
"

another: "Clipping is the technique of cutting away some of the material on the fins of the impeller wheel of the turbocharger. In other words, to 'clip' a turbo is to make the fins in the exhaust path smaller. The cut is usually done at an angle of between 10 and 20 degrees - the bigger the angle, the more material is removed from the fins.

This may seem like a dumb thing to do, since smaller fins mean that the exhaust gases will impart less force to the turbine wheel and consequently increase turbo lag. This is true, but the benefit of clipping is found in the high RPM range of the motor. At higher RPMs, the turbo may have already surpassed the required user-set boost levels and is not contributing to engine power.

Since the impeller wheel in the exhaust stream partially blocks the exhaust gas flow (by design), it can act as a significant restriction at high RPMs, when the exhaust flow rate is highest. Clipping the turbo reduces this restriction and allows more air to flow past the turbo wheel at high RPMs, thereby improving airflow through the engine and increasing top-end response.

"

taken from http://www.dsm.org/menu.epl?item=94

joshwhe

after a point the stock turbine can become more of a restriction then it already is.... sometimes the stock hot side is just not enough to flow what your motor wants to put out.

Mad Cow

So basically, it's causing me to spool slower. I really don't have a use for it as this is on my daily driven GS-R and the turbo won't be maxed out.

Anyone wanna buy a turbo? $380 shipped.

falcongsr

what are the exact specs of the turbo

Mad Cow

turbonetics t3/to4b s-trim w/ .63 a/r stg 1 clipped.

rudebwoy

iTrader: (1)

I did not noticed it said clipped I thought said chipped,

so thats why the turbine wheel on my remanufactured turbo is shaved down, its called clipping? <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rudebwoy &raquo;</TD></TR><TR><TD CLASS="quote">it makes the turbo off balance, therefore the biiger chance for bearing failure.</TD></TR></TABLE>

Mad Cow

ah that makes more sense. Clipped, not chipped.

falcongsr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rudebwoy &raquo;</TD></TR><TR><TD CLASS="quote">I did not noticed it said clipped I thought said chipped,

so thats why the turbine wheel on my remanufactured turbo is shaved down, its called clipping? </TD></TR></TABLE>

depending on how the shave marks are, it might just be that the turbo was properly balanced, not clipped. they actually grind the turbine shaft/nut/assembly down to balance it.

ImAcracker

Why not just put a bigger A/R turbine houseing?

89dxhunchback

Sometimes its not always easy to get a "bolt-on" bigger A/R housing, like in my case with the stock WRX turbo... If I had a T3/garrett I would just buy a stage3 wheel vs a clipped stage1...

Mad Cow

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by falconGSR &raquo;</TD></TR><TR><TD CLASS="quote">depending on how the shave marks are, it might just be that the turbo was properly balanced, not clipped. they actually grind the turbine shaft/nut/assembly down to balance it. </TD></TR></TABLE>

Hm, good point. Mine's definatley clipped tho, Cheapturbo.com told me it was when I bought it.