To clip or not to clip

[Slider925]

What is the purpose of clipping a turbo and is it really worth it?

 

[calcifer]

I beleive it spools a little slower, but gives you better top end power. Most useful for drag racing applications, I think.

 

[psychlow]

Clipping is usually a bad idea, IMO.

Turbo manufacturers usually have these guys called ENGINEERS with degrees and fun stuff like that. They run calculus and algebra equations to get good efficiency rates on the wheels.

Turbo VENDORS (the ones that usually peform the clipping) usually are not running any efficiency equations and such. Therefore, clipping might give you some better top-end (and I emphasize the word MIGHT) but you're usually giving up too much on spool/lowend.

 

[steve]

You can always have a turbo clipped later if you really think you want/need to but it's much harder to go the other direction.

Steve

 

[purpleesi]

"What is clipping?
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. "

http://members.shaw.ca/costall/1000Q/

 

[purpleesi]

Clipping is usually a bad idea, IMO.

Turbo manufacturers usually have these guys called ENGINEERS with degrees and fun stuff like that. They run calculus and algebra equations to get good efficiency rates on the wheels.

Turbo VENDORS (the ones that usually peform the clipping) usually are not running any efficiency equations and such. Therefore, clipping might give you some better top-end (and I emphasize the word MIGHT) but you're usually giving up too much on spool/lowend.

Im sure that ENGINEERS dont design turbochargers for daily driven cars with maximum top end power in mind. Rather they design them while thinking of good street manners and relyability.

Also how do you know what clipping does and does not do? Is yours clipped? Nope. So why are you giving this guy advice on something you obviously know nothing about. If clipping "might" yeild power results then why would anyone even bother to do it?

Next time let the kids that have an idea what they are talking about reply

 

[Steve93Talon]

Clipping isn't just done for more top end power. It's also done to reduce surge on applications with less-than-perfect matching of compressor and turbine wheels. Having just witnessed a clipped TD05H-20G powered car trap 126.79 last night, I'd have to remind the bench racers to put down their calculators and maybe hit a track every now and then.