To follow up on one of the above posts on shaving/clipping...

Shaving and/or clipping the wheel is widely considered to be a bad practice. Powerhaus has had limited success with it but it's an old trick for old turbos that's a bandaid for spoolup at the cost of total power. I'm fairly certain they no longer employ it any more. It kills turbo efficiency for minimal gains in spoolup.

 

Pwerhaus advertises a quick spool option. I wonder what that is.

 

Is a clipped wheel basically what any quickspool adds up to be?

 

Kool:

Negative. "Quick spool" sometimes refers to a ball-bearing center as opposed to a bronze sleave bearing supporting the turbo spindle and adds noticably to how well/quickly a turbo reacts to exhaust pressure. The Garrett GT series turbochargers in particular are ball-bearing supported units and are truely more than "pixie-dust". They offer true improvement over T3/T4 technology which was yet still an improvement over 80's KKK technology.

 

It's not exactly what Powerhaus does. I actually got it out of David but I'm not at liberty to say exactly what they do. Matt and ninefiveone are right about what clipping/shaving and what it's supposed to do and what can happen when not done right, but Powerhaus does things a bit differently and if you look at my cars numbers you'll see. I have a custom K29/8 in my car that took a bit of R&D and money to make. I was the first. He's now selling them to racers all over the country. They're efficient and powerful.

 

question for Dfast: How are you losing 84 horsepower through the drivetrain?

 

15% is normal...

 

Is it 15% of what the motor makes for hp when its stock? That would be 32hp (217 x 0.15). When youy put a bigger turbo in and bump up the boost and make 350 hp you still only lose 32 hp, not 350 x 0.15.

 

No, drivetrain losses are always some percentage. The harder you turn the crank, so to speak, the more it resists.

 

I'd answer but it's already been done. Thanks guys...

 

i realize that 15% is "the standard", but i would never assume that if if all cylinders are making the same amount of power or close to it, it shouldn't be 84 hp loss through the drivetrain

 

I always wondering if the 15% stays the same for the loss after you start to upgrade or if it drops down at all. It makes sense that it would stay at 15% unless you improve the drivetrain some how so there is less friction like new CV joints and what not. Is 15% about what a 951 loses in lost or is it 12%?

 

Theoretically you could reduce rotating mech. weight, and lose marginally less. (lt wt flywl/clutch/pp. ltweight crank. perfect drivetrain) but there will still be weight must be rotated via multiple tranfers. You will lose the hp. 84 hp is 15% of his number.Engineers have been through this MANY times.

 

So its 15% no matter what the hp is?

 

As i said, it could be a bit more, or a bit less, depending on the very specific car, and what has been done to eliminate extra "work" required to transfer the power, but the ratio is the same either way. What you lose is what you lose. If anything more hp could be limited by the ratio more easily than the ratio to the hp. Math is math. Work is work. That's why you need hp to overcome all of the issues that bleed off the effects of the power you create. Torque is what makes you go fast.