Well, a local shop does engine balancing for $400. I'm sure they send it out to someplace reputable, but is how much of a difference will it make? I only plan on revving to 8500, maybe 9000 at most. The entire rotating assembly will be S5 13B-T, with "C" rotors. If I had plenty of money, I would just go ahead and get it done, but I'm on a tight budget and the money could definatly be used elsewhere. Would there be an increase in power due to the reduction of parasitic vibration? If so, how much?



I did some searching, and it seems that it doesn't really need to be done if I'm revving below 9k or so, but I was hoping for some opinons on the difference it will make.

Spend your money elsewhere.



And if your turbocharged, you dont need to rev to 9k unless you wanna break things.

balancing in not a major necessity but does make for a smother and quicker revving engine. Also puts less stress on main bearings and rotor bearings it makes for an over all smother crisper engine I would do it.

I would recommend you do it too. With 9k shift points the half bridge we used in the drag car last summer saw enough shaft flex to very lightly kiss a rotor to the rotor housing. That was a factory matched set of rotors and weights. Balancing isn't going to eliminate flex but it will help. Also, as noted above there are other benefits. If you're doing your typical deal and planning on tearing it down next year to try something even more wild then you might skip it. But if you want it to last above 8500 I'd do it right. Logan at Defined has someone doing balancing. Is pretty close to you so it would save on having to ship the stuff half way across the country.

What have you done to the rest of the motor to be making peak power at 9k? Usually never ever that high.

It's a p-port.



https://www.nopistons.com/forums/ind...howtopic=71334

I was planning on going with a 2-piece e-shaft with a center support bearing next year if this goes well...

If you can resist the temptation to rev the piss out of it then I'd wait. When you get the new e-shaft and the rest of the gear have all of that done up right. If that thing is going to live at 8500+ in the end you should find some ceramic seals as well.

I think its a good idea for those RPM goals but I agree with Ronin that you don't need to run that high on a turbo app comparatively to a non-turbo unless you've got some bridgeporting or more aggressive overlap porting done on the motor. I can have the balancing done for you; $225 plus return shipping.



B

How much clearance were you running?

S5 rotors?