BBK and new wheels

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BBK and new wheels

Postby slvrspd » Thu Dec 16, 2010 11:21 pm

Brian,
I would like to get an opinion re two setups for my car that I want to use for autocross(with stickier 245/255 -40-17 tyres)

1.Enkei 17x9 RPF-1 with RX 8 Brakes as a BBK(since the BB kits for the MX5 do not fit this wheel,which is disappointing since I really like this wheel..+saving 5-6 lbs per corner would have been perfect!)
2. 6ULR 17x9 with one of the BB kits on your site

My issue is with unsprung weight as with the first options whatever I gain by lighter wheels are off set by the heavier brakes..
With the second option the brakes are lighter but the wheels are heavier..all though the second option will still let me shed 1 lb per corner if my math is correct...but more rotational mass per wheel.

In your estimation which is the better way to go for a supercharged NC for autocross
(also my summer time daily driver with 17x8 RS+M wheels)
Thanks
slvrspd
2006 Silver NC ,GT,PP,HT,,FM Stage II Suspension,GWR header, midpipe,Q exhaust,Exedy clutch +flywheel,Cosworth S/C
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Re: BBK and new wheels

Postby Brian » Fri Dec 17, 2010 8:01 am

Can't go wrong with either choice...

With the RPF1 17x9 and our TWO-piece RX8 rotors you would lower your total unsprung weight while adding thermal capacity and wheel width....even as you move up the RX8 factory calipers.

The 48mm 6ULR the wheel is a few pounds more than RPF1 but you save that on the four piston calipers up front and you get a much easier 48mm fit with less fender adjustment.

Thus, in terms of unsprung weight you are close either way....a little more rear unsprung in the second choice, a little more front unsprung in the first choice.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
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Re: BBK and new wheels

Postby skeeler » Fri Dec 17, 2010 11:13 am

slvrspd,

The offset may be the deciding factor. With 255/40-17s, my +49-offset wheels fit much better/more easily than the +45 wheels do.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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Re: BBK and new wheels

Postby slvrspd » Fri Dec 17, 2010 4:59 pm

Thanks for the help guys.
The 6URL wheel would be the easier fitment of the two and then I can fit 255 series tyres with slightly less fender fiddling(the Eastwood is in the garage ,waiting for warmer weather to perform it's magic)
slvrspd
2006 Silver NC ,GT,PP,HT,,FM Stage II Suspension,GWR header, midpipe,Q exhaust,Exedy clutch +flywheel,Cosworth S/C
slvrspd
 
Posts: 39
Joined: Sun Dec 16, 2007 9:36 pm


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