Another thing to keep in mind is how difficult it will be to find wheels that you like and that are lighter by 4-5lbs each. Also the rear rotors are more important as those are the ones where the power goes to.

 

Actually no. Front or back, the motor still has to turn the mass regardless if it's the drive wheels or not. Unless you are doing a wheelie like a dragster.

 

2pc rears aren't as much of a deal breaker as people make out. to retain the factory parking brake you'll end up w/a design that won't save you much. for example, w/OEM Brembo's the the RacingBrake 2pc rear will only save you 1.5lbs(retains factory parking brake). now the Girodiscs will save you 5lbs but you'll have to trim the pads to clear and it doesn't look like you'll keep the parking brake. i highly doubt it'll be any different for the Akebono kit. the 2pc rear's won't save you much, just hope the front 2pc doesn't end up being too expensive. i went w/the OEM Brembos, small but still baller, LOL. i love the Brembo gold, the Akebono's would deff need a color change. the Brembo's are also a lot lighter.

 

2 pc rears aren't really the weight savers a 2pc front are. .

with that, I'd love to have the oem brembos on 2pc front and back rotors. Those would be lighter than even the early 11.5" 03 rotors if I'm not mistaken.

 

yeah, i know... that was my point. everyone is moaning about 2pc rears for the Ake' but it's really not that big a deal. yeah, i'll post up my new setup when it's on. just tryin' to get a few things together before WEKFEST.

 

Jeff, you have the '06+ brake upgrade right? i've seen Willwood caliper upgrade kits for those.

 

You are correct. Not really interested in just a caliper upgrade. Most of the improved brake power is in the rotor size upgrade.

But that's an interesting upgrade. Got a link for that?

 

http://cgi.ebay.com/ebaymotors/Big-B...item230438de8b

 

The reason the rears are more important is because it's basically an extension of the engine's power. Lightening the rotors on the rear is essentially relieving load/weight on the drivetrain. Yes the power provided by the rear will move the car and as a result spin the front. Not saying that lightening the front won't help any, but it's not the same as the rear.

I have the Girodiscs on the front and rear with my OE Brembos. You do need to trim a small section on the pads, but it's not that hard to do with a dremel. You are not removing any pad that comes into contact with the rotor. The parking brakes are preserved.

 

good to hear about the Girodiscs, but yeah the Brembo's aren't that heavy to begin with. you need all the weight saving you can get w/those 20's though. nice build though and sweet lookin' car.

 

also the reason why people "need" front 2pcs is because the fronts are sOoOo heavy on the Ake's. i see what ur sayin' about the rears though.

 

Maybe on a dyno but in real life where the engine has to turn all 4 wheels, it matters. Again, it does not matter what wheels are getting the power.

 

Most of the improved braking is going to be coming from the increased total surface area covered by the pistons. The larger rotor will help by cooling the rotors faster to improve the friction between it and the pads but that's quite small compare to the first.

Yeah those 20s are heavy. There is a thread in the tuning section where I and Hydrazine did some separate testing on the effect of heavier wheels if you are interested.

Thanks for the compliment. It'll be sweeter if it's running though

Like I said, I'm not saying lightening the fronts won't help but the effect on power is not quite the same as if you were to reduce weight on the rears. This does not change whether it's on the dyno or not, that hunk of mass is still connected to the hub. Anyways, we are getting way off topic and the physical reasoning I gave is still the same as above. We have a difference in opinion and lets just leave it at that. Now if you are talking about braking then yes, the fronts and rears are the same and the less rotating weight you have the faster it'll be to stop.

 

I disagree. If you increase the piston area too much, it increases the pedal travel. So bbk makers use more pistons but in general keeps the total area somewhat the same. Most of the increased brake power is from the larger rotor dia. Note the Z32 300z used a 4 piston caliper but kept a small 11.2" rotor. The braking wasn't that great. I paired the same caliper with a 13" rotor and the braking forced increased dramaticly. The torque arm advantage is a powerful thing

Increased rotor weight on the front won't show on a dyno. But increased rotor weight on either side will have an effect on the power needed to rotate either wheel. Does not matter if it's the powered wheels or not.
Let's say you ride a bike. No problem. Now let's make the front wheel 100lbs. Notice the difference. Now make the rear 100lbs. Why would having the 100lb wheel on the powered axle make a difference? (a significant one anyway)

But the weight differentials of lightening the front is also way more than doing the same with the rear

 

I agree.
Whether the front is driven directly or not doesn't matter, you still have to overcome the static inertia of the mass.
It also impacts braking when you have to stop that inertia.