New Wilwood big brake kit input thread
02-01-2007, 08:09 PM
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New Wilwood big brake kit input thread
Hi ya'll! I'm at it again. I'm speaking with a company about developing a big brake kit around Wilwood Superlite calipers and I need your input. Do we want:
1. Affordable price (bear in mind that we're still talking around $1300 here)
2. Two-piece rotors for front and rear.
3. Sizes which are SCCA-friendly
4. setup for no wheel spacers, i.e. perfect fit behind stock wheels
5. maximum heat-shedding capability for long life under track conditions
or would you rather have a cost-no-object, 14" or larger brakes designed to work with 19" or larger wheels and super-grip tires?
Post your input to this thread. I'll be checking in several times per day. Anyone racing in SCCA or track days, please post your thoughts as to what the RX-8 needs.
I'm the one looking at having to foot the bill for the "development spindle, hub, caliper and rotor" from a stock RX-8. I will not be the one selling the kit. I'm not a retailer.
I'm also speaking to them about a bolt-on bump-steer correction kit for the front tie-rods, and possibly for the rear tie-rods too. I haven't found anything like this available, and I'm tired of living with atrocious steering while braking simply because I've lowered my RX-8.
1. Affordable price (bear in mind that we're still talking around $1300 here)
2. Two-piece rotors for front and rear.
3. Sizes which are SCCA-friendly
4. setup for no wheel spacers, i.e. perfect fit behind stock wheels
5. maximum heat-shedding capability for long life under track conditions
or would you rather have a cost-no-object, 14" or larger brakes designed to work with 19" or larger wheels and super-grip tires?
Post your input to this thread. I'll be checking in several times per day. Anyone racing in SCCA or track days, please post your thoughts as to what the RX-8 needs.
I'm the one looking at having to foot the bill for the "development spindle, hub, caliper and rotor" from a stock RX-8. I will not be the one selling the kit. I'm not a retailer.
I'm also speaking to them about a bolt-on bump-steer correction kit for the front tie-rods, and possibly for the rear tie-rods too. I haven't found anything like this available, and I'm tired of living with atrocious steering while braking simply because I've lowered my RX-8.
02-01-2007, 08:29 PM
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I already have a racingbrake BBK, but if they could make this kit lighter, rotors and calipers than the racingbrake bbk I would purchase it.....as long as the quality is as good as racingbrake bbk, lightweight rear calipers would be good too cause Im not sure if any of the BBK out there right now make a rear caliper that retains the E-brake.....
02-01-2007, 09:37 PM
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Originally Posted by RA-Eight
6. Kits that are compatible with pads that are widely available.
02-01-2007, 09:45 PM
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Originally Posted by gr8rx
I already have a racingbrake BBK, but if they could make this kit lighter, rotors and calipers than the racingbrake bbk I would purchase it.....as long as the quality is as good as racingbrake bbk, lightweight rear calipers would be good too cause Im not sure if any of the BBK out there right now make a rear caliper that retains the E-brake.....
I will ask about the rear e-brake cable...
As for quality, this company's products are tops in the BMW world. They make some terrific stuff. I have no worries about that.
02-03-2007, 10:47 AM
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My car is significantly lowered. I can feel the effect caused by bump steer in the front during just light braking, when the front is compressed even further than it is now while moving over bumps in the road. In all suspensions, the front tie rods are positioned for normal suspension height, in relation to the steering rack's mount. By lowering the car, I've changed that relationship, and have induced bump steer. The RX-8 is better than most in this regard, BUT... I'm sorry, but it's still there.
In the rear, the TOE LINKs, which use a "tie rod style" attachment suffer from the same misalignment as the front steering rack/spindle relationship as the car is lowered. Lowering the car changes the RATE at which toe in/out occurs in the rear suspension. In both the front and the rear designs, the relationship changes so that there is toe out under compression.
Let's say, for example that you're cornering hard... at full ride height the compressed side of the front suspension is experiencing negligable toe-out because it's operating within it's parameters, i.e. as the engineers designed it to work. At the rear, on the compressed side, there is an engineered amount of toe-out which is SUPPOSED to occur, in order to help the car turn through the corner. This is an excellent design which does exactly what it's supposed to do. Now, when the suspension is lowered, the front control arms have moved upward in relationship to the steering rod, and now, as they move further upward during compression, the wheel toes out! In a race car, which is typically set for toe-out anyway, the driver is used to the sensation. In a street car, where road surfaces are extremely poor, especially when braking to a stop in southern California, where the roads are repaved about once per lifetime, the effect of bump-steer is quite dramatic.
At the rear, the slight toe-out OEM-engineered effect becomes a more dramatic toe-out effect, again because the relationship between the toe-link and the control arms has changed as the arms were moved upwards by the lowering of the car. This can be felt in mid-corner bumps as the car tries to change its line and cut harder when the suspension compresses, then returns to its previous arc when the suspension resets to "normal cornering position".
Simply sticking your head in the sand and saying "The RX-8 doesn't need a bump-steer correction kit" is to blindly ignore the facts.
I used "Tie Rod" to describe the rear because of its outer mount to the spindle. I noticed that it has no adjustment on the outer end, and there'd be no way to mount a new height-adjustable ball joint on the end. The entire rod would have to be replaced with a new one. My use of terms should not be attributed to the company I'm talking to about the BBK. THEY have numerous SCCA RACING victories with E30, E36, and E46 M3s. They are NOT a part of the bling-bling crowd and again, anyone who pooh-poohs their reputation in the same sentence as a reference to the RX-8 not needing a bump-steer correction kit has lost a measure of credibility with me.
Before someone states the overwhelmingly obvious, yes you CAN adjust the rear toe at the inner mounts, back to stock toe-in settings. This does not change the horizontal relationship of the toe link to the control arms, and by lowering the car, you've screwed it up. Front and rear. It's really that simple guys
TeamRX8, didn't you have an issue with the rear of your car being extremely tail-happy at the SCCA finals last fall? Of course, I'm sure that has nothing to do with bump-steer right? Honestly, it might not, but lacking another explanation, I'd certainly start by looking at that rear toe-link.
In the rear, the TOE LINKs, which use a "tie rod style" attachment suffer from the same misalignment as the front steering rack/spindle relationship as the car is lowered. Lowering the car changes the RATE at which toe in/out occurs in the rear suspension. In both the front and the rear designs, the relationship changes so that there is toe out under compression.
Let's say, for example that you're cornering hard... at full ride height the compressed side of the front suspension is experiencing negligable toe-out because it's operating within it's parameters, i.e. as the engineers designed it to work. At the rear, on the compressed side, there is an engineered amount of toe-out which is SUPPOSED to occur, in order to help the car turn through the corner. This is an excellent design which does exactly what it's supposed to do. Now, when the suspension is lowered, the front control arms have moved upward in relationship to the steering rod, and now, as they move further upward during compression, the wheel toes out! In a race car, which is typically set for toe-out anyway, the driver is used to the sensation. In a street car, where road surfaces are extremely poor, especially when braking to a stop in southern California, where the roads are repaved about once per lifetime, the effect of bump-steer is quite dramatic.
At the rear, the slight toe-out OEM-engineered effect becomes a more dramatic toe-out effect, again because the relationship between the toe-link and the control arms has changed as the arms were moved upwards by the lowering of the car. This can be felt in mid-corner bumps as the car tries to change its line and cut harder when the suspension compresses, then returns to its previous arc when the suspension resets to "normal cornering position".
Simply sticking your head in the sand and saying "The RX-8 doesn't need a bump-steer correction kit" is to blindly ignore the facts.
I used "Tie Rod" to describe the rear because of its outer mount to the spindle. I noticed that it has no adjustment on the outer end, and there'd be no way to mount a new height-adjustable ball joint on the end. The entire rod would have to be replaced with a new one. My use of terms should not be attributed to the company I'm talking to about the BBK. THEY have numerous SCCA RACING victories with E30, E36, and E46 M3s. They are NOT a part of the bling-bling crowd and again, anyone who pooh-poohs their reputation in the same sentence as a reference to the RX-8 not needing a bump-steer correction kit has lost a measure of credibility with me.
Before someone states the overwhelmingly obvious, yes you CAN adjust the rear toe at the inner mounts, back to stock toe-in settings. This does not change the horizontal relationship of the toe link to the control arms, and by lowering the car, you've screwed it up. Front and rear. It's really that simple guys
TeamRX8, didn't you have an issue with the rear of your car being extremely tail-happy at the SCCA finals last fall? Of course, I'm sure that has nothing to do with bump-steer right? Honestly, it might not, but lacking another explanation, I'd certainly start by looking at that rear toe-link.
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