Willwood

[jules325i]

To start i have a 2.8 stroker.

I am very interested in the Willwood big brake kit from ie.
6 piston front
4 piston rear

The car is expected to see quite a few track day events,
and i feel the brakes need upgrading.
However this car will be driven on the road frequently will having such a big brake kit be dangerous in any way.

[xxlbimmer]

I don't believe they would be dangerous. But, depending on the brake pads you run, could definitely be a factor. Many track/high performance pads don't work very well until they are up to temp ( i.e. very hot), so some cold braking may not be up to expectations. Usually, those pads would never get to temp on the street.
That said, a second set of "street" pads could be installed in a few minutes for proper daily use!!
That is where an RX7 kit is realy nice. Pads can be changed in seconds. and are more than adaquate for a dual use car.
Don't forget those big rotors need to be accelerated and decelerated regularly. So, saving weight on a wheel set is negated by huge ( often too big) rotors. I would really look at the usage, and figure out if there is a need for that big.

[Yngvejos]

Run BP20 pads for street use and you will be fine.
The weight isn't too bad on the IE kit.
295mm kit:

[jules325i]

I don't believe they would be dangerous. But, depending on the brake pads you run, could definitely be a factor. Many track/high performance pads don't work very well until they are up to temp ( i.e. very hot), so some cold braking may not be up to expectations. Usually, those pads would never get to temp on the street.
That said, a second set of "street" pads could be installed in a few minutes for proper daily use!!
That is where an RX7 kit is realy nice. Pads can be changed in seconds. and are more than adaquate for a dual use car.
Don't forget those big rotors need to be accelerated and decelerated regularly. So, saving weight on a wheel set is negated by huge ( often too big) rotors. I would really look at the usage, and figure out if there is a need for that big.

accelerated and decelerated????

[jules325i]

Run BP20 pads for street use and you will be fine.
The weight isn't too bad on the IE kit.
295mm kit:

so aslong as i get street/track pads it will be quite driveable on the road.

[xxlbimmer]

accelerated and decelerated????

Yes, Every start and stop, that much more weight would have to be accelerated and decelerated. In other words, more rotating mass. We lighten our flywheels, buy lightweight wheels, than(sometimes) install massive brakes (read: too big) on very lightweight cars. These have to be started and stopped.
Also the calipers are sprung weight. The Dynapro calipers are not skinny. Through discussions with engineers at Wilwood, I have found that a more preferred choice would be a Forged Billet Super Light, about 2 lbs lighter and actually a stiffer piece. I was going to be running those on a GT2 240z, a speed potential at Daytona of 165-170.
I was talked out of 6 piston calipers by the engineers for the reasons I stated.

[E30-323ti]

re: Track Pads in a road car.

I run Pagid RS4-4's (in big Brembos)
I only really use the car to get to the track
Sure cold pad bite is almost non-existant, but with boosted brakes you can easily apply enough pressure to get them to the point of lock-up in an emergency.

Would I have them in a DD, nope.

[SkiFree]

he Dynapro calipers are not skinny. Through discussions with engineers at Wilwood, I have found that a more preferred choice would be a Forged Billet Super Light,

The Dynapro 6's are skinnier than the SuperLights.

[Wh33lhop]

Yes, Every start and stop, that much more weight would have to be accelerated and decelerated. In other words, more rotating mass. We lighten our flywheels, buy lightweight wheels, than(sometimes) install massive brakes (read: too big) on very lightweight cars. These have to be started and stopped.

Typically the rotors offered with big brake kits come in around the same weight (or a lb or two more) as stock rotors due to their 2-piece construction. Overall, you are not going to notice a pound or two per corner. 5 or 6? Maybe. But your tire choice will have much more to do with rotational inertia gain than your brake choice.

I do tend to agree when it comes to "show brakes" with 17" rotors and 12 piston calipers there is no benefit, but most popular bbks offered for E30s fit under 15" wheels.

Also the calipers are sprung weight.

They are unsprung. If they were sprung, they would move with the chassis and not with the spindle. However obviously they are not rotational mass and therefore do not have much effect on accel/decel inertia.

[jules325i]

Cheers everyone there is some good info here.

[JoeyBones]

you tried rebuilding your calipers, installing new stainless lines, good fluid, and good pads? I was shocked at the difference with stainless lines and fluid.

[Yngvejos]

Don't forget those big rotors need to be accelerated and decelerated regularly. So, saving weight on a wheel set is negated by huge ( often too big) rotors. I would really look at the usage, and figure out if there is a need for that big.

I finally got time to weight the original brakes.

IE 295mm disk, caliper and pads:


325i calipers and drilled zimmerman disks.

[burkey001]

Regarding your comment of 'are big brake kits unsafe on the road' your main point of concern here, as with any brakes for the street is the actual brake pad you use.

"track pads" work great at the track when they are at temperature. when theyre not at temperature they typically
a) eat your rotors; and
b) suck as stopping.

The good thing about Wilwood caliper is its EASY to change pads.
If you're driving on the street, dont kid yourself or get 'fuh raze', you NEED street pads. On the street you cannot get race pads up to temperature or keep them there.

Get yourself from BP30 or BP20 as a pretty reasonable compromise between street and track. BP20 are easy on the rotors but are really really soft. YMMV

I have Massive's top end kit on my car (300x32 HD40 rotors front and rear, SL6R and SL4R calipers respectively) so I do have a point of reference.

With regards to other factors of 'are they dangerous' the other point to consider is brake balance. If you're making up your own kit without proper testing or a bias valve then YES they may be dangerous as your brake bias may end up all wrong. This stuff you want to test in a controlled environment first.

That said, if you're buying an 'off the shelf' front or front / rear kits from Massive, UUC, Ireland etc then its reasonable to assume the bias will be OK. Check though. Some front BBK kits assume a rear BBK as well and with OEM rears the bias will be off (possibly bad).

Tasks -
A) if buying a front BBK only, check with the vendors if the are suited to working with OEM rear brakes.
A1) if buying both, be sure to tell the vendor you're buying both, as often they will fiddle with piston sizing.
B) run STREET PADS on the STREET.

that is all.






for reference, my front and rears

[der affe]

R4-s porterfield pads are also a great argessive street pad with a little more initial bite than the BP-20 pads

[AnimalE30]

Have you looked at massive's kit? His 280mil starts at $750 compared to IE's 295mil at $1150...