Group Buy - Massive Rallye BBK

[mwagner10702]

I know this is an old thread. I'm curious if anyone had bought a kit from this group buy that has not used it, or wants to sell it. Let me know.

Sent you a PM.

[Alex Lipowich]

Update:
In looking into using this kit with either Kosei or the recent Tire Rack Sparco rim, I dived a bit into rotor selection, caliper selection and choices. Lee still offers the rear kit, hub or radial option mounts for E30M3. Here seem to be the rotor options and details

(Fuller thickness front rotor options)
Hawk HR8002. 40 curved vane, 13.10 lb 11.75x1.25. (32mm)
Performance Friction 299.32.0045 (11/12) 48 curved vane, 12.25 lb 11.75x1.25 (32mm)
AP (Essex) CP3862 60 curved vane, 10.70 lb 11.75x1.25 (32mm)
Wilwood 160-13497, 13498 (HD-48) 48 curved vane, 10.40 lb 11.75x1.21 (30.7mm)

(Rear thin option to retain 7420 pad and affordable wilwood caliper 1.12x2 piston)
Wilwood 160-12283, 12284 (HD-36) 36 curved vane, 9.15 lb 11.75x0.81 (20mm)
Performance Friction 299.20.0045 (11/12) 48 curved vane. (? lb). 11.75x0.81 (20mm)

The Hawk and PF rotors have weight to their advantage, the Hawk possibly less optimized with less vanes? The PF rotors are not inexpensive close to the AP cost
The AP discs are the most expensive, possibly the best from an engineering standpoint with the 60 vanes and resistance to hot-spots/cold spots leading to cracking & wear. Wilwood offers other choices but not in the heavy duty iron compounds we should be using.

It is interesting that the "vaunted" AP rotor weighs less than the Hawk or PF version. I wonder how the Hawks wear.

Finding a rear Wilwood caliper that supports 1.25 rotor is not easy unless you go to the 1.25x2 piston which shifts bias backwards to .621, less than an E46 CSL even. (or get the AP calipers)
Personally, I think given that the stock rear rotor on the M3 is solid, 282mm x 12mm vs Wilwood 300x20 ventilated, the .81 choice that would allow keeping the 20mm pad might be enough.

I'm not trying to stir the pot or pick a fight with anyone suggesting that thinner rotors might be OK on the rear. I rather suspect that almost everyone using Lee's parts has gone with 1.25 rears, and been happy..... but there is probably little experience trying the 20mm version. I know fully well that people have had cooling issues in the rear, and that Lee recommends the full thickness rear rotor. I thought a concise list of rotor choices might be useful with some data to compare and contrast.

[mwagner10702]

. . . I know fully well that people have had cooling issues in the rear

This surprises me as a majority of the braking is accomplished by the front brakes. I'd be curious to know the situations in which the rear brakes overheated.

I tracked my M3 with the AP CP8350 BBK on the front and stock calipers on the rear (using Hawk DCT-60 pads F/R) and never had an overheating issue in the rear. No F/R bias issues either. Solid, solid setup. Unless you are racing in an endurance scenario, or race with a high HP engine, a rear BBK on the E30 M3 is overkill IMO, although I do understand those who have installed a rear BBK.

[jimmy p.]

I use 11.75" x 1.25 on the front and the .810 on the rear with 7420 pads and no cooling issues on either end. Rear pads literally last me years and thats with very slight bias reduction to the rear.
The only time I ever had cooling issues on the rear of my car was way back when it had stock brakes and the rear reduction valve removed I would blow through rear pads 2:1 with the fronts (at least the rears started doin' some work though).
Since going to the Wilwood race brakes brakes last me a ridiculous amount of time.
I started using the Hawk rotors in the front because they were cheaper than the Wilwoods and they last just fine. No complaints. Its just a lump of metal. I see no benefit from spending alot of money on rotors especially since we dont get paid for this and we win little plastic trophies or a sticker.

[mrsha007]

This surprises me as a majority of the braking is accomplished by the front brakes. I'd be curious to know the situations in which the rear brakes overheated.

I tracked my M3 with the AP CP8350 BBK on the front and stock calipers on the rear (using Hawk DCT-60 pads F/R) and never had an overheating issue in the rear. No F/R bias issues either. Solid, solid setup. Unless you are racing in an endurance scenario, or race with a high HP engine, a rear BBK on the E30 M3 is overkill IMO, although I do understand those who have installed a rear BBK.

especially with how light most of our cars are. Rear BBK is like a parachute on a butterfly.

[Alex Lipowich]

Can anyone confirm with parts they have on hand for stock E30 M3? I'm curious, and there is a lot of noise out there. I don't have a stock example to measure. Most important if someone can measure the asterisk ones and report

Front
Rotor 280mm x 25mm ventilated
* Piston 54mm
* Pad height 55mm (radially)
Rear
Rotor 282mm x 12mm solid
* Piston 38mm
Pad height 40mm (radially)

I gleaned this from this forum for piston diameter, but there were many values suggested, I gleaned it from RealOem for rotor size, and from Hawk website to estimate pad radial height, but I don't have front pads to look at, I had a rear pad to measure.

[Mick]

I have a set sitting on my desk.
- Front pistons are 53mm (Bimmerworld Stainless)
- I don't have a set of front pads unfortunately

- Rear pistons are 37mm (OEM)
- Rear pad height is 40mm (pad material), and 42mm (backing plate)

The pistons are installed in the calipers, so I'm measuring at the leading edge that is projecting ~5mm past the dust seals. Not sure why I'm seeing 1mm less than what you have for dimensions as there is no taper cut into them as far as I know.

According to this page from Pagid the front pads are 57mm measured from the backing plate, so your measurement of 55mm for pad material makes sense, and further confirms your estimate.

I think that Pagid measurement is correct but whoever did the drawing made a mistake. They show the measurement at the thickest points but it should be showing the true radius, which would put the bottom point at the center of the bottom of the backing plate, if that makes sense. ...but then they show the pad depth at 52mm which is confusing.



Edit: this page shows the PFC pad depth at 52mm, so maybe 52 is correct after all.

[Alex Lipowich]

I'm having problems uploading photos. (Invalid image geometry????)

But having said that. I used Lee's kit in the front and with a 10mm spacer for the Sparco wheel 15x8, I can confirm a nice fit. Looks great.

I have available a set of Lee's rear E30 M3 hats and the hardware for rotors. I won't be using them after all. Since I mounted one for fitment, never used, they are very, very slightly less than perfect, and I can not return them.

These are essentially brand new, I can send in email or text plenty of photos. Looking for $220 shipped CONUS. Great for a back up set of rotors ready to mount at the track if needed, or, as the basis for filling in the rest of the kit from Lee for the back.

[Alex Lipowich]

Hats mentioned above sold.