Vented rear disk on an e36 compact?

[Massive Lee]

Ti-specific rear kit. Aluminum hats are lighter than steel ones.
310x32mm discs and 4 pistons SL4R calipers with stainless steel pistons. Will match a front e36 M3 brake set-up or 332/355mm front BBK. 160mm steel handbrake drums optional. 160mm is the diameter of the stock shoes. e36 M3 rear discs use 180mm shoes.

[e36 323ti]

Originally Posted by Massive Lee

Ti-specific rear kit. Aluminum hats are lighter than steel ones.
310x32mm discs and 4 pistons SL4R calipers with stainless steel pistons. Will match a front e36 M3 brake set-up or 332/355mm front BBK. 160mm steel handbrake drums optional. 160mm is the diameter of the stock shoes. e36 M3 rear discs use 180mm shoes.

Could you please provide some more data of your kit? E.g. bias, weight etc?
My guess is that the weight of the kit is at least 11.5kg (25lbs) pr side (disc, bell, caliper, carrier, e-brake insert, e-brake shoes, pads, bolts...) .

... compared to mine which is 8.8kg pr side and stock 318ti which is 7.8kg...

[Massive Lee]

Discs are 4.9Kg each
Aluminum caliper mounts are 0.250Kg
Calipers are 2.4kg each
Miscelanous bolts are 0.1kg
- - - - - - - - - - - - - - - - - - - - - - - - -
Subtotal per side - 7.65Kg

Thick 21mm pads (per side) 1kg (thick and heavy)

Steel handbrake drums/ring (not required on a racecar) - 1.05kg each

- - - - - - - - - - - - - - - - - - -

Total for a street car - 9.7kg per side
Total for a race car - 8.65kg per side

[e36 323ti]

Originally Posted by Massive Lee

Discs are 4.9Kg each
Aluminum caliper mounts are 0.250Kg
Calipers are 2.4kg each
Miscelanous bolts are 0.1kg
- - - - - - - - - - - - - - - - - - - - - - - - -
Subtotal per side - 7.65Kg

Thick 21mm pads (per side) 1kg (thick and heavy)

Steel handbrake drums/ring (not required on a racecar) - 1.05kg each

- - - - - - - - - - - - - - - - - - -

Total for a street car - 9.7kg per side
Total for a race car - 8.65kg per side

Nice numbers. What about bias?

[Massive Lee]

Originally Posted by e36 323ti

Nice numbers. What about bias?

Bias depends oviously on what is fitted at the front. That rear Ti kit was developped initially for the e30 crowd. May having swapped to front e36 M3 suspension and brakes, and rear Ti hub/brakes. This combination is very bad as it puts way too much bias at the front. By a huge margin.

Front e36 M3 pistons are 60mm - 28.27sq.cm
Rear e36 M3 pistons are 40mm - 12.56sq.cm
SL4R piston are 1.12"+ 1.25" (28.6mm + 31.75mm) - 6.42sq.cm + 7.91sq.cm = 14.33sq.cm
Superlite caliper pistons are 1.12" + 1.12" = 12.84sq.cm

14% more piston area in one case, and 2% in the other case. Racers want more rear bias. 14% is not much considering that brake pads friction can double between one type to another.

BTW Cars with stiffer suspension will experience less weight transfer under hard braking. Meaning the rear tires have more pressure on the ground than with a stock suspension. Which can also take more braking power.

[e36 323ti]

Originally Posted by Massive Lee

Bias depends oviously on what is fitted at the front. That rear Ti kit was developped initially for the e30 crowd. May having swapped to front e36 M3 suspension and brakes, and rear Ti hub/brakes. This combination is very bad as it puts way too much bias at the front. By a huge margin.

Front e36 M3 pistons are 60mm - 28.27sq.cm
Rear e36 M3 pistons are 40mm - 12.56sq.cm
SL4R piston are 1.12"+ 1.25" (28.6mm + 31.75mm) - 6.42sq.cm + 7.91sq.cm = 14.33sq.cm
Superlite caliper pistons are 1.12" + 1.12" = 12.84sq.cm

14% more piston area in one case, and 2% in the other case. Racers want more rear bias. 14% is not much considering that brake pads friction can double between one type to another.

BTW Cars with stiffer suspension will experience less weight transfer under hard braking. Meaning the rear tires have more pressure on the ground than with a stock suspension. Which can also take more braking power.

Approx bias figures:
Stock 'ti: 67%
'ti with e36 m3 3.0 front, stock rear: 73%
'ti with e36 m3 3.0 front, massive rear/SL4R: 60%
'ti with e36 m3 3.0 front, massive rear/Superlite: 63%
Stock e36 m3 3.0: 61%

Are the Superlite heavier than the SL4R?

Regarding weight transfer:
Another way to see it: Less weight transfer makes things even worse if bias is moved forwards...

[Massive Lee]

Originally Posted by e36 323ti

Approx bias figures:
Stock 'ti: 67%

Is that for the 318Ti or 323Ti? Different motors, different weights.

Originally Posted by e36 323ti

Regarding weight transfer:
Another way to see it: Less weight transfer makes things even worse if bias is moved forwards...

Correct.

In rgerad of caliper weight. Superlite and SL4R are the same weight, within a few ounces. Thea dapter is heavier with the Superlite as it is made from stainles steel.

[e36 323ti]

Originally Posted by Massive Lee

Is that for the 318Ti or 323Ti? Different motors, different weights.

The m44 in a 318ti is approximately only 16kg lighter than the euro m52b25...

The static bias does not take car weight into account and is hence identical for the 323ti and 318ti (assuming vented front discs). It is based on a pure analysis of the brake system.

A dynamic bias calculation requires knowledge about the center of gravity height (CGH), which I do not know. CGH will also varies with the suspension setup (lowering, coilovers etc.) of the car, affecting weight transfer...

Originally Posted by Massive Lee

Correct.

In rgerad of caliper weight. Superlite and SL4R are the same weight, within a few ounces. Thea dapter is heavier with the Superlite as it is made from stainles steel.

What is the weight of the steel adapter?

[Massive Lee]

Originally Posted by e36 323ti

What is the weight of the steel adapter?

These are 1/2" thick (12.7mm) stainless steel adapters. The weight is 0.450kg each. Two points bolted to the trailingarm, and an extension pushing on the trailing. The extension can be left as is, or tack welded.

Lee

[e36 323ti]

Originally Posted by Massive Lee

These are 1/2" thick (12.7mm) stainless steel adapters. The weight is 0.450kg each. Two points bolted to the trailingarm, and an extension pushing on the trailing. The extension can be left as is, or tack welded.

Lee

Regarding weight: 'ti with e36 m3 3.0 up front and Massive rear adds approx. 8.2kg (8.6kg) to stock weight (numbers in () is the Superlite) . My solution is 3.8kg lighter than stock config. I.e your solution is approx. 12 kg heavier than my solution. There is even options on the market that is approx. 19kg heavier than my solution.

[Massive Lee]

Originally Posted by e36 323ti

... compared to mine which is 8.8kg pr side and stock 318ti which is 7.8kg...

Originally Posted by Massive Lee

Total for a street car - 9.7kg per side
Total for a race car - 8.65kg per side

The pads are huge and probably four times the size of a stock or AP pad, which makes up for the difference in weight. I think that numbers can't be any clearer

Originally Posted by e36 323ti

Regarding weight: 'ti with e36 m3 3.0 up front and Massive rear adds approx. 8.2kg (8.6kg) to stock weight (numbers in () is the Superlite) . My solution is 3.8kg lighter than stock config. I.e your solution is approx. 12 kg heavier than my solution. There is even options on the market that is approx. 19kg heavier than my solution.

You have a very strange ways to accomodate numbers. You claim that Massive's rear set-up is 8,6kg heavier than stock by taking the heaviest kit (while it is only 2kg extra per side for much bigger brakes and much bigger/long lasting pads), which is not very rational, as you are adding the weight of a front e36 M3 kit.

Numbers are clear. A 310x32mm kit that weights less than 1kg extra (race form) and 2kg (sreet form) more than stock, with extra thick discs, extra thick pads and ultra stiff 4 piston calipers. By the time the pads are worn to the same volume as the stock pads, weights will be similar. And you still get a huge rear kit.

I am only presenting a product I have been offering for 3 or 4 years, while you arebeing inventive at finding ways to put up funny numbers. Chill out. It's not a pissing contest.

BTW My brakes equip many, many racecars and are put up to the task of braking high power LS1 swapped cars (running 18" wheels and wide slicks) when racers want lightweight, braking power and especially better heat management.

[e36 323ti]

Originally Posted by Massive Lee

The pads are huge and probably four times the size of a stock or AP pad, which makes up for the difference in weight. I think that numbers can't be any clearer

You have a very strange ways to accomodate numbers. You claim that Massive's rear set-up is 8,6kg heavier than stock by taking the heaviest kit (while it is only 2kg extra per side for much bigger brakes and much bigger/long lasting pads), which is not very rational, as you are adding the weight of a front e36 M3 kit.

Numbers are clear. A 310x32mm kit that weights less than 1kg extra (race form) and 2kg (sreet form) more than stock, with extra thick discs, extra thick pads and ultra stiff 4 piston calipers. By the time the pads are worn to the same volume as the stock pads, weights will be similar. And you still get a huge rear kit.

I am only presenting a product I have been offering for 3 or 4 years, while you are being inventive at finding ways to put up funny numbers. Chill out. It's not a pissing contest.

BTW My brakes equip many, many racecars and are put up to the task of braking high power LS1 swapped cars (running 18" wheels and wide slicks) when racers want lightweight, braking power and especially better heat management.

I do not feel comfortable now. It is not my intention to offend you. Please also remember that English is not may native language...

If you take your time and read what I wrote once more you will see that I do not claim that "Massive rear adds..." but "'ti with e36 m3 3.0 up front and Massive rear adds...". Further, I wrote adds approx. 8.2kg (8.6kg) to stock weight (numbers in () is the Superlite) . I.e. I present the numbers for both your proposed rear solutions with e36 m3 3.0 up front. I realize it could have been better formulated.

I am adding the weight of the front e36 M3 kit as this is the solution you are presenting your rear kit to work with on a 'ti. Also I compare that weight with the total weight (front+rear) on the complete kit currently on my car (named as 'my solution'). I do not find that stranger than comparing the bias in that context.

The interested reader can find the weight of several other combinations in this link: http://www.318ti.org/forum/showthrea...t=32902&page=2

Comparing my BBK with stock shows that in total my custom BBK is 3.8kg lighter than the stock 323ti/318ti configuration.

My kit is summarized in this post: http://www.318ti.org/forum/showpost....&postcount=247 , and it is, for the time being, the only one in the world and not tested on track yet. If it can keep up with the "huge" thermal load expected from an M52B25 remains to see...

I am not questioning your kit. I am not trying to convince anyone about anything. Unlike you, I have nothing to sell. To me it is not funny numbers, it is only cold facts. The fact that a brake kit fit to the car is to me no proof of that it works. The fact that someone, who's reputation is unknown to me, sells a brake kit, is to me no proof of that it works. The fact that parts of a brake kit is working in a high powered track car is no proof to me that it will work in my application in my low powered streetable car.

If I am going to buy a brake kit, I expect that a serious provider of brake kits is able to presents numbers like static bias in any application it is proposed to be used in, at least on request. Also, I expect real numbers from tests showing the proof of that it works (I guess it is not by chance that StopTech is advocating the bias issue).

However, I have learned that my expectations are utopia and since I have the tools to do some of the calculations my self, I am going to bother anyone who is providing brake kits to me with such 'inventive' numbers. To me it is the test a seller has to pass in order to get my confidence...

[pdxmotorhead]

It can go many directions, I've seen Wilwood, Brembo, stop tech kits that sucked, and home brew that rocked. Sometimes its about the numbers, sometimes its a bit about the engineering skills, sometimes its just plain luck...

I've seen some top flight mathematically perfect cars get their lunch money
taken, I've seen junkyard swap jobs that were flat dangerous...

Bias is adjustable and I think its all about your preferences, as to how to attack the problem.

Myself I prefer Wilwood because I have connections to get their parts. There are several equivalent rotors to AP so you have choices. And their pads are well supported.

All good stuff..

Dave

[cooljess76]

I'm all about being practical. Things I'd consider are cost and availability of rotors and pads. As for performance, of course I'd love to have an aftermarket multi-piston setup. It's money well spent, but do you really need it or is it just a bling factor? Having an OE single piston setup in the front and a aftermarket multi-piston setup in the rear looks silly to me. So the question is, how much would a complete Wilwood front and rear setup cost? Probably over 2k. You just lost me. Don't get me wrong, I'm not saying Wilwood isn't better, it most certainly is. But if I could improve braking with OE parts at a fraction of the cost and find pads and rotors anywhere anytime, well I'm going that route. Who knows, maybe I'll change my mind if I hit the lottery or a used set pops up.

[pdxmotorhead]

Wilwood has all levels of calipers. the one equivalent to he AP is not much money... < 110 bucks.

http://www.wilwood.com/Calipers/Cali...napro%20Single

For the front... Just one example... Could go bigger...
http://www.wilwood.com/Calipers/Cali...row%20Dynalite

The pads are the same price as the stock pads IF your buying street performance pads like Hawk or Carbo Tech. Budget 200 to 300 for front + rear...

Like a brembo or AP go high end and cubic dollars are required..

Dave