E31 850 or e32 750 Which brake upgrade better?

[Badger]

i read m535 but all they say is which fits and not the pros and cons to each of these setups. can someone pls enlighten me. thx

[SmokinDav]

Post a link to the page you are refferring to so that I can see what you are looking at and why you are confused.

http://m535i.org/officers/ra/articles.html#brakes

Here are an example list of stages of braking upgrades and the minimum wheel size you can safely fit. The amount of benefit you receive from the upgrade is mainly dependant on the pads and rotors you use.

Stage 1: E32/540i fronts
Minimum wheel size: 15 wheels
Stage 2: E28 M5/ E24 M6 fronts
Minimum wheel size: TRX, only *some* 15 wheels, 16 wheels
Stage 3: E32/540i fronts, E34 solid rears
Minimum wheel size: 15 wheels front and rear
Stage 4: E28 M5/ E24 M6 fronts, E34 solid rears
Minimum wheel size: TRX, only *some* 15, 16 wheels front; 15 wheels rear
Stage 5: E32/540i fronts, E34/E32 vented rears
Minimum wheel size: 15 wheels front and rear
Stage 6: E28 M5/ E24 M6 fronts, E34/E32 vented rears
Minimum wheel size: TRX, only *some* 15, 16 wheels front; 15 wheels rear
Stage 7: E34 US M5/US 540i Sport front and rear
Minimum wheel size: some 16 wheels front; 15 wheels rear
Stage 8: E31 front, E34/E32 vented rears
Minimum wheel size: some 16 wheels front; 15 wheels rear
Stage 9: E34 Euro, E31 850CSi Euro (Nurburgring brakes)
Minimum wheel size: 17 wheels front; 16 wheels rear

Now there are a couple different E31 front brake calipers available. There are the regular single piston calipers and the dual piston Brembos.

Why are you upgrading?

I am upgrading my brakes (UPS should be delivering the fronts today) using E32 front brake calipers, E34 540i/E32 750i (they are the same caliper) vented rears, and an E32 750il master cylinder (bigger bore master cylinder to improve braking feel). Plan to use Porterfield R4 pads at the track.

I am doing these upgrades so I can take my car to the track and safely participate in BMW track days and driver's schools. Since I don't plan to run slicks, or very sticky tires, these brakes should be good for the speeds that I will be seeing. I may experiment with some home made brake ducts and cooling hoses as well, if need be.

[Badger]

yea i was refering to that page. i am in the process of picking up a 745i and lookin for m-tech body kit. so before i get the car on the road i need bigger brakes and some suspension upgrades. i drive fast on the high way and sometimes on back rodes in vermont/nh/ma and want to be able to stop.

[Martin in BellevueWA]

The 850i front brakes use rotors that are nearly 13" diameter. The 750 rotors are 12", and coincidentally are used as better, cheaper rotors for the e28 m5, 4 piston front calipers.

Here's the 850 brakes:


Here's the e28 m5 calipers with the e32 750 rotors:

[SmokinDav]

[QUOTE="Badger"]yea i was refering to that page. i am in the process of picking up a 745i and lookin for m-tech body kit. so before i get the car on the road i need bigger brakes and some suspension upgrades. i drive fast on the high way and sometimes on back rodes in vermont/nh/ma and want to be able to stop.[/QUOTE]

Can't really help you with the 745i. I guess if I were you I would do a few things:

1) Post these questions on a 7-series board, not a 5-series board.
2) Use better English sKiLLz so that
a) You are easier to understand
b) Your quesions are easier to comprehend
3) Go with the Dual Piston Brembo E31 brakes up front, put the vented E32 750iL setup on the back
4) Get a good set of Porterfield R4S street brake pads so that you can stop while you are demonstrating your mad back roads driving sKiLLz

[Shawn D.]

Badger,

As posted in another thread on this board within the past day, there are essentially NO brake upgrades for the 745i, which is an E23.

BTW, I'm with Dave -- please put out a little effort in making your posts less painful to read and easier to comprehend.

-Shawn

[Badger]

Sorry guys been awake for 2 days studying for a grad exam. First off I have an 88 535is, which I will be doing a ton of work to starting in the next several weeks. The euro 745i turbo is for an engine swap into my 535is. I found a complete running car for under 1,000. Seems like the most cost effective way of increasing Hp while still maintaining drivability. My brake question was referring to which was better for the front. The e32 750 or the e31 850 dual piston? I was going to go for the 850 dual pistons but just wanted to see other peoples opinions. Again sorry for my lack of English skillz.

[SmokinDav]

[QUOTE="Badger"]My brake question was referring to which was better for the front. The e32 750 or the e31 850 dual piston? I was going to go for the 850 dual pistons but just wanted to see other peoples opinions. [/QUOTE]

According to the brake guide that we talked about earlier in this thread, here is the info relevant to your question.

E32
Front rotor size 302mm dia x 28mm thick

E31
Front rotor size (single or dual piston calipers) 324mm x 30mm

So it looks like the E31 front brakes use the largest rotor, which of course means that they can handle (abosorb and dissapate) more of the heat generated from braking, so they should be better.

As for the calipers, if you have the money get the e31 dual piston Brembos.

FYI, all E32 fronts are the same, 735, 740 and 750.

And thanks for the better post. Much easier to understand and when you take the time to do it right, it makes me want to take the time to help you find the answer.

[John In Valdosta]

The single piston 850i brakes are actually the most powerful brake that will fit our cars(737ft-lbs). BUT they are also the heaviest, these can actually make your car slower. The absolute best front brake is the 850csi four piston calipers, they are the same as the dinan stage 4 brakes.

If you just want to impress your friends with amazing stopping prowess, go with the big single psitons. If you want the best all around go with the 850csi four pistons. If you want excellent braking and balance go with the E32's.

A very interesting article on Brake Upgrades can be found at http://www.bmwe34.net

[Guest]

Another brake option which is seldom considered are those from the Euro E32 750i. These might actually be the same brake calipers as the E31 850i 4 pot Brembo. They also utilize the 324mm x 32mm rotors.

If you have the money, spring for the E34 M5 Nurburgring Brakes, both front and rear. These monsters are 345mm dia fronts with 328mm dia rears. IIRC they have compound rotors with aluminum hats. You'll need 17" wheels for these.

The best overall brake package for the $$$s is the E32 750i fronts with E34 540i/M5 rears running the E32 750i master cylinder and stainless lines. I ran this setup with Balo rotors and Pagid pads on my deceased 533i. My buddies driving US cars couldn't believe the braking power I had.

Rich


[Edit by Rich Euro M5 on [TIME]1110387196[/TIME]]

[Badger]

thx guys

[Craig -535i- Seattle]

[QUOTE="John In Valdosta"]The absolute best front brake is the 850csi four piston calipers, they are the same as the dinan stage 4 brakes. [/QUOTE]

The 4 piston brakes are found on the '94+ E31 cars (840s, 850s). I got mine (reman) from brakewarehouse.com for $194 each. They have the single piston versions for $130 each. However, these are in short demand so actually finding them in stock could be a problem. I think Martin ordered some and may not have ever gotten a set.



[Edit by Craig -535i- Seattle on [TIME]1110389717[/TIME]]

[Martin in BellevueWA]

Thanks for the reminder there, Craig. The single pot, 850 calipers have been ok, since adding the metal bushings, keeping calipers alinged better, & quieter.