Wanted, dimensions for calipers

RazorbackNOR · February 11, 2008, 12:18:57 PM

I had a look at this page, and was wondering if it could be possible to replace the murenas brake with something like this.

But, then we need some dimensions, like mounting holes etc.

http://www.hispecbrake.co.uk/Start%20Calipers.htm

Oetker · February 11, 2008, 12:41:43 PM

Theo at the dutch forum is busy with this.

http://oscar.messageboard.nl/7101/viewtopic.php?t=550

Don't underestemate it, its not a simple job.

RazorbackNOR · February 11, 2008, 12:56:29 PM

But that was with Porsche calipers, these come in many size and mounts and would hopefully fit without too much effort(as if....)

Oetker · February 11, 2008, 01:16:29 PM

Its not a standard job.
Space behind the wheels is limmited, and the standard rear calipers are Bagheera and Murena only.
You also have to count in the diameter of the cilinders and for the rear a variable regulator is needed to adjust the balance.
Also the size of the reardisk at a 2.2 is 260 mm, and mounting of the caliper is far away from the outside of the disk.
Its not a buy at Halford job.
Till now nobody came up with something better then the standard as far as I know.

RazorbackNOR · February 11, 2008, 01:36:41 PM

Hmm.. thought the caliper was a pug or talbot....

That could make things a little worse...

michaltalbot · February 11, 2008, 02:37:21 PM

Quote from: Oetker on February 11, 2008, 01:16:29 PM

Till now nobody came up with something better then the standard as far as I know.

I can only agree. 4 times a year I am on the race circuit with my Murena and its brakes are really good enough for this car. No overheating and accurate power. Don't forget that front part of the car is very light so there is no need to have huge, ventiled brakes...

krede · February 11, 2008, 02:57:02 PM

Jespers v6 Murena has custom brakes I think.
But I agree with Michael on this one...
I too wanted to .. mostly to get ventilated front rotors.... but "if it ain't broken... don't try to fix it"...
As Roy has pointed out to me once," a Murena will happily lock up all four wheels in the dry... on ANY surface...". and fading doesn't seem to be a problem.

You should also consider why the murena has discs at all four wheels.. and why the rear rotors are not the same used on a 2..2 as on the 1.6...The extra weight of the bigger engine dictated the larger rotors to hold the extra
heat
So..Midengine layout with 35/65 (at best) weight distribution,unequal tracking, different tire widths front and rear..

Do you really want to experiment with a brake set up that has clearly taken some considerable considerations from Matra to get right in the first place?

Black/green stuff(tm) pads and maybe some x-drilled rotors are as far as Im gonna go.

RazorbackNOR · February 11, 2008, 03:23:52 PM

Quote from: krede on February 11, 2008, 02:57:02 PM
Jespers v6 Murena has custom brakes I think.
But I agree with Michael on this one...
I too wanted to .. mostly to get ventilated front rotors.... but "if it ain't broken... don't try to fix it"...
As Roy has pointed out to me once," a Murena will happily lock up all four wheels in the dry... on ANY surface...". and fading doesn't seem to be a problem.

You should also consider why the murena has discs at all four wheels.. and why the rear rotors are not the same used on a 2..2 as on the 1.6...The extra weight of the bigger engine dictated the larger rotors to hold the extra
heat
So..Midengine layout with 35/65 (at best) weight distribution,unequal tracking, different tire widths front and rear..

Do you really want to experiment with a brake set up that has clearly taken some considerable considerations from Matra to get right in the first place?

Black/green stuff(tm) pads and maybe some x-drilled rotors are as far as Im gonna go.

Oh, thought fading and weak brakes indeed was a problem on the Murena.....
Thats why i had plans of upgrading the brakes...

Anders, how is it with the increased HPs and brakes then?

krede · February 11, 2008, 03:59:04 PM

QuoteOh, thought fading and weak brakes indeed was a problem on the Murena.....
Thats why i had plans of upgrading the brakes...

The few problems that I have heard of, has been to do with poor quality brake pads..
If you ask around you will probably find that most people use the "BlackStuff or GreenStuff (tm)" pads, with standard rotors.. and most will agree that it makes a HUGE difference.

(ok I know you asked Anders...but)..
I guess that the standard brakes are adequate up to about 180hp..... and frankly you dont want much more power than that in a car this old.
Matras own 2.2 16v prototype had about that much.. and as far as I know, they didn't plan any modifications of the brakes.

Oskar · February 11, 2008, 05:41:23 PM

didnt saab had a caliper at front with handbrake on it? and solid discs? saab 900 earlier then 87?

Oetker · February 11, 2008, 05:47:26 PM

Indeed, brakepower is sufficient as I already tried out.
The only thing that bothers me is the rattle and sticking problem at the rear, wich comes back regulary because of oxidation between alu and iron.
There are possebillity's to change I think, but have to make the diameter of the disk smaller, or design another.
Not realy my daily job, so if it ever will happen is the question. $:-\$

RazorbackNOR · February 11, 2008, 07:47:51 PM

And I have also heard from some that changing to steelbraided brakehoses removes some of the spoonginess in the pedalmotion. Because they flex less than regular ones.

Can anyone verify or discredit this...?

Lennart Sorth · February 11, 2008, 07:55:20 PM

Quote from: Oetker on February 11, 2008, 05:47:26 PM
The only thing that bothers me is the rattle and sticking problem at the rear

Are you sure the rattle isn't just missing or wrongly placed springs to hold the pads in place ? - that is a very common cause of rattle, especially at the rear, where gravity tends to work agains us/the pads.

/Lennart

Oetker · February 11, 2008, 08:04:22 PM

quote
-------
Are you sure the rattle isn't just missing or wrongly placed springs to hold the pads in place.
---------------------------------------------------------------------------------------------
Everything is mounted as it should.
I ordered a new mounting kit with al the bits and pieces and hope that it will stop the rattle.
The other side thats sticking, well we know the problem.
My disks are also a bit scruffy but in the limits.

krede · February 11, 2008, 08:09:06 PM

QuoteAnd I have also heard from some that changing to steelbraided brakehoses removes some of the spoonginess in the pedalmotion. Because they flex less than regular ones.

Can anyone verify or discredit this...?

Ahhh..
My car has those braided hoses fitted... and has had them since I bought it.. along with blackstuff pads .. ... so maybe the "standard" brakes can be a bit tricky... but ... with those two mods... I have never felt the brakes to be any different from other cars at all .. and have never given it much thought.. apart from wanting ventilated front rotors instead of the standard "solid" ones.... that... as mentioned earlier are quite adequate.

I am not sure that braided steel brakehoses does much on a road car where the brake fluid hopefully shouldn't get so hot that the hoses will become soft.