Saab/Vectra Front Brake Upgrade

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Re: Saab/Vectra Front Brake Upgrade

Postby nitroman » Wed 06.10.2010, 07:37

I had my car up in the mountains last weekend for the first time since I put the Wilwoods on it. It took ONE stop at a light one a very steep downhill gradient for me to remember that one needs to take that sort of thing into account. Remember, the average elevation above sea level in my home county is 18ft. You don't get swift elevation changes when that's the average elevation over 900 square miles! Anywho, this car is the ONLY Wilwooded Elan for which the "mid-size" caliper was chosen. I had to forcefully apply the brakes many times, and knew the car would ALWAYS STOP, basically giving a toss to speed & gravity alike. So whilst fine, I still like the original wrong choice of a massively over-calipered braking-system, as with that, even the most panicked stop still only required the lightest of pedal-pressure on your part. In other words, it made it seem like you were never abusing the machinery; a feeling I despise.
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Re: Saab/Vectra Front Brake Upgrade

Postby dapinky » Thu 07.10.2010, 16:16

test post,

just to see if by adding to the thread, we can stop it being marked as 'unread post' every time i log on!!!!
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Bob's Bits for Saab/Vectra Front Brake Upgrade

Postby bobbrown » Sat 09.10.2010, 09:43

nitroman wrote:
I'd think the cheapest yet biggest bang for the buck on a rear upgrade might be had by retaining the OEM rear caliper, but making a bracket (key Bob) so it could be repositioned further from the hub, to clamp onto a larger diameter replacement rotor. That would also cure the visual impression that the Elan's rear disc was stolen off a toy car!


This is possible and not too expensive.
You would need a new bracket to mount the stock caliper further out again not too much of a problem and a hub conversion that some already have and a new discs about the biggest I can find that should fit is 260mm diameter.
Disc is the correct PCD and would require a spigot ring to align it, slightly down on thickness from 12.65mm to 12mm with a minimum thickness of 10.8mm which is very close to the standard disc at 10.9mm
It does help reduce the differencial change front to rear when the fronts have been upgraded with this conversion and with the Wilwood conversion on the front does get it closer to the stock bias.
Not sure what the brackets would work out at as there is a lot more work to produce them and they would need to be steel due to their thickness but off the top of my head I would think about $100.00 a pair, add in the discs at about $92.00 a pair plus the spigot rings etc you are looking at around $200 excluding any shipping costs etc if you need to add in the hub conversion that is going to add an aditional $210.00.
As a note as the caliper is only a further 2mm further out than the stock fronts then the space saver should still fit (maybe).

Bob

All the above was done on a FED setup with the Saab/Vectra upgrade and the 309mm Wilwood upgrade.
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Re: Bob's Bits for Saab/Vectra Front Brake Upgrade

Postby rip » Sun 10.10.2010, 11:15

esprit888 wrote:Bob, This may sound like (and probably is) a dumb question but the Saab has discs on all four corners. With your rear hub kit could the rears also be replaced with the same Saab/Vectra rear brake upgrade ?


Ok, seeing as this is about rears, we seem to be drifting a bit :offtopic: but.....

What would you gain by this?
Do the rears suffer from poor heat dissipation? I doubt it. If so, the first upgrade would surely be to fit vented discs?
Bigger rotors will increase unsprung weight, which is always unwanted.
The effectiveness of the rear brakes is governed by the proportioning valves. If the efficiency of the rear brake design was the limiting factor, then we wouldn't need these valves....would we?

Why would you want to take away most of the rear hydraulic pressure (by leaving the proportioning valves in place) then maximise what little you have left by fiddling with the rear calipers & rotors?

For those with upgraded front brakes:
Now we stop sharper, we need brake balance moved slightly forward. Not upgrading the rears should achieve this nicely.....shouldn't it?
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Re: Bob's Bits for Saab/Vectra Front Brake Upgrade

Postby bobbrown » Sun 10.10.2010, 12:04

Rip

By upgrading the fronts you move the bias forward in this case 76% front 24% rear (Hi Spec front upgrade is 75:25) so to bring the balance back you need to upgrade the rears.
That said it is not essential to upgrade the rears but if the front brakes are too big you can actually increase the stopping distance, which I do not percieve as being the case with this upgrade, the very large Wilwood upgrade is a different animal as that moves the bias to 81:19 not good.
Heat is far less of a problem on the rears as they do not have to dissipate the same amount of energy as the fronts.
The line pressure to the rears is governed by the proportioning valves but if you increase the rear caliper size or the disc or both you will increase the brake forces on the rear. It is why the rears can not be changed unless the fronts have been upgraded.
There is usually a margin with the brake bias and most manufactures have the bias slightly further forward than ideal as this is always the safer option.

Bob

If a mod wants to move this bit of the topic from the group buy feel free, may be here viewtopic.php?f=80&t=18101
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Re: Bob's Bits for Saab/Vectra Front Brake Upgrade

Postby GeoffSmith » Sun 10.10.2010, 17:30

bobbrown wrote:If a mod wants to move this bit of the topic from the group buy feel free


Sorry Bob, no mods about. Will a kitty fiddler do instead?
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Re: Saab/Vectra Front Brake Upgrade

Postby rip » Mon 11.10.2010, 09:48

I know brake balance is an issue (although with better front brakes, the dynamic weight will be thrown a little further forward anyway so keeping the balance the same as stock may not be entirely ideal).

It just seems strange to me that you would take away all the brake force with the valves then try to put it back again with more unsprung weight.

& who has changed their proportioning valves recently? I doubt there are many Elans out there with these working as efficiently as when they left Hethel.
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Re: Saab/Vectra Front Brake Upgrade

Postby bobbrown » Mon 11.10.2010, 11:11

rip wrote:I know brake balance is an issue (although with better front brakes, the dynamic weight will be thrown a little further forward anyway so keeping the balance the same as stock may not be entirely ideal).

It just seems strange to me that you would take away all the brake force with the valves then try to put it back again with more unsprung weight.

& who has changed their proportioning valves recently? I doubt there are many Elans out there with these working as efficiently as when they left Hethel.


The weight transfer is more to do with deceleration rates than the brakes them selves.
If I am doing weight transfer calculations to keep it simple I only use things like weight, its distribution, wheel base, centre of gravity and the deceleration in G.
For example a deceleration 0.8G gives a weight transfer around 300 kg, bit of a rough guide as I do not know the exact C of G.
A wheel with a certain weight acting on it requires a certain force to stop it as the weight on the rear is transferred forward then the load on the rear reduces and the harder you brake the more is transfered but only up to the point just before the front wheels lock as once they are locked the deceleration rate increases as locked wheels do not provide the same grip.
The reason for the bias valves is the fact that under braking the brake force on the rear is too large and the wheels would lock up before the fronts.
If you look at the line pressures once you get above 15bar they drop off dramatically at the rear to stop the rears locking.
As for the bias valves them selves they are very simple and there is very little to go wrong with them and they are in the main all probably still working as they did when they were fitted.
Also it should be noted that the stock bias is unlikely to be ideal and with all these things is a compromise as you need to take a lot into consideration like tyres, the road surface and conditions e.g. dry, wet, icy
I can only work from the stock setup and as the car was originally biased 70% front and 30 rear then the name of the game is not to go too far away from those figures.
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Re: Saab/Vectra Front Brake Upgrade

Postby racerstev » Mon 25.10.2010, 04:32

Hey guys, I don't see what car and year Calipers and Rotors I need. Or was there only one Saab 9-3 caliper?
I know there are alot of differant Legacy's....
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Re: Saab/Vectra Front Brake Upgrade

Postby tweetdriver63 » Mon 25.10.2010, 05:20

Steve, look at the very first post of this thread. I listed the exact calipers and rotors I got from rockauto.
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Re: Saab/Vectra Front Brake Upgrade

Postby racerstev » Mon 25.10.2010, 14:01

Missed it, thanks!

Just wanted to check and see if there are any racing pads for it.
Seems there is a wide selection from Carbotech and Hawk. The pad number is 819

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Re: Saab/Vectra Front Brake Upgrade

Postby lotos » Mon 25.10.2010, 16:39

I figured upgraded pads wouldn't be hard to find - slotted rotors about quadrupled the price though.

Would stainless brake lines be a good addition when installing this setup?
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Re: Saab/Vectra Front Brake Upgrade

Postby tweetdriver63 » Mon 25.10.2010, 17:19

Stainless lines are always a good move.

When it comes to pads, I got loaded calipers and I'm just using the pads that came in them, and I'm pretty happy. I'll probably upgrade the pads eventually, but there's no hurry.
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Re: Saab/Vectra Front Brake Upgrade

Postby lotos » Mon 25.10.2010, 18:12

Scott (superbad) and I are both interested, I'd guess a few more would be also. Maybe we could do a 2nd group buy for some stainless brake lines... I'd be happy to do the leg work if someone can help me with exactly what we need for this setup.
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Re: Saab/Vectra Front Brake Upgrade

Postby bobbrown » Mon 25.10.2010, 18:51

lotos you have email
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Re: Saab/Vectra Front Brake Upgrade

Postby racerstev » Sat 07.05.2011, 04:10

I mounted mine up today, nice fit and they look great with the huge slotted and drilled rotors. One issue
is the brake hose's, they can't go to the factroy bracket and need to be left loose? If run to the stock mount they
hit the upper control arm..

Also, my 15" wheels fit very nicely over these brakes..

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Re: Saab/Vectra Front Brake Upgrade

Postby bobbrown » Sat 07.05.2011, 09:30

Steve,

I assume that was a typo "15" wheels" ?

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Re: Saab/Vectra Front Brake Upgrade

Postby racerstev » Sat 07.05.2011, 13:43

I'll post pics later but no typo. My 15X8" 949 Racing wheels clear with plenty of room
to spare.
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Re: Saab/Vectra Front Brake Upgrade

Postby racerstev » Sat 07.05.2011, 22:04

Image

Image

Image

Image

Image
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Re: Saab/Vectra Front Brake Upgrade

Postby bobbrown » Sun 08.05.2011, 00:10

racerstev wrote:One issue is the brake hose's, they can't go to the factory bracket and need to be left loose? If run to the stock mount they
hit the upper control arm..
Steve


Looks good but must be quite close to the rim.
I think a trick with the standard hoses is to grind off the lug on the caliper so you can change the position of the banjo, did not have the problem with Rip's as he had braided hoses so a round banjo not a square one.

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