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Discussion Starter #1

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Discussion Starter #2
Got done installing them. Talked Nick into doing it with me tonight. Also have bedded them in. They do seem to combat brake fade somewhat. But after 8-10 hard stops it felt like I was driving a car with 4 wheel drums.
Pads are high performance street pads, so they're not meant for high temps anyway. Shoulda seen how chewed up the OLD pads were! Anyhoo ... got some pics of the installation and on the car. Must say, they look very adequate in those wheels.


http://groups.msn.com/TheSaabGuy/saabsando....msnw?Page=Last

Tell me what you think!
 

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Discussion Starter #5
I wouldn't reccomend doing exactly what I did. Brakeworld.com did mine custom They're stock Viggen rotors that have been custom cross drilled. They actually have Brembos for the 9-5, but I didn't know the 9-5 and 9-3 Viggen have interchangeable front discs! And talking with their manager the part numbers for both the discs and pads were different between the 9-5 and 9-3 Viggen. HOWEVER! If you have an NG900 or 9-3, brakeworld DOES sell direct fit brembo rotors and of course pads! The SP Graphite Metallic pads aren't suitable for track use. But after just getting back from some more err ... "testing"
... I can say they definetly stop better than the factory set! The initial bite is about the same, but after a split second they suddenly grab quite hard and leave you with a distict
feeling, though in the reverse sense. Also the SP pads aren't as expensive as some of the alternatives: Around $55-60.

Downsides: Cross drilling can in some instances make the rotors weak enough to crack. So far so good with these, but that should be noted. (these did get hot enough to turn a light purple-ish tint around the slots and holes) Also, they wear the pads more quickly and don't stop you significantly faster under most normal driving conditions.

After installing mine I followed the brake in procedures described here under "prevention":

http://www.stoptech.com/whitepapers/warped_rotors_myth.htm

I had no trouble with this rather vigorous procedure, but if you're weary of going to the extremes of finding a deserted road late at night to do 10 60-5 mph brake tests in quick sucession without stopping ... the best advice is just to go easy on the brakes for a while.

Well I won't make this too long. Do want to add though, after only driving the car twice since I put the new rotors on, I've already gotten three people complimenting me on them. So you hafta appreciate the cool factor.
 

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Question: What is the shape of the venting vanes inside the rotor? are they straight lines or are they more curved like a fan blade?

If they are curved like mine, it appears that the holes in your rotors will have penetrated the vanes. As I am sure you probably know, this can be bad for the rotors.
 

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Discussion Starter #8
The vanes appear to be straight lines. But I have not looked closely. Either way some of the holes have penetrated the vanes to my dissapointment. So far though, (knock on wood) they seem to be doing quite well. Takes numerous and frequent hard stops to bring on any brake fade, and I think that's just because these are certainly not racing pads. Stock rotors would fade slightly during just one stop. Will be sure to keep everyone posted on any future developments. Keep on Saabin'
 

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I had some Godspeed drilled and grooved discs on my old 900T16S and they were phenomenal. If you tried to give the pedal a decent push, you were left hanging on the seatbelts!! (passenger - nose against windscreen )

These were guaranteed against warpage and although I had them smoking and nearly glowing, they were always fine. When I traded the car I put the standard discs back on and kept the grooved/drilled ones to fit on my newer car.
After fitting, and carefully checking for runout, I bedded the new pads and a couple of hundred miles later decided to try them out. Within a very short time the discs had warped badly. I had huge judder and measuring with a DTI there was alarming thickness variation. My treasured discs were scrap!

When I was checking them, I noticed that the grooves on the discs were handed and when I had refitted them, I had got them in the reverse sense to before. This was such that originally the grooves were angled to 'throw' outwards with rotation, and when I refitted them, the grooves 'scooped inwards'. I put the failure down to this 'misfitting' but I notice on your very smart discs, they AREN'T HANDED.
Obviously with yours, the grooves run one way on the left and the other way on the right - have you noticed any difference?
 

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Discussion Starter #10
The stock rotors were this way. Didn't notice any difference with them. In fact, the WORST wear on the pads occured significantly more on the side that went as it was supposed to.
One of those pads was only maybe 1 or 2 mm short of the metal!
So if pad testament is any indicator it shouldn't be a huge issue. I think as the previously mentioned article states, the primary cause of run out isn't brake warping. Discs don't just warp. What probably happened is that as they were being bedded in they got hot (say you had to make an emergency stop during the first 100 miles, or during the vigorous bedding process) and then some pad material got transferred unevenly to the disc surface. This is what causes the thickness variation. It could be that having discs in the wrong direction could exacerbate any small wrong-doing because it doesn't scoop away the extra material as effectively. But as I said, the original rotors weren't handed, and hopefully, since it made no difference to those, these won't have any adverse affects. *crosses fingers* Cheers! Wish me luck.
 

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Good point SJ- I knew there was something not quite right looking at your discs Adrian. I think you may have them on the wrong way round.

Take a look at this image from the AP site:



Full page here

Certainly if your discs have curved vents like APs, you need to mount them the same. If not, I can see that it would still be beneficial to do so.

From looking at the drilling pattern on your discs, I would say that they are the opposite way round to that recommended by AP.
 

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Discussion Starter #12
lol My discs aren't handed. There is no right or wrong way to mount them. Both front rotors are identical. Also, the discs (I just checked) are straight vaned. So the direction isn't as important. As for performance and wear, doesn't seem to make a lot of difference with the stock rotor setup, and these ARE the stock rotors, just with holes drilled in em to help a lil with cooling hopefully. And they do still give a disctinct
feeling, and look quite purdy, so no complaints here.
 

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Originally posted by Adrian W:
[qb]  They actually have Brembos for the 9-5, but I didn't know the 9-5 and 9-3 Viggen have interchangeable front discs!  And talking with their manager the part numbers for both the discs and pads were different between the 9-5 and 9-3 Viggen.   [/qb][/b]
SAAB part numbers are different for 9-5 aero and 9-3 viggen discs, obviously for some reason the Viggen has grooved.. the heavier 9-5 doesn't??!
But SAAB part numbers for Aero/Viggen pads are the same.
 

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My discs on my 9-3 aren't handed either. KVR Perfromance told me that Saab and a few Mercedes models don't have handed discs. Otherwise, the information on their site is similar to that of what Mark E posted about AP.

Keep a close eye on your discs, Adrian. If the holes penetrated a vane, that is most likely where a crack will begin. I would steer clear of the company you bought them from in the future. There are other companies out there that will cross-drill or slot rotors for a similar price and do the job the correct way. KVR Performance did mine at a cost (including rotors) for $155 for the fronts and $135 for the backs, and CAD plating. I got standard 9-3 rotors slotted. The price is the same for cross-drilled.

One thing KVR does do though, is hand the slots so that at least the slots contact the pads the same on both side, as illustrated in Mark E's post. The only thing is that the vanes inside the rotor are backwards on the right side of the car. Weird.
 

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By the way, Adrian, do you have a pic of the old rotor so you can clear up what you were trying to tell us about the lipping? I am still unsure of what the problem really was. A pic would help alot.
 

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Discussion Starter #16
I tried taking several pictures of it. It never seems to come out very well. It's sort of shaped like this:

**********__/

It's very odd but not thick enough to show up easily with the camera. You can feel it though. Not sure why it would wear so strangely.

Also, I will definetly keep an eye on the rotors. The reason they didn't hand the cross drilling is that the original slots weren't handed and as I said I didn't know at the time that I could just use Aero rotors. If these don't work, we'll hafta see about something a little better in the future. To this company's credit it would have been extremely hard to cross drill properly, following the slots without cutting through a couple vanes, even if I'm dissapointed that this was indeed the case.

edit: As for the part numbers, I was rather desperate to get the rotors quickly. As the pads were wearing out, apparently brakeworld's part numbers for Aero and Viggen pads were different. And what REALLY threw me off was the DAMN OWNERS MANUAL. They told me the Aero uses 308 mm discs ... but my owners manual clearly states the Viggen uses 306 mm discs which is apparently just WRONG! How irritiating! If I'd known they were the same I woulda had them make a handed set with the aero's discs. Oh drat.
 

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The brembo discs I got for my 9k had Right and Left marked into them. Originals didn't.
Still I know someone who has misfitted them. (same Type Discs but on a Mazda) When he turned them into the right position after two months he again noticed an better stopping power.
 

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I belive I read somewere that the Viggen rotor slots point in opposite directions, right side pointing forward and left side pointing backwards????
 

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Originally posted by Søren Hviid:
[qb]I belive I read somewere that the Viggen rotor slots point in opposite directions, right side pointing forward and left side pointing backwards???? [/qb][/b]
If they are not "handed" then yes, this will be the case if the vanes are not radial.
 
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