Huge brake upgrade for S197 chassis

[jayhawk261]

I'm currently looking at a set of 6pistons on ebay. Do you think it will be fairly soon?

I sent you a PM

 

[Mad Hatter]

I love them, big change to the car with a small investment... But that might be because I use aggressive brake pads, and that works out ok with the longer pedal.

If your going to track the car then they are better then the gt500 option with a huge pad and lots of track oriented pad choices. Never tried the floating rotors on the S550 brakes though. I just use OEM or Stoptech rotors since none seems to last me very long.

 

[jayhawk261]

This is the first really negative I have heard about the S550 6 piston conversion. How bad is terrible? I have a set of calipers and rotors ready to go on my car this winter. I haven't bought pads yet, so it may be a good time to look for a pair of the GT500 6 piston calipers.

For me and my comfort level, I thought it was bad bad. I know some people here have no issues with it and are comfortable with tapping the brake pedal with the left foot a couple of times just before the braking zone. After a straight building any speed, I'd go for the brakes, and the pedal would travel 3/4 + before getting any braking power. I had to pump a couple of times to get any real braking which then screwed up my concentration on the turn. For me, I want to have a better comfort level on my brakes so I can have a fun track weekend rather than adding a level of complexity with having to left foot tap the brakes before the braking zone. There are a lot of people that are perfectly ok with doing that, but I'm not experienced enough to want to add another level of complexity to getting around the track for HPDE stuff.

 

[Mad Hatter]

There are a lot of people that are perfectly ok with doing that, but I'm not experienced enough to want to add another level of complexity to getting around the track for HPDE stuff.

Hmm. maybe because my car is a Boss,. never had any problem with having to tap the brake pedal and if I did would have ripped them out right away.. The cars is basically 100% track now and runs in a pretty fast category with hard braking from over 140 mph down to 50mph. Having the S550 brembos keeps me braking with Porsches and cars with really nice (expensive) AP brakes kits.

I have seen the tapping brake and hard pedal problem on automatic cars that went to most any BBK including Stoptech or Brembos (Gt500 or S550).

 

[Coz]

I recall seeing a post where someone installed StopTech anti-knockback springs behind the caliper pistons. I can't find the post and I'm not even sure it was on TMO. I'll.keep looking for it.

There was also something about replacing the anti-rattle clips on the GiroDisc rotors that would supposedly help with that.

 

[Coz]

I should state that I still have the anti rattle clips in my girodiscs. When I replace the rings I’ll remove those and that should settle the knockback some more. Also I tend to see it most on fresh Hoosiers, where the grip levels are highest and only on particular courses. There’s other options like anti-knockback springs but I’ve not been bothered enough to explore.

 

[jayhawk261]

I have read about anti-knockback springs as well, but I'm not 100% sure about using them being that they are a universal kind of part. Seems a little sketchy. I actually went with the Girodiscs because I read they should be better in eliminating knockback than a fixed rotor. Maybe I misunderstood what I read.

 

[jayhawk261]

Hmm. maybe because my car is a Boss,. never had any problem with having to tap the brake pedal and if I did would have ripped them out right away.. The cars is basically 100% track now and runs in a pretty fast category with hard braking from over 140 mph down to 50mph. Having the S550 brembos keeps me braking with Porsches and cars with really nice (expensive) AP brakes kits.

I have seen the tapping brake and hard pedal problem on automatic cars that went to most any BBK including Stoptech or Brembos (Gt500 or S550).

Yeah, it's a sketchy deal. Nothing like 120 - 130 over Alpha into turn 1 and having essentially no brakes until the 3rd pump (which there isn't really time for ). I don't believe there is any difference between the MC on a Boss vs a standard GT. I'm not sure where there would be any difference between the pedal and the calipers that would change the knockback situation. I think there is just too large a discrepancy between the MC piston size/volume it can push. I think the knockback comes from the MC piston being overwhelmed by the caliper pistons in the turns.

If someone has suggestions on how I can fix the issue without going to GT500 6 pistons, I'm all ears! I would rather do that than spend more money on calipers and pads.

 

[Mad Hatter]

Just to be sure, your car is not a automatic is it?? . Is it possible that you have a vacuum leak?? It would be a shame to get the lesser GT500 calipers and have the same thing happen.

One friend had the same trouble with his Stoptech trophy 15" BBK setup. He swapped out the 6R80 automatic and installed a Calimer Stage 1 Mt82 manual. His brakes dramas went away as soon as the car started up. Makes you think its the extra vacuum lines to the manifold that the manual has?

 

[jayhawk261]

Just to be sure, your car is not a automatic is it?? . Is it possible that you have a vacuum leak?? It would be a shame to get the lesser GT500 calipers and have the same thing happen.

One friend had the same trouble with his Stoptech trophy 15" BBK setup. He swapped out the 6R80 automatic and installed a Calimer Stage 1 Mt82 manual. His brakes dramas went away as soon as the car started up. Makes you think its the extra vacuum lines to the manifold that the manual has?

No automatic. I am also running a Calimer Stage 1 MT82 with an Exedy Mach 500 clutch. Definitely no vacuum leaks either. Once I tap the pedal a few times, it stops insanely well. There are no fluid leaks, and I get a good pedal every time I bleed using Motul 660 fluid.

 

[Mad Hatter]

Having to tap the brakes sucks..... and is not normal at least in my case. Would drive me totally nuts. When I let me track buddies try out my car, the first thing they say when they get out of the car is.....Awesome brakes!!

What brake pads do you use?

 

[jayhawk261]

Having to tap the brakes sucks..... and is not normal at least in my case. Would drive me totally nuts. When I let me track buddies try out my car, the first thing they say when they get out of the car is.....Awesome brakes!!

What brake pads do you use?

Carbotech XP20 on the front. I think XP10 on the rear.

 

[67GTA]

Carbotech XP20 on the front. I think XP10 on the rear.

Bearing hubs in good order? I’m running the same setup with OE rotor blanks and never have to pump the brakes.

 

[jayhawk261]

Bearing hubs in good order? I’m running the same setup with OE rotor blanks and never have to pump the brakes.

As far as I can tell. There is no play or any noise on either side. They roll good with a proper amount of resistance. They are original with about 57k on them.

 

[KazarS197]

No automatic. I am also running a Calimer Stage 1 MT82 with an Exedy Mach 500 clutch. Definitely no vacuum leaks either. Once I tap the pedal a few times, it stops insanely well. There are no fluid leaks, and I get a good pedal every time I bleed using Motul 660 fluid.

Did you do the abs bleed procedure with forscan? Is there old fluid or air stuck in the abs block that's giving you grief once everything is hot?

 

[Impact302]

No automatic. I am also running a Calimer Stage 1 MT82 with an Exedy Mach 500 clutch. Definitely no vacuum leaks either. Once I tap the pedal a few times, it stops insanely well. There are no fluid leaks, and I get a good pedal every time I bleed using Motul 660 fluid.

You have to have a mechanical issue or vaccum related issue, I've driven loads off PP1 15 + S550s and those bitches are touchy as hell with stock pads. Rebleed you system ,do an ABS bleed

 

[jayhawk261]

Did you do the abs bleed procedure with forscan? Is there old fluid or air stuck in the abs block that's giving you grief once everything is hot?

ABS bleed done by Rennsport KC. I don't know what computer he uses for it.

 

[jayhawk261]

You have to have a mechanical issue or vaccum related issue, I've driven loads off PP1 15 + S550s and those bitches are touchy as hell with stock pads. Rebleed you system ,do an ABS bleed

Are you saying you've drive S550s with these brakes and had no issues or S197s and never seen an issue. Again, no vacuum leaks whatsoever. Brakes have been bled a minimum of 8 - 10 times including the ABS bleed.

Just curious, how would a vacuum leak contribute to pad knockback?

 

[Fabman]

Are you saying you've drive S550s with these brakes and had no issues or S197s and never seen an issue. Again, no vacuum leaks whatsoever. Brakes have been bled a minimum of 8 - 10 times including the ABS bleed.

Just curious, how would a vacuum leak contribute to pad knockback?

Sorry I'm late to the party but, are you using s550 rear calipers on your pre 2015 car or am I mistaken?

 

[jayhawk261]

Sorry I'm late to the party but, are you using s550 rear calipers on your pre 2015 car or am I mistaken?

2011 S197 with S550 6 piston Brembos on the front.