Upgrade to GT500/Brembo Fr brakes

Philostang · Jul 29, 2010

fiverivers said:
After talking to the stoptech and brembo and carbotech, is was highly recommended not to run TI shims. Ti shims do not allow for heat transfer from the pads to the calipers for proper operating temp for the brake pads. If you are overheating the brakes then it is recommended to run coolings kits, better brake fluids or go to a higher heat capacity calipers or a 2-pc rotor.

Ok, something here is just wrong or conveyed wrong.

There may be a legitimate reason not to run Ti shims (I wouldn't know), but that definitely isn't it. If the Ti shims stop heat from transferring FROM the pads TO the calipers, then GOOD!

First, that's what they're supposed to do, and that's what we want when we pony up a chunk of change for a caliper built with stainless pistons (as opposed to alum.), etc. What we're hoping to do (1st & foremost) is save our brake fluid the distasteful task of managing all that heat. As a minor aside (although, not so minor for some it seems), we're also hoping to insulate our calipers so their metallurgy doesn't go to hell in a hand basket.

Second, if the worry is that the pads won't get up to proper temp, their is absolutely nothing stopping them by blocking heat transfer from the backing plate to anywhere else. The pad compound gets all the heat that matters from direct contact with the rotors. Stopping heat from migrating from the backing plate to the pistons is not going to make one whit of difference. If the worry was that they would somehow retain too much heat (damn those are some effective Ti shims!), then up the pad compound and enjoy your lack of boiled fluid and waxed calipers.

Third, while cooling kits & better fluid are always a good recommendation (and is likely going to have already been done by those contemplating Ti shims), going to a caliper better capable of withstanding heat is usually reserved for those who are seeing their OEM calipers distort to the point described above (bad pad taper is the indication). Perhaps you meant the more common recommendation, higher heat capacity pads? A 2-pc. rotor in and of itself isn't going to help combat overheating brakes, their main benefit is in lighter mass (and some say less tendency to crown at the hub). The vane design is possibly another story, but that can be had in a 1-pc. rotor.

Best,
-j

SoundGuyDave · Jul 29, 2010

My understanding of the FR500S braking rig is a bit different than what's been presented here...

The GT500 HCU (hydraulic control unit) is a different part than the base GT, and is required for the FR500S brake package.

The brake booster is also a different part number, but is NOT required for proper function.

The ABS ECU (the control module) disables all traction control (per the series spec), but still monitors wheel speed sensors. The calibration is based around something on the order of 1.4G max braking effort, BFG R1 tires in 255/45-18 (IIRC), and the spec brake compounds, all on a 3600lb minimum competition weight. Hardly a lightweight! It is NOT a production module. If you look at the parts list, it pretty clearly breaks out FRPP vs. factory part numbers on most items.

Maybe one of the Capaldis, or Steve Poe would chime in with some further insight or data...

DusterRT · Jul 30, 2010

SoundGuyDave said:
The GT500 HCU (hydraulic control unit) is a different part than the base GT, and is required for the FR500S brake package.

The brake booster is also a different part number, but is NOT required for proper function.

Yes and yes...

The ABS ECU (the control module) disables all traction control (per the series spec), but still monitors wheel speed sensors. The calibration is based around something on the order of 1.4G max braking effort, BFG R1 tires in 255/45-18 (IIRC), and the spec brake compounds, all on a 3600lb minimum competition weight. Hardly a lightweight! It is NOT a production module. If you look at the parts list, it pretty clearly breaks out FRPP vs. factory part numbers on most items.

Just putting the GT500 HCU/module in a GT will disable all TC function; the V6/GT computers don't recognize the GT500 module. It trips the dash light (and probably a fault code), but the ABS still functions normally however since it "thinks" for itself.

You're correct about the max braking effort G limit; this is where your main benefit comes in with it while running slicks, race pads, et al. As I previously posted, the deceleration rate is calculated by the wheel sensors; you could have the tires, brakes and downforce capable of a 2G stop, but the ABS system will limit it to what it is calibrated to, since it thinks, "It's physically impossible for this car to be slowing that fast, the wheels must be slipping!" and starts cycling.

As far as the weight it's calibrated for, you might be on to something..they are spec'd at 3600 wet with driver, which is a lot more than I thought (the C cars are about 3100 dry, I assumed the S would be close to this unless they're running a couple hundred pounds of ballast). Perhaps the weight delta between an average street car and the S isn't as great as originally thought, so this could work pretty well (I'm just under 3600# with a half tank and myself in it; and my car is nothing special, nor have I gone all Matt D on it..yet..).

Vapour Trails · Jul 30, 2010

Basically what I've taken from all this is there is never a simple way to have a set of brakes that will stand up to road course use. I though that swapping the mechanical parts would be enough.

I get more disinclined to road race with every new thread in this sub-forum I'm afraid.

STEVE_POE · Jul 30, 2010

Vapour Trails said:
Basically what I've taken from all this is there is never a simple way to have a set of brakes that will stand up to road course use. I though that swapping the mechanical parts would be enough.

I get more disinclined to road race with every new thread in this sub-forum I'm afraid.

it's hard to build a serious road race car and keep it streetable enough to actually be a enjoyable car. Same with the drag racing world as well.

You have to pay to play

TheKurgan · Jul 30, 2010

Mine does all 3 and I do it on a budget. I'm not rich. It takes more time, but not a whole lot more money. The key is being passionate about it. I come here to study threads like this, but I trust my own experience as well. There's no need to make it more difficult than it really is. The key is to have racing in your mindset with everything you do. Accidents happen but most of them are avoidable using common sense and alot of testing. The learning never stops and you have to accept that to succeed in anything.

I'm going to keep running my combination because it has been successful for me. If I see any warning signs or other GT's with this combination fail, I'll revisit this idea of swapping out the HCU and module. Quitting is not an option though.

ArizonaGT · Jul 30, 2010

STEVE_POE said:
it's hard to build a serious road race car and keep it streetable enough to actually be a enjoyable car. Same with the drag racing world as well.

You have to pay to play

Everything else is a compromise

ClassJ · Jul 30, 2010

I am sure that the GT500 has a different booster, etc for reasons. However, just a slight bit of my experience on the situation.

1) Ford sells the kit to convert the GT. Ford racing verbally claims no issue with the conversion. I was told the GT500 booster had reduced boost to reduce pedal sensitivity.

2) The calibration I am sure is different on the GT500. However, that module is calibrated for a 4000lb car with completely different weight bias. So hardly ideal for a converted GT either.

3) Not that it is gospel, but I have had the parts on the car for quite a while (before the kit was even available from FRPP). Been through rain, snow, ice, summer tires, winter tires, normal stops, emergency stops. No track time. I ended up getting approx 45K miles out of the pads. I changed rotors too. Both the front and rear pads wore damn near evenly. Possibly about 15% more matl left on the backs. I am running the ford factory pads front and rear. They are dusty but are a good quiet pad that works on
40 degree wet rainy days and stands up decently well to heat.

Does that mean there is no problem? Maybe not, but is it a time bomb? I am not so sure,

SoundGuyDave · Jul 30, 2010

Just to clear up some possible confusion: there are three, possibly four different ABS ECU modules out there.... The base GT, the GT500, and the FR500S. Possibly a V6, but I honestly don't know about that one, and I'm discounting the SuperSnake "hotrod" modules...

The GT500 module will disable TC in the base GT for the reasons stated above, but with the FR500S module AND the GT500 HCU, the TC is disabled intentionally, as the series is allowing ABS, but not traction control...

The FR500S module is calibrated for all the spec parts (GT500 HCU, GT500 calipers, BFG rubber), and if your "race weight" (minimum fuel load, driver, safety gear, etc.) is around 3600lbs, then that may be the answer to early ABS activation if you're running mondo-sticky tires, like the R1 or the A6/R6.

That was all I was saying. I was never intending to suggest that a swap to the GT500 ABS module would be benficial...

TheKurgan · Jul 30, 2010

SoundGuyDave said:
The FR500S module is calibrated for all the spec parts (GT500 HCU, GT500 calipers, BFG rubber), and if your "race weight" (minimum fuel load, driver, safety gear, etc.) is around 3600lbs, then that may be the answer to early ABS activation if you're running mondo-sticky tires, like the R1 or the A6/R6.

Who's having early ABS activation with this combo ? I'm running BFG R1's with the Brembo's, race pads, on a 3600lb GT and it doesn't happen to me. I'd say my combo is pretty close if not a perfect match.

DusterRT · Jul 30, 2010

SoundGuyDave said:
Just to clear up some possible confusion: there are three, possibly four different ABS ECU modules out there.... The base GT, the GT500, and the FR500S. Possibly a V6, but I honestly don't know about that one, and I'm discounting the SuperSnake "hotrod" modules...

The GT and V6 modules are the same, they contain programming for both and the PCM decides which is used. It has been speculated that the SuperSnake might use the FR500S module, but it was just that...speculation (personally, I doubt it).

SoundGuyDave said:
That was all I was saying. I was never intending to suggest that a swap to the GT500 ABS module would be benficial...

I dug up that post..here's what the Ford guy has to say about the ABS modules/HCU:

This is the hard part. The GT ABS module will limit your braking ability, in that it won't allow you to achieve the deceleration rates that the race modules will. Braking won't be worse then your current situation, but you won't be able to take full advantage of the sticky tires. The problem with the race modules is that they won't work well on the street with street pads (but are fantastic on sticky tires!). The GT500 setup is a good compromise, but then you'll lose your traction control.

It's not in great deail, but it is implied that the GT500 module/HCU is an upgrade from the GT. Also explains a little about the race module. There's a TON of good information in it, I am waiting on permission from the guy who posted it to re-post it here (would be a fantastic sticky).

TheKurgan · Jul 30, 2010

DusterRT said:
The GT and V6 modules are the same, they contain programming for both and the PCM decides which is used. It has been speculated that the SuperSnake might use the FR500S module, but it was just that...speculation (personally, I doubt it).

I dug up that post..here's what the Ford guy has to say about the ABS modules/HCU:

It's not in great deail, but it is implied that the GT500 module/HCU is an upgrade from the GT. Also explains a little about the race module. There's a TON of good information in it, I am waiting on permission from the guy who posted it to re-post it here (would be a fantastic sticky).

Do it! People's lives are on the line! Hell, ask him to get a user id so we can pick his skull lol.

DusterRT · Jul 30, 2010

TheKurgan said:
Do it! People's lives are on the line! Hell, ask him to get a user id so we can pick his skull lol.

I will as soon as I get the green light. It was posted as an email exchange between a forum member and guys at FRPP, on a semi-private forum so I just want to be sure it's ok that I put it up, and if he wants his name or all names removed from it or not..

Philostang · Jul 31, 2010

I hope that we get to see that post. However, from the little bit leaked, there doesn't seem to be a worry about bias from this source. The claim specifically was "Braking won't be worse then your current situation, but you won't be able to take full advantage of the sticky tires."

There's a big difference between optimizing a braking system and preventing all sorts of mayhem (like locking the tires, ABS "freaking out," lives on the line, etc.). Those conditions would be clearly defined as "braking being worse," but this source is specifically saying that this won't be the case.

I'm not saying this is definitive, just trying to be clear about what was claimed and implied.

Best,
-j

Gray Ghost GT · Jul 31, 2010

I've NEVER heard an ABS failure lead to the brakes locking up. I experienced ABS failure first hand in another vehicle that simply meant I lost ABS but NOT the ability to brake and control the car. Is the GT module just "different" than the GT500 because of a number of car design factors, e.g. vehicle weight, or is it a real "upgrade", and if so, what is the upgrade targeting compared to the GT module and why? I would think that is the important question to answer here.

Most people don't use Traction Control and/or Active Handling when on a road course so they can have more control over the car. If the GT module allows me to use ABS while using slicks, then I'm good to go. If it "freaks" out when using slicks, an upgraded brake system (BBK) or aggressive brake pads, then that would be good to know, and why. I haven't heard GT owners complain about their cars on the road courses that are using slicks, BBK and aggressive pads.

DusterRT · Jul 31, 2010

Gray Ghost GT said:
I've NEVER heard an ABS failure lead to the brakes locking up. I experienced ABS failure first hand in another vehicle that simply meant I lost ABS but NOT the ability to brake and control the car.

The concern is an unexpected and untimely lock up due to heavy braking, not the ABS itself causing a lockup. Obviously the number of people who have had issues are in the tiniest minority; case in point, it seems I'm the only one here who's personally had an issue with it, and Steve Poe's the only other one who's witnessed it (I think I've heard of one other person having the same issue I had on a forum somewhere, possibly this one?).

Is the GT module just "different" than the GT500 because of a number of car design factors, e.g. vehicle weight, or is it a real "upgrade", and if so, what is the upgrade targeting compared to the GT module and why? I would think that is the important question to answer here.

I would think that is the case, yes. Larger, stickier tires, higher weight and higher available brake torque, along with other factors like the differing fluid volume requirements from the larger calipers (this last variable is surely a primary reason why the HCU's are different). I have no numbers, data, etc. to back it up but I felt a *slight* reduction in the ABS sensitivity; and what I posted above is basically all that the FRPP guy says about HCU's and modules.

ArizonaGT · Aug 1, 2010

So where's this FRPP Technical post???????????????????????????????????????????????????????????????????

:headscratch:

Gray Ghost GT · Aug 1, 2010

DusterRT said:
...I would think that is the case, yes. Larger, stickier tires, higher weight and higher available brake torque, along with other factors like the differing fluid volume requirements from the larger calipers (this last variable is surely a primary reason why the HCU's are different)....

I had a similar question when upgrading from my OEM brakes to the Wilwood Superlight SL6 (Front) and SL4 (Rear) BBK. Larger calipers = more fluid volume requirements. So I went to the local Ford dealership and asked their senior parts guy if there was a difference between the GT and GT500 brake fluid reservoir - he checked his part numbers, and said no. Can someone confirm this?

Wilwood also said there would be no issue with GT the using their front and rear caliper kits. I'm pretty aggressive on the brakes when running my C5. I'm taking the Mustang GT to VIR on 26 - 29 August with new Wilwood BBK installed and slicks, and will be pounding on the brakes hard for 4 consecutive days. I'll provide an assessment when I get back. If there's going to be a problem with this setup, I'll definitely feel and see it. I'm "hoping" it will be a non-issue.

DusterRT · Aug 1, 2010

ArizonaGT said:
So where's this FRPP Technical post?

Still waiting for the OK from the guy who originally posted it. He hasn't logged on since the 25th. If I don't hear back in a few days here I'll remove the names, paraphrase and post it..I don't see why it would be sensitive information (especially now that it's a couple years old), and I'm probably being over-cautious, but I've never seen it anywhere else so I just want to be careful/respectful.

Gray Ghost GT said:
So I went to the local Ford dealership and asked their senior parts guy if there was a difference between the GT and GT500 brake fluid reservoir - he checked his part numbers, and said no. Can someone confirm this?

MC's are the same, only the boosters differ.

DusterRT · Aug 3, 2010

Interesting bit of tech from a discussion on another board...

GT500 calipers (40/44mm pistons) have just under 5% *LESS* piston area than V6/GT calipers (dual 43mm). I'm still scratching my head as to how that would create a softer pedal. Bueller?

Upgrade to GT500/Brembo Fr brakes

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