I wonder when Brembo is going to be making a kit?

I don't see a reason to do more than maybe lines on this thing. 112ft from 60-0?? Thats F'n amazing for a 4000 lb car. A brake kit would be about what?? 2500-4000 bucks?

Of course I realize brake fade is a factor so we'll have to see how it fares!

hopefully sooner than later. Won't the GXP have brembos?

hopefully sooner than later. Won't the GXP have brembos?
Dunno.

Baer will probably come out with parts and a kit, as well.

with big nice wheels, big nice brakes are required (for looks of course!)

There was a thread awhile ago from an australian company that had a set of coilovers and a BBK from brembo out...

They never got back to me on the price for the brembo's though...

hopefully sooner than later. Won't the GXP have brembos?

I think marketing info on the G8 GXP is that it will have a full Brembo brake package.

It'll probably be cheaper to get the GXP kit list price from GM over getting anything else. Hoping at least...

I don't see a reason to do more than maybe lines on this thing. 112ft from 60-0?? Thats F'n amazing for a 4000 lb car. A brake kit would be about what?? 2500-4000 bucks?

Of course I realize brake fade is a factor so we'll have to see how it fares!
I agree! The brakes on the G8 are superb! I'm a lot more worried about the dip****s behind me that don't understand the laws of physics.

My brakes work well but they sure are squeaking a lot. :(

My brakes work well but they sure are squeaking a lot. :(
Do you garage it or park it outside?

My brakes work well but they sure are squeaking a lot. :(

Could be a little bit of pad glazing on the rotors. They might not have been bedded in properly.

I don't see a reason to do more than maybe lines on this thing. 112ft from 60-0?? Thats F'n amazing for a 4000 lb car. A brake kit would be about what?? 2500-4000 bucks?

Of course I realize brake fade is a factor so we'll have to see how it fares!
You can never be too rich, too thin, or have too much brake.

Testing the G8s liek we have, we have found brake squeel to be fairly common on very light applications. We are also seeing the brakes needing some work if you are going to drive the vehicle in a prolonged "sporty" way.

Pete will be chatting about his brakes and will be updating them once his ProCharger is installed.

mike
dms

I wish to hear more exhaust note but don't want it to sound like a pick-up truck. Did you switch out both the resonator and axleback mufflers at the same time or did you do one before the other? If so, can you tell me how it sounds and do you hear a drone in the car at cruise? I like the exhaust look from SF but not sue if I want to do both for fear it will be too loud or it will drone when not pushing it.

I saw the in-car video but it sounded loud and truck-like to me.

jcar

You can never be too rich, too thin, or have too much brake.

Well you can be too thin...http://www.youtube.com/watch?v=98oPd25EX0M&feature=related

I wish to hear more exhaust note but don't want it to sound like a pick-up truck. Did you switch out both the resonator and axleback mufflers at the same time or did you do one before the other? If so, can you tell me how it sounds and do you hear a drone in the car at cruise? I like the exhaust look from SF but not sue if I want to do both for fear it will be too loud or it will drone when not pushing it.

I saw the in-car video but it sounded loud and truck-like to me.

jcar

This is the brake thread, dude, not the exhaust thread.

Well you can be too thin...http://www.youtube.com/watch?v=98oPd25EX0M&feature=related


Thank god i didnt start eating yet...

Thank god i didnt start eating yet...

:barf:

Well you can be too thin...http://www.youtube.com/watch?v=98oPd25EX0M&feature=related
Mmmmmm, living skeleton! :nuts:

I don't know if Im the only one to notice it but I have not seen the first G8 GT with or without the sport package that had Vented Discs. With all of the brochures and even information seen on this site stating Vented Discs what have I missed? Just a question because when I get a 2009 I WANT VENTED DISCS. I plan on being able to take a 4000 Lb car into the mountains and not have to wory about brake fade.

TP

Mine has vented disks front and rear, maybe you are confusing this with cross drilling?

Do you garage it or park it outside?

95% of the time it is garaged. There have been a few occasions that I was too lazy to pull it in the garage. It happens mostly when backing up and I have begun to notice it when stopping at lights. Doesn't happen real consistently though.

I don't know if Im the only one to notice it but I have not seen the first G8 GT with or without the sport package that had Vented Discs.

Mine has vented disks front and rear, maybe you are confusing this with cross drilling?
Kep is correct, the disks are vented. Not slotted or drilled, but vented.

Thanks for the information. I will yield to the ones "In the Know". So now I need to do some more searching as to the differences between the three.

It's quite simple really. Vented disc brakes are actually two "sandwiched" plates, with "spokes" inbetween the separate discs. These spokes actually scoop up air and let the brakes cool effeciently. If you have a Current Grand Prix, or previous generation one, take a look at your front discs and see it for yourself.

This design allows for maximum braking surface with moderate cooling ability.

The other advanced cooling options are slotted and/or cross-drilled rotors. While these decrease the braking surface, they more than make up for it in sheer cooling capability.

Of course, unless you're on the track, you really won't see the benefit of a cross-drilled and/or slotted rotor.

I don't see a reason to do more than maybe lines on this thing. 112ft from 60-0?? Thats F'n amazing for a 4000 lb car. A brake kit would be about what?? 2500-4000 bucks?

Of course I realize brake fade is a factor so we'll have to see how it fares!Well if we mod the car enough we'll need some big brakes

Now that I have fully Pedderised with an eXtreme systems I found the brakes to be lacking. It isn't that the OE brakes are bad. The chassis is so well designed that it is one of the easiest cars to drive fast I have had the pleasure to run hard. For most people, the OE brakes will be good to go. Having been spoiled by DBA on my GTO with a special set of calipers, 5000 rotors on the front and 4000 rotors on the rear -- the OE brakes just won't cut it with the ProCharger and eXtreme Track System from Pedders.

ProCharger Link:
http://www.g8board.com/forums/forumdisplay.php?f=5

My Suspension Evaluation:
http://www.g8board.com/forums/showthread.php?t=1859

Almost Live Build:
http://forums.peddersusa.com/showthread.php?t=328

I don't see a reason to do more than maybe lines on this thing. 112ft from 60-0?? Thats F'n amazing for a 4000 lb car. A brake kit would be about what?? 2500-4000 bucks?

Of course I realize brake fade is a factor so we'll have to see how it fares!

Where did your info come from? According to Car&Driver (and i know they could be off also) the 70-0 distance is 167 feet. thats a big difference from the 60-0 at 112 feet that you posted. alos has anyone noticed that Car&Driver listed the front rotors as 12.6 inches but the back rotors as 12.8. can anyone confirm or deny this?

Just for measures the 2006 Vette Zo6 takes 113 feet 60-0.

K. If parked outside in some climates (like friggin' Seattle) where we have 33F and 4 in. of snow on the ground today), a thin layer of rust forms on the disks. They will squeak when you drive it the first time in a day, 'specially in reverse.

4" of snow on April 19th???????????? That's just WRONG! :cursin:

I can't tell you the diameter of the discs. I can tell you that the brakes are well matched to the OE suspension. The G8 arrives from the factory as a well balanced car in both 6 and 8 cylinder models. If you upgrade the performance of your vehicle - suspension, power, larger tires and wheels -- you will alter that balance. I was rather impressed with the OE brakes over several cars with different Pedders packages. IMO with a Track II or eXtreme Pedders system on your G8, you will probably feel as I do and start looking at brake upgrades.

I do find that the G8 brake pad composition is squeakier in the morning or when cold.

It's quite simple really. Vented disc brakes are actually two "sandwiched" plates, with "spokes" inbetween the separate discs. These spokes actually scoop up air and let the brakes cool effeciently. If you have a Current Grand Prix, or previous generation one, take a look at your front discs and see it for yourself.

This design allows for maximum braking surface with moderate cooling ability.

The other advanced cooling options are slotted and/or cross-drilled rotors. While these decrease the braking surface, they more than make up for it in sheer cooling capability.

Of course, unless you're on the track, you really won't see the benefit of a cross-drilled and/or slotted rotor.

Okay, I couldn't let this go. Physics does not change when you're at the track. Ether they aide the cooling or they don't. In reality, they don't. It's marketing that claims this.

The benefits of cross drilled/slotted rotors are that they help prevent glazing and, minorly, aid in the evacuation of water. This will also result in greater pad wear and brake dust.

Do not run these on a road course, or at least if you do, make sure you inspect them after they've cooled or listen to them as they cool. Sometimes, you can hear them "pop". You know that persons day was just ruined when that happens.

The benefits of cross drilled/slotted rotors are that they help prevent glazing and, minorly, aid in the evacuation of water. This will also result in greater pad wear and brake dust.

Do not run these on a road course, or at least if you do, make sure you inspect them after they've cooled or listen to them as they cool. Sometimes, you can hear them "pop". You know that persons day was just ruined when that happens.
It has always been my understanding that cross-drilled rotors work by allowing a more efficient escape route for heat buildup. Heat >> fade as the brake fluid overheats.

Are you advising against running drilled disks at a track day, or were you talking about the OEM disks? Almost all motorcycles' front disks are drilled, and even though they are thinner than car disks there are rarely any problems with disks cracking. (Chamfering the holes is a must.)

I have had my ZX-12R at many, many track days and have subjected the bike to very intense braking. At 40,000+ miles I still have the original disks on the bike, with no sign of warping or cracking.

Where did your info come from? According to Car&Driver (and i know they could be off also) the 70-0 distance is 167 feet. thats a big difference from the 60-0 at 112 feet that you posted. alos has anyone noticed that Car&Driver listed the front rotors as 12.6 inches but the back rotors as 12.8. can anyone confirm or deny this?

Just for measures the 2006 Vette Zo6 takes 113 feet 60-0.

Car and Driver (http://www.caranddriver.com/reviews/hot_lists/car_shopping/family_four_doors/2008_pontiac_g8_gt_road_test+t-performance_car_for_the_family_+page-2.html): 70-0: 167ft.

Motortrend (http://www.motortrend.com/roadtests/sedans/112_0802_2008_pontiac_g8_gt_first_test/specs_test_data.html): 60-0: 112ft.

Edmunds.com (http://www.edmunds.com/apps/vdpcontainers/do/vdp/articleId=124883/pageNumber=2): 60-0: 109ft. 30-0: 34ft.

I'm not going to get into the math here, but suffice it to say that the amount of inertia you have does not increase linearly as speed increases. As you can see from Edmund's numbers above, doubling the speed tripled the stopping distance.

For comparison sake, when Motortrend tested a 5.7L GTO (http://www.motortrend.com/roadtests/coupe/112_0405_sport_coupe_comparison/specs_price.html) they did 60-0 in 126ft and 100-0 in 347 ft. That extra 40mph upped the distance 221ft.

And yes, the rear rotors are a hair bigger than the front. Why? You'll have to ask Holden that one, cause I'm stumped.

It has always been my understanding that cross-drilled rotors work by allowing a more efficient escape route for heat buildup. Heat >> fade as the brake fluid overheats.

Are you advising against running drilled disks at a track day, or were you talking about the OEM disks? Almost all motorcycles' front disks are drilled, and even though they are thinner than car disks there are rarely any problems with disks cracking. (Chamfering the holes is a must.)

I have had my ZX-12R at many, many track days and have subjected the bike to very intense braking. At 40,000+ miles I still have the original disks on the bike, with no sign of warping or cracking.

There are most likely some differences between the weight of a motorcycle with it's rider vs. a car with it's driver. I can't speak for motorcycles because it's just not my area of knowledge. As an example, GTO owners were having problems with aftermarket rotors from Baer (& I think Wilwood on a couple of occasions). The problem? Rotor cracking. The drilled holes take away structural integrity from the rotors. Look at most professional race cars. Most of those rotors are only slotted. I have not seen or heard of any cracked rotors on slotted rotors for street cars, even if they were run at the track.

There are most likely some differences between the weight of a motorcycle with it's rider vs. a car with it's driver. I can't speak for motorcycles because it's just not my area of knowledge. As an example, GTO owners were having problems with aftermarket rotors from Baer (& I think Wilwood on a couple of occasions). The problem? Rotor cracking. The drilled holes take away structural integrity from the rotors. Look at most professional race cars. Most of those rotors are only slotted. I have not seen or heard of any cracked rotors on slotted rotors for street cars, even if they were run at the track.
It's possible that the drilled rotors that are cracking don't have chamfered holes. Chamfering aids in stress relief around the hole, and from what I understand if they aren't chamfered a disc is almost guaranteed to crack.

I understand what you're alluding to with the different stresses on bike rotors vs. car rotors. I have done hard enough braking on my bike to invoke noticeable fade, so I know the rotors are being heat-cycled well. On the other hand, bike rotors are quite large in relation to the bike's weight and their aluminum carriers likely dissipate heat more effectively than a car's rotors.

I'm still inclined to think that the rotor cracking is due to an inferior product rather than the fact that they are drilled. But your point about slotted rotors is well made.

A motorcycle and a car rotor are very different animals so as to not compare. All slotted or drilled rotors have the potential to crack. I've seen both crack at the track, yes even the famed "cast-in holes" of Porsche metal brakes. That's in quotes because, although many people have told this to me, I have not found evidence of this. Now, granted, I don't search often for it but I did about 5 years ago and no manufacturer or Porsche reference returned anything about this. One would think that if it was such an advantage, it would broadcast all over. Anyway, I digress.

The historic reasoning for the drilled holes was to allow for escaping gases to removed from between the pad and the rotor, or "out gassing". When this was started, it was common for the friction material on the pad to combined with anything the manufacturer could get cheaply for a binding material. This caused the gasses when the pads were heated beyond normal street ranges. The problem with this is the gas would cause a boundary layer between the pad and the rotor, requiring the out gassing. Since pad material has developed and binder materials that do not normally cause gassing are now used, the need for slotted or cross-drilled rotors has long expired.

You are right chamfering will help with dealing with the stresses. However, the metal is still a crystaline structure and removing any material creates a stress riser. If there happens to be a weak point in the metal near the hole, it will propagate from that point. If the material was still there, it is more likely to remain stable.

However, I will say I like the looks of cross drilled and/or slotted rotors. In fact, one of my cars came with them and I have run it at the track. However, I did keep a close eye on the rotors just to make sure nothing happened. Not to mention it was pretty cold and they were relatively new rotors.

While we're on the topic of brakes and heat, has anyone looked at the feasability of adding brake cooling ducts?

While we're on the topic of brakes and heat, has anyone looked at the feasability of adding brake cooling ducts?
Do you plan on autocrossing yours?

I have autocrossed other vehicles although not as fanatically as others here - to my mind the main advantage of slotted rotors on the street is better wet braking.

The slots help remove water from the disk as they pass under the pads.

Other than the wet advantage, most people won't abuse the brakes on the street hard enough to make use of the advantages of slotted rotors.

Do you plan on autocrossing yours?

I'm fairly seriously considering it. Aside from that, we have some nice twisties north of San Antonio in the hill country and "spirited" driving up there can be tough on the brakes. I figure anything to help extend the life and performance of the brakes is a good thing.

saw a Mercedes CLS 55 AMG on the interstate yesterday. It has nice looking calipers and rotors that were very visable at 75 mph. after seeing that, I REALLY want a good looking (and performing) set of Brembo's. It would make the car look much sportier...IMO.

I'm fairly seriously considering it. Aside from that, we have some nice twisties north of San Antonio in the hill country and "spirited" driving up there can be tough on the brakes. I figure anything to help extend the life and performance of the brakes is a good thing.
It must be nice to live somewhere where there are actually curves in the road. :p

It must be nice to live somewhere where there are actually curves in the road. :p

Yeah, now I just need to find a way to get them to close the road off to other traffic for a few hours and I'll be good to go! :gears:

It's quite simple really. Vented disc brakes are actually two "sandwiched" plates, with "spokes" inbetween the separate discs. These spokes actually scoop up air and let the brakes cool effeciently. If you have a Current Grand Prix, or previous generation one, take a look at your front discs and see it for yourself.

This design allows for maximum braking surface with moderate cooling ability.

The other advanced cooling options are slotted and/or cross-drilled rotors. While these decrease the braking surface, they more than make up for it in sheer cooling capability.

Of course, unless you're on the track, you really won't see the benefit of a cross-drilled and/or slotted rotor.

DBA will have their 4000 series rotors soon to suit the G8 GT in either 4000XS (cross drilled) or the 4000 6x6 wiper slots (slotted)

DBA will have their 4000 series rotors soon to suit the G8 GT in either 4000XS (cross drilled) or the 4000 6x6 wiper slots (slotted)
Excellent, thanks!

A motorcycle and a car rotor are very different animals so as to not compare. All slotted or drilled rotors have the potential to crack. I've seen both crack at the track, yes even the famed "cast-in holes" of Porsche metal brakes. That's in quotes because, although many people have told this to me, I have not found evidence of this. Now, granted, I don't search often for it but I did about 5 years ago and no manufacturer or Porsche reference returned anything about this. One would think that if it was such an advantage, it would broadcast all over. Anyway, I digress.

The historic reasoning for the drilled holes was to allow for escaping gases to removed from between the pad and the rotor, or "out gassing". When this was started, it was common for the friction material on the pad to combined with anything the manufacturer could get cheaply for a binding material. This caused the gasses when the pads were heated beyond normal street ranges. The problem with this is the gas would cause a boundary layer between the pad and the rotor, requiring the out gassing. Since pad material has developed and binder materials that do not normally cause gassing are now used, the need for slotted or cross-drilled rotors has long expired.

You are right chamfering will help with dealing with the stresses. However, the metal is still a crystaline structure and removing any material creates a stress riser. If there happens to be a weak point in the metal near the hole, it will propagate from that point. If the material was still there, it is more likely to remain stable.

However, I will say I like the looks of cross drilled and/or slotted rotors. In fact, one of my cars came with them and I have run it at the track. However, I did keep a close eye on the rotors just to make sure nothing happened. Not to mention it was pretty cold and they were relatively new rotors.Excellent post. A good rule of thumb is slotted and cross drilled look great, but should be used only by the casual 'racer'. Slotteds are for the guys that frequent the track and drive hard. The slots help with pad bite and clearing of brake dust -- which piles up in amazing amounts when a car is tracked really hard.

Okay, I couldn't let this go. Physics does not change when you're at the track. Ether they aide the cooling or they don't. In reality, they don't. It's marketing that claims this.

The benefits of cross drilled/slotted rotors are that they help prevent glazing and, minorly, aid in the evacuation of water. This will also result in greater pad wear and brake dust.

Do not run these on a road course, or at least if you do, make sure you inspect them after they've cooled or listen to them as they cool. Sometimes, you can hear them "pop". You know that persons day was just ruined when that happens.

Well put.

I road race and we in tech dislike to see drilled rotors unless they are cast and/or very high end brake systems.

Most of the drilled rotors out there are not very high quality and lead to cracks and eventual rotor failure.

We use smooth or slotted rotors on our race cars.

-mike

Anyone know if the GXP Brembos will be able to work on the G8 GT? or will it be similar to the CTS v. CTS-V setup where the V gets brembos and a different knuckle, which would not allow the Brembos to be a direct bolt-up?

-mike