Has Anyone Corner Weighed a Sports Roof?

[Aerocoupe 11]

My father and I stripped his 69 FB to the shell and are starting on a rather large undertaking of building his dream car. Its a resto mod with the emphasis on making the car handle the twisties with good power and brakes that complement the power.

 

Originally I believe the car to be a run of the mill 302W, C4, 8", factory AC car of which none was original except the rear end when we got it. It took a couple of years of hashing over what my dad wanted the car to do and how it would look to come up with a 351W injected stroker, Magnum T-56, 9" with 2005 Mustang GT brakes, Vintage Air, and it will have a full Griggs suspension. To date we have the majority of the motor parts (basically the long block), new Painless body harness and injection harness (Fox Mustang), the T-56, the rear end, and the Griggs set up. The shell is ready to go the the media blasters and then be sent to the body shop which will take several months as it is a one man operation.

 

I have run through all of the braking (Jack Hidley at Maximum Motorsports was a huge help) and am down to the front brakes which we are going to get from StopTech. I am working with one of the application engineers there and one of the things they need to know is what the car weighs and the corner weights. This is somewhat difficult to figure out as the car we are going to end up with is not what we started out and we did not weigh it anyhow.

 

Has anyone here weighed a car similiar to this (351W based motor, AC, manual trans, etc) and if you did what was the weight of the car? Not many people corner weigh cars so if I get that information it would be fantastic. Anyhow, I appreciate the help and if you can think of another site where I might find this information please let me know.

 

Thanks,

 

Darren

Edited May 31, 2011 by Aerocoupe

[Aerocoupe 11]

My father and I stripped his 69 FB to the shell and are starting on a rather large undertaking of building his dream car. Its a resto mod with the emphasis on making the car handle the twisties with good power and brakes that complement the power.

 

Originally I believe the car to be a run of the mill 302W, C4, 8", factory AC car of which none was original except the rear end when we got it. It took a couple of years of hashing over what my dad wanted the car to do and how it would look to come up with a 351W injected stroker, Magnum T-56, 9" with 2005 Mustang GT brakes, Vintage Air, and it will have a full Griggs suspension. To date we have the majority of the motor parts (basically the long block), new Painless body harness and injection harness (Fox Mustang), the T-56, the rear end, and the Griggs set up. The shell is ready to go the the media blasters and then be sent to the body shop which will take several months as it is a one man operation.

 

I have run through all of the braking (Jack Hidley at Maximum Motorsports was a huge help) and am down to the front brakes which we are going to get from StopTech. I am working with one of the application engineers there and one of the things they need to know is what the car weighs and the corner weights. This is somewhat difficult to figure out as the car we are going to end up with is not what we started out and we did not weigh it anyhow.

 

Has anyone here weighed a car similiar to this (351W based motor, AC, manual trans, etc) and if you did what was the weight of the car? Not many people corner weigh cars so if I get that information it would be fantastic. Anyhow, I appreciate the help and if you can think of another site where I might find this information please let me know.

 

Thanks,

 

Darren

Edited May 31, 2011 by Aerocoupe

[NJ_Bob 10]

I've had several of my cars weighed over the years (total weight only). After you get it running you can go to a local truck stop / fuel station & they will do it for you & print it out for only a few bucks. I don't know about the corner weights.. you can ask them when you get there.

 

I have the 428 with the C6 & all options, but if I recall, it still came in under 3,800 lbs. The FE engine has the heaviest weight bios on the front at 57% / 43%. The 351 is closer to 55% / 45% front to rear. Don't forget to take your gas tank into account which adds up to 120 lbs of fuel when full. Also if you are going to mount the battery in the trunk, that makes a big difference too.

Edited May 31, 2011 by NJ_Bob

[NJ_Bob 10]

I've had several of my cars weighed over the years (total weight only). After you get it running you can go to a local truck stop / fuel station & they will do it for you & print it out for only a few bucks. I don't know about the corner weights.. you can ask them when you get there.

 

I have the 428 with the C6 & all options, but if I recall, it still came in under 3,800 lbs. The FE engine has the heaviest weight bios on the front at 57% / 43%. The 351 is closer to 55% / 45% front to rear. Don't forget to take your gas tank into account which adds up to 120 lbs of fuel when full. Also if you are going to mount the battery in the trunk, that makes a big difference too.

Edited May 31, 2011 by NJ_Bob

[Aerocoupe 11]

The problem is the car is stripped and I cannot weigh let alone corner weigh the car until we have it all back together which I cannot do without having the front brakes on the car. The Griggs setup uses the SN95 spindles (more specifically the 96+ spindle design) which means I have to have the rotor mounted but I won't know if I am using the 13" or 14" rotor until StopTech can review the data they need from me to lay out the braking system. Basically I am chasing my tail here so I am hoping to see if someone else just happened to do this. I know the cars will not be identical and so do the guys at StopTech but close is better than guessing.

 

Darren

[Aerocoupe 11]

The problem is the car is stripped and I cannot weigh let alone corner weigh the car until we have it all back together which I cannot do without having the front brakes on the car. The Griggs setup uses the SN95 spindles (more specifically the 96+ spindle design) which means I have to have the rotor mounted but I won't know if I am using the 13" or 14" rotor until StopTech can review the data they need from me to lay out the braking system. Basically I am chasing my tail here so I am hoping to see if someone else just happened to do this. I know the cars will not be identical and so do the guys at StopTech but close is better than guessing.

 

Darren

[Hoover 12]

You might want to contact Dynacorn Industries, they make replacement bodies for 67-70 Mustang fastbacks.

http://www.dynacornclassicbodies.com/ford_models2.html

They ship these out as an unit.

[Hoover 12]

You might want to contact Dynacorn Industries, they make replacement bodies for 67-70 Mustang fastbacks.

http://www.dynacornclassicbodies.com/ford_models2.html

They ship these out as an unit.

[TexasEd 191]

The problem is the car is stripped and I cannot weigh let alone corner weigh the car until we have it all back together which I cannot do without having the front brakes on the car. The Griggs setup uses the SN95 spindles (more specifically the 96+ spindle design) which means I have to have the rotor mounted but I won't know if I am using the 13" or 14" rotor until StopTech can review the data they need from me to lay out the braking system. Basically I am chasing my tail here so I am hoping to see if someone else just happened to do this. I know the cars will not be identical and so do the guys at StopTech but close is better than guessing.

 

Darren

 

 

Catch 22?

 

Why do they need to know this? Are they trying to size the brake system to the car and calibrate it?

 

Will round numbers work for sizing?

Can it be re-calibrated after you get the car put back together?

[TexasEd 191]

The problem is the car is stripped and I cannot weigh let alone corner weigh the car until we have it all back together which I cannot do without having the front brakes on the car. The Griggs setup uses the SN95 spindles (more specifically the 96+ spindle design) which means I have to have the rotor mounted but I won't know if I am using the 13" or 14" rotor until StopTech can review the data they need from me to lay out the braking system. Basically I am chasing my tail here so I am hoping to see if someone else just happened to do this. I know the cars will not be identical and so do the guys at StopTech but close is better than guessing.

 

Darren

 

 

Catch 22?

 

Why do they need to know this? Are they trying to size the brake system to the car and calibrate it?

 

Will round numbers work for sizing?

Can it be re-calibrated after you get the car put back together?

[Pakrat 1,043]

I don't know what your wheel plans are but with 13" rotors you will need at least a 17" rim and I would imagine even larger for a 14" rotor. All though some run them, IMHO anything larger than a 17" on these cars really looks out of place and if your dad is old school he is probably already got visions of a 14 or 15" wheel in his head.

[Pakrat 1,043]

I don't know what your wheel plans are but with 13" rotors you will need at least a 17" rim and I would imagine even larger for a 14" rotor. All though some run them, IMHO anything larger than a 17" on these cars really looks out of place and if your dad is old school he is probably already got visions of a 14 or 15" wheel in his head.

[69gmachine 15]

I would just make an executive decision and go with the 13" rotors. There's no way you're going to get any more meaningful number than by guessing anyway since you need someone with a pretty specific set of mods for it to be meaningful.

 

I have not had the chance to weigh my car, but my own guess is that the total empty weight is right at 3300. I 'm also guessing the front rear split is about 53/47. I've put a lot of effort into losing and transferring weight, but I have the basic car you've described without the Griggs suspension. The Griggs K member is fairly heavy itself, and it's at the front of the car, so you need to factor that into the weight guess also. When the temperature and humidity drop enough to where I'm willing to finish adjusting the rocker arms, I'll take it and have it weighed at the trash dump so they won't charge me.

[69gmachine 15]

I would just make an executive decision and go with the 13" rotors. There's no way you're going to get any more meaningful number than by guessing anyway since you need someone with a pretty specific set of mods for it to be meaningful.

 

I have not had the chance to weigh my car, but my own guess is that the total empty weight is right at 3300. I 'm also guessing the front rear split is about 53/47. I've put a lot of effort into losing and transferring weight, but I have the basic car you've described without the Griggs suspension. The Griggs K member is fairly heavy itself, and it's at the front of the car, so you need to factor that into the weight guess also. When the temperature and humidity drop enough to where I'm willing to finish adjusting the rocker arms, I'll take it and have it weighed at the trash dump so they won't charge me.

[Aerocoupe 11]

We are currently looking at 18's in the front (275/40/18) and 19's (305/30/19) in the rear so the rotor diameter is not much of a concern. Surprisingly enough he is leaning towards the Foose Nitrous wheels, he is older but helping me build three cars has exposed him to a variety of parts and vendors. I can understand some not liking the larger diameter wheels on a car but I have seen them with 18's and 19's and they look great to me. 20's are where my eyes are telling me that a wheel is too big.

 

StopTech is very serious about building balanced braking systems. From what I can tell they are leaning towards to different piston diameters on the front calipers. Once the calipers are made then the only tuning I have is with brake pad materials and a manual brake proportioning valve. Granted I could just tell them that I want a dual 43mm piston caliper and that just might be what happens but the engineer wanted the opportunity to look over what data I could provide and see if something else would work better. There is not cost difference between a caliper with two piston sizes versus one with the same piston size so I figured let the guy look it over.

 

In the end I am betting that I will be an educated guess as to what we go with but I figured I would ask anyhow. John George at http://www.chicanewe.com has a call into Bruce Griggs as they have built a few of these cars to see if he can get us any closer to some weights. I appreciate all of the feed back guys!

 

Darren

[Aerocoupe 11]

We are currently looking at 18's in the front (275/40/18) and 19's (305/30/19) in the rear so the rotor diameter is not much of a concern. Surprisingly enough he is leaning towards the Foose Nitrous wheels, he is older but helping me build three cars has exposed him to a variety of parts and vendors. I can understand some not liking the larger diameter wheels on a car but I have seen them with 18's and 19's and they look great to me. 20's are where my eyes are telling me that a wheel is too big.

 

StopTech is very serious about building balanced braking systems. From what I can tell they are leaning towards to different piston diameters on the front calipers. Once the calipers are made then the only tuning I have is with brake pad materials and a manual brake proportioning valve. Granted I could just tell them that I want a dual 43mm piston caliper and that just might be what happens but the engineer wanted the opportunity to look over what data I could provide and see if something else would work better. There is not cost difference between a caliper with two piston sizes versus one with the same piston size so I figured let the guy look it over.

 

In the end I am betting that I will be an educated guess as to what we go with but I figured I would ask anyhow. John George at http://www.chicanewe.com has a call into Bruce Griggs as they have built a few of these cars to see if he can get us any closer to some weights. I appreciate all of the feed back guys!

 

Darren

[fvike 173]

My brother just installed StopTech brakes on his '70 'Barracuda. I'm really impressed with them. They have much greater pedal feel to them than my Wilwoods, but I got 4 pistons, he got 6, so I guess piston volume has something to do with it. We are both running Hydraboost. Are you planning to do that? (it dictates piston size) I'm so impressed with the StopTech's that I might want to upgrade.

[fvike 173]

My brother just installed StopTech brakes on his '70 'Barracuda. I'm really impressed with them. They have much greater pedal feel to them than my Wilwoods, but I got 4 pistons, he got 6, so I guess piston volume has something to do with it. We are both running Hydraboost. Are you planning to do that? (it dictates piston size) I'm so impressed with the StopTech's that I might want to upgrade.

[Aerocoupe 11]

I would not say that a hydroboost (HB) system dictates how many pistons there are in a caliper in a given setup. Typically people switch over to HB systems if there is not enough vacuum to use a traditional vacuum booster which means there is not enough pressure being applied to the brakes. The addition of more pistons to a caliper can simply be to more evenly distribute the clamping force over a caliper body that has a tendency to flex with fewer pistons thus creating uneven pressures across the face of the brake pad. A person can use six pistons that are smaller than four pistons and will create the same clamping force but it would be more evenly distributed across the same caliper body. To put this in perspective look at the area of a cirle which is calculated by multiplying pi times the radius squared. This would mean a 40mm piston has an area of 1,256.64mm where a 20mm piston has an area of 314.16mm. This tells you that a person would have to run four 20mm pistons to equal the same area as one 40mm piston (1256.64 / 314.16 = 4). So with the same master cylinder and brake pedal setup you would exert the same pressure on a brake pad with one 40mm piston as you would four 20mm pistons. Granted a four piston setup would most likely give you better pressure distribution over the brake pad so you would get better braking. How much better is a relative question due to how the caliper body is built as I have seen some pretty bad four piston designs that are all bling and don't perform as good as well designed two piston setup.

 

What generally dictates piston size is the availability of brake fluid volume. This is driven by the master cylinder (MC) bore size and this is where a lot of people get lost in how to design a good brake system and I was definitely in this crowd as the performace level of my vehicles started stepping up. Force is equal to area times pressure so its safe to say that if a person exerts the same amount of force on a piston that is 1-1/8" in diameter versus a 1" diameter piston (typical MC bore sizes) the 1" will generate more pressure. This shows that an increase in MC pressure can be achieved by simply installing a new MC with a smaller bore. The critical thing here is to ensure that the new MC will have enough volume to properly actuate the brake calipers because we know larger bore MC's move more volume. Again, balancing the system is paramount.

 

A couple of other things that will kill a brake system is not paying attention to the pressures the rear brakes are seeing (read adjustable proportioning valve here), what brake pad compounds are being used, and your tires. The brakes are only as good as the frictional adhesion between the tires and the pavement. Dry rotted tires will make a really nice braking system perform like crap. Really good tires will make a moderately good braking system perform to its best ability as if it cannot overcome the tire's ability to stick to the pavement which is lockup. Once a tire locks up the tire compound overheats and you loose braking capacity.

 

I have a 93 Mustang that came with the anemic four lug 11" disc brakes up front and the 9" rear drum brakes. It would barely haul the car to a panic stop with the 4 cylinder in it let along when the 5.0 was swapped in. I bit the bullet and installed a full Cobra braking system off a wrecked 1995 Cobra including the ABS and with the Hawk HP+ pads and good tires. It will snap your neck if I stick the brakes hard enough and it is a vacuum boosted system.

 

Brakes are about balance not just brute force and bigger can sometimes not mean a bit better. Hopefully I am not coming off like I know it all becasue I definitely do not. This is just from 20+ years of messing with this and knowing a few people who have been there and done that like we all have. I learned something on this project that I never really thought about on these older Mustangs. I knew that the older Mustangs had different length brake pedals between the manual and boosted applications. I saw them on the shop floor when we pulled the pedal assmeblies apart years ago. What I did not put together is that the brake pedal ratio definitely plays into brake selection as well as what the pedal feel will be like with different boosters due to the difference in leverage which is equal to pressure.

 

Anyhow, back to some Ranger baseball.

 

Darren

Edited June 1, 2011 by Aerocoupe
One more thing...

[Aerocoupe 11]

I would not say that a hydroboost (HB) system dictates how many pistons there are in a caliper in a given setup. Typically people switch over to HB systems if there is not enough vacuum to use a traditional vacuum booster which means there is not enough pressure being applied to the brakes. The addition of more pistons to a caliper can simply be to more evenly distribute the clamping force over a caliper body that has a tendency to flex with fewer pistons thus creating uneven pressures across the face of the brake pad. A person can use six pistons that are smaller than four pistons and will create the same clamping force but it would be more evenly distributed across the same caliper body. To put this in perspective look at the area of a cirle which is calculated by multiplying pi times the radius squared. This would mean a 40mm piston has an area of 1,256.64mm where a 20mm piston has an area of 314.16mm. This tells you that a person would have to run four 20mm pistons to equal the same area as one 40mm piston (1256.64 / 314.16 = 4). So with the same master cylinder and brake pedal setup you would exert the same pressure on a brake pad with one 40mm piston as you would four 20mm pistons. Granted a four piston setup would most likely give you better pressure distribution over the brake pad so you would get better braking. How much better is a relative question due to how the caliper body is built as I have seen some pretty bad four piston designs that are all bling and don't perform as good as well designed two piston setup.

 

What generally dictates piston size is the availability of brake fluid volume. This is driven by the master cylinder (MC) bore size and this is where a lot of people get lost in how to design a good brake system and I was definitely in this crowd as the performace level of my vehicles started stepping up. Force is equal to area times pressure so its safe to say that if a person exerts the same amount of force on a piston that is 1-1/8" in diameter versus a 1" diameter piston (typical MC bore sizes) the 1" will generate more pressure. This shows that an increase in MC pressure can be achieved by simply installing a new MC with a smaller bore. The critical thing here is to ensure that the new MC will have enough volume to properly actuate the brake calipers because we know larger bore MC's move more volume. Again, balancing the system is paramount.

 

A couple of other things that will kill a brake system is not paying attention to the pressures the rear brakes are seeing (read adjustable proportioning valve here), what brake pad compounds are being used, and your tires. The brakes are only as good as the frictional adhesion between the tires and the pavement. Dry rotted tires will make a really nice braking system perform like crap. Really good tires will make a moderately good braking system perform to its best ability as if it cannot overcome the tire's ability to stick to the pavement which is lockup. Once a tire locks up the tire compound overheats and you loose braking capacity.

 

I have a 93 Mustang that came with the anemic four lug 11" disc brakes up front and the 9" rear drum brakes. It would barely haul the car to a panic stop with the 4 cylinder in it let along when the 5.0 was swapped in. I bit the bullet and installed a full Cobra braking system off a wrecked 1995 Cobra including the ABS and with the Hawk HP+ pads and good tires. It will snap your neck if I stick the brakes hard enough and it is a vacuum boosted system.

 

Brakes are about balance not just brute force and bigger can sometimes not mean a bit better. Hopefully I am not coming off like I know it all becasue I definitely do not. This is just from 20+ years of messing with this and knowing a few people who have been there and done that like we all have. I learned something on this project that I never really thought about on these older Mustangs. I knew that the older Mustangs had different length brake pedals between the manual and boosted applications. I saw them on the shop floor when we pulled the pedal assmeblies apart years ago. What I did not put together is that the brake pedal ratio definitely plays into brake selection as well as what the pedal feel will be like with different boosters due to the difference in leverage which is equal to pressure.

 

Anyhow, back to some Ranger baseball.

 

Darren

Edited June 1, 2011 by Aerocoupe
One more thing...

[fvike 173]

I agree with what you're saying. I might have been a bit vague in my statement. A HB system does not dictate the size of the induvidual pistons, nor the amount. But with a HB system putting out around 1300-1400 psi, it requires both a large bore MC and total piston volume in order to distribute all that pressure. Or else you'd end up with brakes that lock up in an instant, wouldn't you? And like you say, balance. All I know is, the StopTech brakes feels alot better than my Wilwoods. But my front and rear calipers aren't balanced (Have the prop valve installed). Wilwood sells a 6 piston caliper that is balanced the the ones I have in the rear. I'm looking forward to some updates on you project. Sounds like a fun build.

[fvike 173]

I agree with what you're saying. I might have been a bit vague in my statement. A HB system does not dictate the size of the induvidual pistons, nor the amount. But with a HB system putting out around 1300-1400 psi, it requires both a large bore MC and total piston volume in order to distribute all that pressure. Or else you'd end up with brakes that lock up in an instant, wouldn't you? And like you say, balance. All I know is, the StopTech brakes feels alot better than my Wilwoods. But my front and rear calipers aren't balanced (Have the prop valve installed). Wilwood sells a 6 piston caliper that is balanced the the ones I have in the rear. I'm looking forward to some updates on you project. Sounds like a fun build.

[DarkBuddha 107]

Given that Stop Tech seems so serious about building the system correctly and has asked for the corner weight numbers, I'd suggest that you just wait until the car is mostly built and then get the car properly corner weighted and give the correct info to Stop Tech. Details such as the Griggs suspension components, the heads you choose for the motor, your accessory system, whether you run a/c or not, battery placement, etc. will all contribute significantly to how the car sits and weighs, so it's worth waiting to do properly.

 

BTW, any higher level local race shop should have a corner weighting system and should be able to get the data you need. Seems a worthwhile thing to do on such a seriously built car.

[DarkBuddha 107]

Given that Stop Tech seems so serious about building the system correctly and has asked for the corner weight numbers, I'd suggest that you just wait until the car is mostly built and then get the car properly corner weighted and give the correct info to Stop Tech. Details such as the Griggs suspension components, the heads you choose for the motor, your accessory system, whether you run a/c or not, battery placement, etc. will all contribute significantly to how the car sits and weighs, so it's worth waiting to do properly.

 

BTW, any higher level local race shop should have a corner weighting system and should be able to get the data you need. Seems a worthwhile thing to do on such a seriously built car.

[buening 63]

I may have missed it but what is you build timeline? I too think you should wait till the build is further along due to the amount of modifications to the car. Brakes should not affect anything on the build and can be a fairly late addition assuming Stop Tech doesn't take a year to get your design done and parts shipped.