I recently purchased some 5 spoke 17" front and 18" rear wheels for my new 88. I am contemplating the c4 corvette rotor upgrade entirely for the look of the large shiny rotors behind my skimpy wheels. My brakes work great and I still have the s10 booster and new steel braided lines to install, so like i said, I just want that big rotor look. In fact, another reason besides cost that is holding me back is the addition of unsprung weight, which I really want to avoid. Does anyone have pictures of their car with stock brakes and big wheels?
Thanks, Blake
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11:12 PM
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May 16th, 2010
madcurl Member
Posts: 21401 From: In a Van down by the Kern River Registered: Jul 2003
Stock brakes using 19" on all corners. There's a thread that features many Fieros/wheels, but I'm not sure about them being stock brakes--most upgrade the brakes ASAP!
Thanks everyone, pluses for you all. This is a tough choice, I hate adding the un-sprung weight of big rotors, and am not going to pay a grand for light big rotors. hmmm, decisions.
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01:01 AM
Erik Member
Posts: 5625 From: Des Moines, Iowa Registered: Jul 2002
Thanks everyone, pluses for you all. This is a tough choice, I hate adding the un-sprung weight of big rotors, and am not going to pay a grand for light big rotors. hmmm, decisions.
If you go for C4 rotors they are only a 1 or 2 lbs more than 88 rotors. Mine weigh 12lbs. If you go for lighter weight rims in combo with the 12inch rotors you can actually lose some unsprung weight as compared to stock. Another way is to just do the front which will gain you stopping power from stock but not at the same level of possible weight gain by going all 4 corners. That is what I did with mine and it very noticably stops quicker than stock.
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03:50 AM
LZeppelin513 Member
Posts: 761 From: Lake Stevens, Washington Registered: Aug 2003
If you go for C4 rotors they are only a 1 or 2 lbs more than 88 rotors. Mine weigh 12lbs. If you go for lighter weight rims in combo with the 12inch rotors you can actually lose some unsprung weight as compared to stock..
Yeah mine weigh 12 lbs a piece ..they are stock c4 rotors from Napa. They have obiously made a mistake at west coast as far as weight for a stock c4 rotor. I notice no difference in get up and go or handling between stock 88 and c4 rotors other than the nice increase in stopping power
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01:33 AM
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Blacktree Member
Posts: 20770 From: Central Florida Registered: Dec 2001
I guess I'm a little late to the game. But here's a shot of my Fiero with 17" wheels and Grand Am brakes. The Grand Am brake rotors are almost the same as the '88 Fiero rotors.
[This message has been edited by Blacktree (edited 05-21-2010).]
The ass-o-meter does not constitute a valid test, unless there's something you're not telling, such as the use of different pad compounds between the front and rear.
Edit: I realise the tone of this post was sarcastic, but it doesn't make ANY sense that a front-only upgrade would reduce stopping distance.
[This message has been edited by pmbrunelle (edited 05-19-2010).]
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04:57 PM
LZeppelin513 Member
Posts: 761 From: Lake Stevens, Washington Registered: Aug 2003
I guess I'm a little late to the game. But here's a shot of my Fiero with 17" wheels and Grand Am brakes. The Grand Am brake rotors are almost the same as the '88 Fiero rotors.
Blacktree, What size tires are you using? Thanks
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09:54 PM
Blacktree Member
Posts: 20770 From: Central Florida Registered: Dec 2001
They're 215/45-ZR17 front and rear. I'm not sure if you're interested in the brand and model of tire, but just in case they're General Exclaim UHP. Wet weather traction is great. Dry pavement traction is pretty good, too. I wouldn't try to drive 'em in the snow, though.
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10:40 PM
Erik Member
Posts: 5625 From: Des Moines, Iowa Registered: Jul 2002
The ass-o-meter does not constitute a valid test, unless there's something you're not telling, such as the use of different pad compounds between the front and rear.
Edit: I realise the tone of this post was sarcastic, but it doesn't make ANY sense that a front-only upgrade would reduce stopping distance.
I measured the distance it took to stop between stock and the upgrade using stock pad style pads on both setups and although I do not have the exact figure on hand ( did it several yrs ago) it did in fact stopped in a shorter distance.
I recently changed back to stock and I could imediately tell the difference in stopping power and it took awhile to adjust brake timing ( brake earlier ) so I wouldnt run into other cars
Makes sense to me that more leverage will allow you to stop quicker.
Commonly accepted fact: shortest stopping distances are achieved when the tires are just at the verge of lockup (threshold braking).
Stopping power does not equate to short stopping distance. Ultimately, regardless of how many pistons your caliper has, or how large your rotors are, you can't stop any more quickly than your tires will allow. Doesn't matter how much leverage you have. As long as you're capable of locking up the wheels (stock brakes can do this), more leverage isn't going to make any difference.
What happens with a properly balanced brake system? The driver steps on the brake pedal, and modulates the brakes such that all of the car's tires are threshold braking.
What happens with large front brakes and small rear brakes? Remember that the driver only has one brake pedal to control both the front and rear brakes.
The ratio of front:rear braking force (known as bias) is affected by the brake hardware. Large front rotors and stock rear rotors mean increased leverage on the front, but not the rear. Therefore, with the front-only upgrade, the ratio of front:rear braking force is higher than stock.
So the driver steps on the brake pedal, and is able to modulate the pedal to achieve threshold braking on the front brakes. But not the rear brakes? Why not? Now that the rear brakes are weaker compared to the fronts, the rear brakes aren't braking very hard. They aren't anywhere near the threshold. The rear wheels no longer contribute as much to the braking, which increases stopping distance.
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12:16 AM
Erik Member
Posts: 5625 From: Des Moines, Iowa Registered: Jul 2002
Well obviously the upgrade does stop it quicker as I have measured the difference in stopping distance as well have experienced several yrs using the combo then changing back to stock and noticing a decrease in the ability to stop. I doubt the clamping forces from the calipers front to rear change just by changing size in rotors up front so, it just stands to reason that the stopping power from the front brakes more than compensates than any supposed loss of power from the rear hence the measurable decrease in stopping distance
Clamping force of the caliper does not change when installing larger rotors. However, the moment arm *does* increase, and therefore brake torque for a given clamping force increases.
You don't get any more braking force from the front with Corvette rotors compared to stock. The tires are the limiting factor in how quickly you can stop. If you can reach the limit of tire adhesion with stock brakes, you're not going to stop any faster.
Clamping force of the caliper does not change when installing larger rotors. However, the moment arm *does* increase, and therefore brake torque for a given clamping force increases.
You don't get any more braking force from the front with Corvette rotors compared to stock. The tires are the limiting factor in how quickly you can stop. If you can reach the limit of tire adhesion with stock brakes, you're not going to stop any faster.
I cannot lock up the stock brakes with my bigger wheels and wider tires so I am not reaching the limits of tire adhesion. By installing a larger rotor I am able to use all the grip availibe from the wider tire because it has better leverage which equates into more resistance or force in slowing down the wheel faster where as the stock rotor has less leverage
Besides that, what has more clout to me is my own personal driving experience and test that showed an improvement in stopping distance as well as having to adjust to the longer distance required to stop when driving agressively to avoid possibly crashing and going into a ditch or missing a curve after changing back to stock. With the stock brakes I have to brake earlier, with the upgrade I can confidently brake later
I had thought about putting the rear c4 rotors on for even better braking but like the OP, I was concerned about unsprung weight even though a pound or 2 is not that great of a weight increase, I am very picky and choose to just do the fronts as a good compromise in stopping power, unsprung weight as well as for looks.