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Rebel Machine View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel Machine Quote  Post ReplyReply Direct Link To This Post Topic: To Vent or not to Vent
    Posted: Sep/19/2021 at 5:18pm
Looking into new brake calipers and rotors for my AMX. Wilwood offers some kits. One is vented the other isn't.

Is there a benefit to vented rotors on a street car? Probably necessary for road racing but how about street/strip?

Thanks,
-Steve-

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Sep/19/2021 at 6:28pm
If they are 1.25" width or less, vented tend to crack. There is no benefits with breaking on the street. Even non vented work just fine on auto cross and track usage. I rather use the extra money in tire or pad choice.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mixed up Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2021 at 8:34am
No need for vented on street for car 
69 amx 290 auto
65 220 290 4spd
80 ford fairmont
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mbwicz View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mbwicz Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2021 at 9:07am
It depends where you live and how you drive.  If you live in the mountains, or like to drive aggressively, then the vented ones will likely be better for you.  If you live in the plains and drive conservatively, then the solids would be fine.

In the past I've looked at wilwood and some of their non-vented kits are meant for drag racing and they recommend not using them for street use.  

The factory discs on the 68-70 AMX were non vented and in 71 they went to a vented design.

Mike
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2021 at 9:19am
Originally posted by mbwicz mbwicz wrote:

It depends where you live and how you drive.  If you live in the mountains, or like to drive aggressively, then the vented ones will likely be better for you.  If you live in the plains and drive conservatively, then the solids would be fine.

In the past I've looked at wilwood and some of their non-vented kits are meant for drag racing and they recommend not using them for street use.  

The factory discs on the 68-70 AMX were non vented and in 71 they went to a vented design.

Mike


RebelMachine had questioned after market drilled slotted on newer rotors from Wilwood. Yes the nomenclature is confusing, as oem from 71 on up are vented. Though the slotting on the face of the rotor is to add further venting, at the cost of surface area braking. With new technology being used on pads, less surface area is required once heated to optimum tempratures. There is a draw back, since normal driving rarely operates brakes at optimum heat ranges, the cold side of operation will have less braking for sudden stops, which could be lower than a good stock setup.

You can get street friendly pads, but your rotors will never be used as well until pads are swapped for the track.

Rotor thickness and diameter can allow todays slotted vent rotors to work well for both city and track without need to worry. On my 2 cents, there is no need to get them unless you run with ducts and fans. Then, your running at competition level and really need the slotted venting.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mbwicz Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2021 at 9:35am
Ok, he meant drilled rotors, not vented or solid.  Got it.

I completely agree with your opinion that drilled rotors can crack.  Many people like the look, though.

If you are buying replacement rotors, wilwood has directional vane rotors as well. They cool better than straight vane rotors, if you are getting them hot enough to be concerned.

Mike
1970 AMX, one step forward, one step back. Both steps cost time and money.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rebel Machine Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2021 at 6:58pm
Thanks for the input guys. I didn't think I'd need the drilled rotors. From what I've read the drilled holes are to let gasses out from under the brake pad when braking. My AMX is just a street car I race on occasion. Sounds like solid rotors are perfectly okay.

-Steve-
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2021 at 7:22pm
Originally posted by Rebel Machine Rebel Machine wrote:

Thanks for the input guys. I didn't think I'd need the drilled rotors. From what I've read the drilled holes are to let gasses out from under the brake pad when braking. My AMX is just a street car I race on occasion. Sounds like solid rotors are perfectly okay.

-Steve-


If you do strip mostly, the original 4 piston is lighter than any newer vented rotor/caliper option. Any lighter drums would be on order, though you probably would have to setup custom 11" drums. I had 12" drums on my 5,000 lbs Riviera, which stopped well, considering they were ribbed aluminum with 2.5" wide shoes. Did not stop well in the deep puddles from heavy down poors, which was a drawback.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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