Anyone know what a stock SRT-10 brake rotor weighs?

[rcl4668]

I am wondering what the weight of a stock SRT-10 one-piece rotor only (not the calipers and pads) weighs?

Stoptech lists the 355 x 32 Aerorotor used on the ACR as being 15.25 lbs. Just trying to get an exact weight savings by going to the ACR/Stoptech rotors.

Thanks.

/Rich

 

[SnakeEye]

Most probably someone will have the exact weight for you but the savings feels to be in the neighborhood of 35lbs moving to StopTechs. Quite a notable difference for sure considering it is a reduction in rotating mass.

 

[rcl4668]

Most probably someone will have the exact weight for you but the savings feels to be in the neighborhood of 35lbs moving to StopTechs. Quite a notable difference for sure considering it is a reduction in rotating mass.

Snakeeye --

Thanks. I agree the Stoptechs seem like a "win-win" option with no signficant downside: Reduced unsprung weight with improved performance. I spoke with the folks at Stoptech and they said you may see a reduction in pad life due to the slotting on the rotors.

Thus far I have heard a 6 lb reduction per rotor from Jon B, approximately 7.25 lbs from Chris Marshall and 8-9 lbs from Stoptech. I'm just being anal and wanted a more precise figure for my weight reduction estimates.

For anyone else with an 08 on order, if you are interested I will be installing the Sidewinder wheels, an Autoform rollbar and two sets of 6-point Teamtech harnesses in my 2008 convertible. When you throw in an approximate 30 lb weight savings from the Stoptechs, even with the addition of the rolbar and Teamtechs which add back in about 37 lbs, you still come out with the car being about 30 lbs lighter than a stock 2008.

/Rich

 

[slither]

I installed the StopTech rotors (drilled) on my '04 and weighed all four stockers and the StopTechs:

Stock front rotors: 26.6 lbs. each
StopTech fronts: 17.6 lbs. each

Stock rear rotors: 24.2 lbs. each
StopTech rears: 17.6 lbs. each

As you can figure, total weight savings by changing rotors was 31.2 lbs. I also dropped 14.8 lbs total going with aftermarket wheels/tires. Taking 46 lbs. of rotating/unsprung weight off the car makes a pretty noticeable difference in ride quality and will help performance (acceleration/braking) as well, though it's difficult to quantify how much.

 

[repiv]

stoptech can also make you a set of composite rotors for an srt10 for around 10K. not sure how much they weigh per rotor.

 

[rcl4668]

I installed the StopTech rotors (drilled) on my '04 and weighed all four stockers and the StopTechs:

Stock front rotors: 26.6 lbs. each
StopTech fronts: 17.6 lbs. each

Stock rear rotors: 24.2 lbs. each
StopTech rears: 17.6 lbs. each

As you can figure, total weight savings by changing rotors was 31.2 lbs. I also dropped 14.8 lbs total going with aftermarket wheels/tires. Taking 46 lbs. of rotating/unsprung weight off the car makes a pretty noticeable difference in ride quality and will help performance (acceleration/braking) as well, though it's difficult to quantify how much.

Slither --

Thanks very much for posting this info. Interesting, I thought the stock rotors were identical front and rear. I wonder what accounts for the 2 lb difference?

Thanks again!

/Rich

 

[rcl4668]

stoptech can also make you a set of composite rotors for an srt10 for around 10K. not sure how much they weigh per rotor.

Vegas --

Thanks for the tip. When I spoke with Stoptech they mentioned that they had a composite/ceramic rotor in development for the SRT-10 but he could not give me a timeline for production or availability. He indicated that Stoptech is estimating a roughly 20 lb per rotor savings. That would be incredible since it would mean that the entire rotor would have to weigh under 10 lbs.

At any rate, if these rotors do go for $10,000 per set that would be a little spendy for me.

/Rich

 

[twinturbo3150]

Slither --

Thanks very much for posting this info. Interesting, I thought the stock rotors were identical front and rear. I wonder what accounts for the 2 lb difference?

Thanks again!

/Rich

My guess is that the front's take most of brunt when stopping.

 

[Nader]

Fronts rotors are thicker for that reason.

 

[slither]

No problem rcl4668.

Actually, the front and rear rotors are the same thickness at ~32mm. The difference in the weight is due to the front rotors having more material in the "hat", i.e. the distance from the outer face of the rotor to the outer face of the hat is greater on the front than the rear - check out the pic (front rotor is on the left, rear is on the right). If you decide to install the StopTechs, make sure you know which pair is for the front and which is for the rear before the install or you might have a little difficulty putting the wheels back on!

You must be registered for see images attach

 

[Nader]

Fronts still look thicker to me. I think I read it somewhere.

 

[slither]

All I can vouch for is the measurements taken on the rotors I took off my car. Maybe yours are different if you read it somewhere. I read the 2004 service manual.

You must be registered for see images attach

 

[Nader]

Thought I read it here somewhere but i guess that is not correct. Thanks for the info.

 

[YellowViperSRT10]

I am wondering what the weight of a stock SRT-10 one-piece rotor only (not the calipers and pads) weighs?

Stoptech lists the 355 x 32 Aerorotor used on the ACR as being 15.25 lbs. Just trying to get an exact weight savings by going to the ACR/Stoptech rotors.

Thanks.

/Rich

Most of these 2pc aftermarket rotors weigh about the same. Ours are pretty much dead even at 17lbs.

EuroTeck Motorsports -- Home

 

[rcl4668]

I am wondering what the weight of a stock SRT-10 one-piece rotor only (not the calipers and pads) weighs?

Stoptech lists the 355 x 32 Aerorotor used on the ACR as being 15.25 lbs. Just trying to get an exact weight savings by going to the ACR/Stoptech rotors.

Thanks.

/Rich

Upon closer reading of the Stoptech website, I have to amend the 15.25 lb figure I quoted above. This is for the Stoptech rotor only and does not include the aluminum hat. Thus, I think the 17+ lb figure quoted above is more accurate. Still, assuming a 25-27 lb weight for the one-piece stock rotors yields a 7-10 lb saving per corner. That's awesome.

/Rich

 

[AviP]

Rich, since you are being so anal, you should do a before and after rwhp dyno test with your setup. The proof is in the numbers. Another factor to check is the amount of time in secs to go from 2000rpm to 6000rpm before and after the change. That is where rotational mass improvements are most visible.

 

[rcl4668]

AviP --

Interesting info; I will be doing a dyno on the car but I probably won't be doing a before and after baseline on the brakes. My plan is to have my dealer install the Sidewinder rims, Stoptech brake rotors, a rollbar and related safety equipment (harnesses etc) first before picking up the car.

After break in at about 1,200-1,500 miles I will get a baseline on a local Mustang dyno. I will then have the dealer install the Mopar/Belanger headers, Belanger sidepipe exhaust with high flow cats and (if available by then) the Mopar or K&N cold air intake. I will then drive the car an additional 500-1,000 miles and run the car on the same dyno to see the impact of those mods.

I never really thought about doing a dyno to get before and after results for the brakes. Would this really yield a statistically significant change in hp/tq?

/Rich

 

[Kai SRT10]

Why would a change in rotating mass result in better dyno numbers?

Thinking of the physics involved, I can't think why that would be the case.

I don't believe that going to lighter wheels/brakes will change your hp or tq numbers.

It could change your real world acceleration numbers, but that isn't measured by a dyno.

 

[Vipermann]

Why would a change in rotating mass result in better dyno numbers?

Thinking of the physics involved, I can't think why that would be the case.

I don't believe that going to lighter wheels/brakes will change your hp or tq numbers.

It could change your real world acceleration numbers, but that isn't measured by a dyno.

I would think that a dyno measures energy transferred. Greater rotational mass would seem to require more energy to move/turn it, and thus, then less available to be transferred to where the rubber meets the road... so reducing rotational mass should free up energy to the ground ???

 

[Kai SRT10]

I would think that a dyno measures energy transferred. Greater rotational mass would seem to require more energy to move/turn it, and thus, then less available to be transferred to where the rubber meets the road... so reducing rotational mass should free up energy to the ground ???

No. Think way back to high school physics.

Greater rotational mass would require additional time to get up to speed assuming the power remains constant. Once up to speed, however, it does not require any additional energy to keep it moving.

 

[rcl4668]

Why would a change in rotating mass result in better dyno numbers?

Thinking of the physics involved, I can't think why that would be the case.

I don't believe that going to lighter wheels/brakes will change your hp or tq numbers.

It could change your real world acceleration numbers, but that isn't measured by a dyno.

Good questions; I received a fact sheet from Lou Belanger regarding factors to check when dynoing a Viper. In addition to the things you would normally check (ambient air temp being similar on both test days, checking fuel grade and type, clean airflow sensors, etc.), Lou's checklist also points out that the addition of aftermarket wheels and tires can impact the results. I am not sure, however, if Lou included this factor to address a potential change in rolling diameter and its impact on gearing or whether this was to address less/more rotational mass.

Any dyno gurus know the answer?

/Rich