New rotors or driveshaft?

[2015Etrac]

I've been thinking about eventually adding some lighter components since I don't want to mess with my powertrain warranty. I figure the next best option would be to add some lighter items to help with power/weight ratio. Which would be the better investment, a carbon fiber driveshaft, or 2 piece rotors for the front Brembos? I believe the rotors would save 7lbs a side, and the driveshaft for my auto would save about 10lbs.

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[BmacIL]

Rotors will probably have a more pronounced affect, though I've heard plenty about driveshafts too. Rotors reduce rotating and unsprung mass. Twofer.

 

[Nagare]

What point in time is eventually? You mentioned maintaining your powertrain warranty but the driveshaft is part of that. So if this is on the shorter term, then definitely the rotors.

 

[2015Etrac]

Rotors will probably have a more pronounced affect, though I've heard plenty about driveshafts too. Rotors reduce rotating and unsprung mass. Twofer.

That's what I figured. It would save me an additional few pounds going with the rotors vs. the driveshaft. I just picked up some factory 15" rotors for my Brembo swap and those things are HEAVY.

 

[2015Etrac]

What point in time is eventually? You mentioned maintaining your powertrain warranty but the driveshaft is part of that. So if this is on the shorter term, then definitely the rotors.

That's a good point. I'm not sure if most dealers would make an issue over an aftermarket driveshaft if there was an engine or transmission problem, I'd have to find out. Also, I see a lot of post about vibration issues at speed with aftermarket driveshafts.

 

[GregO]

I can’t say enough positive things about Shaftmasters one pc. Driveshaft.
Vibration....... ZERO !
Their design is minimalist, less = more.
For the cost and performance gain I’m shocked this Mod isn’t on the top of the list for most. Then again the false argument over vibration keeps rearing it’s head.
Just one mans opinion.

 

[Norm Peterson]

I can’t say enough positive things about Shaftmasters one pc. Driveshaft.
Vibration....... ZERO !
Their design is minimalist, less = more.
For the cost and performance gain I’m shocked this Mod isn’t on the top of the list for most. Then again the false argument over vibration keeps rearing it’s head.
Just one mans opinion.

If you don't get your pinion angle right, 1-piece driveshafts absolutely will vibrate. Maybe not, or not much with just the driver on board, but add one or two other people or some heavy stuff in the trunk, or lower the car, and you're apt to get it. Maybe not much, if there isn't much angle at the 2-piece's center support.


Neither of these mods will change your ET or autocross run times by much. Enough to win a close race or class where you'd have been only a close 2nd before, sure. Night-and-day difference and you improve from strictly mid-pack to winning, no.


Norm

 

[Cardude99]

Driveshaft is good for about 2 tenths in the 1/4 and the rotors likly the same since the weight loss is similar and it's rotational mass too. However you'll also notice better handling with the rotors whereas the DS has nothing to do with handling. I think the driveshaft is a great mod but in this case I believe rotors win.

Also look at Steeda, I believe they make a lightweight set of two piece rotors that save roughly 15 lbs up front and 4 lbs out back

 

[BmacIL]

For rotors:
https://www.opmustang.com/store/p21...50_Mustang_GT_with_Performance_Package.html#/

 

[GregO]

If you don't get your pinion angle right, 1-piece driveshafts absolutely will vibrate. Maybe not, or not much with just the driver on board, but add one or two other people or some heavy stuff in the trunk, or lower the car, and you're apt to get it.

We're taking about an IRS chassis designed with a center right offset differential yoke. The S550 is designed with a compound driveshaft / pinion angle.

That's as deep in the weeds as I'm going !

The human bodies and junk in the trunk with saggy springs don't apply to the S550 IRS.

 

[Nagare]

For rotors:
https://www.opmustang.com/store/p21...50_Mustang_GT_with_Performance_Package.html#/

Don't have the Brembos either way, but any reason you'd say these instead of the Steeda's? Steeda's save another 5.1 lbs (based on both manufacturer's weight saved per pair over stock) and are cheaper as the full assembly. Both are slotted and floating mount so I'm not sure why pay more (or roughly the same) to save less weight unless there's something else to the design I'm not seeing (very well could be but neither are coming with duct lines).

 

[BmacIL]

Don't have the Brembos either way, but any reason you'd say these instead of the Steeda's? Steeda's save another 5.1 lbs (based on both manufacturer's weight saved per pair over stock) and are cheaper as the full assembly. Both are slotted and floating mount so I'm not sure why pay more (or roughly the same) to save less weight unless there's something else to the design I'm not seeing (very well could be but neither are coming with duct lines).

Not exactly. Girodisc saves approx 3 lbs more per pair. Both are excellent options for certain!

 

[Cardude99]

Not exactly. Girodisc saves approx 3 lbs more per pair. Both are excellent options for certain!

If read the site correctly, then the ones you posted are per rotor not per pair which falls in at around 18 lbs saved vs 15 lbs for Steeda.

 

[BmacIL]

If read the site correctly, then the ones you posted are per rotor not per pair which falls in at around 18 lbs saved vs 15 lbs for Steeda.

Correct.

 

[Nagare]

Not exactly. Girodisc saves approx 3 lbs more per pair. Both are excellent options for certain!

I keep forgetting how heavy rotors are, thought that 33.4 mentioned was for the pair, not each! What things weigh thread does confirm the 33.4 per rotor like @Cardude99 said so yes, additional 3lbs saved.

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