Nice post, JustROLLIN. And it gets us back to my questions about performance gains that aren't about braking.

 

Went with the Z1 2-piece rotors front and back a little over a year ago now. Great upgrade. The reduction in rotational mass was noticeable in acceleration. I upgraded my wheels to 40th anni Z wheels a week later which pretty much brought my rotational mass close to what I was at with much smaller stock wheels and stock rotors (but still less). There was noticeably more gripe but a slight decrease in acceleration could be noted from the added weight. From that I can say you will notice hopefully some more peep in the car with the lighter rotational mass. Obviously the addition of better vented and cooled rotors can be observed during heavy sessions of breaking as well. And they do look sexy as hell, IMO. Lower sprung weight and rotational mass is always a plus in my book. Get a lightweight flywheel and lighter driveshaft and you will notice the benefits as well. However, with the flywheel you have to consider the lose of inertia in the build as your RPMs will drop faster between shift. But, different topic, different thread.

I say pull the trigger on it. And if going in stages, front first as everyone has said.

 

Do you have anything to quantify the increased acceleration, like 1/4 mile times?

I've shopped the Z1 rotors, but I have a hard time justifying the price. I'd be curious to see something more than a butt-dyno to measure gains.

 

Thanks for the input, zer099. Pics of your setup?

 

I sadly do not have 1/4 mile times from before and after, nor track data from before as I didn't really start whipping her until after the upgrade. So sadly no, no quantifiable data; apologies. I just knew from prior build the gains. The math is sound however and I am sure the interweb can back up the claims with actual data if searched hard enough.

And here are some dirty dirty brake pictures for you. Apologies as its been monsooning here in GA the past couple days.











And since I dislike when people say what I just did here are some videos of a reputable engineer explaining this topic:

 

Get the 2 pc rotors w/ those Brembos FTW^^^^ Yum!

 

s
Ignorance will always be bliss.

LAFF

 

You're zero for three in this thread.

Come on, buck your instincts and write something worthwhile. You can do it. Bro.

 

2pcs or bust... DBA fronts

 

Fast Ford UK swapped lightweight wheels onto a Focus ST and did braking, standing start and in gear acceleration, and handling tests.

I can't find the link to the actual site, but this thread has a pdf of the test:

Fast Ford's Lightweight Wheel Test

cliff notes: everything improved except standing start acceleration, the theory being the lightweight wheels were easier to spin.

 

Nice, R1cky! Why did you choose DBA?

And come paint my calipers Da-a-amn.

 

So are we all going to just bypass these fenders!!??

Not to hijack this thread, but more info and pics please.

 

This was a great read, Lego! I'm glad I took the time to review that PDF.

• Braking - small but noticeable improvement
• Handing - significant improvement
• Launch - a loss in traction
• Rolling Launch - big improvement

Although I was predisposed to do the rears first, the negative impact on hard launches gives me pause to think otherwise. Add to that the positive impact of front rotor weight reduction being a full 2x the rears, and considerations like handling and rolling acceleration speak with more authority.

So... fronts first. Rears second, if at all. In fact, it's feeling like rears are mostly a cosmetic consideration compared to the fronts. An important one, though. It could look goofy not having the rears match.


Pretty much. Maybe Zer099 can just link to that discussion.

 

Agreed. I'd probably go with the blanks instead of slotted, so matching isn't as much of a consideration

 

That's a really good point.

I was liking the non-directional look of the small cross-slotted design, but more as a compromise than a need. Overall I tend to dismiss slots and drills as cosmetic nonsense on a street car... so the argument that fronts better match the rears if blank, that makes sense.

Two OEM front rotors are $200.
Two Z1 2-piece front slots are $500.

I don't see Z1 two-piece blanks on their site. Hmm. I should ask Z1... just did. Let's see.

[edit] Whoops, shouldn't have bothered asking. If you hit the drop-down control on their page, blanks are an option. And on a silly note, apparently they refer to their cross-slot design as "Sprinkle Slot", which couldn't possibly be any more flamboyant. Seriously... Sprinkle Slot, LOL.