Brake rotors - 2 sets of left side rotors!!

[fastliz]

I just went by my favorite motorsports tire shop whose owner I'm friends with. He is a major motorhead who has raced competitively many years. Of course, I had to drop by to show off my new Elise. He loved it - no surprise. But, as he inspected it, he noticed something about the brakes. The rotors, which are vented, are all for the left side of the car. IOW, the vents are directional for optimum cooling. The rotors on the RIGHT side of the car are "going the wrong way!"

OK... so... is this a case of or is it a mistake on just my car?

I asked Ernie if this would cause any technical difficulty. He said, "On the road, no. But, under track conditions, you may not get as efficient cooling on those rotors."

OK... have at it... I know there are some experts here. What's the story?????

Mike

[008]

They're all that way. Some say Lotus did extensive testing and that it makes no difference. I tend to think that if it may no difference why through years of motor racing experience did the vents evolve to their current state. Obviously Lotus did it as a cost saving measure and we got slightly screwed.

[Miguel]

This has been discused here:

http://www.elisetalk.com/forums/showthread.php?t=4973

And here:

http://www.elisetalk.com/forums/showthread.php?t=9222

[andykeck]

Originally Posted by mrluky

if you were to brake hard(nearly locking up) in a straight line from a high speed, would u turn to the left slightly becasue of the uneven brake setup on the right side?

No. The friction surface is identical. The only difference in hard usage would be temperature, and the Lotus guys found that the left-right temperature differential was inconsequential.

[andykeck]

Originally Posted by 008

They're all that way. Some say Lotus did extensive testing and that it makes no difference. I tend to think that if it may no difference why through years of motor racing experience did the vents evolve to their current state. Obviously Lotus did it as a cost saving measure and we got slightly screwed.

The only way we got screwed is maybe in looks. There's no performance reason on the Elise to have two different rotors.

[fastliz]

Thanks for the thread links, Miguel. I should've done a search, but I thought, FOR SURE, I was onto something totally new! LOL But, I should have known the E-Talkers had already covered it! DUH!

I guess it's not an issue. Good! I feel better! Thanks!

Mike

[008]

Originally Posted by andykeck

The only way we got screwed is maybe in looks. There's no performance reason on the Elise to have two different rotors.

Have you taken temperatures? Lotus did this as a cost saving measure, for those of us who track our cars extensively, we were screwed. At my last event running race compound endurance pads on an 80 degree day I had over 100 degree variance on the front right from the front left. When I wear these out I will be putting on correctly vented slotted rotors.

Edit: and notice I said slightly. I still believe the Elise has one of the best brake systems for it's size of any stock car. I don't think it makes a huge difference considering I'm still not running cooling ducts (yet), but there is definitely a difference.

[Arno]

The only reason Lotus used curved vanes in the discs on the S2 is to reduce the distortion that straight vanes cause on the surface of a disc because of the difference in cooling of the disc. Straight-vane discs can develop ridges in the surface that correspond to the vanes underneath.

The left-right difference in heat dissipation was determined to be not significant enough to warrant making separate left and right discs.

For track use this is a different story, but then you also want to switch to separate disc/bell 2-piece brakes, so the discs can expand and contract more freely than on a single cast disc and hub. A fully floating setup is overkill though.

Bye, Arno.

[Cisitalia]

Sure cuts down on required spares. Same rotor fits all four corners. Most cars require a separate rotor for each of the four brakes.

[offroadr35]

Originally Posted by Cisitalia

Sure cuts down on required spares. Same rotor fits all four corners. Most cars require a separate rotor for each of the four brakes.

front and rears are still different

[Miguel]

Originally Posted by offroadr35

front and rears are still different

I think all 4 are the same, will have to look later on.

[Cisitalia]

I talked to the parts guy at the dealership and he quoted me one part for all. Same price too ($189 each front or rear).

Thanks for the information. I'm sure you must have more specific knowledge about this. I have not yet actually bought spares. What is the difference between the fronts and the rears? They look the same. Thank you.

[munkleby]

Originally Posted by Arno

The only reason Lotus used curved vanes in the discs on the S2 is to reduce the distortion that straight vanes cause on the surface of a disc because of the difference in cooling of the disc. Straight-vane discs can develop ridges in the surface that correspond to the vanes underneath.

The left-right difference in heat dissipation was determined to be not significant enough to warrant making separate left and right discs.

For track use this is a different story, but then you also want to switch to separate disc/bell 2-piece brakes, so the discs can expand and contract more freely than on a single cast disc and hub. A fully floating setup is overkill though.

Bye, Arno.

Arno, you're my hero. You consistently have something useful to say. How do you know these things?

[Stan]

>>>Have you taken temperatures? Lotus did this as a cost saving measure, for those of us who track our cars extensively, we were screwed. At my last event running race compound endurance pads on an 80 degree day I had over 100 degree variance on the front right from the front left.<<<

Not a problem if the overall temps stay under control. Which was Lotus's point. You *could* add slightly more ducting to one side if desired. Or no ducting but fit a Porsche/BMW style suspension arm air deflector to the leading edge of the a-arm to better cool the "hot" disc. If you do match up the rotors to their corners better, you still won't get them to match perfectly. Again, it may bug you but it's not a problem for most and may not be even on the track for many.

[TimMullen]

Originally Posted by offroadr35

front and rears are still different

No, I believe the hubs, rotors, etc. are the same. Different calipers though...

[008]

Originally Posted by Stan

>>>Have you taken temperatures? Lotus did this as a cost saving measure, for those of us who track our cars extensively, we were screwed. At my last event running race compound endurance pads on an 80 degree day I had over 100 degree variance on the front right from the front left.<<<

Not a problem if the overall temps stay under control. Which was Lotus's point. You *could* add slightly more ducting to one side if desired. Or no ducting but fit a Porsche/BMW style suspension arm air deflector to the leading edge of the a-arm to better cool the "hot" disc. If you do match up the rotors to their corners better, you still won't get them to match perfectly.

Of course they won't match perfectly but I haven't tracked during a really hot day yet and the left right difference has continually crept up as the ambient temp rose. Wtih the new pads I haven't seen a wear difference so as long as the wear of rotors and pads stay somewhat reasonable I don't think it will be a problem but I am going to start playing around with different duct solutions especially if I'm getting fade with the high temp pads during the summer.

[Cisitalia]

I thought they were the same as well. Interesting the Elise Brembo rear calipers take the same brake pad as the early Viper. The front Elise Alcon caliper uses the same pad as the Nissan Skyline. At least that is what I saw in the Porterfield information and the Peformance Friction catelog. I don't know how correct this is though.

[008]

Originally Posted by Cisitalia

I thought they were the same as well. Interesting the Elise Brembo rear calipers take the same brake pad as the early Viper. The front Elise Alcon caliper uses the same pad as the Nissan Skyline. At least that is what I saw in the Porterfield information and the Peformance Friction catelog. I don't know how correct this is though.

That's right. The front uses the same as the 350z, evo, and sti rear as well.

[Stan]

If the overall temps are okay, pad life is good then a simple deflector type air cooling setting ala BMW & Porsche might be nice. Just deflect more air towards the "hot" disc. Here's what Porsche does on the new BS car. The bits I point to are just plastic elements clipped onto the forward portions of the suspension arm. You could also come up with some nice hose ducting if you had all-out braking issues to worry about.



Here is a quickie deflector viewed from the passenger side front of a Viper.

[008]

I have a few different type of plastic ducts left over from when I was building My E46 M3 that are similar to that. I hope those will solve any issue during the hottest months. Well, I really hope I won't need any ducting at all but we'll see.