Upgrading to 2 pot calipers for the Rear. Pad Recommendations? - Page 3 - LotusTalk - The Lotus Cars Community
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post #41 of 60 (permalink) Old 10-29-2018, 11:46 AM
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almost positive it's the same diameter as the front. I bought them used from a forum member who had the BOE stainless steel pistons installed on them.

And I think it's 44mm front? So I'm running 44mm front and 44mm rear...different compounds but still experiencing too much rear bias...most noticeable in downhill braking (which is expected I suppose). Something I'm gonna have to figure out this off season.
Yep - you're right. Stock front is 44mm. I had it in my head that the 41.3mm were the same as the fronts.

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post #42 of 60 (permalink) Old 10-29-2018, 11:48 AM
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There are smaller caliper options too if the 44MM is too big. I think there's a 38MM option if I remember correctly. It's essentially the same housing, uses the same pads, but smaller caliper

But I haven't seen much written up about it.

Last edited by Ls1Rx7; 10-29-2018 at 12:38 PM.
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post #43 of 60 (permalink) Old 10-29-2018, 12:04 PM
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There are smaller caliper options too if the 44MM is too big. I think there's a 38MM option if I remember correctly. It's essentially the same caliper, uses the same pads, but smaller caliper

But I haven't seen much written up about it.
I believe there are 3 size options, the stock being the biggest. The one in the middle can be found but when I tried to track down the smallest version the wait time was several months out and the few distributors that would deal with it could not provide an actual lead time. Not much written about them though as I'm not sure how easy they are to order.
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post #44 of 60 (permalink) Old 10-29-2018, 12:11 PM
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You guys should just switch to manual brakes with a bias bar and delete the ABS. It's awesome.

You could also try running REALLY crappy pads in the rear. I have some off amazon I never used

2007 Exige S with almost every track mod...
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post #45 of 60 (permalink) Old 10-29-2018, 12:24 PM Thread Starter
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You guys should just switch to manual brakes with a bias bar and delete the ABS. It's awesome.

You could also try running REALLY crappy pads in the rear. I have some off amazon I never used
I've followed your brake bias post and some of your other comments prior to installing it and running with the 2 pots all around.

But yea, the brake bias cage seems to be the route I'm headed as well.

But before that, I was considering throwing in the stock pads that used to be up front to my rear...or maybe the Ferodo DS2500's...I have those in a box as well.

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post #46 of 60 (permalink) Old 10-29-2018, 12:55 PM
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I am headed down the manual brake path right now but am still interested in the overall options, so thanks all for the inputs!

Question: what is the front/rear pressure ratio out of the stock tandem master cylinder, equal?

Question: with the stock/5317, are you using the same rotors (diameters)?

Cheers!

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post #47 of 60 (permalink) Old 10-29-2018, 01:03 PM
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I am headed down the manual brake path right now but am still interested in the overall options, so thanks all for the inputs!

Question: what is the front/rear pressure ratio out of the stock tandem master cylinder, equal?

Question: with the stock/5317, are you using the same rotors (diameters)?

Cheers!
1. Equal
2. I am using the BWR rear rotors that they used to sell that have the larger hat and smaller rotor size but same OD. This results in a net loss of a TINY bit of surface area on the pad, but also has the center of the pad 1mm further away from the center. This is because I have a washer between the caliper and the mount. Resulting in what I expect to be a very similar net force.

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post #48 of 60 (permalink) Old 10-29-2018, 01:28 PM
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@kfennell - yes we all want the fancy setup BOE offers for breaking, it's only a net of about $3,500 above purchasing a new set of stock calipers for the rear. I believe Phil set a few records with the stock calipers too though...

Damn you, now I'm rethinking my winter upgrades.
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post #49 of 60 (permalink) Old 10-29-2018, 02:52 PM
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What disc diameters? I have the Sector111 two-piece 288mm diameter intended for fronts, all round.

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post #50 of 60 (permalink) Old 10-29-2018, 03:33 PM
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@kfennell - yes we all want the fancy setup BOE offers for breaking, it's only a net of about $3,500 above purchasing a new set of stock calipers for the rear. I believe Phil set a few records with the stock calipers too though...

Damn you, now I'm rethinking my winter upgrades.
It's $1680 if you have them do the plumbing, hardly $3500?

Or do you mean with the larger fronts as well? Hardly anyone would NEED those. I just have the stock fronts as well and I have a track record with more to come. The larger fronts just make lap 6+ at cota a little more friendly unless you are over 300 WHP and on A7's

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post #51 of 60 (permalink) Old 10-29-2018, 03:33 PM
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What disc diameters? I have the Sector111 two-piece 288mm diameter intended for fronts, all round.
Yea 288

2007 Exige S with almost every track mod...
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post #52 of 60 (permalink) Old 10-29-2018, 03:43 PM
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It's $1680 if you have them do the plumbing, hardly $3500?

Or do you mean with the larger fronts as well? Hardly anyone would NEED those. I just have the stock fronts as well and I have a track record with more to come. The larger fronts just make lap 6+ at cota a little more friendly unless you are over 300 WHP and on A7's
I meant with the larger fronts. Didnít think about just the cage as a stand alone upgrade. Any idea how much front/rear bias you are actually running? Do you change bais on the fly at all?
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post #53 of 60 (permalink) Old 10-29-2018, 04:12 PM
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I meant with the larger fronts. Didnít think about just the cage as a stand alone upgrade. Any idea how much front/rear bias you are actually running? Do you change bais on the fly at all?
Yeah it's a perfect stand alone upgrade.

I run about 54-57 % front. It depends on tire quality and track demands. Cota more rear others less

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post #54 of 60 (permalink) Old 10-29-2018, 06:54 PM
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You guys should just switch to manual brakes with a bias bar and delete the ABS. It's awesome.

You could also try running REALLY crappy pads in the rear. I have some off amazon I never used
Good point.
But within my current budget I can afford either the BOE setup keeping stock rears, or the 2-pot rear upgrade.
Given that choice - what would you recommend?

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post #55 of 60 (permalink) Old 10-29-2018, 07:02 PM
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Good point.
But within my current budget I can afford either the BOE setup keeping stock rears, or the 2-pot rear upgrade.
Given that choice - what would you recommend?
Stick with stock IMO until you can do both. Its about $2400 so it's not too much of a stretch to save up.

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post #56 of 60 (permalink) Old 10-29-2018, 07:42 PM
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If anyone regrets their 44mm 2 pots on the rear and are selling them, I am in the market to buy a set to match with my 4 pot fronts. PM if you're selling...

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post #57 of 60 (permalink) Old 10-29-2018, 07:47 PM
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Stick with stock IMO until you can do both. Its about $2400 so it's not too much of a stretch to save up.
I understand that the complete BOE solution with the rear caliper upgrade is awesome.
But if I understood you correctly, you think only upgrading from stock to rear calipers with proper bias, without complete BOE setup is worse than doing nothing?
May I as why you disagree with Phil on the staged approach?
As far as I understand there is hardly any difference in work or parts between doing it in stages or all at once.

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post #58 of 60 (permalink) Old 10-29-2018, 09:03 PM
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I understand that the complete BOE solution with the rear caliper upgrade is awesome.
But if I understood you correctly, you think only upgrading from stock to rear calipers with proper bias, without complete BOE setup is worse than doing nothing?
May I as why you disagree with Phil on the staged approach?
As far as I understand there is hardly any difference in work or parts between doing it in stages or all at once.
I think that under a lot of circumstances (noting that, apart from brakes, you have to factor track/road, driver style, wheels, tires, ride height, suspension compliance, car weight and distribution, with driver), having the same braking on all 4 corners yields a car with too much rear bias (speaking for the S2). Upgrading the rear calipers in an 08+ car is a no-brainer, but for us with 07- cars, the situation is less clear. Edit: 08+ Exige is 4-pot in front, I don't know about the Elise line.

I am only guessing that this is the basis of the @kfennell recommendation, but I would make the same recommendation (Phil can jump in).

I admit, I am talking only about track driving, and I know I am prone to jump on the brakes.

I also guess that I have boiled the OEM rear brakes on track more than once in the stock configuration (I guess because when I was rebuilding the calipers, I found carbonation inside the cylinder). I say this just to note that a bias cage used to work those poor Brembos harder is likely a bad idea.

Last edited by thebuzzard; 10-29-2018 at 09:45 PM. Reason: Added detail
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post #59 of 60 (permalink) Old 10-30-2018, 05:50 AM
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I think that under a lot of circumstances (noting that, apart from brakes, you have to factor track/road, driver style, wheels, tires, ride height, suspension compliance, car weight and distribution, with driver), having the same braking on all 4 corners yields a car with too much rear bias (speaking for the S2). Upgrading the rear calipers in an 08+ car is a no-brainer, but for us with 07- cars, the situation is less clear. Edit: 08+ Exige is 4-pot in front, I don't know about the Elise line.

I am only guessing that this is the basis of the @kfennell recommendation, but I would make the same recommendation (Phil can jump in).

I admit, I am talking only about track driving, and I know I am prone to jump on the brakes.

I also guess that I have boiled the OEM rear brakes on track more than once in the stock configuration (I guess because when I was rebuilding the calipers, I found carbonation inside the cylinder). I say this just to note that a bias cage used to work those poor Brembos harder is likely a bad idea.
Agree with everything here. Just the 2 pot rear is too much rear bias. Just the balance bar is mostly wasted becuase the rear calipers cant do much more and they don't do a good job of braking consistently anyways.

The only catch would be if you could ind a brake pad stagger that worked well with 2 pot all around but so far I don't think many are happy.

2007 Exige S with almost every track mod...
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post #60 of 60 (permalink) Old 10-30-2018, 07:22 AM
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Agree with everything here. Just the 2 pot rear is too much rear bias. Just the balance bar is mostly wasted becuase the rear calipers cant do much more and they don't do a good job of braking consistently anyways.

The only catch would be if you could ind a brake pad stagger that worked well with 2 pot all around but so far I don't think many are happy.
Anyone using stock or near stoc pads in the rear?
As long as they survive a 20 minute HPDE I'd be fine with them. Obvioulsy ideal for the street too.

I've had the fluid boil but haven't had issue with the RC5+s yet, but the brakes are inconssitent and lack feel, most of which I'm guessing are the slide calipers out back
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