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Discussion Starter #21
I think you'd be the first person considering going to the full BOE setup with what is basically a stock car with an OEM SC. I get that its not enjoyable. My first few times on track I had some similar problems to you... the car just didn't stop as fast as I thought it would. I did more or less what has already been recommended - new pads, new rotors, new brake fluid, and when I bled the fronts I took them off the uprights, turned them upside down, and banged the crap out of them.

After that, I still had the initial dead travel of an inch or so, but the car stopped great and I was able to proceed with confidence.

If you're in CA, seems like it would be easy to find someone on track with the same car, and swap for a couple of laps.
I would be okay with being the first ;) I was the only one I know to put an AP Racing big brake kit on my WRX (non STI) and guess what? I would gain about 1 second per corner by braking hard and late compared to other sport sedans. The blood would rush to the front of my face and it felt like I was going to fly out the front window. In the Lotus, the experience is not even close. Maybe until you experience what a world class braking setup is capable of, you don't know what you are missing?
 

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I have the AP Racing 4-wheel BBK and 281rwhp on the MP-62 OEM Exige S supercharger with a Blade 300 kit. I'm also in SoCal.

San
 

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About the brake of the Elise vs Exige with big front brake... The Exige bias is just worst, this is why so many peoples are switching the rear caliper to improve the bias.

Bigger brake can help the felling, or putting better brake pads too. If your car do not brake so well, maybe it is caused by the installation of average brake pads. Bigger disc forces to install bigger wheel dia, and 16 min on Exige. For race, 16 tires have limited choice. I prefer running in 15 front, forcing me to run small disc dia (295 on mine), and I am using the OEM Elise caliper with my 450 hp Elise. I don't think changing for an Exige for the brake is the way to go.

But the Exige look better for track tool. For street, the Elise is more convenient.
 

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Something is wrong I'd guess.

R&T road test of '05 Elise.
Braking is rock-solid (a new R&T best of 105 ft. from 60-0 mph), the 4-wheel vented discs and ABS work together transparently for major deceleration with minimal concern.

Golf R: 70 mph, 159', C&D
60 mph/107', MT (Which chose Elise #15 of 30 fast-stopping cars)

Cayman GTS: 70 mph, 159' (C&D)
60 mph/ 106' Edmunds

As you can see, the Elise stops better than almost anything!!

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When stopped, press on brake pedal hard. If it sinks:

And comes back up with pumping, you may have air in the lines. IIRC, if pads are too worn, pedal doesn't come up, but memory is foggy here.
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How OLD is your brake fluid??

Who bedded in the pads and when?
 

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About the brake of the Elise vs Exige with big front brake... The Exige bias is just worst, this is why so many peoples are switching the rear caliper to improve the bias.

Bigger brake can help the felling, or putting better brake pads too. If your car do not brake so well, maybe it is caused by the installation of average brake pads. Bigger disc forces to install bigger wheel dia, and 16 min on Exige. For race, 16 tires have limited choice. I prefer running in 15 front, forcing me to run small disc dia (295 on mine), and I am using the OEM Elise caliper with my 450 hp Elise. I don't think changing for an Exige for the brake is the way to go.

But the Exige look better for track tool. For street, the Elise is more convenient.
Why is Exige a better "track tool" to you?
 

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Why is Exige a better "track tool" to you?
LOL, just because it look better for race... and maybe the scoop on the top to add air to the engine bay. if my car was an exige, maybe my intercooler could be located a little better...
 

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The brakes on my '07 Exige worked good stock and even better with the front caliper (smaller version) mounted on the rear.

Couple thoughts on your situation. I'm not familiar enough with the pads you are running but it seems others are and I haven't seen anyone say to just change those, but different pads have different initial bite... Brake pads also work better at a specific temp, so maybe the pads you have need to be up to temp before they work well vs. a cold pad. The weight of the Elise is less than the cars you are comparing to, I'd try to find some data to compare (g force meter, straight road where you can test stopping distance using GPS speed and not the cluster). You should be find doing several full speed stops if you have the road to do it. The Elige can also be a little picky to how you apply brakes, stabbing the brakes vs. setting the weight then hitting them hard can make a big difference.

I think there is a used BOE brake setup for sale still around this site somewhere.
 

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JasonB,

Are there moments when your brakes feel better or worse?

If so, pls describe those situations for us.

Thx

g
 

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I would be okay with being the first ;) I was the only one I know to put an AP Racing big brake kit on my WRX (non STI) and guess what? I would gain about 1 second per corner by braking hard and late compared to other sport sedans. The blood would rush to the front of my face and it felt like I was going to fly out the front window. In the Lotus, the experience is not even close. Maybe until you experience what a world class braking setup is capable of, you don't know what you are missing?
What you're describing is the tires, not the brakes. If you can lock the tires, you have enough brakes (as long as they aren't overheating).
 

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Discussion Starter #31
What you're describing is the tires, not the brakes. If you can lock the tires, you have enough brakes (as long as they aren't overheating).
It is not clear to me that the tires are locking. They are awful quiet if they are locking and I don't experience the typical ABS shutter / rapidly pulsing
 

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I've had the experience of being not able to trigger ABS/lockup when tracking with street pads that got too hot and faded away.

Sent from my Pixel 3 using Tapatalk
 

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What you're describing is the tires, not the brakes. If you can lock the tires, you have enough brakes (as long as they aren't overheating).
I've no idea why we would think this is the case. I don't think there were clues pointing us this way. Pls explain.
 

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Jason, pls respond to questions from #24 and #29.
 

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It is not clear to me that the tires are locking. They are awful quiet if they are locking and I don't experience the typical ABS shutter / rapidly pulsing
@JasonB You can tell when the brakes are fading, they get mushy and the car takes longer to slow down. I've had it in my MR2 track car, it's pretty scary. Unless you've got air bubbles or a lot of water in the lines, this happens over time and heat cycles, not with the first corner. If you can't lock the brakes on the first corner, there's something wrong with your car. I've never had a hard time activating the ABS on my A048s and there aren't many stickier tires unless it's a complete slick.
 

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I've no idea why we would think this is the case. I don't think there were clues pointing us this way. Pls explain.
It's pretty simple, maximum traction occurs at the limit of static (rolling) friction between the tires and the road, the point just before the brakes lock. As long as the brakes can lock the tires, they are capable of bringing the tires to this point. To improve braking force beyond this, you increase tire grip, not brake size. Bigger brakes will add to the torque that you apply to the wheels when you hit the pedal with a given force at the pad, so they do have more stopping power, but once you've locked the tire, big or small, the brakes can't do anything more.

As noted earlier, if the brake bias is off, and the front tires have more braking force than they should (fronts generally have 60%ish more force than rears, this is related to the car's weight distribution) then there is potential grip lost by what the rear tires could have done. This also isn't a brake size problem, it's a biasing problem. Ideally, the fronts should lock just before the rears to maintain stability. If you ever try stopping a car just with the parking brake, you'll see that there's a pretty severe loss of control.

Upgrading to bigger brakes is important when:
  • You can't lock up the tires because they have a very high level of grip.
  • You are experiencing fade because the disks can't dissipate the heat fast enough. Larger disks have more thermal mass, ie- bigger brakes take longer to get to the temperature where the pads will fade. Upgrading pads may work to mitigate this as well, with less weight and cost.
  • You want to change the feel of the braking system. With higher torque on the wheel, the brakes will have a different feel. They'll feel more powerful and it takes less force to apply a set amount of stopping power. You might consider a change to the master cylinder along with this, as brake pedal travel increases with larger calipers.
  • You have $$$ burning a hole in your pocket and there's an aesthetic interest.
 

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Discussion Starter #39
Jason, pls respond to questions from #24 and #29.
How OLD is your brake fluid??

-- Brand new Castrol SRF last time I went to the track.

Who bedded in the pads and when?
-- I had the pads installed by a local shop in the Bay Area, I assume they bedded them in but I can check.

Are there moments when your brakes feel better or worse?

-- Yes, brakes feel fine starting the day. Pedal is firm enough. After a few sessions or sometimes int the first session towards the end of the session, the pedal has a lot more travel and the car seems to be not stopping as fast. At this point I am pushing the pedal very hard to stop the car and it seems like the "ice mode" is kicking in. As in once I push the pedal hard enough, the car actually is decelerating slower. This happens especially going up the hill at Laguna Seca righ
 

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The first move would be to re-bleed the brakes using my technique. First because it's very cheap and extremely effective.



“How to bleed brakes”:

www.lotustalk.com/forums/f101/how-bleed-brakes-241138/

Note that many people disagree with my method, so judge for yourself.

Taught to me by semi-famous Toyota engineer, who built championship winning cars and bikes.

1. Get Sears brake bleed kit (canister, hoses, adaptors for bleed valves) and their hand vacuum pump. Kits there have both components. Inexpensive.

2. Pour a little b/f in canister, hook up hoses and use the tightest adaptor you can.

3. Pump vacuum to 20-25” with bleeder valve closed.

4. Tap caliper with small hammer or similar. This releases the air bubbles clinging to the caliper into the stream. WHATEVER method you use, DON’T skip this step.

5. Open bleed valve.

6. When vacuum is almost gone, close bleed valve.

7. Check level in master cylinder. Do this often.

8. Repeat as needed.

Benefits:

*Never got a firmer pedal using any other method.

*Requires only one person. Your wife/so will thank us both.

*You will not be pushing the piston in m/c into the rough area normally unused, thereby not prematurely wearing that seal. (Clutch m/cs are always used to full range.)

Note: On my Elise, I needn’t even remove the wheels.

Yeah, yeah, people use pressure bleeders, but my racecar mechanic friends don’t like these.

Yeah, I know about speed bleeders.

The above is my opinion. No responsibility for screw ups, injuries, maiming or deaths.

Take it, leave it. OK with me.
 
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