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Who's upgraded their rear braking system ?


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Front are all but done with my monster AP setup so I need to look at the rears sometime pretty soon.

I'm curently thinking AP again becuase they are the best but using a similar system to the S300 / X180R (for Travis :thumbsup: ) which means 4 pots on all 4 wheels, bias valve and so on. Not sure if anyone's done this before so I might end up being the 1st.

Disk is going to be S350 spec (320mm, most probably 28mm thick (I know they are 26mm originally but try finding them !))

I was thinking of fitting a mechanical spot caliper to the setup but I dont like the look of them, they dont seem man enough, I think it's probably time for the brembo floating rears to go on a diet of about 2kg each.

Hi-spec do a spot caliper :

http://www.hispecbrake.co.uk/calipers/sva_spot.htm

Wonder what the quality is like (never been a huge fan of hi-spec after my cousins car rolled away due to handbrake failure)

Needs to be gapped out as well to fit a 28mm disk - main concern is can this piddly caliper stop the car in an emergency ?

Thinking this for the rears :

http://www.apracing.com/calipers/products.asp?product=4+Piston+Caliper+Families-CP5040-2%2F-3%2F-4%2F-5S4+-+152mm+Centres%3Cbr%3E%3Cimg+border%3D%222%22+src%3D%22http%3A%2F%2Fwww.apracing.com%2Fpics%2Fproductpics%2Fcp5040-2_1.jpg%22%2F%3E_2679_2678

Quite reasonably priced ~

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The mechanical handbrakes may not look man enough but when you consider they are only used to clamp the disc when the car is stationary they will do this very easily. The other huge avantage over calipers with built in handbrakes is when the brakes are warm the heat does not transfere to the fluid!!! This is a must if you plan on doing any track days.

There is a company I have found in Ellesmere Port that can make one off brake cables, can dig out there details if you want.

I think I will be going for the Hi-Spec ones on the rear of mine......when I next get motivated .

Also the chances of both circuits failing at the same time is most unlikely ( in 20years working on cars I have never seen it). From an Mot point of view they have to be 16% efficent, which equates to about 250kg's for both or 125kg's of effort for each wheel,. The only thing to be carefull of is if you create a single circuit system then the efficencies will then need to be 50% ( the reason for this being the likely hood of a failure on the main sytem is far higher !!!!!)

So to sum all that lot up..... Stick with a twin sytem set-up and the seperate handbrake calipers will be fine...

Edited by cobraesprit
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Cool, thanks for the info - I must admit I do like the Hi-spec Spot caliper, never thought I'd be saying that.

The amount of weight you'll save wrt a track car is immense as well, funny I bought the GT2 as a test bed, but ending up using the GT3 LOL.

The Brembo combined rear caliper weights a metric ton (not really but 6kg inc bracket)

If I ask nicely at a MOT station can they test the braking force ratio on the wheels ?

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Jonathan,

Not only do you have to worry about brake balance but you also change the dynamics of the ABS system too. I read just such an article recently whilst sitting in the airport. It was an interesting article and one that I think most never think about.

Christopher

p.s. I will search for article and post in this thread

Found it Jonathan...rather interesting...right up your alley

ABS dynamics with regards to brake upgrades

Edited by cjtpb13
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The brake effrort is recorded using the roller brake tester ( there is however a way of avoiding this by telling the tester it is fitted with a limited slip diff ). The amount of effrot is really low 125kg's per wheel is very very easy to achieve.

Glad you brought up the fact about weight aswell, keeping the unsprung weight to a minimum is a must for any car .

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What I mean Paul is to determine the balance, I mean I could drive it and mess about with a biasing valve but if I could measure the force on a machine I could get it a lot closer to the requirement than hit and hope method.

Christopher, that makes interesting reading...

Basically the essense of it is that the car's wheels can decelerate too quickly fooling the ABS computer to cut in too early which is a fair point. This is why I went with as close to the Lotus setup as possible but taking into account we have the delco ABS and not the Kelsey Hayes one fitted in the later cars - In fairness I could have gone to a 6 pot front but on a 4 cylinder I don't think thats needed, I think the 4 pots and the 330mm rotor is more than adequate. I also have wider than stock tyres so that is another factor.

I dont know much about the Delco kit other than it is rather intrusive, I dunno how far you can really take the whole chassis dynamics sort of thing and I wonder (being that the ABS systems are not Lotus' own) whether they were programmed for the car at all ?

Again though is this not something that can be monitored on brake roller tester ? I know my brembos were showing lock at some specific level on the last test.

By nature I am a tinkerer so I'll do these things becuase it's in my dna to mess about with bolts and stuff, do I really need it ?...probably not, to be fair I hardly use the brakes esp on motorways becuase I read the road so far ahead I know when to lift off. In the twisties yes but in all fairness the Brembo system is by far adequate enough.

On the GT2 track car type thing this wont matter as the ABS is off but I do take the point of ABS seriously and I'll look into it. There must be a machine that'll do all that for me (ie work out the deceleration / force in comparison).

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The problem on a RBT is that the speed is only 5mph max so you can't really set a biasing valve accuratly. The only real way is by the "feel" of the brakes, this changes dramatically with different conditions, eg a rain setting will not work as well as a setting done in the dry.

It is by nature a trail and error approach......the best place to do this is on a race track where outside influences can be reduced and mistakes dont involve costly repairs, brake temperatures also affect the amount of pressure that can be applied.

In addition as you brake from higher speeds areodynamics and inertia come into play ( therefore what may seem great at say 50 mph could feel dreadful at 120 mph on a track) ......what I am trying to say is if you were to try to draw the the pressure/effort on a graph you end up with a non-linear tracing......

OMG >>>>> getting way to techy for a monday night lol

Edited by cobraesprit
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Jonathan,

Figured you would find that article interesting. That is why I also am interested to see if ErikS4 via Espritmon breaks into the Delco ABS system further. I realise that on the track car that it is useless information. And quite honestly on the road as well to most of us. I have found in experience that most people still use their brakes incorrectly. Forgetting that in many cases the pedal on the right will get you out of many situations too. I just figured, from reading your posts, that this intrigues you to figure out all the dynamics and facets of an issue. It just allows greater understanding and knowledge.

After much research and speaking with a friend of mine in Detroit ( works for GM in the office/engineering side of the business ) I ended up with the 6pot wilwood in front and 4pot in the rear with 12.2" rotors on all corners. I have the separate parking brake calipers but find them a bit of an annoyance.

My educated guess, I own an international business, is that GM has a programme specific for the Lotus Esprit. I think that would be the only way they could have gotten it through Federal regulations here in the States. Plus, as Bibs so pointed out with humour in another brake thread the other day, the litigation issues here in the US would almost for certain lead them to develop the computer software specific to the original brake setup for a specific vehicle.

Christopher

Edited by cjtpb13
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So your system will be approximatly the same as mine - how do you find braking in your car with that setup ?

Got any pics of the rear mount - I'm pretty much 100% on how I want to do it - I just find looking at other people's tried and tested methods can jog the inspiration :lol:

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I plan to use a Hi-Spec billet 4 with built in mechanical handbrake mechanism. Unlike previous versions, it's not hydraulic, it's purely mechanical and in the event of hydraulic failure, your car won't roll down the road. You can also get monster 4 calipers for rear with handbrake mechanism but I reckon you'd need mega monsters up front to balance things out.

I know you don't like Hi-spec so you're only left with one other option, AP. Do they do an integral handbrake caliper?

David

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No they dont make one :thumbup:

I was looking at a spot handbrake and using a cheap AP rear caliper which is only a few quid more than just the hispec ones.

I do like the Hispec design, I wish other companies would cotton on - but tbh Dave they were total assholes to my cousin and caused all sorts of grief AND they are only 10 miles from my/his door so it was a case of getting in their face. I know they have caused a lot of heart ache for others as well so I'd be loathed to use them, although I know of people that have zero probs too...once bitten...

Thing is their 4 pot hand brake chaps are

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Jonathan,

I have been satisfied completely with my brakes. Though I have a 1994 S4 it was manufactured in Oct '93 so it had the TMC brakes. It was one of the first things I changed on the car after 10k miles on the originals. What a profound difference. Having never driven another Esprit with either the Bembro or AP Racing brake system I do not know how to compare.

I found that the dead feel and pulsating of the brake pedal feedback diminished. The ABS system still works, yes I tested it in non scientific way...lol. I do know that I have decreased the stopping distances. All seemed balanced in normal braking, hard braking and braking whilst manoeuvring thru hard turns. As I said only thing I do not like is the parking brake, at low speeds the way the Wilood design is the pad floats...leading to an annoying squeak. One of the things I was going to sort out this winter finally. The brakes do hold the car on a slope so that was satisfying.

I do indeed have photographs of the set up and the brackets too. Unfortunately they are on my main computer at my MD house and I will not be there for another week and a half. Nice thing is the Wilwood parking brake calipers allowed for no change or modification in the cables. I just had to remove the seat to adjust. Easy enough for me to throw the car on the lift and undo the four seat bolts.

I have a friend, for what it is worth, whom was one of the chief driving instructors at Raceway Atlanta, he found the revised brake setup fantastic.

Christopher

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Yeah I'm hoping for the same, thing is I neglected to do any stopping distances before/after type thing, it's not worth putting the old ones back on to see any difference.

You should have the same ABS as me and seeing that the braking system is fairly close they should perform similarly :lol:

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Jonathan,

I do have spacers on all four corners, but the standard tyre size, running Goodyear F1 GS-D3's before and after brake uprate. How much did you increase your tyre diminsions?

Funny thing is I forgot to do same kind of tests. Can tell you this, sort of childish...got pulled over by State Trooper whilst I was in the middle of a group of speeders. Police officer was behind me where all I could see was his grill. pulled to the hard shoulder hit the flashers and pressed firmly on the brakes. My stopping distance was shorter than his...something he will not forget...

Edited by cjtpb13
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Mine has standard V8 wheels and tyres so more grip to be had in every aspect, handles nicely too since Lotus played with it.

It's dumb, I wanted to take mine on a slip road (off ramp) and slam the anchors in and test it before and after and I just forgot - it's really annoying LOL.

The spec for an Esprit is 126 feet from 60mph but to be fair a 60-0 is not much test as not many cars can do that in under 110 feet, it's from say 120mph (on the track) where the benefits come in and also sustained braking not only from high speed but on twisty roads/tracks where you use the brakes frequently.

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Hi Jonathan,

Here's another option for you. Willwood do a 4 pot rear handbrake caliper. If it's any good then I am willing to work with you on this a produce a kit together. Get in touch if you are interested. They are only

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I understand the annoyance of forgetting to do the testing. I am one for empirical data also.

I know that the uprated brakes feel more balanced and stronger than the TMC's. My one mechanic had noticed a remarkable improvement as did my youngest brother, who is caretaker of my vehicles whilst I am on travel, so he gets the advantage of driving exotics and not the money issues that go along with them...lol

I have had mine on the track but find myself using my Esprit for many of my trips. I will have runs of 1200 miles in a day or two of straight driving. I will find myself on the windy mountain roads using the brakes frequently to speeding along the interstate and firm braking to drop speed down the second the radar detector signals. What I have noticed with the uprates, not as much brake fade especially during mountain descents ( reminds me...one day I would love to drive the New Road off the A39 near Porlock coming thru the Exmoor National Park in an Esprit). I seasoned my brakes in using the method suggested by a close friend that races in many SCAA races here in the US. Most people are trained here in the US not to use their brakes hard for the first several hundred miles...so it feels wrong whilst your seasoning in new brakes. Where I live there are several straight empty roads allowing runs at 80mph with slim chance of law enforcement officers being nearby. My goal this winter ( before the deer committed suicide using my Esprit ) was to change out the fluid to an upgraded brake fluid ( now on hold til the Lotus dealership is finished with the vehicle ). I often wonder how many brake issues are due to the fact that many people seem to ignore the brake fluid.

You also brought up another fine point so many seem to overlook...the role that the suspension and its geometry play in the effects of braking. I had forgotten that you had your car at Hethel getting the suspension geometry done. Shame that Lotus has nothing of the sort here in the States as far as I know.

I had a chuckle about carrying the chock with you. I once saw someone park his car, rather rusty AMC Eagle Wagon ( an American classic...lol ), and get out as it was rolling backwards and throw an old alternator behind the wheel. I had to sit in my car and wait for him to finish shopping at the Lowes ( similar to a Homebase for you ) to see him leave...too funny...was well worth the lost time waiting...

Dave..Yes Wilwood do produce spot calipers. One main reason for using them was the ability not to have to modify the existing handbrake cables. I have the full Wilwood setup and have been pleased with the system. As I was explaining to Jonathan just a bit of annoying brake squeal at low speeds from the spot calipers. I believe that a bit of anti-squeal on the pad would help. One point that seems to be brought up with the Wilwood is that there are no cup seals on the pistons. In 20,000+ miles of driving in various conditions, dirt roads too, I have had no issues with them.And for what it is worth, important to some, available in colours...lol

Edited by cjtpb13
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It will only suck up a 22mm disk though, probably OK for the standard setup.

I like Wilwood stuff, most probably going to go that route for the E-type but for the rears i really need something for a 28mm disc which looks to be the cheapest option.

Funny, my 330x32's cost

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Jonathan,

I installed a set of Wilwood (6piston front, 4 piston rear) on a friend's 89SE years ago. He is happy with them, and I have not heard any problems with balance (no ABS on the 89SE though).

http://vulcangrey.lotuscolorado.com/gallery/main.php/v/Upgrades/brakes/wilwood_brakes/

P8010499.JPG

That kit uses the wilwood mechanical spot caliper, that I also bought for my setup, and the owner has not complained (lives on a mountain). I also bought the brembo rear caliper to use as a mechanical parking caliper, and I haven't decided which I want to use yet.

The X180-R does have ABS, but I do not remember seeing a different proportioning valve, in the X180-R parts supplement, for use with those larger brakes...

You might also consider the Stoptech parking caliper or the Brembo aluminum parking caliper, as those are much lighter than the Esprit/Elise rear Brembo parking caliper!

Edited by Vulcan Grey

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Nice 1 Travis, nice install, any reason why they opted to do it that way around though ?

I thought bringing the heavy part closer to the pivot / centre of gravity would reduce it's effective unsprung 'weight' or effect on the moving parts ?

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That is how Claudius did that wilwood kit.

Personally I am going with a trailing front caliper and a leading rear caliper, and the parking calipers in a trailing position like the X180-R

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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