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91yesprit

Front Brake Upgrade

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After going through the excitement of complete brake failure I'd like to upgrade my brakes starting at the front.

At the moment I'm looking at PNM - Lotus Esprit Front 310mm Kit http://www.pnmengineering.com/lotus-esprit-brakes88.html as I can retain the original alloys.

I've heard good things about these but was wondering if anyone has any suggestions ? Thanks

 

 

 

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Hi Matt,

Don't see why you should not proceed with the 310mm kit, no experience to share but I will going to comparable spec with my S2. Regarding complete temporary failure it's typically boiled brake fluid if the pedal goes to the floor, pad overheat if the pedal remains firm-ish but braking distance is too long. Bigger, better components see to overheat issues nicely. Are you aware that brake fluid must be refreshed throughout the system with adequate spec from time to time? Conventional fluids are inclined to absorb water over time and will thus boil at a lower temperature. In no case should silicone based fluid ever be used, particularly for any car that is driven hard. Remind me though, does your SE have ABS?

Cheers 

 

 

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It was actually a corroded brake pipe that failed near the calliper. Luckily it was quiet road so was able to use the handbrake and engine braking to slow down but not a nice feeling when the brake pedal goes straight to the floor.

The SE has ABS and seem to work fine for the age of the car, although I'm not that keen on the pump system.

Thanks for the info on brake fluid I'll take a look.

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I have no experience in working on ABS, though well acquainted with driving cars so equipped. Take care to check fluid specs as they pertain to ABS as there may be further details relevant.

Your experience illustrates why so many of us advise that the wise owner remains engaged with detailed maintenance of the cars. They are such a joy to drive and one lucky enough to realize this should feel free to explore the limits without much worry of a sudden component failure. That's the sweet spot in life:).

 

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I have the pnm brake kit front and rear, using V8 Brembo calipers at the front, and the standard Elise calipers at the back. Think mine are 330mm as I have the bigger Sport 350 alloys.

I’ts a good kit, pnm really do engineer everything really nicely.

Braking isn’t quite as good as on my M4, but is still pretty excellent and certainly a lot better than standard.

 

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I have the PNM kit.

Front 4 pot 286mm disc and 300mm 4 pot at the rear. I am on the older Hi Spec calipers.

I have since upgraded the front to 310mm and upgraded to stainless steel braided hose too.

Now PNM is using their own brand calipers, not sure who was the main supplier, but I believe it should be better than the Hi Spec,

I like them cos they are quite responsive to my queries and has most of the parts in stock so turn around time is not long.

 

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I have the 4 pot Hispec on my turbo, vast improvement over the older setup. No ABS.


Amateurs built the Ark

Professionals built the Titanic

"I haven't ridden in cars pulled by cows before" "Bullocks, Mr.Belcher" "No, I haven't, honestly"

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Good kit for the front. Go for as large as will fit under your wheels and make sure you get performance pads as the standards are from a Volvo p1800 and are rubbish. Hawk or Mintex are better options.

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 My first upgrade was with the PNM  4 pots all round.  What I found was the spot brake for the hand brake was crap,  almost not capable of MOT standards.   I changed to the 4 pot rear with the full pad hydraulic hand brake , much better but not perfect.  The biggest problem i found was the brake squeal on the front when using decent pads like Mintex 1144 .. The braking was very good but the squeal unbearable , with lesser pads like green stuff the brakes were better than standard but in my opinion still lacking. but virtually no squeal.. After discussing in depth the problem with PNM then Hi Spec, I moved over to the 6 pot front with larger thicker disc.   To my surprise ' No change'  , squealed like hell , bloody amazing  braking but could not cope with the squeal , fitted green stuff , squeal only slight.   All this time I had no issue with squeal on the rears when fitted with M1144 .  However to give you an idea of the difference between the pads,  When M1144 fitted to rear and green stuff in the front , under medium to firm braking when you threw the clutch in to come down a gear, the rear wheels would lock and send you sideways ..  To initially compensate this I fitted a bias valve to balance out using M1144 on the rear and green stuff front.. this was better than green stuff all round..   As time passed the only thing i could think could be causing the issue was the mounting bell for the front discs. This was PNM 's own unit to facilitate the two piece disc on the SE front hub rear mount.  I questioned PNM on the possibilities that it induced harmonics due to its design.. The reply was no one else had complained. 

My only assumption was it was the pad type and the bell as a combination that caused the problem .. Over a period of time I asked those with the same conversion if they had similar issues.. Strangely enough only those who used pads like the M1144 had suffered squeal..   So what to do ..  Choice 1.   is to fit forward hub mounting bell , same as on the S4 onward.  Problem  here is the hubs are different and the concentric wheel mount gets used with the mounting bell. also the extra 8mm acts as a spacer which changes the front handling characteristics . So a pair of S4 front hubs would also be needed..  An added factor that does not effect me as i have changed wheel size , would be brake size restriction as you go more outboard with the smaller SE wheels..  Choice 2.  to fit a different design bell in same place, problem here is no one does them . PNM could not help and no other suppliers had anything close..  So on to the drawing board to design bespoke unit.. At this point it must be said that the large brake set up PNM supplied with the 10mm std mounting bell caused the disc to foul the steering arm , initially the arm had to be spaced to clear it.. I believe the set up now comes with an 8mm bell to correct this error.  However the track rod end is still bloody close to the disc to a point that the rubber gator failed from heat off the disc.. The new design will have to also address this point..      

The outcome was the new mounting bell with M1144 has virtually no squeal , just a bit on warm up as the green stuff did. the braking is amazing with no heat related issues..       all of the above only applies to those using SE type front hubs..  I hope my experiences help you with you choices.. 

original PNM set up 

IMG_20180308_175946960_HDR.thumb.jpg.caafdcd06a398c74f3134200066b1ab8.jpg

bespoke set up . 

IMG_20180308_180000421.thumb.jpg.2b2bdb8981cb6971b727d65db8f589dc.jpg

  

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Ah, I didn’t have any of those issues and I remember why now. I fitted S4 front hubs at the same time, and already ran S4 wheels.

When I was on the older but original hubs and fitted later GT3 wheels, I had to turn the older hubs down by 1mm. When I fitted the newer hubs, my later wheels just went straight on as they were designed for those hubs. Same when I fitted the Magnesios.

The later hubs do go straight on though. I don’t remember any massive dramas fitting them.

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I too wanted better braking on my 1990 Turbo SE (no abs), so looked into the various offerings.

I also looked at the PNM big disc solution. The 322mm vented all four corners. Lotus branded AP Sport350 calipers front and 4 piston calipers back.

I have kept the original SE hubs, so had PNM make the bells in aluminium as per AP for the front brakes, similar to what Changes have done.

Pads are Hawk carbon pads and while they demand really long bedding in, they brake okay and no sound what so ever, even under repeated hard braking. They were spoken of as giving very Little dust, but I've never really com across a pad that does not dust quite much when using them hard(-ish).

The point of bigger discs and better ventilation is many further had stops can be done without overheating. Bite is pads and amount piston surface, plus tires, tire pressure and suspension and bushings. You'll be amazed of how much a bad or worn suspention (as a total) can influence the stopping distance.

The Turbo SE vacuum booster for brakes is just not very pronounced. Once accustomed to this, it's quite okay with the brake setup I now have.

Still feel I could use more braking power and more bite, so 6 piston calipers are on the list, but I cannot get a permit from authorities here so far, which are ultra strict, which have the unfortunate effect, taht old original bad brakes are leagal, and new powerfull super brakes are not leagal...

Will look more into that later, to try and get a permission for 4 piston front calipers.

I have mesured and looked at the brake boost vacuum and all is at spec. No leaks, no lack of vacuum.

The standard brakes are outright dangerous and should never have been installed on such a fast car! Just my personal point of view.

AS you said, there's alimit to how big you can go with standard SE Wheels. But get the biggest and baddest you can. You'll be wondering how on Earth you were able to stop before the change. It makes the car so much safer to drive, knowing you at least have a decent chance to stop in due time.

I am trying to look up better pads that is good on street and the occasional track day with no preheat.

Regarding the parking brake, the pnm/tour choice 4 piston spot brake is non-functioning to a silly level as mentioned by Changes. PNM no makes brackets to install the Brembo rear calipers seperately for the parking function. Works well. They also now have the Electric rear calipers as far as I know.

Kind regards,

Jacques


Nobody does it better - than Lotus ;)

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Quote

Regarding the parking brake, the pnm/tour choice 4 piston spot brake is non-functioning to a silly level as mentioned by Changes. PNM no makes brackets to install the Brembo rear calipers seperately for the parking function. Works well. They also now have the Electric rear calipers as far as I know.

I recently purchased the spot pads, and they looked pathetic... hahah

I didn't know they had an alternative for the parking brake. Don't seem to be able to find them at PNM's website ....

@CHANGES 

Quote

What I found was the spot brake for the hand brake was crap,  almost not capable of MOT standards.   I changed to the 4 pot rear with the full pad hydraulic hand brake , much better but not perfect

Is this from PNM or Hi Spec?

Thanks

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On 02/08/2018 at 10:55, hspeck said:

I recently purchased the spot pads, and they looked pathetic... hahah

I didn't know they had an alternative for the parking brake. Don't seem to be able to find them at PNM's website ....

@CHANGES 

Is this from PNM or Hi Spec?

Thanks

Not sure if I got the Hydraulic hand brake ones  direct from Hi Spec.  There is also the possibility they were discontinued in favor of the electronic park brake setup.  There was some talk about them releasing when the brake cooled so you would need to leave in gear to be on safe side..   The EPB is a good option as an independent spot brake , but i believe the full caliper with the EPB as part of, is a single sliding caliper , which may not give you what you are looking for as a performance rear brake..      

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PNM is not using the single piston sliding caliper, they are supplying the Hi-Spec 4-piston with a bracket to use the original Brembo rear caliper as a parking brake. That is for performance reasons as Dave said. I spoke to Pete a few weeks back, he hasn’t got the brackets done for the electronic parking brake. Not enough call for them as yet.


Margate Exotics.

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I have an upgrade fitted to the Excel (same  hub setup etc as Esprit), and a slightly different version on the Turbo Esprit. The one on the excel fits nicely under 15inch wheels and gives more than enough braking for (what was then) less than off-the-shelf upgrades.

It used a Peugeot 406 disc ~300mm and 26mm/28mm  thick. Modified, by boring out the centre and re-drilling mounting holes to match the Toyota donor part.

Nissan 300 ZX  (4 pot) calipers, modified. Slit apart, and 2mm removed from the mating surface. ~2mm of waste material removed from the face of the mounting lugs

Dust/stone guard modified to suit.

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I have V8 wheels fitted on 88 turbo hubs and running this disc with Mintex 1144. Once hot they squeal louder than I’d like when lightly using the brake.

310%20upgrade.JPG

I was going to try carbon Lorraine rc5+ pads mainly to get increased bite but also in an attempt to reduce squeal.
Might have to start researching Bell mounting shapes and get something made.
Doh! What am I thinking?!? I still have to finish off the climate control mod!!
 
 

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Change the mounting plate. Get rid of the holes as it makes them ring and squeal


Only here once

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It’s really not that hard to change the front hubs from the standard ones to the later style ones. Makes things a lot easier when it comes to brakes as they work like normal hubs, not that weird 4 hole 5 hole arrangement.

assuming you can still get front hubs..

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I swapped my old hubs for newer ones to allow me to fit the 4 pot HiSpec with S4 wheels. I still have the old hubs in the garage.


Amateurs built the Ark

Professionals built the Titanic

"I haven't ridden in cars pulled by cows before" "Bullocks, Mr.Belcher" "No, I haven't, honestly"

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As i said the squeal went when i changed the bell mount design.    But they are still on the early hubs mounted internally..  You can design anything along these lines to suit your requirement, wheel size type etc..   I found the more grip the pad gave the more squeal i got,  until i changed the bell mount. 

HPIM0579.thumb.JPG.9d05b0b17538fda900dd1dabb0be4da7.JPG

HPIM0581.thumb.JPG.4c95b33fc888aaacd823f953b200be06.JPG 

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On ‎03‎/‎08‎/‎2018 at 23:58, CHANGES said:

Not sure if I got the Hydraulic hand brake ones  direct from Hi Spec.  There is also the possibility they were discontinued in favor of the electronic park brake setup.  There was some talk about them releasing when the brake cooled so you would need to leave in gear to be on safe side..   The EPB is a good option as an independent spot brake , but i believe the full caliper with the EPB as part of, is a single sliding caliper , which may not give you what you are looking for as a performance rear brake..      

Alrighty, thanks, but EPB is not allowed in my country as an aftermarket add-on..

On ‎04‎/‎08‎/‎2018 at 00:39, Chillidoggy said:

PNM is not using the single piston sliding caliper, they are supplying the Hi-Spec 4-piston with a bracket to use the original Brembo rear caliper as a parking brake. That is for performance reasons as Dave said. I spoke to Pete a few weeks back, he hasn’t got the brackets done for the electronic parking brake. Not enough call for them as yet.

thanks for the information

On ‎04‎/‎08‎/‎2018 at 14:20, chris said:

I have V8 wheels fitted on 88 turbo hubs and running this disc with Mintex 1144. Once hot they squeal louder than I’d like when lightly using the brake.

310%20upgrade.JPG

I was going to try carbon Lorraine rc5+ pads mainly to get increased bite but also in an attempt to reduce squeal.
Might have to start researching Bell mounting shapes and get something made.
Doh! What am I thinking?!? I still have to finish off the climate control mod!!
 
 

this is the same as I have now on my front, after changing to the 310mm disc....

so it will probably squeal too  ....

the brakes were quiet when they were on the 286mm disc with the more conventional bell mounting ..

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I agree with Dave about the squealing from the M1144 pads on the 323mm discs. They do pull the car up well, but the noise is disconcerting, and distracting.

To be fair, Hi-Spec did warn me that would be the case. The EBC Yellowstuff I used previously also squealed, but not quite as much. Both of those materials pulled up very well, though. At present I'm trying M1230 (Mintex heavier-duty compound than normal road) to try to get around the noise problem, but already I can say that they don't stop my car anywhere near as well as the aforementioned two types.


Margate Exotics.

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Noise is from that beautifully constructed and machined ringing bell plate. Looks just the sort of thing that belongs in a musical instrument.


Only here once

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4 hours ago, Barrykearley said:

Noise is from that beautifully constructed and machined ringing bell plate. Looks just the sort of thing that belongs in a musical instrument.

I wonder why it was designed to be so??

to reduce the weight?

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As part of a trial I’m doing, I’ve refitted the original Brembo front calipers with the 323mm disc, and done a road test this afternoon. Using the standard Brembo pads, there is no squealing, indeed there is no noise whatsoever under braking.

Ergo, it cannot be the discs making the noise. It’s the pads. Just as Hi-Spec advised me a couple of weeks ago.


Margate Exotics.

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