Just collected my new Exige S with PP and have a question about the brakes. On all the pictures you see the front discs appear to have 2 part discs - a centre with the disc bolted to it. It also mentions this in the handbook about bedding the brakes in. The car I have has the 4 pot AP racing calipers but the disc looks solid. They also look the same size as the ones on the Exige S I just sold. So my question is what discs should the car have?
Yes, I noticed this with mine too, I have the solid version, also the AP calipers are slightly different to the original advertised ones.
The manual also states that if you have the uprated brakes then you will not get locking wheel nuts on the front wheels, but mine does??!!
I have been meaning to query it, but I guess Lotus found a slightly cheaper solution from AP and I think all literature says ‘Lotus reserve the right to change any spec…’
No idea if they are any better or worse though
This car has the bolted type, as you say may be a model year change, or Lotus found a cheaper supplier. However, I’d check with Lotus - mistakes do happen!
The AP Big Brake should be the spec on the PP Exige S - this comes with the 2-part aluminium belled disc. The locking wheel bolts should not be fitted to this kit, longer bolts should be supplied!
Follow the bedding in procedure, even the decelerations from 120-70 , you just needto find a private road or track to do it!
Used cars for sale - PistonHeads UK
This car has the bolted type, as you say may be a model year change, or Lotus found a cheaper supplier. However, I’d check with Lotus - mistakes do happen!
Try this one :
The one you show has been in there showroom since before I ordered mine from them, so is few months earlier car. The one above is new in and has the different discs and calipers.
Confusing huh??
I can understand that Lotus has changed the disks. The new solution looks cheaper, fabricationwise. The missing bolts are a different matter. I had an urgent recall (not general, but on chassisnumber) about these bolts. The newer ones are about 2mm longer than the original ones. The bigger calipers made it necessary that the bell had to be adjusted and therefore slightly longer wheelbolts were needed.
Nico
Now I’m worried I retro fitted my AP’s do I need longer wheel bolts?
Back to the thread, I would feel absolutely cheated if they supplied me solid discs when I was expecting ally belled, changing the spec of an item is one thing but not supplying an item fullstop I would think is totally wrong…
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Try this one :
This is the car I ordered from them until they told me 4 days before I was due to collect it that they couldn’t go through with the deal. Fortunatley I was able to get a car with better spec at short notice for the same price. Now having seen the pictures I am glad because I also order the leather upgrade which it doesn’t have.
Those brake discs are the ones I have as opposed to the ones with the ally bells. Must be a spec change but will contact the dealer and see what they have to say.
I pick my car up this week (hopefully). PP Exige S, SP & TP. I will be checking the front discs to make sure thay are the 2 part discs. The solid discs will be heavier & if they look the same as is on the std S then they are the wrong ones. Here is the extract from the Lotus Sport 4 POT BRAKE UPGRADE. Part Number: DLS3T0011F
This big brake kit will provide increased heat capacity, which means substantially more resistance to brake fade and calliper distortion with multiple stops from high speed. A firmer pedal due to stronger and stiffer components, as well as better modulation characteristics under threshold braking is also typical with this properly balanced brake upgrade. By sizing the calliper pistons properly for S2 Exige models, it has been able to optimize the performance and feel of the system. We have found that the increased heat capacity of this brake upgrade kit, resists fade much better and calliper distortion during race or track only applications. The whole brake system is stiffer which should provide a firmer pedal, as well as better modulation characteristics under threshold braking.
PADS: The pads are 16mm thick, 46.2 mm radial depth, with an area 43. 2 cm2 and are a Pagid RS14 friction material. This is a full race pad with a medium-to-high friction value. It is a ceramic-type compound with very good modulation, high fade resistance, low heat conductivity, and a good wear rate up to a temperature of 650�C. It is kind on discs, with visible grooving, but a limitation of hairline cracks. Lotus Sport has used this friction material on the Lotus Sport Exige GT3 racecar and Lotus Sport Exige Cup 240 vehicles.
This bigger pad benefits heat capacity and wear rate, as it will absorb more initial heat (less thermal shock), and have better wear characteristics (longer pad life).
Although brake torque is directly proportional to piston area, system pressure, friction coefficient and effective radii, it is not affected by pad area. This pad profile benefits the heat capacity and wear rate of the components, as it will absorb more initial heat (less thermal shock), and have better wear characteristics (longer pad life)(Although in the case of a larger pad, the pad can mask a larger portion of the rotor face, absorbing more radiant energy and shielding the area from cooling). Lastly, the pad geometry is improved, since rubbing speed between the disc and the pad is greater at the periphery of the disc, the pad geometry is designed to reduce the area toward the center of the disc. This is done in an effort to produce even temperature and pressure distribution across the face of the pad.
DISCS: The discs are 308mm outside diameter, 28mm thick with 48 vanes, 14mm air gap and weigh 4.9kg.
The aluminium bell for the hub section of the disc saves weight over a one-piece solid disc, as this is both rotating and un sprung, it will benefit the acceleration, braking, and handling of the vehicle. This brake upgrade kit will handle the large temperature changes that the brake disc experiences during track use. Temperature differences will be evident in a one-piece disc and could cause warping of the disc. This results in vibration of the vehicle, pulsing of the brake pedal, but also pushes the pistons farther away from the disc (pad knock off). With this two-piece disc assembly, the iron disc heats up more evenly. This allows the disc to be used under severe conditions without having a detrimental effect.
CALIPERS: The calliper is a two-piece aluminium alloy body with 36 mm and 31.75 mm piston diameter bores, aluminium alloy pistons with dirt seals and is of the radial mount
type. The calliper weight is 2.3kg
Will speak to the dealer but the performance pack doesn’t say big brake kit it says “308 mm front discs with AP racing four-piston callipers, uprated front and rear brake pads” haven’t physically checked the pads but it does have the AP 4 pot callipers and the braided hoses.
Sent a mail off to Lotus this morning & got this reply.
The brakes you describe sound like the front brakes that used to be
fitted to Exige S with Performance Pack. Discs are 26 mm thick. This
kit has now been revised to use bespoke callipers which bolt directly to
the hub carrier without the need for an adaptor bracket. The discs are
also now one-piece, although two-piece discs are still used on Cup 260
cars.
They’ve just done a cost cutting, I would be miffed it mine turned up different to what I had been shown and was expecting without prior knowledge
This explains why all of the cars on the production line at the 60th anniversary had these ‘new’ discs. I’m glad I had mine done when they were fitting the ali belled variety.
I will be having words if mine turns up with these. I paid for the two-piece belled discs, There are obvious advantages of the two-piece discs over the one-piece, they will perform better and weigh less.
I have sent another mail to Lotus asking why they have done this. Still wating a reply
can someone explain why this is true specifically the pad area bit:
“Although brake torque is directly proportional to piston area, system pressure, friction coefficient and effective radii, it is not affected by pad area”
Yes. The force exerted by the piston is spread across the pad to give a pressure (force/unit area) dependent on pad area. The larger the pad the smaller the pressure, and vice versa.
In other words each unit area of pad grips with more force for a small pad or less force for a large pad. Add up all the unit areas to make the total frictional force, which will be the same regardless of pad area.
Another interesting fact is that friction is largely independent of speed, although heating can have some effect.
I don’t think I agree here.
Surely the smaller pad, if it is having to grip harder is going to get hotter and fade before the bigger pad??
In my experiance when it comes to brakes bigger is better everywhere!!!
In the real world you are right. I was talking about brakes that are operating within the manufacturer’s working limits. Once they get too hot, yes, they will exhibit different characteristics, but then they’re outside the design envelope so anything can happen.
I’m sure there’s a brake designer/manufacturer out there who can add to the discussion, anyone?
This is correct. The early cars with the pp had ap calipers and ali belled discs.
The latest version is a cost engineered solution, I was told this at the factory, the calipers and discs are different but look the same (well the calipers anyway)
Only motorsport cars have the “real” ap kit fitted unless you have an early 08 year 240pp
I can understand them changing the specification on parts of the base car as any cost saving they make on production is money in thier pocket. But people who then specify additional equipment, and pay for it, should get what they pay for and not an inferior item.