23 replies to this topic

[Applepie]

Has any one fitted this caliper to there VX, if so Good or bad I have seen some bad reports on this site and others about hi spec's poor customer servive & a lot of deflectoin in the calipers,disk distorting. But i am only intrested in the caliper being any good. It is said to be 3Kg lighter than standard wether thats each or for the pair i am not sure. It uses the same pad as the front AP caliper. The botom pic is one fitted to an elise so shows differant mount to Vx but is the basically same caliper as VX  Hi_spec_Handbrake_VX220.gif   17.21KB   13 downloads  Rear_ali_Caliper_LRG.jpg   67.84KB   10 downloads

[Arno]

Has any one fitted this caliper to there VX, if so Good or bad

The one sold by Eliseparts currently only fits onto their GT uprights and not the normal rear uprights. (uses radial mount vs. the standard knuckle mount), so gets quite expensive if you need to fit those at the same time.

HiSpec supposedly sells a version that's a direct replacement for the normal rear brakes, but so far they seem to be complete vaporware when it comes to actual product deliveries. (But then again.. That seems to be HiSpecs reputation unfortunately)

Pity, as the idea is a really good one and the normal rear iron caliper weighs a tonne. Easy weight saving.

Bye, Arno.

[Applepie]

http://www.hispecmot.../vx220_rear.htm


They do make one for the VX straight bolt on, i held one in my hand at the Autosports show last sunday, but you do have to change the hand brake cable or at least the ends

£155 + vat each
check above web site.

[Arno]

They do make one for the VX straight bolt on, i held one in my hand at the Autosports show last sunday, but you do have to change the hand brake cable or at least the ends

Yup.. Those have been on the site and shown at shows since early last year, but so far I know of nobody who has ever been able to really get them. Would love to know if someone has actually received some!

Asked HiSpec serveral times about availability and delivery times, but so far they either don't respond or come back with 'in a few months' responses.. Never been able to get them to come up with a fixed delivery date.. That's all I want and I'd order them rightaway

I'd say keep bugging them for these and please do a write-up if you get them.

Bye, Arno.

[siztenboots]

Has any one fitted this caliper to there VX, if so Good or bad

Pity, as the idea is a really good one and the normal rear iron caliper weighs a tonne. Easy weight saving.

Bye, Arno.

Is it really that heavy ? Do you have any figures to compare others to

[rik]

the rear calipers (compared to the front calipers) do weigh a ton. I removed them to strip the paint off and carried them home in my back pack and it was very very heavy. Fronts are alu I guess.. they weigh nothing

[Applepie]

I have been told standard calipers weigh 4kg each i need to get round to weighing one myself. I am off on hols now so i look into it more when i get back. Hopefully other people will post some more info over the comming week. Cheers Paul.

[mandarinvx]

I may be completely wrong here so no if I am It seems to me that the front brakes in a standard guise are biased to the front. From the size of the pads/calipers this seems to be somewhere in the region of 2:1 (ie front brake applies twice as much combination of pressure/surface area as rear), mainly due to most of the weight distribution being over the rear half of the car. If you were to fit the same size calipers to the rear as the front, this distribution would be cancelled, and in theory may result in the front end going light(er) under heavy braking - which presumably is the last thing you want when entering a corner. Although if you also had the AP racing big brake kit on the front..... different story

[AndyVXT]

I guess there could be a couple of issues: - Brake force bias; ie if you increase the rear braking force then the rears would be more likely to lock, especially under hard braking when a lot of weight is thrown forward. - Might there also be issues with the change in bore sizes and the fact that there would now be 2 of them. How much fluid would have to travel for the extra piston and what is the surface area of the new pistons. As force = pressure x area might not (relative to the front) braking force be increased significantly due to the larger piston area? I note on the elise parts site they mention different piston sizes in order to maintain balance with the standard master cylinder.

Edited by AndyVXT, 20 January 2007 - 12:52 PM.

[Thorney]

We've been looking into this for some time so hopefully will have some answers for epople soon as.

[vxr36]

I have looked at this issue before when upgrading my car. I was worried about the balance when changing the fronts to the bigger AP (which BTW are lighter than the standard fronts by quite a bit themselves). The options are limited by the handbrake mechanism. Plans to a big rear brake (from a Ferrari) but it is expensive (as you could guess). It ideally requires a bigger configuration at the front too. In the end I went for AP4 pots at the front and an ally bell and pagids at the back. You don't get any more breaking at the front IMO with the bigger kit but you do get a lighter setup, more progressive/controllable breaking (different size pots) and no break fade when being a little frisky. Therefore I don't think the bias thing was much of an issue for me. I believe I would have had more of an issue if the rears were the Ferrari spec without improving the fronts further... noone wants the rears to lock ages before the fronts! There are other options but they are fiddly - such as having a seperate handbrake caliper. This has been done before on this forum.

[Arno]

If you were to fit the same size calipers to the rear as the front, this distribution would be cancelled, and in theory may result in the front end going light(er) under heavy braking - which presumably is the last thing you want when entering a corner.

Brake pad size is not that relevant for the brake bias/grip, although it does help to reduce brake pad temperatures.

The trick here is that the total surface of the 2 opposing pistons in the HiSpec calipers is pretty much the same as the surface of the big single piston in the OEM caliper.

This results in the same clamping force and pedal travel. This means you should keep the same brake balance as orignally intended.

At least that's the theory

ElisepParts do sell a version with larger piston size to be used in combination with their 4-pot AP front upgrade. This works on the Elise, because (unlike the VX AFAIK) it has too much front brake bias so getting more rear braking is a good thing here.

Bye, Arno.

[Ormes]

Holy thread resurrection. Any update/experience?

[Ormes]

OK guess not... I will write to them and enquire.

[vocky]

I think the feedback was to avoid them as they probably seize up

[Ormes]

Thanks Vocky.

[Ormes]

EMAIL TO HI SPEC

 

Hi, Wonder if you could help me? I am looking for a plug and play caliper to replace the rear brembo setup on the Elise/Exige/Europa/VX220, which includes a cable handbrake mechanism compatible with that of the standard car... ideally 2 pot with the same overall piston diameter as standard. I understand these have been developed and even shown at various shows etc., but not seen any for sale. Please could you confirm if and when you intend to release? Given the number of older Elise derived cars on the roads, with questionable rear calipers that are very expensive to replace, and very difficult to rebuild well, I am sure there is a market for a plug and play replacement! Look forward to hearing from you. Kind regards REPLY Hello Alex, that is a caliper that we used to sell, but was discontinued 4-5 years ago. Kind Regards ...So that will be a no then

[Scuffers]

EP one is the only one I know that fits and works...

 

yes, it's redial mounted, but no reason you can't use it on a std upright with radial mount adaptor that I know of?

 

all that said, if your going to the expense of rear calliper upgrade, then I would suggest the MS upright is actually a higher priority for track performance. 

 

[Ormes]

EP one is the only one I know that fits and works...

 

yes, it's redial mounted, but no reason you can't use it on a std upright with radial mount adaptor that I know of?

 

all that said, if your going to the expense of rear calliper upgrade, then I would suggest the MS upright is actually a higher priority for track performance. 

 

--img--

 

Cheers Scuffers Do you have any more info/link... or best to just contact EP?

[Scuffers]

well, All I have is pretty much what you see, a 4 pot with additional spot calliper for the park brake.

 

not sure they are on EP's site yet as Geary only puts stuff up that's 100% on the shelf ready to ship, but they are made etc.

 

By default, they use the same piston sizes as the smaller option of their 4 Pot calliper (31/34.5mm) and so are roughly equivalent to the std 2 pot AP front in clamp load.

 

Park brake cable also needs to be changed to match the new callipers (just the rear part, not the in-car bit).

 

This development has been a long time in coming, with a few false starts (the Hi-Spec one, etc), but where it is now should be good, and 100% MOT/SVA compliant.