22 replies to this topic

[kek700]

does anyone know how to reduce the brake (over servo'ed effect) of the servo. tried removing the vacumme pipe to the servo but this makes the brakes needing too much force to stop the car in an emergency? but gives the brakes much much better feel, can rearlly get the car to stop without continually locking front wheels.

[alanoo]

you have to change the master cylinder to a smaller sized one

[kek700]

thanks for the reply. But a smaller master cylinder will make matters worse, ie more brakeing with even less effort. plus pedal travel will increase. i need a master cylinder of (very approx 1.5 inchs in diameter.) i do not thick such a master cylinder exits for a passenger car.

[kek700]

perhaps **thick** applies, i should have wrote think?

[Anarchy]

does anyone know how to reduce the brake (over servo'ed effect) of the servo.
tried removing the vacumme pipe to the servo but this makes the brakes needing too much force to stop the car in an emergency?
but gives the brakes much much better feel, can rearlly get the car to stop without continually locking front wheels.

Id like the opposite, how could you make the servo apply more force?

[Retset]

Has anybody ever ditched the lot and fitted servo/cylinder etc. from an Elise. Surely a non-servo, non-ABS system is the way to go for feel..... Would save a little bit of weight as well I guess. As long as the brake pedal was set high enough that it all came together for heel and toe, I believe this is an option I would persue ... except I am not technically minded enough to be a ground breaker ... I am only capable of following the crowd .... baa baa

[kek700]

Well, you say you’re not technically minded but you’re quickly onto the end game. The vx has the worst brakes I have ever used on a car. Almost impossible to heal and toe. The slightest pressure locks the front wheels, the abs doesn’t know the difference between ice or wet roads or dry roads come to that. There is the narrowest window between slowing down slowly and locking the front wheels. It is almost there with the servo removed. I would like to solve this without experimenting and consequently spending a lot of money. Inherently the brakes are more than capable with the right brake pads. If I could find a way of removing 75 percent of the servo effect, I am sure they would Be more than adequate.

[Retset]

Well, you say you’re not technically minded but you’re quickly onto the end game.

I meant as in actually doing the spannering and ending up with a working car I'm fully convinced I don't want the servo/ABS

[MrSimba]

The vx has the worst brakes I have ever used on a car. Almost impossible to heal and toe.

The slightest pressure locks the front wheels, the abs doesn’t know the difference between ice or wet roads or dry roads come to that.

Well my standard (apart form the 1144's and 16 groove disc's & 5.1 with Goodridge lines) must be well fettled with then!

I'm no 'driving god' but a mate who has raced single seaters has driven my VX several times and it heel and toes b e a u t i f u l l y

Apart from the fact he finds it the nost neutral car he's ever driven (thanks Scared Stiff!) he really rates the brakes and the ballance, but then again like I said he's damn good!

So if I have a problem I know its me not the car!!!

[Jameshs]

Well, you say you’re not technically minded but you’re quickly onto the end game.

The vx has the worst brakes I have ever used on a car. Almost impossible to heal and toe.

The slightest pressure locks the front wheels, the abs doesn’t know the difference between ice or wet roads or dry roads come to that.

There is the narrowest window between slowing down slowly and locking the front wheels.

It is almost there with the servo removed.

I would like to solve this without experimenting and consequently spending a lot of money.

Inherently the brakes are more than capable with the right brake pads.

If I could find a way of removing 75 percent of the servo effect, I am sure they would

Be more than adequate.

Are you using seel toe-caps by any chance. I find my vx very easy to heel toe and not even think about locking up. Thats both on track and road with either the ABS on or off. Maybe you should look at your driving style before you start playing.

Have you ever driven an elise?

[SteveA]

I find my knee hits the steering column when heel & toeing. I have driven an Atom without a servo and i'd say the braking feel was much worse and also a bit scary.

[rsg]

I find my vx very easy to heel toe and not even think about locking up.

[kek700]

I have never driven any other vx or elise. My vx was one of the first to be made.... not sure but I think it may have been one of the press cars. After these reponses, perhaps I should drive another vx... mine may not be up to much. Just for the record, I have raced and owned a large number of race cars, including formula fords and formula 3. My vx is well set up, I know cause i did it?? and as you say handles very well in fact it reminds me of a late type formula ford. ........but I stll think the brakes are poorly thought out, and heel and toeing is very difficult to achieve with the very over sensitive servo assistance, and, as I said before, without the servo they are then very good. does anyone know how to reduce the vaccum pressure....

[Exmantaa]

I do have to say I find the initial braking also to "easy" for my taste. Heel & toe is difficult. Not sure how pads will change this behavior? Maybe you can fit another servo/cilinder combo from another (small) car where the braking is more your taste? As a quick fix, the servo assistance (= underpressure) should be less when you fit a spring assisted check valve in the vacuum hose. The cracking (opening) spring pressure is then added to the underpressure in the servo. (Pservo + Pcheck = Pvacuum => Pservo is less.) (You can buy adjustable checkvalves, but you should choose one with a big enough internal diameter.) I give no warranty on this mod!

Edited by Exmantaa, 13 February 2009 - 05:21 PM.

[kek700]

Thanks for the response.. Any ideas were I might locate such a device??? I have tried EBC yellows and have considered using EBC blues in an attempt to reduce friction, but as I am trying to do this on a budget, I am not to sure about the outcome of this route. (EBC yellow have very simular response from cold to standard pads, which i did not expect).

[Retset]

Since having the geo done, the car stops well and doesn't want to lock up all the time and I now feel I can live with my servo. I still think for best feel, it would have been nicer with no servo like a Caterham .. I shall not bother to change anything now though.

[zebwach]

I'm knocking on the door of 6 feet 3 inch's and I find 'heel & toe' impossible. I never had a problem in my previous car so it isn't that I can't. There is just not enough room to twist your leg around without hitting the steering wheel, for people aflicted with lanky legs or lacking double jointed knees!

[Jameshs]

Since having the geo done, the car stops well and doesn't want to lock up all the time and I now feel I can live with my servo. I still think for best feel, it would have been nicer with no servo like a Caterham .. I shall not bother to change anything now though.

How do you rate the 1155's??

[rik]

brakes in a s1 were scary to me (no servo).. but i'm sure some find that better for track driving as there's room to be more accurate with the force you apply.. If you want to try without the servo.. just unplug the vacuum hose (and block it up)

[Exmantaa]

I'm not sure if our vx has the same brake pedal lever ratio as an S1 Elise. Without servo you seem to need a lot of force to shed some speed...

Edited by Exmantaa, 17 February 2009 - 03:32 PM.