Pedal boxes

[Alex Hodgkinson]

Hello all,

We're currently building a Mazda RX-7 to race in the GT Cup and/or Britcar.

These cars are very small, so getting things to fit in the cockpit (let alone the driver) is a struggle. Having spent two days fitting the seat and electric power steering system correctly we're now looking at pedal boxes.
As the driver I have a total dislike of pedals which hang down, so we've been looking at floor mounted pedal boxes, all the time looking for a really short box (<150mm/6in)

I found these on the ap site which looked just the job;

http://apracing.com/info/products.as...edal_2351_2342

Phoned up AP today and the chap on the other end told me to "make sure I was sitting down" - they're £3000!!

So, basically I'm looking for a pedal box which is floor mounted, very short and under £1000. I've seen these - http://www.tiltonracing.com/content....st2&id=399&m=b - but I'm not sure how much they'll be. Probably somewhere around the £1500 mark, I'm expecting.

I know a few of you have done this sort of project yourselfs, so what can you all suggest?

[vjay48]

if your could cure you dislike of pedals that hang down a mk 2 escort pedal box for a couple hundred quid,will fit a lot of cars with a bit of tweaking,i think because its simple you can adapt it? have a look on rally design.

[vjay48]

just had a look on rally design,do a floor mounting pedal box,looks good value,we bought box from them,good price,works well

[zac510]

They are a third that price on that 'demon' website as an example.. But without the cylinders. Tiltons are cheaper.

[Alex Hodgkinson]

Demon Thieves? I always avoid buying from that lot. Actually I notice that they don't advertise the AP product I was looking at. They'd probably be asking £4000 for it if they did.

I have had a look at those on rally design before, Wilwood I believe? I'm not sure if they're right for us or not. They could be too deep. The important mesurement for me is that from the closest part of the pedal box to the engine bulkhead to the pedal pivot points. The problem is that I'm nearly 6ft tall and Japanese people are not!

Can you find any dimensions for the Wilwood pedal boxes? I've had a quick look but can't find any.

[zac510]

http://www.wilwood.com/Products/005-...fmbp/index.asp
155.7mm it appears.

[Alex Hodgkinson]

Thanks. Although I actually meant with the master cylinder present. Anyway I think that's illustrated my packaging problems, I need a pedal box to be around 155mm in length with master cylinders present. Doesn't matter about reservoir pots as they'll be mounted seperately.

I'm going to give Tilton a bell about the 900-Series tomorrow. I was just hoping there was a cheaper example out there which somebody could tell me about.

[zac510]

Yeah that rules the Wilwood out.
Have you followed the progress of the Rx7 already in Britcar? What class are you building it for? (I've no experience, just curious!)

[tristancliffe]

Can you design and make your own? Pedals aren't complicated really, and you can add all sorts of nice things like the spherical bearing mounted m'cyls that have become popular at the higher price regions.

[Alex Hodgkinson]

We're hoping that we should be able to get it on GT3 pace, so most likely class 2. Just as a reference the RX7 currently in Britcar runs in class 4, against Honda Civics and suchlike, but they have the potential to do so much more than that. With 50/50 weight distribution, low Cd (0.29) 950kg, 385bhp and a proper aero package I'm sure you can see where I'm coming from.

It does look like we're going to be building our own pedal arrangement, yes. I had hoped that we'd be able to find something which we could buy and adapt for our own needs, but it seems not. In which case all I need are some example master cylinders and we can crack on.

[MikeHart]

Have you maybe thought about fabricating one yourself? You can get some pretty accurate stuff made with laser cutting these days, and the pedal box in our 2008 Formula Student car is pretty compact with vertically mounted master cylinders.

You can just about see it here:

[Tony C]

How about the wilwood reverse swing unit and turn it upside down

[MechaniX_034]

Originally Posted by MikeHart

Have you maybe thought about fabricating one yourself? You can get some pretty accurate stuff made with laser cutting these days, and the pedal box in our 2008 Formula Student car is pretty compact with vertically mounted master cylinders.

You can just about see it here:

Just out of curiousity, what would be involved in fabricating one(tolerances-wise) I must apologise up front for my ignorance, but I've never tried putting a pedal box together before and it sounds like a nice project to keep myself occupied for the next few months.

[dgh.mr2]

Though not fitted yet I have just bought a complete system from OBP (Optimum Braking Products) for a Toyota MR2. For £395 including VAT and postage!

This consists of three floor mounted pedals - inward (in cockpit) fluid reservoirs, master cylinders and balance brake bar etc. and aloy cover/false floor - description from their site as below:

"All 3 pedal in one unit Hydraulic clutch cockpit fit system (kit includes 3 x M/Cyl, 3 x Res, 1 x Bias Bar, 1 x Res Bracket, 1 x Bias Cable Adjuster) with OBP0208 Top Cover."

The guy I dealt wth - Grant - was very helpful and has offered any help and to make changes should it not fit me comfortably or I need leverages and resistance etc. altered (they have several clinder designs with different pistons/ capacities so can adjust to suit the car/driver.

[MikeHart]

Originally Posted by MechaniX_034

Just out of curiousity, what would be involved in fabricating one(tolerances-wise) I must apologise up front for my ignorance, but I've never tried putting a pedal box together before and it sounds like a nice project to keep myself occupied for the next few months.

Well, if you want to get it laser cut, you fundamentally just need to get to grips with a CAD package. If you've not used one before, you might struggle a bit, but there are plenty out there to have a 'go' with If you'd rather just stick to the old elbow grease method, then just get hold of some 2mm or thereabouts, sheet steel and start bending and cutting stuff to appropriate sizes and shapes. One good way to start though is to just use some modelling card to mock the whole thing up first.

There are three main things you need to be aware of when designing the thing though, one being that the mounting for the master cylinders needs to be rock solid to prevent any flex and hence poor pedal feel. This can be achieved either by using thicker sheet or by making sure you strengthen the structure around that area. Numbers two and three relate to the virtical location of the master cylinders. You need to have a play around either on CAD or with bits of wood to check you get your ratio of travel right in the cam that converts the forward and backwards motion of the pedal to up and down for the master cylinders. The other is that you need remote brake and clutch reservoirs and to bleed them you'll need to turn the pedal box through 90deg which can be done fairly easily if you design in a removable mounting.

Personally, for the sake of the space in an RX-7 which must be miles more than in our FSAE car I'd go for normal horizontally mounted master cylinders. You could still come up with a far more compact solution for a lot less money though. If you really want to go for minimal space, our virtically mounted pedal box is less than 200mm from the pedal face to the back of the box structure.

For the laser cutting route, use a CAD package and then you can simply send the unfolded drawings of the sheet parts to a company like Midtherm. It's pretty inexpensive and the quality you get is as good as a mass produced pressing. The tolerances are also a lot better too....a 40mm hole will be bang on 40mm.

Once you're all welded up the final thing should be a matter of mm within the design. It certainly wouldn't be enough to worry about. I'll try and get some better pictures of the thing later.

Hope that helps. Let me know if you need any more info.