What are locosts like for wheelspin?? I mention this because they have half of naff all weight over the rear wheels, and hence surely have little or no grip on the rear??

Ed.

erm not a lot of fun in the wet

wheel spin is directly proportional to how heavy your right foot is at any given time, in other words, yup the wheels can be made to spin, thats 1/2 the fun, your driving somthing that needs driving and driver input rather than point and go...

seat of the pants tells the driver everything he needs to know.

on an irs car you'll also get a bit of torque reaction on the dif, meaning the rear right should go before the rear left does! hicost's car had a lot of wheelspin on 0-80 (private road obviously officer) when he took me for a ride. stevem's live axle car also wheelspun at brooklands (live axle 1600xflow on loose concrete)

Ned.

Ned.

kind of opposite to wheelspin is engine braking - making you lock up the rear wheels.

i came round a slight bend to a roundabout (know the road well) and was pasting it in 3rd, then braked and then hooked 2nd whilst still going a little to fast, foot off clutch and facing the wrong way!

It just locked up the rear wheels as if doing a handbrake turn, that was a dry road too, anyone else experienced this magnitude of angine braking?

I know my dad had a jeep cherokee 2.5TD that was a bastard for doing that, again on dry roads too.

I did something similar once in my old triumh toledo in the dark on a damp road at a t junction. i hoofed it round and ended up facing completely the wrong way out of the juction as opposed to turning into it!

I also managed ot drag the rear quarter panel of a saxo i once owned through a hedge from simlar circumstances.

Ned.

I'm looking forward to seeing how a IRS BEC with LSD behaves... I expect the BEC to be rear heavy & not a lot of weight transfer due to acceleration with low CofG and I'm going for quite a high geared diff. My last project was rover V8 in a mazda mx5 - this now has a 4.6 in - & I was concerned that wheelspin & general tail happy lunacy might be a problem - but no, paradoxically it's much better behaved than it was as a 1.6, traction is phenomenal. Obviously you can lose it if you try hard enough but I generally try not to do that on the queens highway (not too often anyway...) That has IRS and LSD & the chassis is a bit better than stock 'cos I put an extra wee triangulated subframe to close the bottom of the transmission tunnel.
Bob C

I know that live axles get torque reaction and one wheel going before the other.. there are trailing arm mods in my suspension book to correct it and give you better straight-line traction than an LSD.

I didn't know IRS suffered from it as well.. Are you sure? I can't quite see how that would work.. have to think about it.

I went to Silverstone to drive an Elise round and it was very very wet indeed. They couldn't stress enough about taking your time with downshifting under braking. It helps a bit that they are mid engined but only up to a point since there's more mass that wants to come swinging round.
Really nice car though Only had it sideways once

Heel and toe, Heel and toe, Heel and toe, Heel and toe, Heel and toe, Heel and toe, Heel and toe...



lets sing along together,

Heel and toe, Heel and toe, ...

love it.

once you've practised it enough and got it right, you can use it to prevent the driven wheels locking up under engine braking. The idea is to pick the revs up to match the new gear youre selecting, thus preventing the huge engine braking effect.

I find myself doing almost every gear change now! Bit of a waste of effort most of the time but practise makes perfect and I always make sure of it when, whats the word, "hacking" it along the lanes, oh and empty roundabouts.

I can't physically do it in my current car, hopefully the Puma is better

right can someone explain this heel and toe thingy to me, i have heard it plenty of times but not sure about it really

Heel and toe is a bit of an exaggeration - basically you use your toes on the brake to be slowing the car down, and the heel to "blip" the throttle to get the revs up to the right level for the lower gear being selected. Hence, when you release the clutch there is no engine braking because the engine is at the right speed. Exaggeration because it is typically ball of the foot on the brake and side on the throttle.

Ideally combined with double de-clutching for the smoothest gearchange and least wear on components. That means releasing the clutch when in neutral during the change, blipping the throttle then, then down with the clutch again and into the lower gear. This makes sure the gearbox shafts are spinning at the right pace as well as the engine.

Probably clear as mud that I should think!!

[Edited on 27/2/04 by andyps]

andyps, really good explanation, but I have never driven a car where I could use my heel. I usually brake with most of my right foot and the trottle pedal is sufficiently close to the brake to blip the throttle with the outside of my foot. Italian cars seem best set up for this. I copied the pedal spacing of a X19 with my sierra pedals, to make sure it was as intuitive as the marvelous if decaying X19

i worked it out myself, unfortunately the wrong way round though! so i brake with my heel and tap the throttle with my toes. i actually set the pedals up like this on the locost so i best not try doing it the proper way!

I brake with the heel and blip with the toes too, on my primera.. other way round didn't seem to work for me.

then again, I'm not very good at it anyway.. but I am ok at just blipping without braking, makes for smoother shift-downs and less bothering my clutch (which is on the way out anyway)

Guys,
I'm building my pedal box at present and would appreciate any advice on the best placement of pedals. I have size 10 feet (quite narrow too) so hopefully some of you out there will be similar.

What is the best spacing between pedal centre's and how do I set my throttle pedal up best for heel and toe? I'm hoping to just use the Sierra pedals with various mods to straighten them out. On that subject, I was following your recommendations (Mark A) on Sierra pedal mods but it appears that my Sierra master cylinder is of a different design to the one you are using and I can't get all the holes to line up between the pedal box and the master cylinder mounts. My master cylinder is the one with the Ford logo on it and three outlets. It also has the numbers 22 on the side. I think it is a bendix type going by brakepart's website.

Should I try to get a different m/cyl or do you have any other suggestions?

Cheers,
Craig.

It seems that I heel & toe differently to anyone else, so pedal spacing must be to personal preference. I brake with the ball part of my foot at the base of the big toe, and rock my foot to the right to blip the throttle with my little toe. I cannot image braking with my heel and dabbing the throttle with my toes, my shoe laces would get tangled in the steering column!

Sorry to hear about your master cylinder, if you took your pedal box to the scrappies (show the rottweiller on the way in!), and match up a master cylinder from a sierra, I think that most have the same cylinder as mine (89 2.0i). The setup I have used does save a hell of a lot of f@cking about, and special expensive M/C's

Mark,
Thanks for that and for what it's worth I think your heel and toe technique is "normal". I have watched Tony Pond on the "TT Challenge" video and also footage of F1 drivers and Colin McRae and they all seem to brake with the ball of their foot and sort of clumsily dab the throttle with the side of the foot and perhaps the side of the heel. I can't see how it can be done with the heel on the brake and toe on the throttle unless you have double jointed ankles! I can't make my toe come up far enough!

As for the m/cyl, I have got two now from randomly selected 1989-1990 sierra's and both were the same type as described. At least I now know what to look for next time. In the meantime I will look into simple welding a thick plate onto the front of the pedal box to mount both the brake and Rover SD1 clutch master cyls onto. This may well be a good route anyway as I'm not using the cable clutch mechanism and will need a plate for the clutch m/cyl anyway.

Cheers,
Craig.

I had a go at heel and toeing using the heel on the brake and toe on the accelerator today - I reckon you must need strange jointing in ankles for that to work

I'm going to stick with toe/ball of foot on brake, heel on accelerator thanks!

Craig,

I don't know if you saw my reply to "fully welded seat belt mounting" but, I've popped a few more pics in the archive, including my pdeal box.

I've reordered the spacing of the washers and spacer, which now go:

1. Spring clip
2. Washer
3. Clutch pedal
4. Spring
5. Frame of box
6. Large Bush
7. Brake pedal
8. Large Bush
9. Spring Clip
10. Small bush
11. Outer frame of box

Throttle pedal separate

Gap betweeen pedal rubbers and footwell walls

Inner wall to clutch pedal - 35mm
Clutch pedal to Brake - 71mm
Brake pedal to throttle pedal - 71mm
Throttle to outer wall 11mm

HTH

ATB

Simon

Simon,
Thanks for that, I'll take another look at it tomorrow night and see if I can apply any of that to my car. Obviously you have gone for the reverse assembly whereas I think I have enough room for the traditional assembly so I'm not sure what differences this will produce.

Do you find the spacing to be "comfortable" and are the dimensions from centre to centre or between closest points?

I'm not long in from the garage and I've decided to just weld the pedal box onto a 4mm thick piece of steel plate which will be bolted or welded onto the top inside vertex of the tube just above my steering column lower support bush. I'll also support the sierra pedal box at the upper slotted mount using some sort of bracket.

I've measured my "ideal" pedal rubber centre point to be 7" off the floor and this translates into 18" from floor to centre of pedal pivot. This also takes account of the required slope of the master cylinder which I worked out to be 12 degrees upwards (from mounting face to the end of the m/cyl)

Sorry if this has taken the thread off topic a bit...

Cheers,
Craig.

just a quicky,

Simon, where did you get the clutch master cylinder from and can you give me an idea on price please.

Many thanks

Craig,

The distances I quoted were for the spaces between pedal rubbers or pedal rubber to inside footwell walll. As for comfort, seems to be ok. If anything pedals could do with being a little higher, but I don't won't to lose any "leverage" by shortening them.


Colin,

Got clutch m/c from Raldes - Part no RD3620 (0.70" bore) - £28.50 +del/VAT.

FYI
RD3619 = 0.625" Bore
RD3621 = 0.750"
RD3632 = 0.813"

All intregal reservoir

Non intergal also available.

I'm not sure I've got he right one though (need to investigate clutch before I comment further!)

ATB

Simon

Simon,
Thanks for the dimensions and other information, it should come in handy in the next few days.

Here is a picture of what I am trying to build. There are another 6 or 7 pictures on my website from different angles. Check out my March Diary for details. The plate at the back is 4mm thick mild steel inclined at 12 degrees from the vertical (to suit the master cylinder reservior) and I am using self tappers to secure the Sierra pedal box to it while I evaluate the positioning. Once I am happy with the positioning I can weld the sierra pedal box to the 4mm plate which will itself be held in place by bolting it to a couple of 5mm thick brackets. I will then build a bracket to secure the upper mount which is important to prevent the pedal box from twisting under load.

Finally I will drill a large (41mm) hole for the brake master cylinder and another for the clutch m/cyl.

Comments very welcome!
Cheers,
Craig.




[Edited on 2/3/2004 by craig1410]

Here's another shot showing the brake m/cyl in approximate position. It should be far enough away from the exhaust but I can fit a heat shield if necessary.

Great minds............................
Rescued attachment Pedals.jpg

I know its probably wrong, but on the Avon Tiger mount the M/C horizontal!
So that means the fluid reservoir slopes down.

I'm not bothered cause I cut off all that crap and went floor mounted

Craig,

Think what you are doing is perfectly ok (see http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=10000017.jpg)

It was what I was going to do, except I was going to have m/cyl horizontal, rather than inclined (per Sierra).

It's what Tiger do in their book - though they weld the upright to the chassis, and bolt p/box to bracketry. Same difference I guess, though reckon your p/b will be a lot stronger!

ATB

Simon

I know it looks a bit like a railway bridge, but it's strong!
Rescued attachment Pedal Box.jpg

Mark,
I must admit that your design inspired some aspects of mine although due to the different master cylinder that I am using with the different hole spacing, I can't do it exactly as you have done. This is why I am making the 4mm plate an integral part of the pedal box and then bolting this entire assembly to the chassis rather than welding the 4mm plate to the chassis and bolting the pedalbox to this plate.

I had some fun last night drilling a 42mm and 35mm hole in the 4mm plate for my two m/cyls. I used the multiple holes around the perimeter technique and broke about 5 drills in the process...

Anyway, the two m/cyls now fit like a glove and I should have the pedals fully installed by the weekend with continuing luck. Next up will be the handbrake cable mounting.

As for the master cylinder reservoir, I disagree with Tiger for making it sloped and I am surprised that they can get away with that as it will alter the way that the two circuits behave in the event of a low fluid situation and will reduce the capacity of the rearmost circuit. It seems a bit daft that some folk fail SVA for silly things when the brake m/cyl isn't mounted correctly and this doesn't seem to matter. In my case the slanted 4mm plate helps my pedal position and gives me slightly more leg room while still giving enough reserve pedal movement.

Thanks again guys,
Craig.