Fostek's R&D department

[boffer8]

Re: Fostek's R&D department

Excellent build and amazing to read. Love the Joystick gearshift and the exact weight saving that has gone on throughout.

[FOSSIE]

Re: Fostek's R&D department

Well the car was out on track at Croft for the RSOC trackday back in June, successful day all round really, car performed very well and I'm pleased to say I think we've got the gearshift gremlins sorted out at last.

The performance took us all by surprise to be honest - keep in mind this is a rally car and shouldn't really be at home round a race circuit - but there's a video knocking about of it pulling away from a Time Attack Evo down the back straight!

The only potential show-stopper was being black flagged for being too noisey! I wasn't surprised, I always knew it was sailing a bit close to the wind in terms of noise, but I was very surprised by the solution! Taking the silencer off, I was expecting to find it empty - my experience of re-packable silencers would suggest that they tend to blow the packing out and need re-stuffing from time to time - but this one was packed solid! The scrutineer suggested taking some packing out, which we did (about 50%) and the result was something like 20dB quieter through the noise trap... I'd never have guessed that - learn something every day. Happy days though - it means we don't have to start adding more silencers...

Looking at the data logs I still think it's over-cooling, but I'm not sure what I'm going to do about that yet.

The new anti-roll bar made a big difference, felt much better on the longer bends, although a touch more understeer on the tigher bends, so I reckon the softer bar would be needed for a twistier track.

Couple of gremlins with the throttle system, but it looks like we've got to the bottom of that...

So the only changes before the next track session is a new steering column! The one in the car was just a butchered OE Escort column. I wasn't sure whether the car was going to need power-steering or not, so we decided to try it out without first, before spending any effort on a properly engineered one. Anyway for whatever reason, maybe the suspension geometry, or the fact it's only running little wheels, the steering is lovely and light even with 8" slicks on the front - so we decided EPAS wasn't needed and we knocked up a new inner-column purpose made for the job.

This new one is made from a single piece of EN24T, with the bottom end splined for the Escort knuckle, and the top end has the detail for the quick-release boss machined directly into the shaft rather than welding on a boss (which concerns me a bit) Nothing out of the ordinary, just neat, simple, strong and best of all - light









Next outing is Donnington park trackday sometime in August, to test the new throttle setup, some different brake pads and possibly some different tyres...

[Warrior]

Re: Fostek's R&D department

Me and John ( fossie's dad) were talking about this at a charity day recently. How many conversations we had both have with people about there lightweight new gucci bits and the driver weighed 20 stone

Haha brilliant

[mexicotait]

Re: Fostek's R&D department

Me and John ( fossie's dad) were talking about this at a charity day recently. How many conversations we had both have with people about there lightweight new gucci bits and the driver weighed 20 stone

[Warrior]

Re: Fostek's R&D department

This thing is a work of art,

A bloke was telling me how he was saving grams of weight here and there in his mk2 escort hill climb car,

He's not the smallest guy buy far, I'd gess twice my weight so if I were driving that's 70kg to start with, or get mexicotait as where a similar size

[FOSSIE]

Re: Fostek's R&D department

Why the hollow shafts?
Is it a significant weight saving?

About 500g per shaft I seem to recall. Obviously you can bore a bigger hole, but you're weakening the shaft, so it's a trade-off.

[Forest_rallying]

Re: Fostek's R&D department

That axle's so Sexy it makes you want to sleep with it.
Fantastic work, have you any idea what the dry weight of it complete with brakes will be?

[Graham]

Re: Fostek's R&D department

Why the hollow shafts?
Is it a significant weight saving?

probably not a significant saving, but if you look at every little bit of weight you can save it adds up,

like a jar full of pennys, each one isnt worth much but when you have a huge jar full suddenly you have a decent amount

[mexicotait]

Re: Fostek's R&D department

Why the hollow shafts?
Is it a significant weight saving?

Last Road rally I did my car was the lightest by far just because my navigator and I were at least four stone lighter than any other crew

So if you are looking for a light weight test pilot you know who to ask!

[Graham]

Re: Fostek's R&D department

very very cool tom a core plug could be a very simple effective way of keeping the oil in or out the shafts depending on which end you it it to

[FOSSIE]

Re: Fostek's R&D department

So just to re-cap: back end of last year the engine & box were out whilst we made a few mods to the gearshift system... Didn't get a whole lot of testing done afterwards but enough to prove the mods worked. So the car was tucked up for the winter and we made a start on some new bits ready for this year.

The new axle is well under-way. Well actually, this is the "proper" axle which was destined for the car all along - the one that's currently in the car is a bit of a test mule. This one is truly 1-of-a-kind - the casing was done in the final days of Fostek and I'm not sure I could do another one now if I tried, being a bit out of practice! The tubes (and bracketry) are all made to fit this shell, and are made from very thin wall 4130, welded as an assembly, then heat treated, before final machining and fitting into the diff housing (which is Alloy).

Here you can see the hubs, flanges, bells, discs etc all taking shape. Some big weight savings were made here - the hub assembly for example is rotational mass as well as un-sprung mass, so it's worth going to town on. Those studs are titanium: nut guns are banned!





Hollow halfshafts & pinion... Although it just occurred to me I need to think of some way of stopping the oil running out the shafts! It took nearly a year to make these - they're certainly well travelled - having been through no less than 7 different operations/companies; Rough machining, gun drilling, splining, heat treatment, more machining, shot-peening, straightening. They even shot-peened inside the gun-drill hole! I'll be most upset if one of these breaks.



Also knocked up a couple more anti-roll bars. The front suspension is all a bit new to me, and I have no idea what rate of roll bar will be required. The one on the car (lets call that the "medium" stiffness) is approx the same rate as a typical GP4 Escort tarmac type ARB. Then there's one which is 25% softer and one 25% stiffer, which should be enough to give us an idea what's required...



There's also a new steering column on the way, no pictures as yet though, watch this space.

[Nelly]

Re: Fostek's R&D department

I think maybe I'll have to do the same as no one seems to sell a decent roll bar to use on a circuit.

[Fosworth]

Re: Fostek's R&D department

Sorry, its not a kit but is a one off we made for this car. Most of the components on this car are also one offs.

[Nelly]

Re: Fostek's R&D department

Is that antiroll bar available as a kit?

[philipmax]

Re: Fostek's R&D department

Deadly machine