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Author: Subject: MK vs Caterham steering
laserblues2

posted on 5/9/07 at 07:57 AM Reply With Quote
MK vs Caterham steering

When i've driven Caterhams i've always found the steering to be very close and very precise.... driven 2 MK's and didnt feel the same way. Just wondering if ppl leave them like that or change the steering racks??

Nick

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DarrenW

posted on 5/9/07 at 08:00 AM Reply With Quote
Do you mean the Indy or GTR?

I guess part of the answer lies if you are comparing like for like ref ratio's or not. I guess the geometry will make a difference too. Something leads me to suspect most Caterhams will be well set up but a lot of MK's may still have the DIY settings and could benefit from a pro set up.






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worX

posted on 5/9/07 at 08:00 AM Reply With Quote
You would need to know whether the MK's were fitted with quickracks for a start. If so then you can go on from there!!!

Steve






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StevieB

posted on 5/9/07 at 10:16 AM Reply With Quote
Isn't the Caterham rack 2.2 turns? the best sierra quick rack I've seen is 2.8 turns, so this could have a bearing.

I'd like to upgrade my sierra rack to a quick rack, and have been thinking about maybe fitting a Caterham or mk2 escort quick rack as there seems to be sme better options available (and they look a lot lighter in weight too!)

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tks

posted on 5/9/07 at 11:05 AM Reply With Quote
MK2 Escort quickrack is 2.4 ratio.

from raldes 100quid i thought it was

Tks





The above comments are always meant to be from the above persons perspective.

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Hellfire

posted on 5/9/07 at 11:15 AM Reply With Quote
I would imagine it has a lot to do with the Sierra donor running gear up front as well as the steering rack. Get rid of the heavy Sierra discs and calipers for some lightweight stuff (Wilwood, Hi-Spec etc), drop a quickrack in and I doubt there would be so much difference.

Phil






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britishtrident

posted on 5/9/07 at 11:16 AM Reply With Quote
All down to Bump steer and corner weights.

Even a standard Escort rack is much too wide between the inner ball joints - it gives massive bump & roll steer..





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procomp

posted on 5/9/07 at 01:38 PM Reply With Quote
Hi as britishtrident says ^^ its all down to the geometry and setting inc castor wich is what gives the feedback through the wheel.

But comparing caterham's and MK' is like comparing chalk and cheese. The difference in the two is huge.

cheers matt

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RickRick

posted on 5/9/07 at 02:07 PM Reply With Quote
how does the width of the steering rack effect bump and roll steer, i can understand how the poition of the rack would effect handling. and how would you go about improving it
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StevieB

posted on 5/9/07 at 02:52 PM Reply With Quote
I guess the big question is how to improve the Indy handling and feedback as simply as possible

I was thinking of using a modified mk2 escort rack (or maybe just getting a Caterham item) and shifting the mounting position (don't know where to, but that's the tricky bit!)

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britishtrident

posted on 5/9/07 at 06:10 PM Reply With Quote
Yes getting castor right is crucial - especial getting it exactly equal both sides.

With the Escort rack the way to start getting rid of bump steer is to get the rack width between the track rod inner ball centres reduced by a machine shop. Then the track rods will need extenteding and the track rod ends replaced with spherical rod end bearings with spacers to allow the track rod ends to be adjusted for height.

The steering rack height also requires to be made adjustable.

After that it is just a matter bolting everything up in a best guess position and constructing bump steer curves by measurig the toe-in at different ride heights.
Use the data from the bump steer curve to adjust the rack or track rod end heights and repeat the procedure.
It takes a few itterations to get it somewhere close to right.





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erwe

posted on 5/9/07 at 07:05 PM Reply With Quote
The setup of the front suspension is very different to the MK indy.
An escort steering rack fits with no shortening and there is a little anti dive geometry.
Also the anti roll bar makes a lot of difference.

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Hellfire

posted on 5/9/07 at 07:57 PM Reply With Quote
laserblues2 - MK's vs Caterham is hardly a fair comparison - there's about 15000+ between them for a start. I dont mean to sound patronising but by intimating that by changing the steering rack will cure the problem is inviting few jibes. As Caterhams are the market leader (by a long way) they have more resources to cater for the generally better heeled Kit Car buyer... The MK Indy is not a Caterham and never will be.

StevieB - the simple solution is to allow a professional race team to setup your MK Indy to the best of what it is capable of (considering above) and hand over the money for the priveledge. Then pull over to the right when that Caterham is riding your arse...

Ultimately - with the same driver and as near as dammit engine/setup, a Caterham will run rings around most 7 type cars due to its superior handling - from what I have seen.

Steve






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RickRick

posted on 5/9/07 at 08:27 PM Reply With Quote
ok so, going for fast road/ amature track use can someone give a base setting for, camber, toe, caster and the other stuff. Also can someone give me the length of the steering rack caterham style.
Thanks.
ps i know i'm asking some aquard, annoying questions but i only want to build once, going for right first time, and for the right price i'm telling myself 7k and expecting to spend 10k

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britishtrident

posted on 6/9/07 at 12:08 PM Reply With Quote
quote:


Ultimately - with the same driver and as near as dammit engine/setup, a Caterham will run rings around most 7 type cars due to its superior handling - from what I have seen.

Steve


Not sure if that is the case I know of one xperienced club racer who switched from a Caterham to pre lit Westie and swears there was no real difference except for health of his bank balance.

To put some numbers to the steering rack bump steer issue by my reckoning the Escort rack is anything up to 6.5 inches too wide across the inner track rod ball joints for a "book build" Locost.

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Peteff

posted on 6/9/07 at 12:41 PM Reply With Quote
I built and drive a book locost

What's bump steer ? It goes where I point it and that's all I ask for.

[Edited on 6/9/07 by Peteff]





yours, Pete

I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.

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StevieB

posted on 6/9/07 at 04:57 PM Reply With Quote
quote:
Originally posted by Hellfire

StevieB - the simple solution is to allow a professional race team to setup your MK Indy to the best of what it is capable of (considering above) and hand over the money for the priveledge. Then pull over to the right when that Caterham is riding your arse...

Steve


I'd rather fiddle with the setting myself and learn as I go along through research - at least I'll learn a lot more about how to make my car handle in certain ways.

Will more than likely learn how to make my car handle worse at first though!

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britishtrident

posted on 7/9/07 at 07:37 AM Reply With Quote
quote:
Originally posted by Peteff
What's bump steer ? It goes where I point it and that's all I ask for.

[Edited on 6/9/07 by Peteff]


Too really appreciate how much bump steer takes away from the driving experience you have driven a car which has had it dialed out.


First time I drove a decent properly set up Van Diemen FF I realised how much work I had to do on my Davrians front end.





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procomp

posted on 7/9/07 at 08:40 AM Reply With Quote
Hi this is turning into the ussual sort of post where nothing being said has anything to do with what acctually happens in the real world.

Book cahassis can get the bumpsteer down to 15 tho of in in bumpsteer from static R/H with the std escort rack. Where all the BS of it needs shortening comes from i have no idea.

The difference between a car from the world of locost ect and a caterham is not down to 's it is down to the fact that the suspension geometry is working. Westfield RAW and others can get the handeling pretty close to a caterham. But the fact is that manny of the manufactureres in the world of locost have verry little if any idea of what they are doing. Many of the manufacturers cant even get thier chassis the same length both sides never mind the sus geometyr right. It is not monney that make this difference but putting the effort in to the prodject and sorting problems out as they appear. Every one knows of a certain car that has majore flaws in its handeling but has that manufacturere ever done any thing about it NO.

I think that many people should go and acctivly seek a drive in a good well setup westfield raw caterham ect to give them an idea of what a kit car is supposed to handel like rather than constantly being told that cars from the world of locost are exceponaly good handeling. Compared to what the sierra donnor because in some cases the sierra handels better than the car it is destined to become.

And yes people will say that they do not need the car to handel like a race car ect ect. But then start to ask questions about why it dosent when they start driving them. There is no excuse for the fact that some kitcars dont handel well ect. Its just that the manufacturer dose not want to put the effort in to the car to achive what is now expected of a light weight sports car.

Sorry about this rant but when people are spending many 's it is verry sad when they have eventually finished the build that they are so dissapointed whith it On the handeling front. And then end up selling which leaves them many 's out of pocket.

cheers matt

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livelee

posted on 26/8/08 at 11:16 AM Reply With Quote
Sorry to bump an old thread but..

..This is an interesting topic and one very relevant to me. I have to race, and try to beat, many caterham drivers from our local club at events. I have the ability, just not the bank balance.

I have a MAC#1 ZR Zetec and it badly needs a setup. Procomp you sound like you know what you're talking about (I don't I just drive). The car has GAS shocks with, i'm told, 325 front springs and 175 rear springs. The car has a standard 4.25 lock to lock sierra steering rack. Where should I start in getting what I have as good as possible, what parts should be changed etc? The 2.4 turn MK2 escort rack looks like a good start. Hopefully this will be an easy job to change.

You mention Westfield RAW above but no amount of googling from me can find them. Do they have a webpage? Are they located on the south coast by any chance? If they happen to be out of range for me could you reccomend anybody closer (I'm on the Isle of Wight)

Many Thanks for any advice, kind regards

Dan.

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dhutch

posted on 26/8/08 at 12:32 PM Reply With Quote
quote:
Originally posted by livelee
Sorry to bump an old thread but..

..This is an interesting topic and one very relevant to me. I have to race, and try to beat, many caterham drivers from our local club at events. I have the ability, just not the bank balance.

I have a MAC#1 ZR Zetec and it badly needs a setup. Procomp you sound like you know what you're talking about (I don't I just drive). The car has GAS shocks with, i'm told, 325 front springs and 175 rear springs. The car has a standard 4.25 lock to lock sierra steering rack. Where should I start in getting what I have as good as possible, what parts should be changed etc? The 2.4 turn MK2 escort rack looks like a good start. Hopefully this will be an easy job to change.

You mention Westfield RAW above but no amount of googling from me can find them. Do they have a webpage? Are they located on the south coast by any chance? If they happen to be out of range for me could you reccomend anybody closer (I'm on the Isle of Wight)

Many Thanks for any advice, kind regards

Dan.

Cant really help further other than suggest procomps post left out a comma.

RAW:- http://www.rawengineering.co.uk
Westfeild:- http://www.westfield-sportscars.co.uk


Daniel

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livelee

posted on 26/8/08 at 12:47 PM Reply With Quote
Ahh, that makes sense now. Procomp meant those kit car makers can get their cars pretty close to a caterham.
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