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How Wide...?
Chr!S - 30/1/07 at 12:03 AM

I searched the site a bit prior to building and came across several posts saying that the sierra based cars need to be +4s. So ive started building one....

However, now ive been searching again and seem to find some people saying that it fits in the standard book chassis and some saying its +7!

Im a bit confused. The actual width is goverened by my chassis (~1466mm off the top of my head...) as the axle will be made to the distance between the suspension links, which is +4" from the book anyway. The only thing worrying me is that i have done this because I wanted the extra track width and to avoid chopping shafts.

Will the sierra shafts and diff really go into a +4"? being as the diff between a MK2 esc and sierra IIRC was about 6.8"... If not im assuming the diff can be moved forwards/backwards anyway, is it true that it is biased to one side? (ie bigger shaft on one side?)

Any response would be excellent as I would like to install the axle (using de-dion) at some point this week....

Thanks in advance, Chr!S


smart51 - 30/1/07 at 07:52 AM

My car is about 1700mm across the rear arches.


macnab - 30/1/07 at 08:10 AM

and mines nearly 2m...


3GEComponents - 30/1/07 at 08:24 AM

2m? that's what my Land Rover is!!!!

Man, that's wide, no chance of flipping that over


macnab - 30/1/07 at 08:53 AM

that's the idea


MikeRJ - 30/1/07 at 08:53 AM

The Sierra rear drivetrain can be fitted either to a book width chassis or a +4 chassis. The difference is that on a book chassis you have to fit extra wide rear arches to cover the wheels (unless you cut down the driveshafts). You also need extra long front wishbones if you are using the Sierra front uprights, to match the rear track.

By going +4" you can use normal width arches and you have much more choice of seats etc.


Chr!S - 30/1/07 at 11:21 AM

Cheers guys. I had another look at the designs and realised that it didnt matter as I could make the axle and hub carriers match the chassis width and just offset the hubs if the shafts were too long etc...

Ive had a look at the rorty de dion, but surely there's missing dimensions in the sketches? I dont have a sierra hub to hand so I cant measure the separation distances but Im going to have another look in case you can 'super-impose' the holes from the caliper bracket to find the missing dimensions...

I take it that track rod ends and wishbones on the front need to be extended +2 from the book? Definetly noticed the improved choice of seats after looking through a catalogue!

[EDIT]: Double checked rorty, definetly something missing, even using both the cali and hub sketches...

[Edited on 30/1/07 by Chr!S]

[Edited on 30/1/07 by Chr!S]


ecosse - 30/1/07 at 11:57 AM

quote:
Originally posted by Chr!S


I take it that track rod ends and wishbones on the front need to be extended +2 from the book? Definetly noticed the improved choice of seats after looking through a catalogue!

[EDIT]: Double checked rorty, definetly something missing, even using both the cali and hub sketches...

[Edited on 30/1/07 by Chr!S]

[Edited on 30/1/07 by Chr!S]


Can't help with the dimensions, but you might have a word with JRoberts about it (he makes them!).
And +2 on the wishbones seems to be about right (its what I did anyway! Although that is no guarantee )

Cheers

Alex


Chr!S - 30/1/07 at 12:06 PM

Cheers. Ill have to look him up.

Am in university at the moment sitting with the SolidWorks and HAAS CnC setup - then realised about 5 measurements were missing. The plate geometry can be guessed its just the bolt hole locations i wanted to check...

Still good plans I thought. On another topic, being as im only 25% finished on the chassis I was wondering if it was worth starting again with the third book? As its supposed to be a sierra based +2 Last time I looked. Im not sure about IRS / DD, so im juggling the thoughts at the moment...


ecosse - 30/1/07 at 01:00 PM

I haven't seen the third book yet so can't comment on it, but you will find plenty threads on the dedion vs irs route if you search for them
From what I have read, I think that dedion is viewed as easier than irs although not quite as good (presuming that the IRS is done right and setup correctly) but is better than a live axle.
But at the end of the day you pay your money and make your choice (I went the dedion route)

Cheers

Alex


blueshift - 30/1/07 at 01:48 PM

Another thing to consider if you go +4 is that a standard escort mkII type steering rack will be almost exactly the right dimensions, ie rack end balljoints in line with suspension pickups. GTS sell track rod extenders (very nice anodised alloy) to make up the width.

If you fit a rack like that to a book chassis you may have to fiddle around more with its location to avoid unacceptable bump steer.

Also with a +4 you get more room for your arse and a wider choice of seats that will fit. Perhaps don't have to be so delicate trying to shave millimetres off the width of your tranny tunnel.

And your footwell will be roomier: could be a factor depending on your engine/gearbox combo.


MikeRJ - 30/1/07 at 04:16 PM

quote:
Originally posted by blueshift
GTS sell track rod extenders (very nice anodised alloy) to make up the width.


1) I'm not convinced that aluminium alloy is the right material for this job
2) The extensions I bought from GTS turned out to be for a chopped down sierra rack and were far too long for an escort rack. Do they sell different length ones?


blueshift - 31/1/07 at 09:35 AM

1) why not?

2) ask GTS


MikeRJ - 31/1/07 at 01:04 PM

quote:
Originally posted by blueshift
1) why not?


Because it's nothing like as strong as steel and it fatigues. Probably less importantly, you are inviting bi-metallic corrosion by screwing alloy parts into steel.

quote:
Originally posted by blueshift
2) ask GTS


I made some short extensions from steel in the end, so I only asked about the lengths as it may be useful to others.

Please don't get me wrong, I'm not GTS bashing as I have bought loads of bits from Darren including wishbones and a full +4" body set and I've been happy with the quality of everything. The track rod extensions also very well made, they just didn't fit and as said I have reservations about the material.


3GEComponents - 31/1/07 at 03:06 PM

These dimensions?


Simon - 2/2/07 at 08:12 PM

Plus 4" looks better anyway

Ducks and legs it

ATB

Simon