DarrellMe
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| posted on 17/7/03 at 02:18 PM |
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Donor car for a BEC
Hi peeps
What is the best donor car for a BEC. I am going for a live axel instead of IRS so that it is easier and quicker to get on the road. Therefore, what
is the best donor car, and what parts do I need from it. Do I need things like the steering rack, uprights, hubs, front and rear axel, etc, etc. If it
is an escort, does it matter whether it is escort car/van, patrol/diesel
Also, how or what gearbox do you use for a BEC
Thanks
Darrell
[Edited on 17/7/03 by DarrellMe]
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StuartA
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| posted on 17/7/03 at 03:41 PM |
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Can't comment on the best donor car for a BEC, as we sourced our components individually so have a Cortina rear axle and uprights, Sierra
steering column, escort rack etc etc. However, regarding the question about gearbox; you simply use the one with the bike engine. The only reason to
use another box is for a reverse gear, but these are aftermarket jobs rather than acquired from the donor (Quaiffe is the most common make) or you
could use the electric reverse like that provided by MK. Most BECs don't bother though from what I can gather. 
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Jasper
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| posted on 17/7/03 at 03:57 PM |
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Darrell
With live axle if you go for an Escort one, then the back end will be narrower with the wheels sitting in from the arches, BUT, there are different
diffs available to help with the gearing. Cortina's are wider and fill wide arches perfectly with Sierra offset alloys, but you're
restricted to diffs or 3.5, 3.89 or 4.11, which means 15 inch alloys will give you better gearing than 13", but cut slick tyres for these (eg
Yoko A032's) are harder to get and more expensive.
I got a 'tina donor, was then able to use the uprights as well, but my donor turned out to be a 4.11 (from an estate), so I've now sourced
a 2L one with a 3.75 diff, which will mean more top end and less gear changing.
Racks from escorts, you can get donor, re-con ones or buy a quick rack 'off the shelf'. The Yahoo BEC group is currently getting one made
of them, and should be available soon.
Steering column from escort/cortina is ok, but make sure it's collapsable for SVA, many people get one from a Sierra. It will nedd lengthening
though
[Edited on 17/7/03 by Jasper]
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DarrellMe
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| posted on 21/7/03 at 01:11 PM |
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When you say use the standard gearbox from the bike, how do you go about changing the gears, do you have to get a sequential paddle type gear lever,
or is there some other contraption that will allow you to have a normal gear stick to change the gears with, or am I missing the point ??
So, what is the deal with the differentials. Basically I want to have ludicrous speed 0-60 but I don't want to have a top end of under 120. Is
this pheasible and what diff would be the best for this.
Thanks.
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Jasper
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| posted on 21/7/03 at 01:29 PM |
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Gears - very simple. You either use a cable (thick one from Demon Tweeks) or a linking using rods and rose joints (again more simple than it may sound
- you need to see one installed) You then put a ball joint on the end of the gear selector arm and pull it up and down from a simple forward/backward
gear shift. Paddle shift can be linked up as well. Check people's photo archives.
If you want a good top end you will probably need an Escort diff with 3.1 ish diff. ALL BEC's accelerate like stink anyway, if fact mine is so
low geared I would happily trade some top end for less acceleration.
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andyd
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| posted on 21/7/03 at 05:23 PM |
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quote:
Originally posted by Jasper
<snip> if fact mine is so low geared I would happily trade some top end for less acceleration.<snip>
Jasper, surely that's blasphemy! Less acceleration? You've clearly had too much fresh air! 
Andy
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DarrellMe
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| posted on 24/7/03 at 03:12 PM |
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So am I right in saying that to get more acceleration you have a higher differential (lower the number, i.e. 3.1 is better than 3.54) and if I want
some more top end then I have to lower the differential (3.54 has better top end than 3.1)
Also, is the ford the best car, whether it be an escort, sierra or cortina. Has anyone used any parts from VW's for example.
Also, does anyone have any plans for the cradle that is required for a bike engine. I am planning on the R1 engine so for this one would be the
better, but any ideas that anyone can provide would be appreciated.
Just as a side note, is anyone going to the Northern kit car show on the 16th 17th August
Thanks
D
[Edited on 24/7/03 by DarrellMe]
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Jasper
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| posted on 24/7/03 at 03:26 PM |
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No - lower diff ratio - 3.11, higher top end.
And for cradle - easy, just lower the ngine to where you want and weld a frame around it.
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ned
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| posted on 24/7/03 at 03:36 PM |
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am i way out of my depth by suggesting the use of a capri rear axle?
I know they're a bit wider, but aren't there various dif ratios about for them too?
Ned.
----------
I see you've just put a wanted up for one of these jasper!!
[Edited on 24/7/03 by ned]
beware, I've got yellow skin
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ChrisGamlin
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| posted on 24/7/03 at 06:35 PM |
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Jasper, just a note on what you said above about Escort diff ratios, you can't get an Escort ratio higher (lower number) than 3.54 unless you
get one specially made for big wonga, there is no 3.11 freely available
However, a 3.54 should be fine in a BEC to give 120mph+ top end, mine tops out at about 128 with 205/60-13" tyres
Chris
[Edited on 24/7/03 by ChrisGamlin]
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Jasper
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| posted on 27/7/03 at 12:08 PM |
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I've done the sums with the diff calculator and to get to 128mph with 15" wheels I need a 3.2 at the least. This will then give me more
acceleration on smaller tracks with a set of 13" with A032's on. The ZX9 is lower geared than the blade, unfortunately.
I was practically falling asleep at Brunty yesterday on the straights, topping out at 96mph, still the engine went well and didn't overheat,
even with permanent 5th and 6th at 8k revs + all the time.
[Edited on 27/7/03 by Jasper]
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ChrisGamlin
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| posted on 27/7/03 at 07:33 PM |
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Hi Jasper, what tyre diameters have you got, or what tyre size? There are a fair few ZX9'ers on the BEC list and none seem to suffer like you
with diff ratios etc, you sure you havent got a close ratio gearbox in your engine or something?
By my calculations using the original spreadsheet that was on the BEC list and using a 12,500rpm red line, even with a 4.11 diff and 185/60-13"
tyres, you'd top out at 103mph, and you should top out at 125mph using 205/60-13" tyres and a 3.54 diff, which is fine, certainly wouldnt
want to go much higher (Ive never hit the limiter in top on track yet).
Chris
[Edited on 27/7/03 by ChrisGamlin]
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Jasper
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| posted on 27/7/03 at 08:02 PM |
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I think the gearbox is standard, for the calcs I've use the Haynes ratio's - I'll email you over the speed calc sheet I've
been using that seems to verify it. I've also put the gear ratio's into the Digidash and it comes out the same, tops out at 97mph. The ZX9
red lines at 11,750 I think.
Seems strange to me, but the spread sheet verifies reality.
Tyres are 195x50x15's.
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ChrisGamlin
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| posted on 28/7/03 at 05:35 PM |
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Hi Jasper, I thought the ZX9 revved more than the blade, that is one of its advantages against the blade (which hits its limit at 11750).
Ive got your e-mail, but can you let me know what size tyres you have on the wheels
cheers
Chris
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