livelee
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posted on 13/8/08 at 12:31 PM |
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Throttle Travel
Not sure if this should be in here or the engine section.
Anyway. I have a Mac#1 ZR with a Zetec Engine. It's running 45 throttle bodies.
The throttle travel is far too long and the pivot point is already as wide as can be. Does anybody have any suggestions of how to shorten the
throw?
Thanks
Dan
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ash_hammond
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posted on 13/8/08 at 12:44 PM |
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Hey.....
Wooden blocks on the pedals work a treat . You could alway replace the throttle with a micro switch with 3mm travel ON-OFF-ON-OFF drivin style
![](/images//smilies/bigsmile.gif) .
I run a ZR as well and personally like the travel, its nice to the able to vary the throttle round corners once you get used it you will be fine.
Another excuse to go for a drive.
.: www.mac1motorsports.co.uk | www.m1moc.com :.
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livelee
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posted on 13/8/08 at 01:07 PM |
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My legs are long enough. I like to be able to use my ankle to apply the throttle rather than having to extend my leg.
I guess it's normal then?
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multanen
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posted on 13/8/08 at 01:32 PM |
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Slightly OT:
Schumacher had very long throttle pedal travel in his Ferrari F1 car. Barrichello used short pedal travel instead.
Wich one you wan't to copy? ![](/images//smilies/bigsmile.gif)
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livelee
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posted on 13/8/08 at 01:33 PM |
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![](/images//smilies/bigsmile.gif)
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livelee
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posted on 13/8/08 at 07:27 PM |
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Barrichello it is.
I need a much shorter pedal. When driving I like to rotate my foot on my heel to flick between brake and throttle. With my throttle fully down I
lave to lift and bend my whole leg back in order to press the brake down.
Surely is is not normal? However I can't see any way to improve it.
I will measure the length of the travel and take some photos to show how bad it is.
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DarrenW
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posted on 15/8/08 at 08:56 AM |
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Can you move the position where the cable connects to the pedal in relation to the pivot point?
The throttle bodies will dictate how much movement you need to get full power but i think proximity to pivot point alters the pedal movement a bit.
Maybe not by a lot but might help.
When changing it you dont really want to be pulling excessively against the cable on full throttle. There is a tendancy when you want to go that bit
faster to push harder on pedal, this can cause cable to snap eventually. Careful use of pedal stop prevent overstressing the cable.
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livelee
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posted on 25/8/08 at 02:26 PM |
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Still not resolved. We are going to need to make a new pedal I feel.
There is 7" of travel to pull the cable 2".
Anybody care to measure theirs. I think somewhere around 4"/5" pedal travel would be much better.
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Mix
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posted on 25/8/08 at 03:11 PM |
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Hi
In addition to altering the throttle pedal you could also consider reducing the length of the lever at the throttle body or fitting an idler linkage
to give the required advantage.
Regards Mick
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C10CoryM
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posted on 26/8/08 at 03:21 AM |
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I think your choices are: re-make the throttle pedal, or add another pivot with a ratio in the middle somewhere.
Not much else to be done I think.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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DarrenW
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posted on 27/8/08 at 02:49 PM |
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I very much doubt you need a new pedal.
The pivot point will be near the bottom, bit you push with foot at the top. below the pivot point is where the cable attaches. If the cable attachment
point is very close to pivot you will have long foot movements to move the cable a short way, however if you reposition the attachment point further
away (lower down) the cable pull will be greater.
Do some sketches and you may be able to calculate what ratio you need and where the new hole needs to be drilled for the cable. Draw the pedal to
scale on paper. Assume first position is throttle off. Then draw a new pedal over the top in the fully forward position. You should then be able to
measure what cable pulls you can achieve by moving the attachment point. You can even get fancy by cutting 2 pedal drawings out and attach them at the
pivot point so you can work out where you need the cable to be.
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livelee
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posted on 27/8/08 at 03:05 PM |
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That is all correct. However the pivot point is at the highest point on the pedal and the cable is attached at the lowest point on the pedal. The
only adjustment I have would increase throttle travel, not decrease it.
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DarrenW
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posted on 27/8/08 at 03:24 PM |
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Oh i see you problem. Ill have to take a better look at my pedal later.
Do you have an option of changing the ratio at the throttle body end?
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livelee
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posted on 1/9/08 at 08:25 PM |
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Peddals:
No room below for lower cable attachment:
Off:
On:
Look at the actual peddal, it moves 7" front to back and the peddal is nearly pointing up 90 degrees at full throttle.
TB wide open:
![](http://farm4.static.flickr.com/3077/2818190027_40493df5fa_o.jpg)
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DarrenW
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posted on 5/9/08 at 08:16 AM |
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Sorry for late reply.
From your pics your pedals are same as mine (no surprise there i guess).
Without re-engineering your pedal i guess your options are either to get used to it or change the throttle body end. From memory your car has nice set
of jenveys. Have you tried looking at Jenvey catalogues to see if there is anything available that could change the length of travel needed.
Is there any way the position that the cable attaches to the TB's can be moved closer to the pivot point? Even if its just modelled up for a
static trial to test the theory?
I probs dont have the issue as im running bike carbs that only need a short pull.
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livelee
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posted on 5/9/08 at 08:27 AM |
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Does your foot not slip off the peddal at full throttle? Look at the actual peddal when pressed all the way down, it's nearly at 45 degrees
from it's starting angle.
I'm going to remove the peddals and bend / shape / cut / weld to get them spot on.
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DarrenW
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posted on 12/9/08 at 08:18 AM |
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To be totally honest when buildiing the car i thought it wouldnt be right but after being on the road for a while i never give it a second thought
now.
No harm in modifying it to suit you better. Shouldnt be too hard to do either. Give some thought to where you want the pedal to be in relation to the
others. Left foot braking and all that. Might also be worth fitting some adjustable stop arrangement too while you are on. Its worth stopping the
pedal just before excessive strain is applied to the cable, ive had one snap before.
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