Modified Accelerator Cable

Started by tmsmini, May 01, 2020, 09:06:41 AM

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tmsmini

This is great, thank you so much

John Gervais

Quote from: Willie_B on May 02, 2020, 01:52:20 PM
Simple lathe projects are fun. Could not find 3/8 brass rod so used aluminum. I can mail it to you if you want to try it.

Not trying to interfere or criticize - I like the concept - but if it were a tad longer a cotter pin on the backside could help hold it in place.
- Pave the Bay -

MiniDave

The same spring tension that holds the throttle closed should hold the tab in the slot on the pedal linkage....

But.....the OEM cable has a ball of sorts on the end which allows the pedal to pivot without binding up the cable, not sure it matters in such a limited amount of travel, but there it is......
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

John Gervais

That's sorta what I was thinking, along with reducing the likelihood of any eventual slack in the cable from causing it to jam or jump from the slot.
- Pave the Bay -

Willie_B

Quote from: John Gervais on May 02, 2020, 05:26:00 PM
Quote from: Willie_B on May 02, 2020, 01:52:20 PM
Simple lathe projects are fun. Could not find 3/8 brass rod so used aluminum. I can mail it to you if you want to try it.

Not trying to interfere or criticize - I like the concept - but if it were a tad longer a cotter pin on the backside could help hold it in place.

There is a bottom to the hole in the pedal. A ferrule cannot go all the way thru the arm for a clip on the rear side. But a good idea anyway.

John Gervais

- Pave the Bay -

tmsmini

#31
And the use of this clip helps keep things in place.


Although I have not been using it with this setup up to this point.

And it may not work as it will need to be reversed.

tmsmini

Waiting for a spring to try, I ordered a short  one from the twin setup.
I am wondering if I need to bend the plate towards the quadrant to get a better spring angle?

A Dremel and bench grinder do OK to make a spring attachment point. I order a used HIF abutment plate that I thought of using To attach the spring, but this might work.

MiniDave

I see what you mean about the angle, ideally you'd want a dead straight pull.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

MPlayle

I don't know if there will be room when you put the fuel rails back on, but if you could very slightly straighten one of these two bends to get a straighter pull of the cable into its sleeve you may not need the return spring.


John Gervais

Quote from: MiniDave on May 06, 2020, 01:19:46 PM
I see what you mean about the angle, ideally you'd want a dead straight pull.

Agreed - I'd be tempted to try to either oval the hole and walk the cable over, or insert a shim (bronze washer) behind the throttle quadrant and use a longer screw to hold it all together.
- Pave the Bay -

tmsmini

If I go back to the cable end the TB is supplied with, then I might be able to bend the bracket. With t he Venhill there is no room.

The spring works, but as you approach WOT, it touches the pivot point.
Bending the spring attachment might help the angle as well

tsumini

Does the arm have a torsional return spring? It may not be strong enough if it does. You may try to tweak it to increase the torsion or get a stronger one. From your video it won't take much increase to work.

tmsmini

There is a torsional spring. On the 50 mm TB there are six coils and strong return. I can't tell how many coils on this one as it is covered by the quadrant.

tsumini

Quote from: tmsmini on May 06, 2020, 05:07:12 PM
There is a torsional spring. On the 50 mm TB there are six coils and strong return. I can't tell how many coils on this one as it is covered by the quadrant.
Is the 50 mm spring stronger than this one and will it fit on this one? The one you tried seems way too strong just to pull it back a few mm's. IMO.

tmsmini

The design of the quadrants is different on the versions I have.
I agree the spring is too strong and may cause issues either the throttle shaft eventually.
Still reviewing options

tmsmini

Bent the plate to get a better angle and reduced tension, still not convinced this is the way to go.


I will wait for the custom ferrule to arrive and try some other alternatives. The problem is that the sticking doesn't show up trying in the driveway all the time , I need to take it for a drive

John Gervais

Is it possible to elongate the hole in order to slide the cable further to the right?
- Pave the Bay -

tmsmini

In this photo, are you suggesting moving it to the right? Or down?

tmsmini

Only because there is a threaded hole in the quadrant at that point.
I am not sure I want to drill a hole in the quadrant yet.

John Gervais

#45
It may only be the angle of the photo and video, but is the cable lined up with the cam or is it biased to the side?
- Pave the Bay -

tsumini

Any chance of rotating the quadrant 180 deg. and coming up from the bottom with the cable? Would eliminate the loop fouling the bonnet.

tmsmini

Nicholas Upton looked into that on the original install with the 50 mm TB and because of the way the spring locating holes are machined, it was not possible. I have not taken the 45 mm apart to see if it is the same.

I am going to try a number of the ideas mentioned to see if I can sort this out. The custom ferrule should come today.

94touring

Didn't read through the whole post but watching that vid you could probably use a 2nd spring at the end of the arm going nearly straight down to that plate to snap it back without the less than stellar pivot point you have.  Maybe two lighter tension springs vs 1 stiff....dunno, just spit balling.

tsumini

Quote from: tmsmini on May 06, 2020, 05:07:12 PM
There is a torsional spring. On the 50 mm TB there are six coils and strong return. I can't tell how many coils on this one as it is covered by the quadrant.
I keep coming bck to the torsional spring. Is it possible to strengthen it by permanently by winding/unwinding it maybe 1/4 turn? make a new one with thicker wire? IMO the return spring would be the simplest solution.

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