pro's &con's throttle linkage Vs cable

[tuska]

hi eveyone,
getting to pedal fitting stage, which is better cable or linkage for throttle

[LMH]

Cable is easier to run but just looks oh so wrong.
Linkage is more involved in setting it up but looks fantastic.
That's my $.02!
Larry

[bill37341]

My $.02 is that cables hang and kink (sometimes wide open) and linkage doesn't. Bill.

[Cobra #3170]

Cable will allow you to design an opening cam that will make the car far more drivable because you can make the first two inches of travel only open the throttle 25%. The OEM's went away from linkage for a reason, broken engine mount = full throttle whether you want it or not. It doesn't look original but is a lot better from a drivability standpoint. I have a 1650 cfm throttle body that was absolutely undrivable until I changed to cable with a slow take up cam.

[Mother]

I feel that cable linkage will have less chance of hanging up with the use of a double spring.

[tuska]

i've seen lots using both versions so was unsure of advantages.....i think i get what you mean by progressive opening cam....but have ya got any pic's
?

[Rick Parker]

If you decide on a cable setup, get one that has plastic lined cable housing and plastic coated inner cable so it has a minimum of friction. You can spend $$ on Lokar and others or make one from a cable intended for something else such as Motor cycle throttle or (as I did with no regrets) a Honda lawnmower clutch cable $12-$15.

[marco454v8]

I changed from cable to linkage because the plastic sleeving melted on a bend above the headers, meaning I couldn't get WOT as the metal inner cable would pop out of the plastic sleeve ( an once on track got stuck out, meaning I had to hook the pedal up with my foot!)
Linkage works well, gives you pedal position adjustment and course adjustment very easily.
Oh, and it looks good!

Mark

[Dwight]

we changed a cable for a linkage system a few months ago for a buddy of mine because the cable had a sharp S bend in it. He has used the cable for 13 years but always had trouble with it. He loves the new linkage.
I think you can design your linkage to slow down the travel.

Dwight

[Ralphy]

Years ago I saw a friends linkage bind due to a motor mount breaking in a 1965 Impala. Dangerous as hell because the Z bar clutch lever fell out/off also. You get throttle with no clutch. Just make sure if you use a linkage it has plenty of ability to rotate.


Ralphy

[Dwight]

This is a picture of the linkage we made. We copied Unique's throttle linkage but custom fit it for travel. By using rod ends I don't think you will get a bind.
Cost about $50 in material and a couple of hours of time.
Dwight

[Luce]

No mater how nice, if cables are not almost straight, they drag, and I HATE that. I pitched my $150 worth of Locar pedal and cable in the trash for this bit of Home Depot mild steel tubing.

At this point, I'm still using the inner cable and ends, but without the outer sleeve.

[lnfletcher]

Move from cable to linkage and wouldn't do it any other way!
Could not get any cable to operate smoothly no matter what I spent. Worked up a simple linkage and could adjust ratio and had a definite stop at WOT to keep from stressing the carb.
Larry's Home Page

[strictlypersonl]

Originally Posted by Cobra #3170

...The OEM's went away from linkage for a reason, broken engine mount = full throttle whether you want it or not. It doesn't look original but is a lot better from a drivability standpoint. I have a 1650 cfm throttle body that was absolutely undrivable until I changed to cable with a slow take up cam.

If the inner end of the cross-rod is pivoted on an engine-mounted bracket, any engine movement's influence is minimized. That's the way the original Shelbys worked.

[CHANMADD]

As, I see in
the pictures with the rod from the carb going to the firewall, this looks very dangerous to me if
the motor moves at all!!! This fulcrum should be attached to the motor for sure....

[ERA Chas]

Originally Posted by strictlypersonl

If the inner end of the cross-rod is pivoted on an engine-mounted bracket, any engine movement's influence is minimized. That's the way the original Shelbys worked.

Bob's exactly right. I had a driver side mount delaminate at WOT at the drag strip. Raised engine about 1 1/2" because the pipes hit the body. Had complete throttle control throughout because of the pivot on the cross shaft.

[lnfletcher]

Originally Posted by CHANMADD

As, I see in
the pictures with the rod from the carb going to the firewall, this looks very dangerous to me if
the motor moves at all!!! This fulcrum should be attached to the motor for sure....

There is much more of a chance of the cable sticking than the engine mount breaking allowing the engine to torque enough to cause WOT.

I have had a number of vehicles in the past with cables that stuck, only one with a broken engine mount that would cause this problem and even with a cable it caused the same situation. (68 Firebird 400 with cable).

Using this logic seems more of a way of justifying your setup than reality. After all, push the clutch in and let her blow!

I'm in much more danger from my showing out than equipment failure in one of these cars!

[Cobra #3170]

Originally Posted by lnfletcher

There is much more of a chance of the cable sticking than the engine mount breaking allowing the engine to torque enough to cause WOT.

I have had a number of vehicle in the past with cables that stuck, only one with a broken engine mount that would cause this problem and even with a cable it caused the same situation. (68 Firebird 400 with cable).

Using this logic seems more of a way of justifying your setup than reality. After all, push the clutch in and let her blow!

I'm in much more danger from my showing out than equipment failure in one of these cars!

Lets see, there have been approximately half a billion cars sold in the US since direct throttle linkage was dropped. There have been instances of throttles sticking for sure, but a tiny percentage of total vehicles produced.
Throttle cables must be routed correctly observing minimum bend radii and staying away from high heat sources. They are extremely reliable when installed properly with far fewer moving parts than conventional linkage with rod ends and clamped arms that can slip on shafts. Drive by wire is even better if you can program opening rates but if you can't, linkage would be a
2nd choice over cable. I can see using linkage on a show or concours car that must be absolutely correct from a judging stand point. Conversely from a functional stand point they can be very trying. My linkage broke at the arm that mounts on the pedal cross shaft in 1966 when the car was new. I then had a series of slippages on linkage arms till I welded then to the engine to body cross shaft. I broke a motor mount at an autocross in the late 1970's that gave enough throttle to slide the front wheels and over ride the rear brakes while headed toward a group of people at the finish of an autox. Turning the key off saved the day, it wasn't full throttle but it was enough.
Slowing down the throttle opening rate really improves car control unless you are dealing with less that 400 HP where you probably don't need it. I would bet that some of the accidents that have occurred with Cobras over the years could have been avoided with a long pedal slow opening throttle.

Personally, I would much rather have a car that is drivable over a car that is eye candy but that is an individual choice that only you can make.

[Wbulk]

I believe this question is one of those situations that there are no easy answers. It depends on the situation for the specific car. I have a very similar mechanical linkage like Larry's. It is a very simple set-up that works well in this situation. Years ago they did not make linkages with ball ends that allows you to do things that you can today. I did it not for originality or looks becasue it didn't apply in my case. I did it because the radical angles and loops reguired to get the cable to the carb was a real negative. Yes, many do it with my brand of car but many have complained of problems. In this case, if a motor mount broke, the engine could not tillt further than the exhaust raising and hitting the body would allow. In this case Larry's linkage is just about a one to one ratio, but some are not that way.

In general terms, not specific to Cobras, I would say "no question" that cables have a lot of advantages. If you are not talking originality or design for looks and the cable works fine, keep it. If, on the other hand, you have had problems with the cable and mechanical linkage is the solution, then convert over. We in the US are too sensitive to originality and trying to pretend better than others. We are still little boys just grown up playing games and having fun.

[ERA Chas]

I did mine with heim joints and rod linkage because I valued the rock solid feel and feedback through the pedal. Not 'originality'...