Has anyone here gotten ride of the throttle cable and made a solid linkage set up? If so could you lend some insight on how you did it? Pictures or what pedal was used or any other ideas for me. I am using a Co2 starting line control with a cable and not getting the results I would like. This is a race only car so modifications to the firewall are not a problem.

 

Anyone??

 

Not yet, but I plan on making a linkage as you describe. I think I am going to use a rod mounted on the firewall with rod-ends and go up and down from there. The only issue I forsee is keeping the linkage from bending if long lenghts are used on the pedal shaft or the carb shaft side. This might call for some bracing for the movement of the assembly.

 

I use solid linkage.

I have a modified pedal from some mini van. Can't remember what it was out of but the pedal has a nice return spring built right into it.

I fabricated a mount to relocate the pedal position back from the firewall. It's almost inline with the brake pedal. I needed to do this because my seat sits back farther and I need to reach the pedals without having to stretch to push the throttle to the floor.

Technically, I can't push the throttle to the floor. I have a stop built in so it will only go to WOT.

The inside pedal linkage isn't pretty. Basically some 3/8" solid rods bent so that the pedal can reach up so that it's about inline with the carb linkage which is just a 1/4" rod. I cut a hole through the firewall and used a glad hand seal with dirt flaps to allow the rod to go through and it seals the hole up enough to pass tech without binding on the rod.

My CO2 cylinder is mounted in the rod that goes through the firewall. It's adjustable but I only use it as as SLE and never adjust it like when used as a throttle stop.

I don't have any pictures under the dash but here's a picture of the CO2 cylinder on the engine and where it goes through the firewall. You just need to fabricate a pedal to join up with the rod. I use a quick disconnect ball socket fitting on the inside and a rod end on the engine. Lots of custom fabrication to make it work. I needed to make a bunch of different adapters to hook it all up.

 

Thanks Stephen that is the way I planned on doing it. your cylinder is in the same place as mine. I guess its off to the junkyard for some pedal searching and then fab the rest.

 

OK, went and took a couple of pictures. I think the throttle pedal assembly was out of a Toyota mini van. This isn't pretty and it's a very mickey mouse setup. It could have been redesigned much better but it works fine for me.

The horizontal bolt above the pivot point is the throttle stop to keep the linkage from pulling past WOT. That's a trial and error fit. As required under NHRA/IHRA rules, there's also a toe hook installed above the pedal pad. The only thing I'd like to do with this current setup is to bend the lower rod so it's straight down and away from the tranny tunnel. I eventually want to make a removable and larger tranny tunnel.

 

Thanks again, that looks just like the way I will do it. It does not have to look pretty for a race car as long as it works.

 

The bolt for the linkage stop is also required when the air cylinder is activated so that the butterflies will close instead of the pedal falling right down to the floor.

I use my CO2 cylinder as a starting line enhancer. Just before I trip the prestage bulb, I bush a bump button on the delay box. This vents the CO2 from the cylinder and the pedal drops to the linkage stop as the cylinder lengthens the rod. Engine is at an idle and the foot is pushing the throttle pedal all the way down.

I can program the delay box different ways but basically, as soon as I let go of the transbrake button, the CO2 cylinder is reactivated, shortening the length of the rod and the engine goes to WOT (2-step). As soon as the last yellow light comes on, the transbrake releases and away I go.

I can sit on the start line with my stage bulb lit as long as I want, waiting for my opponent. I'm ready to go and only need to release the transbrake button to start the launch sequences. I'm not worried about engine rpm or bouncing off the rev limiter for long periods of time. As soon as both stage bulbs are lit, I then just concentrate on the top yellow light. Using the delay box, I only have to react to one light. If I feel I'm reacting too quick and get a red light, I just add more delay until I don't red light any more.

 

That is the same way I have been using mine. I have a switch set on my clutch pedal when I push the clutch to the floor it releases the Co2. I then can push the pedal to the floor and it will only go to the rpm that I have pre set with the adjustable rod. When I release the clutch it goes to WOT. I also have a adjustable needle valve in the Co2 line that will slow down the rate of opening. If the track is not hooking as good I can slow the opening rate so the tires do not brake loose. The way I have it now with the cable it does not always stay at the same rpm launch everytime that is why I am going to make a solid linkage to have a more posotive feel. Here is the link to the Co2 Assy. that I have in case you are interested in the in-line needle valve.
http://cgi.ebay.com/ebaymotors/M1025...Q5fCarQ5fParts

 

The solenoid on my air cylinder also has a needle valve. You can see it on the end of the solenoid in the above picture of it. I don't need to adjust it because my throttle goes to WOT before I start moving. With a transbrake launch, My engine is already at 4500-5000 rpm when the transbrake releases. The throttle never closes until after I cross the finish line. I can use the second stage timer in the delay box to allow the cylinder to close the throttle after a run as a top end safety feature if I want to.

 

I just got done with the solid linkage here are a few pics. The pedal is from a early 80's Old's Delta 88, an old creaper wheel for my foot roller and some all thread. I just need to weld a toe hook on it and it is all done. Works very smooth and I do not see having any problems with it.

 

Not bad. I'm not sure I like the wheel idea. A small pad is enough. The main reason I did mine the way I did it was because I had to move the pedal off the firewall so that I could reach it. With my seat sitting so far back. To push the throttle to WOT, I had to really stretch my leg to do it.