I'm building a 3rd gen with a BBC for drag race only and wondering what you guys have used for throttle linkage??

I will be using a SLE and not sure how to hook it up to the gas pedal. Any advise will be welcome.

 

I am using the locar setup it took about 15 minutes to install. how i did it was since the hole in the firewall was bigger than the firewall fitting on the cable was i put a stainless washer behind a plastic plug to hold the hood liner on with a hole drilled through it so when done you can not see the washer it is behind a black plastic plug . as you can see in the photo. on the pedal side it just clipped in and on the carb side you cut to lenght and tighten the set screw.

 

An SLE will work with a cable system but I fabricated a completely new pedal assembly and use a solid rod linkage system for mine. The pedal I use is out of some mini van. Everything else was fabricated to make it work. My pedal isn't attached to the firewall. It hangs down from above and is inline with the brake pedal.

 

That is exactly how I did it with our S10 we put a SBC in. It works well, but am hoping to figure out a better more robust way to do my race car.

 

Sounds interesting, could you by chance post a few pictures of your install.

I've never installed a ALE and don't really know what is involved.

 

A SLE simply lengthens the throttle linkage to close the throttle blades to a preset position while your foot is at WOT. Mine uses a CO2 solenoid. My delay box has a SLE feature so I use it.

As I'm rolling into the beams, I push what's called a bump button. CO2 is vented, the solenoid extends from return spring pressure and the pedal falls to the floor. I keep my foot to the floor, the engine is at an idle and I roll into the prestage and stage bulbs. As soon as both cars are staged, I push the transbrake button and wait for my top bulb to light up. The engine is still at an idle and my foot is to the floor. If I'm against a slower car, I can sit there as long as I want at an idle and I'm not up on the 2 step or converter.

As soon as I see my top bulb light up, I let go of the transbrake button, the solenoid is activated with CO2 and the throttle is snapped to WOT. If I have the delay box set correctly, the transbrake will release the car when the last yellow light comes on. I just have to sit and wait for the release.

A SLE works well for a Full tree as you have time for the engine to reach it's launch rpm. With a Pro tree, the engine needs to be at WOT when the tree comes on. My delay box doesn't have a pro tree option. The Pro tree option would have the SLE drop the throttle to an idle for you to stage but as soon as you push the transbrake button, the engine would go to WOT. Since I do very little Pro tree racing, it's not something I need. My SLE only works when the transbrake button is released, not when it's pressed.

Although it's pricey, you may find it's better to just buy an inline throttle stop kit than it is to piece together something that works. There's nothing wrong with an inline throttle stop used as a SLE. A plate style stop under the carb probably doesn't work well as a SLE but I've never used one.

To build one, you need to fabricate linkage, get a CO2 bottle and regulator, lines, fittings and CO2/air solenoid. You would also need a delay box that has a SLE feature. I have a second CO2 bottle as a spare in case the one in the car loses pressure from a burst disk or I forget to turn the bottle off and it leaks down before the next race weekend. The 10oz bottles cost me $15 to get them filled at a fire extinguisher filling store. I can usually get a season out of one bottle. Less if I use my CO2 shifter.

Biondo and Dedenbear are the most popular choices.

 

Alkyiroc, thanks for the school, I need all I can get. I have everything to make this all work but the linkage from the SLE to my foot.

The SLE is an ACD. I also have a Mega 350 delay box coming. It all should be here next Wed.

Any thing else you can tell me is welcome!

 

Sounds like you're off to a good start. Finding a way to connect the SLE with a throttle cable, you're on your own. A suggestion would be to use the cable to activate a linkage system that's attached to a CO2 cylinder. The theory would all be the same. It just depends on how you make it work.

Like I said, my throttle pedal is all fabricated. I made some brackets that reposition a minivan pedal back away from the firewall so I can reach it (I sit farther back than normal). The pedal assembly pivots and goes up and inward more over the tranny tunnel. There's a hole cut through the firewall that the rod goes through and the air solenoid is mounted on the engine. I use a rubber grommet in the hole to pass tech. I use a tunnel ram with a bellcrank near the middle to change linkage direction.

I went digging through all my pictures to see if I had anything. These are the best I could find. In the engine picture, you can see the CO2 solenoid beside the tunnel ram. The under dash picture, you can see the pedal system I fabricated. That pedal was my first design. It's changed slightly to make it a bit stronger plus put a positive stop on the linkage. I now also use a manual transmission brake pedal.

On the throttle pedal, you can also see a toe hook which is required for all mechanical linkage systems.

You can always but a pedal kit like this.
http://www.swracecars.com/store/Thro...74=15-028.aspx

 

Couple of questions. I've reread your previous post about 10 times. You leave on the top yellow bulb right, so you would put 1.5 sec of delay in the delay box? And this is + what you have as roll out?

Also you say the SLE only works when the transbrake button is released. So CO2 keeps the SLE in the closed position. What exactly does this "bump button" do and what is it connected too? Trying to piece this all together in my mind.

 

I can't remember what my current box setting is but it's something like 1.045. Normally there's 0.500 seconds between the lights. Some tracks have adjusted for LED lights by putting something like 0.470 between the lights. As with all bracket racing, you want to launch on the last yellow light. There's 0.500 second between when it comes on and the green light comes on. By the time you and the car react and the car starts to move, the green light should come on just as the front wheels break the starting beam. If you react and launch on the green light, you'll have a very, very slow reaction time and in a bracket race, you will lose. During test and tune, reaction time means nothing. The ET timer doesn't start until you break the starting beam. The light can be green and you can sit there for 5 seconds. It won't change your ET. You'll see that during testing with turbo cars. Light will be green and they sit there building boost before they launch to get a fast qualifying time.

When setting the delay box, don't go chasing bad lights. Only adjust it so you'll never get a red light. If you can react fast enough to get a red light, add more time to the box. Night time racing typically needs more delay because you'll see and react to the light faster. The easiest way to figure out the delay is testing. Put 1.000 in the box and see what kind of red light you get. Add time until you can't red light. If you get a really slow light, it's the driver reaction, not the electronics unless you're repeatably slow.

It's easy and fast to react off the top bulb. As soon as you see a flash of yellow, let go of the button. Top bulb racing with a delay box takes all the guesswork out. When you're bottom bulb racing, you're trying to time yourself to the lights you see coming down and humans are terrible timing devices. How accurate are you when you're mentally thinking 1, 2, go!

With top bulb racing, you just stare at that top bulb and filter out everything else going around you. Don't look at what your opponent is doing, don't look at gauges. Just stare at that bulb even if your opponent has a 10 second head start. As soon as you see that flicker of yellow, you let the button go. Then you can look around to see what else is happening for a second before the car launches.

During normal operation, the CO2 keeps the SLE closed (short) and throttle operation is normal. If I have no CO2, there's no throttle pedal because the SLE is fully extended. I have a replacement rod the same length as the SLE closed length just in case I need to swap it out.

The bump button is connected to the delay box. It just sends a ground signal to the box to tell it to activate and vent the CO2 from the SLE. It's a momentary switch that I have mounted under the delay box. If I forget to hit the bump button, the SLE will still vent the CO2 as soon as I press the transbrake button. I use 2 transbrake buttons on my steering wheel. One button will activate the SLE and transbrake with delay. The other button is set up as transbrake only with no SLE or delay. If for whatever reason I screw up or figure I cut a bad light before the transbrake releases, I can hit the second button and launch off the bottom bulb. I also use the button if I want to do testing like full converter stalls where I don't want the SLE or delay to be active.

Technically, my delay box allows me to have 3 hits at the tree but there's too much going on in a short period of time to do that. If I'm the faster car, my opponent launches first. I can put my opponents dial in and my own into the box. If the top bulbs are unshielded, I can release one button on his light, release a second button off my own top light. The delay box will figure out which is the better reaction time. If I don't like either, press and release a third button before the transbrake releases and launch off the bottom button.

There's no way I can be co-ordinated enough to use 3 buttons in such a short period of time. Launching off my own top bulb is more than enough.

When you get your delay box, absorb the instructions. There will be a lot to take in and understand. Don't even worry about how to use a throttle stop.

Remember, you only need enough delay to slow yourself down to keep from getting red lights. You can't use the delay box to compensate for getting a bad light. If your reaction times are consistent, anything worse than a 0.100 reaction time is considered very slow. You should be able to get low 0.0xx lights all the time with a delay box.

Two years ago I got 2 perfect .000 reaction times in the same day however they were both during time trials when they didn't mean anything except bragging rights.

 

Thanks, I think I get it now. Looking forward to trying this new stuff out! Can't hardly wait till April, but got a lot of work to do between now and then. Feel like a kid at Christmas time again.

Probably have more questions later if you don't mind.

 

The linkage rod that goes through the firewall, does it actually go through the air tank just below the windshield? It looks like mine will, at least that is how it lines up with where the carb linkage will be.

 

You mean the CO2 solenoid/air cylinder? The cylinder changes the length of the rod. The rod is attached to the fixed end of the cylinder and the shaft end of the cylinder is connected to the carb linkage. When CO2 is applied, the cylinder is in the retracted position. When the CO2 is vented, the cylinder extends. Since the throttle plates can't close any more, the throttle pedal falls to the floor.

 

I'm sorry, I wasn't clear about my terminology. Just below the windshield is a open area that normally has a plastic grille over it to keep leaves, etc. out. Fresh air box I guess would be a better term for it. Anyway just eyeballing it, it looks like my linkage from my pedal to the little air cylinder/co2 solenoid will go through this air box. Does yours?

 

The cowl has been removed from my car. I only have a single layer of sheetmetal for a firewall.

The throttle rod itself actually goes through the sheetmetal below the cowl area.