Dan Jacobs

Juan's setup looks like the ****. 500 is cheaper then missing a race
I've never had a problem with the stock stuff when maintained as neccesary
with Porsche, not aftermarket, parts

rlm328

I am using the 944 version and have had no problems with it. It does have a number of adjustments to customize it for your use.

Juan Lopez

Well said. Missing a race is much more expensive and not having to design, test, source or fabricate is worth a lot of money too.

My other car has nicely maintained factory pedal.

FrankyV

Mostly the problem has been caused by the drivers foot catching the pedal and pulling it off of the snap on linkage connection on the back of the pedal. It happened to my co driver at Sebring and to me at VIR last year year and I have known it to happen on other cars driven by other racers. I put on a new stock pedal for Mid Ohio last year and it happened on the first lap my co-driver took, so we drilled holes in the pedal and wired it to the linkage as a back up. I ran all weekend at Sebring with that set up with no problems untill Sunday when it breaks right at the hinge joint half way through the enduro.

Dan I am with you on using stock parts whenever possible, and I don't really care for any of the aftermarket pedal options, so what part of the set up should I be examining at that could possibly cause this?

Dan Jacobs

Frank,
Was your pedal from Porsche or was it aftermarket oem ? There is a difference in quality
I think looking at the whole system from one end to the other and making sure that it is all working correctly is super important. For example if something other then the pedal is limiting full throttle
your straining the whole linkage. Is your footboard really up to snuff ? etc.
I think Rennline is a great company and I use many of their fine products But I'm not a fan of the gas pedal

Cory M

Maybe you could adjust your brake pedal height so the edge of the foot wont clip the accelerator and knock it off?

FrankyV

Pelican Parts advertises it as Genuine Porsche. And it turns out I was not getting to WOT at the race so I bet that is what led the busted the pedal.

Great idea.

kurt M

I see this far more than you might guess. The stock bell crank and rod system is a real poor setup when you look at it. Too many ways to be at sub WOT and many ways to have a stuck or no throttle condition.

FrankyV

Yup the stuck throttle is the real worry, happened to a fellow racer at Summit Point, next stop - tire wall. Problem is that the Stock class rules would likely be interpreted to prohibit the redesign you suggested. As for enforcement, far more egregious violations are not really policed so maybe it is worth the risk. For now I think I will put a stock pedal back on it, evaluate and adjust the entire system and continue researching the issue.

kurt M

Hmm..... Had not thought of stock or not aspect but keep in mind the pedal is the stock part. I plan to ask about that when the chance comes up. The mod does not add power or change weight dist. It makes the car safer. I too have seen more than one stuck throttle on track. One caused a overrev that bent all the valves. I was doing a evaluation drive on a 66 912 and the throttle stuck wide open. (yes, I noticed that the throttle was stuck but it did take a while) Had to do the key off and coast to a stop deal after a toe under the pedal trick only poped it off the rod.

analogmike

Agree, I have gone full throttle on a '72 and '73 911 more than probably anyone here in the last 30 years with no failures (and a 914 before that).

Make sure your throttle stop is adjusted right.

No use going MORE than full throttle.

Juan Lopez

Mike, are you saying the throttle pedals are not like some amps? They don't go to 11.

Kind regards!

Gary R.

Fred C. has been known to store his cell phone down there (never know when you need to call AAA!) so you should take a good look...

Mahler9th

I am curious about your set up Kurt M.

"I am using a teflon coated tandem bike rear shifter cable and cable guide that runs from a bar on the pedal to a custom built throttle setup. Smooth as silk with good feel and no slop or loop feedback surges. No bell cranks, bushings, long and short rods, ball ends and all the other junk that changes with time and temp. 0.0 chance of not having a WOT due to some sloppy bushing on a bell crank or from body flex."

Do you have any pictures? Any further details?

I broke a factory pedal at the hinge about a year after I got my 911 race car. I am not sure whether it was the original pedal from 1975 or a newer one. I replaced it with a simple alu pedal that has the same attachment mechanism as the the factory part. I also replaced the throttle stop with a fabbed up deal that is a bit more robust, yet as easy to adjust. No issues with stuck throttle or anything of that nature. Unfortunately, the simple yet effective alu pedal (I paid $60 to Devek back in the day) is NLA.

I have a 3.8 engine with a 993 intake and a hot rod 80 mm throttle body, so the linkage is a bit of a one off of various Porsche parts. I mounted a microswitch to the throttle body and it actuates a light in my dash at WOT. Despite numerous attempts to adjust things in the garage and paddock, I do not consistently get WOT out on track. I get close, but not quite there. I am thinking about going to a cable set up.

kurt M

All I have in hand are these, the car is on the lift with another one under it at the moment. The one of the motor was taken during testing and I went back and replaced the nuts with locking types. The green spring acts as a shock of sorts. When the cable pulls the throttle to WOT the spring will compress slightly to prevent any over travel stress on the throttle body and arm. This added takeup allows me to ajust so I am dead sure I get WOT when the pedal is on the stop and to account for any thermal elongation of the cable. A cable system is not affected by motor mount or body distortion so thermal changes are the only variables to contend with. Changing the shape of the curved cable guide changes the ratio of pedal to throttle whithin the stroke. Raising or lowering the guide on the rod changes the overall ratio of pedal inch to throttle degree of movement. Not shown is an added return spring that is on the far side of the take up spring. The stock throttle spring was more than enough to pull the pedal back but I wanted to add in some more pedal feel and pushback as well as add in some insurance from a stuck open throttle.

The image of the pedal area was taken during rough in and function testing and the tested, tuned and finished setup is a bit cleaner. At the time the cable and guide were not installed yet. There is a squggily red line sort of showning the path of the cable in its guide from the assembly back to the motor. The pedal and cable system was cleaned up a bit after it was proven anf the cable and guids were run out of the way of damage. as shown all I did to the pedal was add a shaft to the pedal that extends up and acts as the cable pull. The framework that holds the cable sleeve also acts as the pedal idle position stop. not seen is a strong pedal stop that suports the pedal all the way across the pedal right under where I tend to keep my foot. This puts the "faster damit!" foot mash force through the pedal and into the stop without stressing the pedal.
This setup has worked from day one without any issues.

Bell crank and rod systems are tried and true and i have 2 other Porsches with them in use. The fact is they are subject to being pulled out of ajustment from body twising, the motor and trans moving in the mounts and thermal elongation. All of this can change the settings while on track. Overtensioning only loads up the throttle rod and all that goes along with it. Under tension can mean you are not at WOT at times.

Rennlist will not let me post the images. Please go to this page for the images.

http://dorkiphus.net/porsche/showthr...=11702&page=14