More precise throttling

[greasemonkee]

Rather than, or in addition to visual gauging of engine load, how about a pedal feedback and dampening in one? A simple spring or modified throttle plate cam would never be accurate enough because throttle position and manifold pressure is relative to rpm.

Idea I had when I was asleep last night:

I imagine the success of the idea would mainly depend on the size of the vacuum tank and how well the air cylinder is sealed, along with internal friction of the air cylinder - is the break away force going to be excessive? Doubtful, as it would be a very small diameter cylinder. The rest is pretty obvious, but hopefully I haven't overlooked something painfully simple, if so maybe someone can catch it.

[wagonman76]

Maybe one could yank a cruise control actuator from a junkyard and use that in combination with a spring. Does sound like a good idea. Kinda like some system I read about by Toyota (maybe?) that had some sort of positive pedal feedback to discourage you from giving it too much gas.

[pgfpro]

Originally Posted by greasemonkee

Rather than, or in addition to visual gauging of engine load, how about a pedal feedback and dampening in one? A simple spring or modified throttle plate cam would never be accurate enough because throttle position and manifold pressure is relative to rpm.

Idea I had when I was asleep last night:

I imagine the success of the idea would mainly depend on the size of the vacuum tank and how well the air cylinder is sealed, along with internal friction of the air cylinder - is the break away force going to be excessive? Doubtful, as it would be a very small diameter cylinder. The rest is pretty obvious, but hopefully I haven't overlooked something painfully simple, if so maybe someone can catch it.

Very cool idea I like it!!!

[Christ]

You overlooked a simple air-filled rubber sack behind the gas pedal... You can already buy them, and there is no complicated (or even not-complicated) installation. You blow it up and put it behind the pedal. If you want more feedback, blow it up harder.

[robchalmers]

or - add an additional throttle return spring and sit further back...... that way you'll have to make omre of a concious effort to add more throttle !

[greasemonkee]

The only problem I see with simply adding a fixed resistance to the throttle pedal is this: at 1500 rpm & 20% throttle position would be lets say 7in/hg manifold pressure. At 2000 rpm 20% throttle position may be 12in/hg man pressure. So you see the trend anyway. I question whether any fixed force is gonna cut it. In the picture I drew out, you'll have the same amount of force pushing back on the gas pedal at all rpm for a given load. Turn on the headlights and AC and it will push back that much more.

I like the feedback a little caster gives the steering and the feedback I get from pushing the brakes harder. Why not feedback from the throttle? In fact, I would be surprised if someone somewhere in racing isn't using something similar so the driver has an idea how much torque he's putting on the ground.

[robchalmers]

In racing it not really needed - it you have too, much torque, the wheels will spool up. if you're running TC you you'll feel and hear it kicking in - trust me on this you FEEL TC on a race car as evrything is solid mounted. Every sensation in a race car is amplified. and you can tell much more clearly that you're togging (over throttle bogging) bass increases yet rate of acceleration doesn't - in endurance racing its the key thing to learn as its a razors edge, as you want max accel and min over throttle.

[Christ]

Originally Posted by greasemonkee

The only problem I see with simply adding a fixed resistance to the throttle pedal is this: at 1500 rpm & 20% throttle position would be lets say 7in/hg manifold pressure. At 2000 rpm 20% throttle position may be 12in/hg man pressure. So you see the trend anyway. I question whether any fixed force is gonna cut it. In the picture I drew out, you'll have the same amount of force pushing back on the gas pedal at all rpm for a given load. Turn on the headlights and AC and it will push back that much more.

I like the feedback a little caster gives the steering and the feedback I get from pushing the brakes harder. Why not feedback from the throttle? In fact, I would be surprised if someone somewhere in racing isn't using something similar so the driver has an idea how much torque he's putting on the ground.

That air sack thing increases feedback with an increase in positive pressure against it, something about the shape, I think.

How I imagine it works (without looking):

Since it's shaped like a pillow, wider than thick, you're applying a lot of pressure to a large area (by pushing on the pedal) which makes the air attempt to "get out of the way". That forces the sides to expand slightly, and the air compresses slightly. Since you're attempting to expand an area physically more resistive than the area that you're pushing on, it creates a leveraged pressure effect, sort of like working a hydraulic jack, only in reverse (where you're making the larger surface area work the smaller surface area).

[greasemonkee]

Interesting. Does it change it's pressure/pedal resistance with manifold vacuum? If so, that would be an easier way to achieve the same thing.

[bluetwo]

I've always just used my big toe when I wanted more feel from the pedal. On a long trip (three days or more) it starts to hurt a little but most of the time it isn't a problem.

You can wear racing shoes to increase the feel, which you probably already knew, and people might go WTF if you go around wearing them very often. I got some Import Racing racing shoes for less than 40 bucks not too long ago.