Shortly after I got my own HP Tuners software, I discovered how GM programmed their drive-by-wire throttle positioning. It's an electronic version of the same progressive throttle system that Pontiac first used on the 1965 tri-power engines and hot rodders had developed years before that for multiple carbs. When 4-barrel carbs came upon the scene in the 50's, it was quickly recognized that it was too easy to dump too much fuel or allow too much air in too quickly. Along came vacuum secondaries to ease the transition, including vacuum controls for multiple carbs. However, fuel injection changed all those requirements, because it was far easier to control the fuel mixture.

With that personal experience to draw upon, I set about creating a mechanical regressive system that attached directly to the throttle arm in place of the spring loaded swivel gas pedal. It had 25% at the throttle blade when the pedal was depressed 25% of the way and 50% throttle at 50% pedal, and so on.

As you might expect, the throttle response was AMAZINGLY quick in relationship to the pedal position. So much so, that it became very difficult to control low engine speeds, especially on bumpy roads where a slight movement or jerk of the pedal produced either instant acceleration or deceleration. After trying it for about 2 weeks, I pulled it off after loosing traction trying to accelerate easily, yet quickly, on a wet road in traffic and nearly causing an accident.

I now use my foot movement to control the throttle more precisely at lower RPM over a longer range of pedal movement and still agressively when desired. If 50% on the pedal isn't enough, I just push harder. It's an electronic progressive system that gives the driver better control.

I just wanted to share my personal experiences regarding throttle control and mention that it doesn't take much change of the throttle blade position to unleash a bunch more power when you have 400+ on tap.

Super quick is best related to the speed of your right foot.

 

This sounds like a mechanical fix to Chuck's Programmed Fix for throttle response.

 

So are you saying you are NOT bringing this product to market?

 

My old M3(E46) had a option that did something similar. I did not like it much as I felt the response was to sensitive. It was an OEM component.

Maybe better for the track than around town.

 

Dang, I would like to know more. And just today, first gear and a little down hill, barely could touch the throttle and had huge swings in RPM's and an annoying bucking tendency. Please tell us more

 

Tossed it in the trash along with the couple others that didn't work quite as well. It was far too dangerous to be using with high horsepower.

I only posted this in response to the electronic versions offered by a few companies in the past couple of months. What I created mechanically, while it sounded good theoretically, was a disaster in reality. The first couple of days I thought it was really great, but then as the novelty wore off and I stopped playing with it, the difficulty of fine low speed control slowly sunk in.

If you've ever driven cars built in the '30s - '50s with manual steering, you'll remember they had something like 5 to 6 turns lock-to-lock and the ratio was constant. Later on when power steering became far more common, the lock-to-lock became much less and the difficulty of higher speed straight line driving was resolved by creating variable ratios. That allowed a larger movement of the steering wheel in relation to the front wheel when close to the center position, while becoming quicker as the steering wheel approached the end of travel. Great for both highway and parking.

Well GM has applied the same concept to drive-by-wire by reducing the pedal sensitivity at partial throttle and gradually increasing it as you approach WOT. It allows finer control of RPM at lower car speeds, so driving in traffic with lots of horsepower capability doesn't release that HP with just a tiny touch of the pedal. On lower HP cars the sensitivity can be adjusted to provide smooth and controlable low speed operation by allowing a large percentage of power for a similar pedal movement.

Changing the rate of pedal position to throttle blade opening from a constantly increasing variable ratio to a straight 1 to 1 ratio makes it nearly impossible to maintain a constant low speed RPM level.

What I did created a very touchy throttle. It's a bad idea, which is why I trashed it.

 

Very interesting post and I feel it deserves a bump to add to the discussions as of late.

 

I agree with HOXXOH's decision to abandon the idea. That could be very dangerous on a powerful car. Very unforgiving for a new owner/operator. Could lead to an increase in minor damage claims and a higher insurance surcharge for all owners. Imagine the havoc of a similar "improvement" on a powerful motorcycle!!

I know that many people want to invent a better mousetrap....but, maybe GM really knows what they are doing. Well....at least most of the time!!! : )

This reminds me of the old days of shackles and air shocks. Just because we can make a change just necessarily mean that we should. The mere possession of a screwdriver and wrench does not make one smarter than the GM engineers and their design computers.

No offense to the OP or anyone else....I am just reinforcing the OP's decision to abandon an idea.

Just my opinion!

Andy