TP control?

[Harpo]

Howdy Guys - Now that I have the introduction formalities out of the way, I have my first question.

I love and hate Cruise Control. In my truck, it's so nice for those flat level roads, even when towing. Cruise seems to give me "the" best mileage when non-stop. However, any significant hill load starts feeding in the gas. I'd much rather have a TP Control instead.

There in, my question. Has anyone toyed with the idea of making a cruise control into a Throttle Position control? I'm considering that as one of my future mods for the Civic. I have a 8 mile stretch of good county road (55mph) that begs for a fixed TP due to it's slight rolling nature. My Civic VP doesn't have Cruise Control, but I'd sure like to have fixed TP control, with electronic release (switch/brake) and not rely so much on my stupid foot. I’ve got two left feet and they’re both on my right side.

[Harpo]

So on my Data Logger Tach I have on the Coronet, I have conventional tach input and driveshaft sensor which simply sends a pulse to the tach as the magnet crosses the sensor. It lets me calcualte converter slippage, tire spin, and tire growth/mph. I making the assumption that aftermarket/OEM receives wheelspeed sensor data the same way.

So, I thought, if I can build a little 12v digital circuit that can generate a suitable pulse, have a LED average display and a input device (keypad +/-) I could interface that with the cruise control circuit, and "set" a pulse count or width. Since the wheel sensor would be removed, the pulse would be consistent leading to a "fixed" throttle position.

I could easily calculate the approximate wheel speed data to get starting point for a few different common speeds. I'm dropping by the local wrecking yard to look at some LXs w/ cruise control.

Crazy talk or not?

[SVOboy]

I don't know anyone who has actually done it. I think the closest anyone has gotten was a hand controlled throttle that basjoos rigged up, but I'm sure it's possible, na? I spose if you removed the brains from the cruise control (somehow) you could have it just clamp the TP and not the speed.

[Harpo]

What I propose is just to spoof the wheel sensor input. Therein, never having to break the unit open. I want to ensure I retain the brake switch and manual disconnect. I'll probably try to wire a power relayed circuit to switch sources from WheelSpeed to Spoofed Mode. That way I can flow with traffic if required.

[s2man]

Somebody around here modded his CC to limit the amount it can open the throttle. All else works as OEM. Downhill and level driving are normal, but it allows the car to slow on the uphills.

[Harpo]

Originally Posted by s2man

Somebody around here modded his CC to limit the amount it can open the throttle. All else works as OEM. Downhill and level driving are normal, but it allows the car to slow on the uphills.

That's good idea and would work in most situations. I'll look at some of the OEM gear and see how that's possible. Much in like my manual throttle stop on the Coronet to keep from running under the index.

[RH77]

Originally Posted by s2man

Somebody around here modded his CC to limit the amount it can open the throttle. All else works as OEM. Downhill and level driving are normal, but it allows the car to slow on the uphills.

That would be me. I have the CC limited at 21% TPS, which allows for approximately 60 mph or slower (depending on wind resistance) on flat roads or downhill with no wind, and a slight slow-down uphill or "load into wind". It's for those trips where you're tired or can't focus on driving with load.

At the CC control box, I rigged up a hex wrench to limit the travel of the cog that pulls on the throttle cable. With the proper-sized wrench wedged in there and secured, it allowed a max TPS of my choosing. For the utmost in safety, there is virtually no possibility of the throttle getting stuck -- it's only a single-direction limiter.

Drawbacks: the CC usually freaks out and cancels itself on most engagements. It just requires the CC on-off button to be cycled and a retry of the "set" function (and then it takes it). 90% of the time it will hold without it getting upset about it and cancelling. Also, if another driver attempts to use it, they get a surprise. Otherwise it works fairly well...

RH77

[s2man]

I looked at mine last week and didn't see an easy way to limit it. It looks like I'll have to open the CC unit to modify it. :S

Not to hijack the thread RH, but how is your adjustable HAI working? I added WAI two weeks ago, and within days I was going "I gotta get it adjustable, like Rick's".

[RH77]

Originally Posted by s2man

Not to hijack the thread RH, but how is your adjustable HAI working? I added WAI two weeks ago, and within days I was going "I gotta get it adjustable, like Rick's".

I talked about it in the Daily Drive Thread.. Yeah, it's not adjustable (yet). If you come up with something let us know My biggest problem is sourcing the cool air in Summer.

-RH77/Rick

[LostCause]

Originally Posted by Harpo

So on my Data Logger Tach I have on the Coronet...

...I'm dropping by the local wrecking yard to look at some LXs w/ cruise control.

Crazy talk or not?

That sounds super complex.

The throttle is controlled by a servo, right? I'd just tap directly into the servo and connect it to a potentiometer. Chuck the CC brains and just control the throttle directly with a knob reading 0-100%. Figure out some sort of switch that kills power to the servo when the brakes depressed, CC cancelled, etc. and you are done.

I'm no EE, so I can't tell you how to carry this mod out, but conceptually that is how I would approach the situation.

- LostCause