speed limiter

[bedbull]

guestion ... what kind of signal goes to the ecu to tell it that the vehicle is moving and when the car reaches max speed.... because i feel if i knew what goes to it i could build a eliminator please let me know
what kind of signal goes to the ecu is it a pulse or is it 12v + or - voltage flashing to it and goes faster as the vehicle reaches maximum speed ( i have a 165 3sgte in a 91 corolla)

[Piddy]

I don't know.... but you would be my god if you could build something... lol. Greddy makes them... but I'm not sure how it works. Would you be able to tell from the wiring diagrams?

[aosmith]

iirc voltages to the ecu pr between 1 and 5v for inputs like tach, mass air, 02 sensors....if you could just put a 1v campacitor in the way of the speed line youd be golden (maintian 1 v all the time tell the car its moving at a constant speed)...i think that would work but not sure

[aosmith]

if you email me i have a diagram of the electrical pin out on an 86 ecu

[Toysrme]

You can't eliminate the signal. That would be quite bad!
What you can do is intercept and replicate the signal exactly. Then when you pass XXX, stop replicating the signal exactly and start replicating the last stored signal.

SMT piggybacks have this capability.

I would suggest anyone doing any modification to the signal "freeze" the signal somewhere definately above the last gearchange, and the highest point possible before the ECU does a fuel/ignition cut.

[aosmith]

i didnt sya eliminate i said keep voltage under a certain point, so if it generates 3v at 80mph use a 3v campacitor so the maximum voltage ahcived would be 3v -> the car only thiks its going 80 when it is really going a lot faster

[Pineapple]

Its not a voltage signal, its a pulsing signal. Putting a cap to keep it constant will be 100% duty cycle which most likely means a very fast speed
Put a scrope on the signal to check the pulse.

[aosmith]

are you sure its a pulse...i know 02 are voltage (how 02 gauges work), but i guess it could be pulsing

[TekPhobia]

Yea, caps filter DC so that wouldn't do any good. If/when I get a chance I could easily build something like this. It's simply a 50% duty-cycle signal at 4 pulses per wheel rotation. Ahh....good times...

-Tim

[Pineapple]

O2 got nothing to do with speed. The raw signal for any rotational sensor is pulse. You can use an encoder circult to make it voltage or current but it'll not be as accurate. Computers are digital, counting pulse is what its good at and simplest.
Go to howstuff work website and do some reading.

[mr2trd]

better yet, does anyone know the top speed of a genIII 3S-GTE powered MR2 with the speed limiter removed? i saw a video clip of an H22a Civic hitting 170mph. supposedly a stock engine with the speed limiter removed.

[aosmith]

i would doubt 170 stock...for some reason i would think its areodynamicly limited around 120