Tricking the electric power steering
11-30-2004, 10:15 AM
#1
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Tricking the electric power steering
Is there a way to trick the electronic power steering into thinking the car is at low speeds? Perhaps soldering a resistor or something?
The reason for this is to negate the decreased steering angle at higher speeds
The reason for this is to negate the decreased steering angle at higher speeds
11-30-2004, 10:38 AM
#2
Your reasoning doesn't make sense. The car's speed only changes the amount of "power" the steering gear needs, and not the steering angle. As the car increases speed, the amount of assist demanded by the power steering unit diminishes.
11-30-2004, 11:00 AM
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As the speed increases, the steering wheel gets increasingly harder to bring to full opposite lock... this is what I meant be decreasing steering angle. One is more or less fighting the steering wheel at higher speeds.
What I'm proposing is keeping the full power steering effect, even at higher speeds, thus making it easier to countersteer, by somehow tricking the system. However I do not know how the electronic system in the S2k works but I'm sure someone on this board does.
And if you are STILL wondering why anyone wants to do this... it is for drifting. People with the money swap in the p/s and rack from the 3rd generation RX7 than to modify the OE p/s system... but since it is electronic, I'm sure there is a way to cause it to think it is at low speeds, and thus it has maximum assist (or whatever the correct terminology is)
What I'm proposing is keeping the full power steering effect, even at higher speeds, thus making it easier to countersteer, by somehow tricking the system. However I do not know how the electronic system in the S2k works but I'm sure someone on this board does.
And if you are STILL wondering why anyone wants to do this... it is for drifting. People with the money swap in the p/s and rack from the 3rd generation RX7 than to modify the OE p/s system... but since it is electronic, I'm sure there is a way to cause it to think it is at low speeds, and thus it has maximum assist (or whatever the correct terminology is)
11-30-2004, 01:37 PM
#4
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You mean "decrease steering effort."
But I have no idea how it works. I'd assume it's done through the ECU, so perhaps if you disconnect the speed sensor altogether (I've heard that it's a wire coming out of the transmission?) the ECU will read 0mph all the time, and will provide full steering assist all the time. I have no idea if this'll throw a CEL or hamper the engine's operation though.
But I have no idea how it works. I'd assume it's done through the ECU, so perhaps if you disconnect the speed sensor altogether (I've heard that it's a wire coming out of the transmission?) the ECU will read 0mph all the time, and will provide full steering assist all the time. I have no idea if this'll throw a CEL or hamper the engine's operation though.
11-30-2004, 03:50 PM
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the reason people are swapping out the rack from the 3rd Gen RX-7 is not for the feel of the steering wheel but, for the angle of which the front wheels can be turned.
if you are going to use your car on the street i suggest you find a different method of changing the "feel" of the steering wheel because you don't want to drive on the freeway with too sensitive of steering.
if you are going to use your car on the street i suggest you find a different method of changing the "feel" of the steering wheel because you don't want to drive on the freeway with too sensitive of steering.
11-30-2004, 04:22 PM
#6
Figure out which wire to the rack is getting the variable voltage (Helm manual) from where ever (ECU, .....), measure the voltage that corresponds to full boost (sitting in the garage idling), wire it up to only and always see that voltage ..... DONE!
11-30-2004, 04:36 PM
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Originally Posted by RT,Nov 30 2004, 05:22 PM
Figure out which wire to the rack is getting the variable voltage (Helm manual) from where ever (ECU, .....), measure the voltage that corresponds to full boost (sitting in the garage idling), wire it up to only and always see that voltage ..... DONE!
I was more or less looking for a) confirmation that it can be done and b) to see if someone has done it, or wants to do it to test it out.
felonyruckus - so am I right to assume that the S2k wheel doesn't turn very much? Why do you think they designed it this way?... I noticed this when I was autoxing... the wheels wouldnt turn as much as in my 240.
Anyone feel up to taking on the task of having the power steering always full on?
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11-30-2004, 07:26 PM
#8
I'm doing this from memory so suggest you check the wiring diagrams.
The EPS takes its speed signal from the instrument cluster. The instrument cluster takes a speed input from the sensor on the gear box and halves the pulse rate before sending the signal to the headlight, roof, abs, airbag, wiper and other systems.
The speed signal is a uneven duty cycle square wave pulse so cannot be altered with a simple resistor.
If you want to trick the EPS into thinking the vehicle is travelling slower, you will need to put something like a yellow box on the speed wire to the EPS so it sees a lower road speed. You could also put a switch in the line so it thinks the car is stationary and provides maximum assistance. A switch is easy to try, and undo if you like playing.
BTW, if your car is from a market with the 180km/h speed limiter, putting the PCM after the instrument panel will lift the max speed to 360km/h, enough for most people.
Chris.
The EPS takes its speed signal from the instrument cluster. The instrument cluster takes a speed input from the sensor on the gear box and halves the pulse rate before sending the signal to the headlight, roof, abs, airbag, wiper and other systems.
The speed signal is a uneven duty cycle square wave pulse so cannot be altered with a simple resistor.
If you want to trick the EPS into thinking the vehicle is travelling slower, you will need to put something like a yellow box on the speed wire to the EPS so it sees a lower road speed. You could also put a switch in the line so it thinks the car is stationary and provides maximum assistance. A switch is easy to try, and undo if you like playing.
BTW, if your car is from a market with the 180km/h speed limiter, putting the PCM after the instrument panel will lift the max speed to 360km/h, enough for most people.
Chris.
11-30-2004, 08:29 PM
#10
Originally Posted by chris_barry,Nov 30 2004, 08:26 PM
I'm doing this from memory so suggest you check the wiring diagrams.
The EPS takes its speed signal from the instrument cluster. The instrument cluster takes a speed input from the sensor on the gear box and halves the pulse rate before sending the signal to the headlight, roof, abs, airbag, wiper and other systems.
The speed signal is a uneven duty cycle square wave pulse so cannot be altered with a simple resistor.
If you want to trick the EPS into thinking the vehicle is travelling slower, you will need to put something like a yellow box on the speed wire to the EPS so it sees a lower road speed. You could also put a switch in the line so it thinks the car is stationary and provides maximum assistance. A switch is easy to try, and undo if you like playing.
BTW, if your car is from a market with the 180km/h speed limiter, putting the PCM after the instrument panel will lift the max speed to 360km/h, enough for most people.
Chris.
The EPS takes its speed signal from the instrument cluster. The instrument cluster takes a speed input from the sensor on the gear box and halves the pulse rate before sending the signal to the headlight, roof, abs, airbag, wiper and other systems.
The speed signal is a uneven duty cycle square wave pulse so cannot be altered with a simple resistor.
If you want to trick the EPS into thinking the vehicle is travelling slower, you will need to put something like a yellow box on the speed wire to the EPS so it sees a lower road speed. You could also put a switch in the line so it thinks the car is stationary and provides maximum assistance. A switch is easy to try, and undo if you like playing.
BTW, if your car is from a market with the 180km/h speed limiter, putting the PCM after the instrument panel will lift the max speed to 360km/h, enough for most people.
Chris.
