V6 Touchy throttle at takeoff and passing

[bob-o]

mine was built in canada in october. it has the cts. i find the tip-in too aggressive and it has noticeable lag in the midrange.

the pedal assembly is just a pot. you can measure the voltage vs. travel, and it will probably be linear. the spring force probably will not be. I think the lag is caused by a slow sample rate of the analog signal, and because the i-throttle samples at a higher rate it might reduce the lag by feeding more up-to date data to the ECU at each sample time. people claim it is noticeable. we are going to the hot springs for a couple of days so I will have a chance to play with the different profiles.

[Dr. Dyno]

Originally Posted by bob-o

If your only issue is the pedal resistance, they only cost about $100 so you might buy an extra and take it apart to see if a stronger spring would give you what you want.

A stronger spring would definitely help Gaza's issue.

Reminds me of removing springs from the carburetor linkage to make the car feel faster.
But that was back when my Toyota had 69 HP , not 269!

[Dr. Dyno]

Originally Posted by bob-o

the pedal assembly is just a pot. you can measure the voltage vs. travel, and it will probably be linear.

That's the test we really need, a plot of voltage out vs. pedal position.

I think the lag is caused by a slow sample rate of the analog signal, and because the i-throttle samples at a higher rate it might reduce the lag by feeding more up-to date data to the ECU at each sample time.

I kinda doubt it's a sample rate issue since the i-throttle would have to convert the signal back to the analog the ECU expects to see and it would still be sampled at the ECU's stock rate.

we are going to the hot springs for a couple of days so I will have a chance to play with the different profiles.

Be waiting for your experience. BTW, how does one change the profiles? Can it be done on the fly?

[bob-o]

the i-throttle output is active, and might produce more drive current than the stock sensor, driving the input of the ecu to the desired voltage more quickly if there is any RC filtering on the ECU input. I don't know. I agree about the sample rate issue.

You can change the profile at any time the unit is on. a button cycles through the modes and the display indicates the one selected. there is a mode for no mod to the profile. There is also an output wire you can connect to the brake signal to shut down the throttle signal when the brake is activated to protection against the thing going wild and flooring the pedal. They say connecting it is optional. I'll have to find out if the feature of the vehicle that I think already does that works the way I expect.

When I said the sensor was "just a pot" I meant that it produces a linear analog voltage with travel. It might be a resistive element, but I suspect it is probably a Hall effect sensor and magnets like the cheap throttles on my electric bikes. If this is the case, the curve could be modified by adding or changing magnets. I'm not taking mine apart to find out.

My first car was an MG midget with a 1098cc engine that produced 65 hp. It had drive by wire too, but this was just one wire that pulled on the SU carbeuretor linkage. Worst carbs ever made, IMO.

Off to soak for a couple of days. Have fun all..

[JuneBug]

Speedslave, my 2008 was made in Japan and has the Denso pedal. Some may call it too aggressive, but I got used to it a long time ago. The only "fix" was to trim down the bottom of the pedal to prevent snagging on a floor mat.

[Steverino]

Originally Posted by Gaza

I find Im getting a sore leg because I have to hold my foot in a mid-air like position .
The pedal is so light I cant put any weight on the gas without it going to the floor . Other cars I dont have a problem. There is just not enough mechanical resistance in this pedal.
I have to drive using my big toe only which is nuts .


2009 ZR6.

I had a similar problem with my Honda Fit and found this solution:

DIY: How to Stiffen a GD3 Drive-by-Wire Gas Pedal - Unofficial Honda FIT Forums

Cost me all of maybe $4 and has been working wonderfully. I know the RAV's gas pedal is a bit different, but I'm planning to look into a similar mod on our RAV.

[rav4two]

Originally Posted by Dr. Dyno

That's the test we really need, a plot of voltage out vs. pedal position.

I kinda doubt it's a sample rate issue since the i-throttle would have to convert the signal back to the analog the ECU expects to see and it would still be sampled at the ECU's stock rate.

Be waiting for your experience. BTW, how does one change the profiles? Can it be done on the fly?

In my Corvette, the pedal provides a linear signal to the ECU in regards to pedal position, but the internal mapping of the input signal to actual throttle position is more complex.

A sudden stab at the throttle produces a deliberately slow response in actual throttle position, such that you can actually get 10% throttle with a 50% pedal movement. Gradually, the throttle is fed in until you get the final setting of about 30% throttle with a 50% pedal position.

If, however, you are already at some throttle position and the vehicle is moving, and you apply a sudden 50% pedal travel input, the ECU doles out throttle in a faster manner, but this manner also changes depending on steering wheel and accelerometer data.

So on that system, it's not a matter of input linearity or sample rate, but also the time-acceleration of input sensing along with the instantaneous dynamic context of the vehicle. I'd expect the Rav's system to work in roughly the same way.

[autotechazo]

I did not read all of this thread so this may have been brought up already. as far as shifting down to save on brakes due as you will brakes are cheaper than transmissions, I suggest using brake over agressive down shift dragging. just my thoughts but again. I will fix either

[Dr. Dyno]

Originally Posted by bob-o

the i-throttle output is active, and might produce more drive current than the stock sensor, driving the input of the ecu to the desired voltage more quickly if there is any RC filtering on the ECU input.

True, the i-throttle could have a lower output impedance.

My first car was an MG midget with a 1098cc engine that produced 65 hp. It had drive by wire too, but this was just one wire that pulled on the SU carbeuretor linkage. Worst carbs ever made, IMO.

Hey, I had dual SUs on a Volvo P1800 and really liked them. Simple & functional. Liked the way I could adjust throttle response by changing the viscosity of the oil on the plungers.

Even had one of the shops I tuned for retro them onto Harleys. He said they solved a problem I thought didn't exist but he sold a lot of them.

[Dr. Dyno]

Originally Posted by autotechazo

I did not read all of this thread so this may have been brought up already. As far as shifting down to save on brakes, do as you will, (but) brakes are cheaper than transmissions. I suggest using brake over aggressive down shift dragging. Just my thoughts but again, I will fix either.

Don't think it was on this thread but I have mentioned it several times mostly wrt manual transmissions & clutches.