Drive by Wire Throttle tune = ~3 MPG gain & more

[Occasionally6]

I have seen quite a few plug and play devices that intercept the pedal position sensors and change the response of DBW throttles. They are aimed at increasing the throttle movement though, the opposite of what is wanted (for economy driving).

One guy did a write up of one such device (in what he called a "White Paper") on it. If I recall it was in a Mercedes-Benz but they'll all operate similarly. His conclusion was that it was likely using Op-Amps to change the two (some do use three) voltage signals out of the pedal position sensors.

P-hack's suggestion of using a microcontroller seems reasonable, if the ECU mapping can't be accessed. The failure modes include dropping the throttle back to idle position if the brake pedal is applied so it won't be particularly dangerous if it did fail.

[redpoint5]

I located the throttle on the electric "car" I built in high school on the steering column to provide finer control, and reduce spikes in throttle position due to potholes.

I'm surprised a throttle hasn't been incorporated on steering wheels of conventional cars. Not only does it provide a finer level of control, but it encourages drivers to keep their hands on the wheel.

At any rate, I have a "chip" on my diesel that changes the throttle mapping, and cars such as the Prius have increasingly adopted driving modes that re-map throttle response.

[bobdbilder]

P Hack's got me thinking of modifying the signals from the MAP (or T-MAPs) and Engine Temp while retaining factory ECU maps. The nett effect would be similar to remaps. I have actually reduced vacuum along the intake with a secondary intake (as per Autospeed). It affects the T-MAP and therefore you get less fluctuation in the manifold pressure.

[Baltothewolf]

I don't totally understand what's being said here, but from what I do understand, I think my 1995 Toyota Camry does the same dang thing. Sometimes in the city I barely put my foot down and it will just spike in RPM's and jolt me (does it in freeway traffic as well when I'm on and off the throttle alot). I wish there was a solution for it but I doubt it as my engine is only OBD-1 (does that make a difference?).

[101Volts]

I could just look it up but for the thread and anyone else wondering, Is there a complete list of vehicles with DBW Throttles on the internet at least for so many years? And when were they first incorporated into vehicles?

*EDIT* I read this, Is it true?

"Just look at the accelerator pedal assembly. If you see a cable that moves with the pedal and goes through the firewall then it almost certainly is not DBW.

Read more: http://www.city-data.com/forum/autom...#ixzz2l3rwoHKY "

I read it is true there. On a similar subject, Could I adjust the cable in the Caravan to be looser, For fuel economy? Could it work? *Second edit* It's not a DBW Throttle.

[Occasionally6]

The earliest example of DBW throttle in a car that I can recall is in the mid to late '80s BMW 7-Series, with the then new V12. That used two TB's. DBW throttle became much more widespread around 10-15 years ago, although even now I don't think they are ubiquitous.

Creating slack in the cable won't do much other than prevent full throttle opening. It is possible, in principle at least, depending on skill, to play with the throttle linkage. Unlike DBW, you can't have it change with rpm though.

If there is a cam that the cable wraps around, the shape of that determines how far the throttle opens for a given pedal movement. You might find one from another vehicle that can be adapted.

If there is a simple stud connection, that can be moved.

You might also move the pivot point for the pedal.

The cable travel at the throttle and at the pedal still have to match at wide open throttle and you don't want to go over centre.

You will also alter the pedal spring force. Actually, that might work too; use a stiffer spring.

[bobdbilder]

ever green's screen capture looks very much like OpenEcu.org/Tactrix stuff. They've got software and an OBDII connector/dongle that's capable to reflash most Mitsu's and Subaru's ECU. So it's pretty limited at the moment to those marques.

A few years ago VDO/Siemens would advertise the specs for their ECUs and you could actually find out how fast they work. A better ECU or Microcontroller would then be one that has a faster scan rate. Better scan rates would enable usage of faster sensors like Bosch Motorsports Piezo MAP sensors which would run at 0.2ms instead of the Bosch's standard OEM stuff of 1ms response time. Again it doesn't mean a thing if your ECUs don't run as fast or have big enough look up tables.

[TexasCotton]

Originally Posted by P-hack

Ah, folks are doing something similar. Plug and play but expensive, and not quite the feature set I would hope for:
Pedal Commandertoyota Prius 1 8L Hybrid Throttle Controller Faster Acceleration | eBay

Yea IF I am inclined or motivated to this I would not use the above hardware that is out of country however this might be a better alternative
Weapon R I Throttle Controller Booster Boost Selectable | eBay

[2007 ion2]

wow, I can't imagine having a car with this throttle map! my car is DBW, but GM made it more of a linear feel. I can also have mine tuned any way I want, and have the shift points and lockup tuned if I had an automatic.

[brucey]

My 2013 Subaru is having similar issues, now that I've gotten a feel for it. The throttle is either "Off, Normal, or Too Much"

I can't have light throttle. I back my foot off the pedal and nothing changes, so I back it off more and it goes into fuel cut immediately.