Adjusting shift points and TC lockup

[orange4boy]

Originally Posted by mechman600

You're on Bowen Island, hey? I'm in Surrey. Trying to hypermile in the lower mainland is pretty much impossible because most people are simply just a-holes when it comes to driving. I guess that's another reason for going with the ecomod angle vs. the hypermile with what you got.

So true. Everyone is in a big rush to go nowhere. One "advantage" to extreme aero mods is that people often slow down to stare/laugh/take pictures/ask questions. When hypermiling, one must endeavour to ignore the ignoramus.

[JeepNmpg2]

Not to quench your voracity in questing for TC lockup, but I remember reading that at least for my TC, it only locks up in low-load conditions (IE-overdrive) so as to protect some drivetrain components. Not that the same completely applies to your vehicle, but it would be good to look at before potentially causing several thousand dollars in damage.

My two cents. Happy hunting!

[comptiger5000]

Many transmissions do that because the torque converter clutch is undersized (for cost reasons). If you shift kit the transmission, and can bump up the engagement pressure, you'll be less likely to slip it under heavier loads, so it's safe to lock up with more throttle (not at WOT, but that's not an issue here).

[orange4boy]

I think most ecomodders would not slip the TCC. It is good to know about though. I don't use mine while hard downshifting for that reason.

There is a simple way to increase the engagement pressure in a Toyota, at least, that has the kick down throttle linkage. You simply tighten the cable by moving the lock nuts. This also reduces wear on the bands.

Explained better here:The Free Mod Series - Part I Quicker Transmission Shifting

Also there is lots of info for Toyota transmission modding here:The Free Mod Series: Part VIII Manual Electronic Transmission Controller

[mechman600]

Originally Posted by orange4boy

I think most ecomodders would not slip the TCC.

Exactly. I am actually surprised how much throttle it takes for my Matrix to unlock the TC. I'm guessing around 25% and low revs, and maybe a bit less at higher revs. I plan to make my proposed control circuit unlock the TC at the same throttle % as the ECU would to avoid any possibility of damage. Still working on the control circuit because it's still not right. Tomorrow at work I'm going to make my two relay override for some preliminary testing:

Picasa Web Albums - jamespvoth

When the control side is grounded, the first relay breaks the connection between the ECM and transmission while the second relay creates an artificial circuit to trick the ECM into thinking it is still connected to a solenoid.

[Daox]

Bumping for anymore info? I take it this is dead in the water though?

It sounds like my 1997 Sunfire is similar to your setup. From my testing (just driving), TCC lockup has massive effects on FE. I'd love to at the very least have a TCC lockup switch if not full control of shifting.

[backpacker3]

Daox have you seen the B&M. Shift plus for j body cars it's supposed to improve the shift points and it's only about 30 bucks. Just as a question though doesn't just using the selectable gears on an automatic do the same thing?

[Daox]

Unfortunately, as I've been reading, the automatic trans in the sunfire isn't electronically controlled. Only the TCC solenoid is.

[backpacker3]

Wait you can't choose 1st and 2nd gear? I can choose 1st 2nd & 3rd gears on my 4 speed I thought that you could at least choose 1st and 2nd on the 3 speed. I would look into the AutoTrans Interceptor though I posted about in your sunfire build thread that does work with the 3 speed

[ever_green]

I did an ECU flash on my car and adjusted the Drive By Wire settings. I basically made the throttle slightly more sensitive. This way I have to press the accelerator pedal less to get going and it makes the transmission think i'm just cruising and it causes extreme short shifts and Torque converter locks. By extreme I mean the car mostly operates at 1200-1700 RPM range now. Whats more is if i'm not in hypermiling mood I just select sports mode and that adds ~1000 RPM to the shift points.

Was it worth the trouble and risk? No. Did I get any considerable improvements in mileage? No. in fact my mileage did not change at all. Whether you generate 40 HP at 2000 RPM or at 3000 RPM don't really matter much these days, at least not with my car...so long as you don't go to extremes.

the biggest effect on Fuel economy in terms of mods is closed loop and open loop fueling. Running lean REALLY REALLY helps. I improved my mileage by about 10% when changing the unnecessarily rich fuel maps. I'm not really sure why manufacturers are making fuel maps richer and richer every year. i guess it has to do with higher compression, timing and output. Eitherway this can be fixed by running leaner and cutting a couple degress of timing for safety under load. I prefer the Lean and moderate timing strategy compared to the pig rich and mean timing.

my fueling is completely vacuum/load based now and I can run as lean as 15:1 at 4000 RPM if there is enough vacuum!