WOT shifting for autos

[SVOboy]

I seem to be the only on here that believe in the merits of WOT shifting; I also happen to drive an auto so I can't practice it much.

However, since I no longer am able to use my kickdown cable (tells the tranny when to shift based on pedal pressure) I can rig it up any way I like. I plan to stretch it only as much as needed so that it always shifts at 1800, no matter what. This will allow me to just floor it through all the gears and keep my rpms low, hopefully I can test this theory well.

What does we thinks?

[krousdb]

I look forward to some results.

I plan of accelerating more briskly on this tank, although not WOT. There is a point in 5th gear, at 17 in hg and higher that my instantaneous FE spikes. The sooner I get to speed the sooner I can cruise in this high FE zone.

[SVOboy]

I have been doing it in my mom's car but our driving styles are just too different to compare. I hope it does work, have you seen the insight forum quote about why it's supported over there?

[krousdb]

No but I would expect that it is for the same reason that I mentioned above. WOT means less time accelerating and more time cruising in lean burn. I think that the benefit of lean burn might outweigh any drawbacks of WOT.

But for those without lean burn, WOT may not work as well. WOT means open loop, which means less than stoich.

I dunno, just my opinion. meh

[SVOboy]

Run a search for my original thread on it and you will see the quote. The idea is mainly that you reduce pumping losses enough that in combination with getting to speed quicker you're still saving. You're prolly at 13.5:1 or so when you're at WOT, it could prolly be tuned down a bit also.

[krousdb]

Yes, the target afr at WOT (for my ecu) is about 13.5. I plan on changing that to 14.7 so that I won't have a WOT penalty. In that case, I would agree with your WOT theory.

[SVOboy]

Well, even with that decrease the fuel injected at WOT will still be a large amount above greater vacuum. Also, there's a lot of blown up engine issues when you mess with WOT afrs,

[krousdb]

Originally Posted by SVOboy

Also, there's a lot of blown up engine issues when you mess with WOT afrs,

Hah! A blown engine will give me a good excuse to go Z1. The holy grail! :-)

It reminds me of when I bought my dad's 68 Rambler American in the early 80's, my first car. It only had 83k miles on the 199 cid inline six, three on the tree. I ran that engine in first gear, WOT for miles and miles. I could not get it to blow. Finally I had to tell a white lie to my dad that the engine blew. Thats when I put in the 401 cid and a chrysler 8 3/4 rear end. Ahhhh those were the days. NOw I am in persuit of the ultimate measure of performance... FE! :-)

[Compaq888]

Originally Posted by krousdb

Yes, the target afr at WOT (for my ecu) is about 13.5. I plan on changing that to 14.7 so that I won't have a WOT penalty. In that case, I would agree with your WOT theory.

The max you could go for WOT a/f ratio is 13.5:1, anything leaner and you can easily blow your engine.

[zpiloto]

I've tried this with the scan gauge and there is a sweet spot where MPG drops from 6 to 2.8 with out much increase in acceleration. When I ran my 41 mile test loop(rolling terrrain with 15 stops but no traffic) the increase in MPG between each trip was an increase of .4 MPG using the near max acceleration. I do not shut the engine off(which would yeild better results) when coasting but shift into neutral. I'd be interested in the results of the lower shift point and the effects on MPG. My point is 2500 RPM.

[SVOboy]

I've tried this with the scan gauge and there is a sweet spot where MPG drops from 6 to 2.8 with out much increase in acceleration.

Excuse me kindly, but I am a bit confused on this part.

What I take from the whole, however, is that WOT or near WOT shifting has been tested by you with your scangauge to yeild a slight benefit?

[zpiloto]

When I am near WOT the scan gauge shows a slight increase in MPG. This info comes from only 2 runs. If I accelerate hard the scan gauge will show 6 MPG then if I floor it the MPG drops to 2.8 MPG with out much increase in accleration. Just for reference time to 50 mph is about 11 seconds.

[rh77]

Unless modified, I think Hondas run in open-loop under WOT (unless modified not to). You may want to consider like 80% throttle input.

RH77

[SVOboy]

I've scrapped this because even with no kickdown cable if I go WOT it just rev up to 3k quickly and sits there through acceleration, time to swap the manual in,

[Compaq888]

after I adjusted my throttle cable and took out the extra fluid from the tranny it's shifting right. In fact after I reset the ecu it doesn't jump between gears when going up hills. Even when racing now if I shift it at 6000rpm it goes right for the redline(6100) and shifts into the next gear. I think the ecu has a lot to do with shifting too.

[rh77]

Originally Posted by Compaq888

I think the ecu has a lot to do with shifting too.

Huh. Thought it was mystical powers that shifted the transmission, like a leprechaun or something. Dammit, now I'm going to have to cancel the Warlock that was going to wave the magic wand to change the shift points.

RH77
"They're Always After Me Lucky Charms!"

[Compaq888]

try reseting your ECU RH, and your tranmission module too.

Resetting the ecu is easy, just follow instruction on ecu itself. The transmission module reset has a lot of steps including turning the key a lot and pressing the gas pedal in special modifications.

After I reset my ecu my shifting got so much better. 1st gear grabs better, stays in 4th when going up small hills, and when racing it shifts hard and fast and goes all the way to redline.

[rh77]

I posted this a while back, and didn't get a idea on if it worked. In the TL, the manu-matic shift allows you to select a gear and hold it despite pedal pressure. You can't put it in top (4th) gear until a certain speed.

With that in mind, I generally stay in the highest gear and nearly floor it most of the time to accelerate. Since I can't test economy on that car right now, is it better to stay away from WOT because of the Honda open-loop circuit in that situation, or stay with 80% throttle at top gear? Furthermore, at 35 mph, in 4th gear, accelerating up an on-ramp to the highway seems like it would take a toll on the transmission -- it's at 1500 RPM, WOT, and steadily increases in speed until 60-65, then the TC kicks in. Is there slipping going on? I've heard though that more throttle means more ATF pressure to the selected gear (I've had some low-throttle, hi-load, low 3rd gear fluid pressure CELs now and then -- maybe like every 6 months). That's kinda why I'm worried about the tranny (and with the history of the 5-speeds in 2000-2004 in the TL (especially the Type S) and the MDX. I lucked out and got the 4-speed. I've heard of 5-speeds lasting 40,000 miles even after replaced new. This is, by far, the biggest smudge on the clean record of Honda reliability.

RH77

[red91sit]

welll this is a tricky topic, all the companies use differnt programs to control their auto's and engines. Whats' best for one car might be very different for another. My car's auto tranny is completely seperate of the motor, I found best economy to be had by giong 50% throttle, and then letting off the gas to make it shift, then getting back on the gas haha, works great,

[BluEyes]

Originally Posted by SVOboy

However, since I no longer am able to use my kickdown cable (tells the tranny when to shift based on pedal pressure)

Be careful with this. I'm not familiar with the Honda transmission, but I know that other manufacturers use the throttle cable to not only determine shift points, but also to regulate transmission fluid pressure. The end result is if you have the pedal to the floor, but are only have the cable pulled in a tiny bit (to make the trans shift at low RPM's) the fluid pressure that applies the clutches inside the trans might not be enough to hold the torque, leading to slippage and fried trannies.

[bbgobie]

Hate to bring up something so old, but I thought it was interesting. If i'm getting it, we are looking to accelerate as hard as we can while staying in closed loop and shifting early?

I wouldn't mind helping to test this out since i have the manual "auto" feature in my RSX. Just wanna make sure I have the concept right, and wondering if anyone else has more info on their results.

[zpiloto]

Originally Posted by bbgobie

Hate to bring up something so old, but I thought it was interesting. If i'm getting it, we are looking to accelerate as hard as we can while staying in closed loop and shifting early?

I wouldn't mind helping to test this out since i have the manual "auto" feature in my RSX. Just wanna make sure I have the concept right, and wondering if anyone else has more info on their results.

Here's a thread on it.
What I found is that the numbers are so close that the way you accelerate is really not much of a factor. In a perfect world it might result is a very slight increase in FE but there are so many varibles dependending on traffic, lenght of runup till you stop again and slope that you really have to master all three accleration techniques to get the best possible FE. YMMV

[bbgobie]

If there is gonna be negligible difference WOT IT IS!

I tried driving around that way today. I got worse than my normal FE. But I made a bunch of short trips, with 2 bikes and the rack on the hitch, and A/C for the GF.

TOmmorow is wide open throttle day as I'll have my car at the track, but on monday its back to FE Driving for the daily commute. This tank of gas is gonna suck!

Originally Posted by zpiloto

Here's a thread on it.
What I found is that the numbers are so close that the way you accelerate is really not much of a factor. In a perfect world it might result is a very slight increase in FE but there are so many varibles dependending on traffic, lenght of runup till you stop again and slope that you really have to master all three accleration techniques to get the best possible FE. YMMV

[BluEyes]

I think whether or not WOT shifting makes sense depends on the traffic pattern. If you are in stop and go traffic it is not going to work. You are going to spend lots of energy to get up to speed then have to stop soon anyways. OTOH, on the highway get up to cruising speed quickly so you can get your best economy more quickly.