Well actually, the top 2 gears are the only ones I'm really interested in, esp the top one. Would it be as simple as finding out which solenoid valves are in or out for the high gear, and mimicing this w/ toggle switches or a relay or two?
I would imagine these race kits are not cheap,either, and also unlikely to be made for a 4x4 pickup! Didn't mention 4x4 earlier, and hopefully it doesn't affect the discussion--I wouldn't be fooling with this in anything but 2WD drive mode. Thanks,
---------------------------- Mr. P.V.'d formerly Droll Troll
Yes, and people who rush to the next red light typically get up to a *higher* speed (only to have to bleed off the energy via braking). Or said from a slightly different perspective: no sense in accelerating toward a red light.
Certainly you'd want to read through a good service manual that covers the particular transmission. They should give the details on what solenoids are operating what apply bands and also what the computer is actually monitoring which might help you keep it from complaining too much.
If you rig a switch to keep the OD apply band on you'll certainly have to make sure you've got control of the other solenoids so that the computer can't try to switch in another gear. Having the computer switch in 3rd while you've got OD locked in would certainly do some damage.
You would also need to override control of the TC clutch to insure that it remained engaged. If the TCC clutch were to be switched out for an extended time you'd likely overheat the TC. Probably need to rig an interlock with the brake switch as well so the TCC will disengage appropriately.
Changing or reprogramming the computer to a manual transmission configuration would keep it from complaining about anything you do with the tranny, but would require you to properly manage all tranny functions.
An interesting project / experiment, but a lot of work for what might get you perhaps 1 MPG...
I don't think the 2WD vs. 4WD would make a difference, it's the transmission model that would matter. The 2WD vs. 4WD versions probably only differ in the output shaft configuration. People race 4WD trucks too you know.
Well, they couldn't race the Frontier, unless they used the whole bed for a gas tank! :)
Ito improved mpg's, it would depend on what kind of driving. The improvement would be zero on the highway, but in that 'fast city" driving, it might be much better than 1--mebbe 2?? :) Which for the Frontier, would be a whopping improvement!
But, sounds like not only a bit of work/sleuthing, but also a good shot a doing some inadvertent damage, esp. with a neophyte (me) at the helm.
It was mentioned that the shift point could be altered in the computer. Can this in fact be done? By a tech? By me, w/ a suitable interface? This way, if the engine did start to lug, I could always drop down a gear via the shifter, no problem. Thanks.
---------------------------- Mr. P.V.'d formerly Droll Troll
There are numerous chips and programmers that can adjust the AT shift points for various vehicles, look at Summit Racing for some examples. I use a programmer from Hypertech to adjust things on my truck, particularly to recalibrate for different tire sizes. Real service type programmers give you more options, but cost a lot more.
Well, the 4x4's I drive and see which are mostly Jeeps of all vintages work opposite to what you are thinking.
Keeping them in too high a gear causes them to just drink gas and the owners manuals say there is a real danger of blowing out OD if the engine lugs it. Reality says the owners manual is right, folks toast
5th or OD out easy from lugging it on the highway.
I have oversized tires on one Jeep which gives it a low ratio (3.31's turning 33" muds) but if I use 5th on the highway at 65 mph it puts my rpm down to 1750 or so and I get about 17-18 mpg. I still have tons of pull, but....
If however I keep it in 4th which puts the rpm at 2300, my gas mileage jumps to 23 mpg.
Same for city driving. If I forget I have a 4th gear and only use 3rd up to 40 mph, my mileage goes way up.
I think the 4x4 trucks behave differently that a light car when it comes to rpm and mileage.
If I am in a high gear, I need to use a lot of gas pedal to keep my speed even for hills and wind. If I am in the lower gear, I only need to twitch the gas pedal to keep the speed even.
I know a lot of folks that have seen the same increase in mileage in their Jeeps by forgetting they have an overdrive also.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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