4HI conversion, it works!

[orion]

I followed the Planetisuzoo article and now have 4Hi. this was a very easy mod to do. it only took 2 hours total. now I'm just drooling for the first big snow storm. i did a search and found a few people say they were going to do this but no one posted back to say they did it. am i the only one? well, sorry no pics as my camera has died. I'll try to get some later.

[nfpgasmask]

So wait, are you just saying you created a toggle for the TOD?

Bart

[ZEUS]

I gotsta try that! So with the fan mod and the 4hi mod behind you, what's next?

[orion]

not just a switch http://www.planetisuzoo.com/articles.htm/109...............and as for what's next, you'll see, you'l all see!:rotate: HA HA HAHA HA HA(mad scientist laugh):evil2:

[ZEUS]

Ah crap! My VX is a '99. I read that article before and was scared off because of the minor differences between years - I'm prob'ly just being a lazy whiner!

[Rogue]

I followed the Planetisuzoo article and now have 4Hi. this was a very easy mod to do. it only took 2 hours total. now I'm just drooling for the first big snow storm. i did a search and found a few people say they were going to do this but no one posted back to say they did it. am i the only one? well, sorry no pics as my camera has died. I'll try to get some later.

Please forgive my lack of knowledge in this subject,
Does this mean you can now switch between 2WD and 4WD?
If so does the car seem quicker and/or more efficient in 2WD mode?
Thanks
Joe

[etlsport]

i'm not positive, orion may have to chime in, but i think what it does is it tells the computer that the wheels are slipping.. so it keeps the power distribution 50/50 at all times front to rear (instead of normal 15/85 and changing with conditions) but it does this without gearing down into 4wheel low so you can still maintain higher speeds... you wouldnt feel any difference switching to 2wd because the front wheels would still be connected to the drive line, you would have to remove the connections to make the front wheels truely free spinning to realize any sort of performance or economy gain from running it as a rear wheel drive

[ZEUS]

i'm not positive, orion may have to chime in, but i think what it does is it tells the computer that the wheels are slipping.. so it keeps the power distribution 50/50 at all times front to rear (instead of normal 15/85 and changing with conditions) but it does this without gearing down into 4wheel low so you can still maintain higher speeds... you wouldnt feel any difference switching to 2wd because the front wheels would still be connected to the drive line, you would have to remove the connections to make the front wheels truely free spinning to realize any sort of performance or economy gain from running it as a rear wheel drive
BINGO!

[Techy-D]

Thanks Orion,

I was thinking about that myself, but hadn't seen that link. The reason I was wondering, was about low speed when coming up out of a steep gravel driveway, it wouldn't pull in the front because I was going to slow (untill it spun and grabbed hard).

QUESTION: Does this leave the front locked in even at very slow speeds? (Is there some safety in the Transfer case itself that drops it out at low speeds or was it the controller making that decision?)

[MrCrowley]

Another advantage is it wont "bang" in and out of TOD which is alarming and damaging to your drivetrain in certain loose traction situations.

[orion]

here's how it works, when you hit the switch it puts 12 volts to the clutch, giving you 50/50 split. as long as the switch is on, the clutch stays on. the TOD sees the two resisters and thinks all is well, no codes, no problems. the resisters act as a fake clutch, so if the TOD wants to add traction, like on hard acceleration, the voltage goes through the resisters to ground. TOD wont see wheel slip so you will only see the first bar light up. with the switch off the TOD works normally. this does not give you 2WD. if you read the last part of the article the author had no problems with the transfer case, remember he did this with a trooper that can switch to 2WD, so he has to be in TOD mode for it to work. I am thinking of swapping to the trooper transfer case, TOD computer and switches to get 2WD. from my research it looks to be the best way.

[ZEUS]

I am thinking of swapping to the trooper transfer case, TOD computer and switches to get 2WD. from my research it looks to be the best way.
Ah HA! BUSTED!! Now we know what you have planned next! I had that in mind too when I was considering the SAS but stopped short of the entire project... it is so much easier to SAY you are going to do things than it is to do them, ya know! At least for me, anyway... you might actually do it!

[Triathlete]

Orion, sounds like you may be doing some of my homework for me. Does the Tod send any signals to the anything other than the TOD system (the tranny, engine managment)? I ask because I want to swap my TOD for a manual T Case.

[Rogue]

here's how it works, when you hit the switch it puts 12 volts to the clutch, giving you 50/50 split. as long as the switch is on, the clutch stays on. the TOD sees the two resisters and thinks all is well, no codes, no problems. the resisters act as a fake clutch, so if the TOD wants to add traction, like on hard acceleration, the voltage goes through the resisters to ground. TOD wont see wheel slip so you will only see the first bar light up. with the switch off the TOD works normally. this does not give you 2WD. if you read the last part of the article the author had no problems with the transfer case, remember he did this with a trooper that can switch to 2WD, so he has to be in TOD mode for it to work. I am thinking of swapping to the trooper transfer case, TOD computer and switches to get 2WD. from my research it looks to be the best way.

Ok, two part question. What are the benefits to a 50/50 all time type of set-up? Meaning in real world driving situations, when would you feel the pleasures of 50/50? When would it be ideal? Where would you use it, on daily driven roads or in the dirt?
Second part of the question, let’s say one was to do the intelligent thing and switch to a TROOPER Transfer case. Would it be a simple plug-N-play type situation, where you have a switch to go from 4wd to 2wd? What would unlock the hubs to make the front wheels spin freely? Would the TOD display on the dash work?
Just a few questions that could motivate someone to do the switch over.
The reason for all this is really quite simple, I drive a 2002 LWB trooper at times and being in 2wd in regular driving conditions makes the vehicle very "drivable" and pleasant. It feels light and it is also QUICK!
There is also the pleasure of skidding into turns etc. then switch into 4wd and rockcrawling….
The motor in the VX is strong and powerful on a small truck like the VX yet we do not feed the pep it has in TOD mode.
Anyone driven an Infinity FX35? The motor has the same general specs as ours yet it would be a dream to keep up to one of those.

[MrCrowley]

I may be mistaken on some of my recollections, but I think the difference with the T-cases has to do with an added function or unit between the tranny and T-case for the TOD on/off. However, if mods are going to be done, you might as well try to do something else. Plus, old Troopers for years had automatic hubs for front axle disengage/engage. Drive forward in 4wd they engaged. go to 2wd back up several feet and they disengaged. They werent the stoutest hubs, but also one of the aftermarket companies warn?, superwinch?, etc. had an auto hub that also you could get out and manually engage for "rougher" use. For what its worth to ya.

[ZEUS]

Ok, two part question. What are the benefits to a 50/50 all time type of set-up? More predictable driving experience in treacherous conditions. Meaning in real world driving situations, when would you feel the pleasures of 50/50? When would it be ideal? Where would you use it, on daily driven roads or in the dirt? Snow, icy streets, and soupy substances.
Second part of the question... What would unlock the hubs to make the front wheels spin freely? Aisin hubs, Superlift hubs, Warn hubs (discontinued?) all are manual locking hubs. :)

[orion]

Triathlete, the TOD only receives input, from the engine it's throttle position, and the tranny it's speed and gear selection. with the TOD gone the other computers wont care. now I'm not 100% on this but i can't find any instance were the other computers need input from TOD. but I'm still researching this.

[Chopper]

Ok, two part question. What are the benefits to a 50/50 all time type of set-up? Meaning in real world driving situations, when would you feel the pleasures of 50/50? When would it be ideal? Where would you use it, on daily driven roads or in the dirt?
Second part of the question, let’s say one was to do the intelligent thing and switch to a TROOPER Transfer case. Would it be a simple plug-N-play type situation, where you have a switch to go from 4wd to 2wd? What would unlock the hubs to make the front wheels spin freely? Would the TOD display on the dash work?
Just a few questions that could motivate someone to do the switch over.
The reason for all this is really quite simple, I drive a 2002 LWB trooper at times and being in 2wd in regular driving conditions makes the vehicle very "drivable" and pleasant. It feels light and it is also QUICK!
There is also the pleasure of skidding into turns etc. then switch into 4wd and rockcrawling….
The motor in the VX is strong and powerful on a small truck like the VX yet we do not feed the pep it has in TOD mode.
Anyone driven an Infinity FX35? The motor has the same general specs as ours yet it would be a dream to keep up to one of those.The only commonality between the VQ and this mill...is that they both have six cylinders

[orion]

posted By Rouge
Second part of the question, let’s say one was to do the intelligent thing and switch to a TROOPER Transfer case. Would it be a simple plug-N-play type situation, where you have a switch to go from 4wd to 2wd? What would unlock the hubs to make the front wheels spin freely? Would the TOD display on the dash work?
you would have to swap the trooper front Axel as well as all related wiring harnesses, the trooper disengages the front wheels in the axle not at the hubs.

[ZEUS]

Orion, the t-case does have a gear selection for 2wd, doesn't it? If so, then you wouldn't need to swap the Trooper axle components unless you just did not want the manual hubs, correct? If you were to swap in the axle components instead of selectable hubs then you would still be turning the CV shafts, causing wear on the boots, and re-creating that bit of parasistic drag, even when in 2wd. With disengaged hubs though, (assuming the t-case does have a 2wd option) nothing would be turning in regards to the front drive components. I am assuming the axle disconnect in the Trooper is vaccuum-actuated like on some GM models. Select 2wd by lever or button and the t-case disconnects the front driveline from the gears, and the front axle disconnect device is actuated at the same time. In any case, I don't think that actuator would have any effect on the TOD, if it did, couldn't you just run another wire to trick the computer into thinking it was engaged?

[mbeach]

This one has been beat to death, and sadly, I never got to finish my work on it before I sold 0723. Now the test mule (complete with my custom made TOD eavesdrop harness) is laying dead behind a BMW dealership in Anchorage...

The E-clutch that engages the TOD is activated by a modulated voltage -NOT direct current. While DC will lock up the clutch, engaging the front driveshaft, it will also burn out the e-clutch over time.
You might be able to search my gallery for photos of the TOD computer in operation (look for the o-scope pics).

In order to have reliable 4hi, you need to generate the 88% (iirc) PWM signal that simulates the TOD computer's signal, and send that to the blue wire.
Google "DC Speed Controller" to get an idea of how PWM is used to control inductive devices like motors and clutches.

A few of us got a long way into figuring this out, and we pretty much had the solution on paper. Picture a knob, that allowed you to dial in the exact amount of torque you wanted to go to the front axles. Pretty cool.
However, no one really managed the jump from paper to reality for whatever reason.
Mine was a lethal combination of laziness and wife.

There are also two huge reasons that this knob solution never took a priority:
1. The Ball Ramp Mechanism. The original purpose of the TOD controller was 2hi, not just 4 hi. Two-wheel-drive has all kinds of practical daily benefits, not just the occasional mud run. Unfortunately, even with the blue wire disconnected (toggled), there is a mechanism within the Borg-Warner T-case that still transfers rotation to the front driveshaft. The e-clutch simply modulates this rotation to create torque. Tone discovered this phenomenon on a 2wd dyno, with disasterous results. So, unless your front wheels are suspended in the air (no friction at all), 2hi is unobtainable.
2. TOD is awesome. There was an army of engineers behind this one, and us lowly mortals could never improve its function. The truth is, that with a mechanical T-case, there is no way to reliably control it's doings from the driver's seat. The DCCD in the Subaru STI is on a viscous center diff, like the Evo -this is not a mechanical transfer case. I know that the Baja VXs have a torque controller (at least you can see the knob from the pics), but they also have a warehouse full of spare parts...

So, Tad's solution on PI is great, but use it with care (just like the owners of Air Lockers do). If you leave it on for an extended period, you will break something -it's about the size of a hockey puck and it's buried deep within your transfer case.

Not finishing the TOD speed controller has been one of the greatest automotive letdowns of my life. I really wanted to finish this one up, if only to say it was done.
I still have all of the files though...

[orion]

ZEUS, the Trooper t-case has the 4LO lever only just like us, 2WD is just the TOD turned off and the front axle disengaged. if your looking for minimal parasitic loss I'd go with a fully mechanical t-case, and ditch the TOD. getting the Trooper TOD system to work with manual huds just seem like a lot of work. I don't like the idea of having to get out and locking the hubs when i have the sudden urge to get the old girl all dirty:naughty:.

[ZEUS]

ZEUS, the Trooper t-case has the 4LO lever only just like us, 2WD is just the TOD turned off and the front axle disengaged. if your looking for minimal parasitic loss I'd go with a fully mechanical t-case, and ditch the TOD. getting the Trooper TOD system to work with manual hubs just seem like a lot of work. I don't like the idea of having to get out and locking the hubs when i have the sudden urge to get the old girl all dirty:naughty:.
It's not a lot of work... all you have to do is take the axle disconnect components from the Trooper axle and have a machinist fab up some mounts, driveshaft housing, driveshaft, and then rig the driveshaft to disconnect like the CV shaft normally would! It should only cost you around $3000! See, nothing to it! :rolleyes:

[MrCrowley]

Lololol! Heres one even better.

Go buy a good trooper, take the body off, have the VX body shell limo-stretched, and voila! :dance: Just dont forget to put the VX suspension goodies on the new ride!

[orion]

SNOW TEST DOEN.... got 8 inches of heavy snow last night and drove around for a little over an hour in "4HI" with no problems. and the difference is very noticeable with it on then off. for any of you that have snowy winters, i highly recommend doing this mod. it's soooo much fun :jump:

[twistedsymphony]

...
In order to have reliable 4hi, you need to generate the 88% (iirc) PWM signal that simulates the TOD computer's signal, and send that to the blue wire.
Google "DC Speed Controller" to get an idea of how PWM is used to control inductive devices like motors and clutches.

A few of us got a long way into figuring this out, and we pretty much had the solution on paper. Picture a knob, that allowed you to dial in the exact amount of torque you wanted to go to the front axles. Pretty cool.
However, no one really managed the jump from paper to reality for whatever reason.
...
Not finishing the TOD speed controller has been one of the greatest automotive letdowns of my life. I really wanted to finish this one up, if only to say it was done.
I still have all of the files though...

I don't mean to bump a long dead thread but I was just perusing through the archives and came across this.

I don't have my VX yet (put a deposit down, should only be another week or so) but I'm very interested in what you discovered here... I do LOTS with electronics in my spare time (I can show you some of my projects if you're interested). Creating a PWM signal is easy peasy... and you could probably even take it further than that with a little display to tell you the % rate you're sending or whatever...

I'd probably use an MCU to get the job done but there are other cheaper/easier methods if one were so inclined. :work:

[Knigh7s]

I don't mean to bump a long dead thread but I was just perusing through the archives and came across this.

I don't have my VX yet (put a deposit down, should only be another week or so) but I'm very interested in what you discovered here... I do LOTS with electronics in my spare time (I can show you some of my projects if you're interested). Creating a PWM signal is easy peasy... and you could probably even take it further than that with a little display to tell you the % rate you're sending or whatever...

I'd probably use an MCU to get the job done but there are other cheaper/easier methods if one were so inclined. :work:

you should check out this thread: http://vehicross.info/forums/showthread.php?t=8286&highlight=tod+switch .

The project died awhile back and then was revived again by Orion... We are all waiting for the results of his tests, but it looks pretty good so far...

Oh, welcome to the VX Fam! Looks like you are awaiting the addiction! LoL

[Greasemonkey]

True 4hi can only be obtained mechanically like the Trooper , Rodeo etc without TOD , even a VX with TOD has to have a mechanical lock to put it into 4lo this also locks the gearbox and non of the electronic clutches are working while you are in 4lo its all locked in place - and you will create transmission wind up if you are not on soft or slippery surfaces - unlike TOD which doesn't wind up - so the easiest way to obtain 50/50 drive is to fool the transfer case into telling the transmission its in low box then the TOD locks itself to 50/50 - surely this has been thought of but i just have not read it - everyone seems intent on rewiring the TOD - to achieve something which it does already - all it needs it the lo box lever sensor rewiring
cheers
Steve

[VehiGAZ]

Creating a PWM signal is easy peasy...

DO IT BROTHER!!! I'm dying for this mod. It'll be perfect for winter driving!

[taylorRichie]

DO IT BROTHER!!! I'm dying for this mod. It'll be perfect for winter driving!


I've already done it :D...

I'm just wrapping another project before I can get the boards shot. I'll try to get a deadline set, and let you guys know.

We've already got the legwork done (THANKS MBEACH!!) and have done a proof of concept. We're even planning on controlling the TOD Christmas tree so you can see where you're at.

We'll all have this mod soon enough. :cool: