1987 voyager with displacement on demand...

[sgt. minivan]

im going to get torn apart for this... BUT i can take it!!!

OK SO ive wired what i like to call DOD on my 1987 plymouth voyager 3.0l 3speed auto., i was bored and looking for better fuel economy, heres what i did, i recognized that this specfic 3.0l fires its injectors in "batch", SOOoooo i took advantage of this (did to to my fiero too LOL) i took and cut up the fuel injector harness (omg i know!) and wired cyl's 2' 4' 6' together to a switch that is mounted on the drivers A piller. at the flick of the switch it shuts off thoes 3 injectors, so now i have a 3cyl engine, granted (well granted a bunch of shit) but it is "dragging" the other 3 dead pistons through compression, which does not help + its only got 23hp per cyl which is ~70 hp - the drag from dead pistons so il assume 50 fwhp total, il sure all of you are raising eyebrows at me thinking wtf is this guys major malfunction, well il tell you what, at 70mph im getting ~ 35mpg, where as i only get 26 normally, BUT you have to be doing at least 65mph for it to work, unless i unplug the tq lockup, then it works at 55mph.. but i dont like that, so bacically, click the switch at 70+ mph, click the cruise on and enjoy! i drove it this way for a 60 mile trip, i cruised at 73mph the entire time, smooth as can be, no issues afterwards, i dont know of long term effects... but this IS cool.. + its fun to try and drive around town like that lol!!! its WOT the entire way.. unless i dont have someone on my ass.. then i can "ease" to the speed limit, also when on at idel, it wants to die (never has tho) it will idle around 400rpm (seriously) and just pur like a kitten, it runs like a 3cyl metro, not like i just disconected 3 random spark plug wires lol... it is quite interesting... i just though id share it... btw. it was a complete failur on my fiero, it just plain out did not have the HP to back it up., OH OH and you know that sound you exhaust makes when your slowing down from a high speed while still in gear, thats what this sounds like... its weird!! and its so fun to cruise at like 30mph with it on, and punch the gas, its so freking funny!! it kickes down into 1rst gear but you accerate SO slowly, then if you flip the switch back while still at WOT... omg what a rush! lol...... ..alright let the bashing begin.

[lookin]

I think you will find that people here, will admire your ingenuity, instead of just bashing you for trying this Adam.

Are you nuts? Absolutely! You fit right in dear.

Natasha

[sgt. minivan]

Quote:

Originally Posted by lookin I think you will find that people here, will admire your ingenuity, instead of just bashing you for trying this Adam. Are you nuts? Absolutely! You fit right in dear. Natasha

WOAH!!
not to hi jack my own thread... but dude.. i i i mean..... your a ... ... . .... are you???!!!

[lookin]

A woman? Yes. No biggie. Women design cars and drive formula and Le Mans races now. I accept our differences however, and I respect the male sex.

[sgt. minivan]

oh i wasnt saying that!... i just though you were a guy.. through me off! its awsome tho!! i can respect you 100%!...youd better respect my male sex! lol lol j/k

[lookin]

Don't worry about it. Most car guys assume real women aren't into cars, and I don't overcompensate by being all hyper feminine over it. I am too old for that crap nowadays anyway.

[crazymadbastard]

A woman with a shaggin wagon!

Your numbers speak for themselves. very cool! Cadillac did this back in the 80s and I am sure someone else has this too.
When I read your tittle I though of a saab engine that actually had/has variable compression on a turbo 4(the head goes up and down). Off iddle the compression goes up and once boost goes up the cr goes down.

[HolsetShelby]

Something about women + cars = a big turn on. Im not trying to offend anyone, i am simply saying that it would be the greatest thing since sliced bread if my girlfriend wanted to work on my cars with me.

[lookin]

Well really it's a camper and 'nap time' for long road trips van.

Variable compression? I never heard of this before. Does it work well? Amazing idea.

[lookin]

They are out there HolsetShelby. I am however near 60, and so the turn on factor dims a bit there.

[crazymadbastard]

Quote:

Originally Posted by HolsetShelby Something about women + cars = a big turn on. Im not trying to offend anyone, i am simply saying that it would be the greatest thing since sliced bread if my girlfriend wanted to work on my cars with me.

my wife helps plenty, git ma' beer womens!
She likes to stay away while I am wrenching.

back on topic on that, if there was a way to hang maybe the exhaust valve open during the compression stroke then you might get even more mileage.

[Ondonti]

anyone know the effects of not having combustion in 3 cylinders long term? increase cylinder wear? scuffing? what?

Anyways, you need 1 whole bank firing (obviously you know this) otherwise the engine shakes like crazy because its imbalanced. I drove my spirit once 50 miles on cylinders 1 2 and 4. Not good.

Ive done a lot of idle testing with 1 2 and 3 cylinders on my duster though with all my fouling problems.

[mightymulhern]

This is an interesting idea and based on your numbers I don't think anyone can argue with you.

After thinking about it, I would think the air sucked through the cylinders that aren't being fueled/fired would add more O2 to the exhaust, make the computer think lean, and try to compensate with more fuel making the 3 running cylinders extra rich. If so and if you could resolve that you might eek out some more mileage on top of what you've already found.

You would need a scan tool to monitor the fuel correction factors to see if this is actually happening. ...if so, moving your O2 sensor so that it's only in the exhaust stream for the cylinders being used would resolve it.

Kudos on an very interesting idea. If you can get a minivan up to 35mpg, I've got to wonder how a car would do.

[sgt. minivan]

acually it does very quickly add extra fuel, its kinda weird, if i flip the switch on idle, the engine surges down to around 200rpms, barly barly running, then all the sudden you hear the intake just start wistling, and the rpms steady at 400 to 450, i think the wistling intake is the cpu adding fuel... would this also make the exhaust really hot?, yeah if i could ditch the o2 sensor and hang an E valve...... it would be a MPG machine!, its kind of inpractical on most highways (of speed limit 60 or 65) which is most, but luckly everyone i travle around here is 70mph, for it to work the rpms have to be decently up (70 mph), if you try and do it at 60mph, click the cruise, watch the accelerator pedal lay on the floor + slowly loosing speed., hey im going home (where my van is) in a few days... il try to take a video of this in action + pics so you can get a better understanding, its been like 3 years since ive used that function, and my parents dont use it... so hopefully i dont have any issues with mice in the wireing or some bs..

[ShelbyDodgeImp]

Are you the same guy who was doing DOD who was posting on Allpar for a while back or are there TWO of these vans running DOD these days?

As to gender and cars, you'd be pretty surprised how many girls are on some of these boards. I know a few who don't really make it known that they're girls because of the attention (not all of which is good) that it can generate.

There was a girl on DI.net that basically stopped posting because she kept getting crap about her car, people saying it isn't a "girl's car" and she needed to get something that wasn't a "guy's car"

Generally speaking its not as bad on these boards as some of the military related boards out there... the more stereotypically male you get the more problems there are probably going to be, if I were to venture a guess.

Its a field wide problem to be honest, my roommate used to be a mechanic but had to leave the field work/career wise because every job she got, no matter what shop it was, either tried to push her into secretary work or- when that wasn't a problem, parts suppliers kept thinking since she was a girl they could pull whatever tricks they wanted on her. Now she does metal fabrication and only does cars as a hobby, no matter how much past shops want to grab her back (especially with the fabrication expierence now).