Awd, Boosted, 5spd, Hybrid Gas/Electric 1990 Caravan?

[RoadWarrior222]

Does that work for electrics? thought they made peak torque at stall... ima hafta go math at it...

Vigo probably realises this but I'll mention it for anyone humming along, the T1 injectors are rated 27lb at 55psi, and on a stock 3.0 regulator (48psi IIRC) will be a little lower, probably around 25lb.

[zin]

Does that work for electrics? thought they made peak torque at stall... ima hafta go math at it...

Yep, the formula uses torque to get HP at a particular RPM, so if you know one, you can find the other! That's one of the reasons why I'm curious as to the RPM it make the HP at, if it is low enough, the torque should be quite high, couple of hundred foot pounds I would think... But then again, if the motor was designed to run through a trans, it might not be that much...

Still, a couple hundred foot pounds should help quite a bit when you need it most, starting from a stand-still....

Mike

[moparman76_69]

Wish I would've seen this before going the ditch a leaf and ride on bump stop method of lowering the rear of my van.

[Vigo]

Sorry, i wanted to keep it to myself until i was sure that it worked.

If you know the RPM that the rated HP is taken, you can back into the torque, just do the HP formula backwards... Good Ol Algebra, who would have guessed we'd use it so much (Trig too!)

Unfortunately, i DONT know. All i know right now is the max rpm of the motor. If it makes 52hp @ 7000 rpm it would only have like ~40lb ft at that rpm. If it makes 52hp at low speed it could have 400 lb ft.

BTW, have you calculated the wheel RPMs for the ratio and tire size you'll be running? It might not be nearly as high as you think...

I know its a lot of info to read through but i DID post that if i dont add any gear multiplication between the motor and diff, it would take 160 mph (with my tire size) to hit the 7000 rpm redline on the motor. That's leaving a lot of the rev range unusable on the electric motor, so i will DEFINITELY have a gear reduction in there.

Vigo probably realises this but I'll mention it for anyone humming along, the T1 injectors are rated 27lb at 55psi, and on a stock 3.0 regulator (48psi IIRC) will be a little lower, probably around 25lb.

Since you can now scale for injectors on an 89 3.0 smec afaik, i can just up the base pressure and set the cal for whatever injector size the upped pressure calculates out to. Im only planning on running 5-10 psi at first so i have some headroom with fuel pressure. I havent done any math with my pulley diameters so im not sure what the boost is going to be other than ballpark.

[Kreel]

Since you can now scale for injectors on an 89 3.0 smec afaik, i can just up the base pressure and set the cal for whatever injector size the upped pressure calculates out to. Im only planning on running 5-10 psi at first so i have some headroom with fuel pressure. I havent done any math with my pulley diameters so im not sure what the boost is going to be other than ballpark.

How wide is the NB pulley? My FM pulley is ~ 5.25" IIRC. Using some rough calculations I guessed an stock m90 (3.8") on a stock 3.0L would yield 8-10psi. For my van I've opted to start with a 3.4" pulley since I'll have major headwork done, exhaust, headers (maybe not at first), and a ported m90. I'll probably have to drop even further if I want to hit 10psi...only time will tell.

Very cool project btw! Not only because I'm a fan of 3.0L m90 powered vans but the hybrid aspect gives it something totally unique which looks like it will pan out well

[RoadWarrior222]

Opposed cone pullies and a spring tensioner... actuate hub separation with a choke cable = variable boost

[Vigo]

Here's the other Department of Energy document i was talking about, just click view document:
http://www.osti.gov/bridge/purl.cove...I1FKI3/native/

It suggests that the peak torque of this motor is 110lbft. I can honestly say i was wishing for a lot more.

Im going to try emailing UniQ and see what they can tell me.

[RoadWarrior222]

Peak torque of a ~90HP IC motor is around 110ftlb so doesn't seem too terrible.

[raccoon]

its always going to have that torque. even at low RPM its more then it seems.

[Vigo]

It just presents challenges for trying to use this motor to give enough acceleration to be comparable to a regular AWD 5spd with a physical connection to the gas motor.

If i use a 3:1 reduction in front of the motor it's 110 X 3 X 3.45 = 1138 at the wheel.

Compare that to a stock 2.5 turbo in 1st gear (3.85 523), assuming 200lb ft its 200 X 3.29 X 3.85 = ~2500. Thats for a stock motor at peak torque.

In fact, you'd have to put the gas motor in 3rd gear to get the torque number down to ~1100 at the wheel.

So basically, at 20mph, the electric motor would be pushing the van about as hard as if you had it floored in 3rd gear at 20mph. Wooptydo.

There comes a point where i have to question if the weight and drag of the setup isnt going to hurt its acceleration more than it helps over something as long as a 1/4 mile.. Im not being pessimistic, but i want to be pragmatic.

[Vigo]

Im pretty much settled on a 3:1 reduction now. The trick is going to be finding one and making it work. I think i need a planety gearhead, but when i google that theres thousands of them. So.. a little overwhelming. I might put off finding one until i have some other stuff figured out, like getting the diff and motor mounted in the van.

[RoadWarrior222]

If it helps any, microlight aircraft with a belt reduction drive need 6 V belts to transmit 50-60HP through a 3:1 reduction pulley (Just in case you thought you wanted to stack pullies) .... but, no driveline shocks, so dunno if that would hold on a minivan.

[Vigo]

Im not interested in using belts on anything. Im hoping to use a planetary gearhead, just have to figure out the right one and the right price... $$$

[RoadWarrior222]

I'd be thinking of something like a geo metro manual trans then, left in 2nd gear... though dunno if it would be worth the weight of pulling the unused shafts and gears out compared to the convenience of being able to select a ratio when stopped.

[RoadWarrior222]

Actually you just posted elsewhere you can get 2.6-3.7 ratios from an A413 in the transfer and ring and pinion, you could cut a spare A413 right down, even put an OBX in it.

Edit: oh wait are you already counting the rear diff ratio?

[Vigo]

Yes im counting it. I dont have room for a full size transmission back there. The only kind of car transmission i could see using would be some rwd mini-car like an old Starlet or something with a really small trans case and even that is REALLY iffy. Right now im not seriously considering using a car transmission back there.

[bakes]

What about a gear vendors overdrive unit for a 4X4.

[Vigo]

An overdrive unit is only going to have a ~.7:1 ratio and id have to run it backwards to get a reduction, and it wouldnt be much reduction (~1.4:1?), and they cost too much.

I just need to get in contact with someone who designs or builds a lot of electrically driven systems that might use planetary gearheads. Id really prefer to snag something used out of a junk pile, but we'll see how it goes. This might be one of those situations where i actually have to pay full price for something.

[Vigo]

A lot of 4wd transfer cases have 2.72:1 low ranges.. If i could find the smallest, lightest 2-range 4wd transfer case, that MIGHT work. Whats a TINY 4wd transfer case? Samurai? Tracker/Sidekick? Gimme some ideas...

Samurai t-case looks pretty small.. How funny would it be to have a shifter coming up through the floor in front of the 3rd row of seats?

[RoadWarrior222]

Raider? (Power Ram) D50?