TeamSwift

So from what I know about EFI systems... the injector shuts down when the throttle is closed (down to a set RPM) right? But as you close the throttle, the car declerates from the vacume produced from the closed throttle plate. So what if you rigged up a momentary contact button/switch to the injector or the injector relay (do these cars have an injector relay?) that would shut down the injector while you keep your foot on the throttle to prevent the normal deceleration. Right? I'm sure this would set of a CEL but if that dosen't bother you... it should be good for some more miles per gallon.

Just an idea


CityCon

It doesn't matter so much if the throttle is open or not, the engine is still fighting compression from the compression stroke of the cycle. The car will still slow down. In fact it might slow down faster becuase the throttle is open and letting in air that is building more compression.

Try it, just turn the key off, compare it to when the throttle plates are closed...

Now I thought of this... but my diesel dosen't have a throttle plate and when I let off the throttle it coasts pretty good, less I engage the exhaust brake. Even on downshifting it dosen't really slow down that much (engine friction and wind/tire resistance play a part) compared to a gas engine with the throttle closed. Plus, that Detroit Diesel has some monster compression (along the lines of 15:1 , before being turbocharged) so I'm curious how a low compression engine would handle it.



Soon as the little metro in the impound yard clears lean sale, I will try it the right way. Killing the engine while I'm driving dosen't strike me as safe... And being a tow-truck driver I see all sorts of wreck for wierd reasons, I don't want to add one to the list.

i don't know about shutting off the engine while you're coasting, but you can always put in the clutch or take it out of gear and take your foot off the throttle

Well for emmisions the injector shuts down under deceleration till it reaches a set RPM. If you shift into nuteral the engine will idle and the injector will pulse and keep the engine running. Plus in some states it's illegal to coast out of gear. "technically" this isn't breaking the law because the engine is still in gear... right?

I'm sure the savings in MPG might be minor, might not even be a difference. But soon as I get my metro I'll try it out. Nothing ventured, nothing gained. Right?

CityCon

I have found that if I drive at 55MPH in 5th gear my car can reach over 55 MPG's even with the big cam.

But,but,but,but... you have no interior!

I don't think the weight makes a huge difference at a constant speed.

I know all 3 cylinder Metros have what is called "Fuel Shut Off On Deceleration. The ECU detects that the TPS is at closed throttle. Since there is no need for extra fuel while braking or coasting, the ECU shuts down the injector pulse width.

An awesome solution to gain complete control over your fuel injector would be to apply George Wiseman's Electronic Diverter circuit so that you can vary the pulse width on the fly while driving. Simply turn the potentiometer to dial it in. No need for an expensive and complicated engine management system.

This would work best after reaching your desired operating speed after going through the gears while on the highway. The ECU will see this as a "lean" condition and therefore would compensate by trying to give it more fuel.

Instead of having this negative effect, an EFIE or Electronic Fuel Injection Enhancer produced by Wiseman is a must have. This goes for ANY mileage improvement modifications that cause a leaning condition to the air/fuel mixture. What this does is give the ECU a voltage offset. The ECU senses that everything is within its narrow band of operating millivolts and you are able to lean out without the computer trying to compensate by adding more fuel.

With the EFIE and Electronic Diverter circuits in place, you are in control of the parameters instead of the ECU.

The EFIE is available from Wiseman's website http://www.eagle-research.com for $50 and the Electronic Diverter circuit for varying the injector pulse width is located in one of George's books he sells. I think it is in his Hyzor manual, his version of a hydrogen/oxygen generator. The only drawback is that he does not sell the ED, but provides the circuit schematic, so you or someone who is up on there electronics building would have to make this circuit up. From what I remember the parts for this thing cost next to nothing.
This guy is up on his stuff.
Anyone who is serious about mpg should check him out.

Sam

This is my first visit to this site so I haven't read a whole lot of posts but I was wondering what was the best mileage anyone has heard of with a 3 cylinder in a small car?

also I was wondering if anyone had swapped out their gas 3cyl. for a Diesel 3 Cylinder if so was their much increase in MPG? thanks Howard
H_N_H@msn.com

What 3 cylinder diesel are you referring to?

Oh and Sam, that is some awesome information! If you find the schematic for the diverter circuit, please post it here.

I will hunt it down like a rabid dog and post it, or a link to it, once I find it and get it digitized.

thanks,
Sam

I did this a time or three...

Cut into the injector circuit and put a toggle switch in betwixt. Mounted the sucka on my stick shift on my modified '90 XFi.

I would run in wide open throttle in 1st and 2nd gear, hit the toggle switch, popped the shifter in neutral and then coast.

For every 1/8 mile that I would be running wide open, I would coast for 7/8 of a mile. When I got down to 20 mph, I would flip the toggle switch on and then pop the clutch in 1st and start the cycle over again.

I achieved 100 mpg in the modified Metro with this technique and without this momentum driving technique, I would get 75 mpg as long as I maintained a speed of 55 mph.


I suffered no problems whatsoever by doing this technique, but there was not any traffic to deal with. Normal traffic conditions would not be very safe doing this and is not advised. But you can take it to the bank.
It definitely works.

Sam

P.S. Have you ever experienced going through all the gears while still idling the engine? After hitting 4th I would be at a constant speed of 45 mph. If I gently feathered the gas pedal I would be cruizing at 55.
Awesome low end torque!
That's what I'm talking about...

I was refering to a perkins 3 cylinder Diesel. Also I think Cummins makes a 3 cylinder Diesel Thanks Howard

I can't remember where I saw it, but someone had swapped a 2 cylinder air cooled diesel in a metro. It was pretty wierd looking, the engine was half out of the hood. I'll see if I can find the link.

CityCon

ok Thanks

City Connection, I looked at your car and I thought if I found one I would try and lighten it up a bit also but I was just thinking about the rear seats and the passenger seat mainly but if that gets you some more mpg's I say go for it. I know one of the main things to do to increase mpg or power to the wheels is to REDUCE UNSPRUNG WEIGHT such as a lighter
wheel and tire combination and or remove hub caps, & install lightweight Rotors. HOWARD

SORRY CITY CONNECTION I was looking at METROPWR'S car
not your's the one with out the interior. HOWARD

http://www.ewire.com/display.cfm/Wire_ID/1305

So far this is all I could find. It's not the one I was looking for, but it's all I got for now. I'll have to check the history on my work computer for the other link.

Sorry,

CityCon

This is probably what you're looking for:
http://www.utterpower.com/10hp_chevy.htm

Yup! Thats the one! Thanks man!


CityCon

I guess thats pretty good for a variable Transmission I think I might want a little more power though. I'd say a 3 cylinder diesel might be the minimum amount of power I would like to have. Howard

Doesn't Kubota make a 3 cyl diesel?

Yes, so does Yanmar, Iseki and Mitsubishi. All used in small tractors. They're a lot heavier than a G10.