uzzled: I've been hovering over the plans for an EFI and a good number of electric pumps for the 455 which is why this appeals to me... Yesterday I ran accross a GM concept vehicle (Chev Truck) that was switching off its engine when under no load (Downhill, traffic etc.) PB/PS/Cooling/oil pumps were all maintained electrically while the engine was off. When the accelerator was pressed the engine started and shifted into drive. This doesn't seem like a difficult thing to do if you're already at the electric pump stage... I can't shake the idea that this is possible with the 455 and some minor electrical idiocy. It'd need an override, a damn reliable starter, and a battery upgrade at least... but what else? Am I totally off? o No:
Clint - It could probably be done. I can't picture it being very cost effective - if it's just designed to save gas. What benefits were they claiming?
So let me understand this. Instead of belt-driven accessories, you would have to have an electric PS pump, and electric water pump, an electric vacuum pump for your brakes, an electric fuel pump, and even an electric oil pump? Seems like a helluva lot of tax on your alternator (or do they give you an electric alternator too), and you'd have to have TONS of reserve capacity (read: multiple batteries). So, all this extra weight buys you... what? I can think of the following list of benefits of shutting down an engine on a downhill- - lots of extra weight from the electrical junk pulls you down the hill faster And the "cons" of this system? Where shall I begin? - Starter motor wears out faster - Transmission wear (no lubrication to tranny seals w/o engine running, unless they made an electric tranny pump too) - oil cooking earlier (not splashing on the bottom end) - Loss of acceleration during the restarting process (at least a second, I would assume) - The risk that the motor doesn't start when you need it to (hot starter motor, needs to crank longer than the pre-set time, whatever) - more stuff to break downas the car ages - no air conditioning on downhills (unless that's powered by an electric motor too) I suppose anything's possible, I could drive from here to St. Louis in Reverse if I wanted. But the question is, Why? Now if this were an electric powered vehicle, that would be a different story. FWIW, Mercedes used to have a transmission that would automatically shift into neutral on a downhill, etc., but that would seem a lot easier to keep stuff running (A/C, P/S, etc.) -Bob Cunningham bobc@gnttype.org
I have heard of some electric/small diesel engine hybrids that shut the car off every time you come to a stop. Makes sense on one of those cars - not too sure on a gas powered vehicle.
Good points all around guys... The only benefit they indicated was a fuel savings. I figure someone at GM must have done the math so I tried it myself. Idling, my 455 consumes (conservatively) about 1.1l/h and about an hour on average idling in traffic 5 days a week. Translates to about $4.42/week in gas after paying the Canuck taxes, about $230/year. If I'm already putting in the electric pumps as part of the EFI then the additional cost for the electrical cutoffs make sense, which is why I asked. Now we're not talking heavy electrical work here, and things break on the car wether electrical or mechanical, and a bypass swich allows acceleration to come back up to normal driving standards, so I'm running out of reasons not to try it... ...of course the simple answer is to just buy a more effecient daily driver...
A friend of mine put a 440cc artic cat snowmobile into one. It was no BBB but it would do all the burnouts you could ask for. ________ WEB SHOWS
