Lets improve our MPGs - Page 3

Beav · #31 06-24-2006, 09:44 AM

Quote:

Originally Posted by TheSTig

It is. Like on most engines. We were talking about hte transmission.

The transmission also has its own oil pump. It is driven by the outside of the torque convertor stub. It provides the pressure needed to operate the hydraulics inside and also provide lubrication. The torque convertor, as a rule of thumb, does not pump oil for these purposes (actually, the oil pump needs to be present and functioning in order to fill the convertor in order for it to work.) Almost all automatics have their pump mounted at the front of the transmission and require the engine running to build pressure. That is why you can't push-start an autobox. There may be more, but the only automatic I'm aware of that has its pump in the rear of the trans and is able to be push-started is found in very old Chrysler family products. I'm not quite sure if they were using the 'TorqFlite' moniker yet.

Coasting in neutral, with or without the engine running, is not advised by any manufacturer. Some of the lubrication in many transmissions is provided by the 'spilled' fluid, i.e. fluid that is released by valves, clutches, the cooler return, etc. This spilled fluid may not be available in neutral and/or coasting situations.

nipper · #32 06-24-2006, 11:01 PM

Quote:

Originally Posted by Beav

The transmission also has its own oil pump. It is driven by the outside of the torque convertor stub. It provides the pressure needed to operate the hydraulics inside and also provide lubrication. The torque convertor, as a rule of thumb, does not pump oil for these purposes (actually, the oil pump needs to be present and functioning in order to fill the convertor in order for it to work.) Almost all automatics have their pump mounted at the front of the transmission and require the engine running to build pressure. That is why you can't push-start an autobox. There may be more, but the only automatic I'm aware of that has its pump in the rear of the trans and is able to be push-started is found in very old Chrysler family products. I'm not quite sure if they were using the 'TorqFlite' moniker yet.

Coasting in neutral, with or without the engine running, is not advised by any manufacturer. Some of the lubrication in many transmissions is provided by the 'spilled' fluid, i.e. fluid that is released by valves, clutches, the cooler return, etc. This spilled fluid may not be available in neutral and/or coasting situations.

yes and .....

up untill the mid to late 60's almost all the automatic transmissions had rear pumps. Buy the 70's they were all gone as they were considered redundant, un needed, power consuming and extra weight. i think there is still one car around with a rear pump, but its either a hybrid or an exotic (i forget).

Neutral coasting, your right and wrong. Neutral coasting with the engine running is considered dnagerous and in most states illegal. In Neutral it is thought that in a panick situation (which can require the need to stomp on the little pedal) you wont have the aceleration you need. Also you loose engine braking.
Flat Towing a modern automatic is one of the fastest ways to fry the tranny. It can be done for a very short distance at low speed, but the car needs to be started every 15 minutes to cool off the tranny fluid, and circulate the oil. Its easier not to do it at all.
The only excpetion to this rule is an automatic coupled up to a TRUE 4wd transfer case that has a neutral setting.

nipper

Yoda3000 · #33 06-25-2006, 12:34 AM

so... is neutral coasting with the engine on actually bad on the tranny or is it just unwise because you can't romp on the gas.
(Geo Metros are also unsafe because you can't romp on the gas in emergencies)

also, does this apply to autos only or manuals too?

nipper · #34 06-25-2006, 12:45 AM

its not bad for the tranny, just unsake since you are disconnected from the drivline.
nipper

JeffN · #35 06-25-2006, 08:55 AM

Over 100k in 2 svxs, about 16-17 in suburban and about 25 on the road. And that's driving very conservatively...FL & Ny.

lovemysvx · #36 06-26-2006, 12:11 AM

I didnt get to finish the tank, and believe me if you want,

but on one fill up of Super premium Unleaded, I got up to 310 miles on 3/4 of a tank...that was all freeway driving, i bet i could have gotten up to 370

Alycone · #37 06-26-2006, 01:43 AM

I'm happy with my mileage.

intelisevil · #38 06-26-2006, 10:49 AM

If my mileage stays over about 16-17 mpg, I'll still be saving money over my other vehicle - '89 Toyota Landcruiser. No, I don't 17 mpg in the 'Cruiser (I wish!), I'm adjusting for price of Premium vs. Regular.

Yes, my cars are all old, but the bank doesn't own any of them!

I filled up with $2.999 Premium yesterday. The price has finally broken the $3.00 barrier, the correct direction.

Dan

Earthworm · #39 06-27-2006, 01:27 PM

Quote:

Originally Posted by CDG

I'm paying $73 per fillup these days. Thats about 57 litres, average. 1Imp Gallon ~= 4.546 litres, 1US Gallon ~=3.983 litres, fyi.

Ouch, that's expensive...where are you filling up, Revelstoke?

The MOST I've had to pay was $71 (for 94 octane).

#40 06-27-2006, 04:17 PM

Quote:

Originally Posted by lovemysvx

I didnt get to finish the tank, and believe me if you want,

but on one fill up of Super premium Unleaded, I got up to 310 miles on 3/4 of a tank...that was all freeway driving, i bet i could have gotten up to 370

I've gotten over 400 quite a few times. >shrug<

Yoda3000 · #41 06-27-2006, 04:25 PM

94 Octane! That must run well. I don't even think you can get that in the states. I've heard that lower octane = better gas mileage too. I use 91 here in New Mexico.

Earthworm · #42 06-27-2006, 06:07 PM

Quote:

Originally Posted by Yoda3000

94 Octane! That must run well. I don't even think you can get that in the states. I've heard that lower octane = better gas mileage too. I use 91 here in New Mexico.

87 and 91 are normal here. I only get 94 because on thursdays it costs the same as 87. I also get 2 cents/litre back on CAA (like AAA).

GreenMarine · #43 06-27-2006, 10:51 PM

I managed right around 25mpg on the way back from the NASIOC Dragon meet earlier this month... I think I get right around 21mpg on average though... I am rather "slow" around town when I drive it...

$ gest24 $ · #44 06-27-2006, 10:57 PM

Little late getting in on this thread... I was averageing 22 mpg. before my mods. Then it went to 18.5 or so. I recently switched to Royal Purple fluids in everything and after my 2nd oil change with RP I jumped up to 19.8. I'm not light on the throttle either, I work on Sat and Sun so the freeway is EMPTY! So I usually average 85 the whole way to work, about 22 miles. Then on Mondays and Fridays I get stuck in traffic going onto base and traffic coming home. Hopefully I'll be back up in the 20s after the 6spd.

CDG · #45 06-28-2006, 01:18 AM

Quote:

Originally Posted by Earthworm

Ouch, that's expensive...where are you filling up, Revelstoke?

The MOST I've had to pay was $71 (for 94 octane).

lol. Burnaby actually, I think it was $1.14.5/litre for 87 Octane, I think it was $1.32.8/litre for 92 at an Esso. Some days they have a 3 cent discount per litre some days they don't, confuses the crap out of me.