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Old 06-14-2018, 09:06 AM   #26
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Why does everyone think batch fire is so bad? I think it gives the fuel a little more time to vaporize, but I'm no expert.
I think it might make the mixtures a little more consistent over all the cylinders at idle, but really, when the revs are higher, it really doesn't make much of a difference. I wired up my 16V with sequential injection using an MS3X, so with a couple of clicks, I could change it from sequential, to batch.

Could I tell a difference? Hell no. Not even at idle. On the sequential setting, you can specify the timing of the injection event, I played around with that once, as you'd expect (since batch fire didn't make any noticeable difference), the timing didn't seem to make much of a difference either.

I'm sure there are situations where it would make a difference, perhaps at cold idle (where the fuel needs more time to vaporize?), but mostly, I think the differences are going to be too subtle to detect by the seat of the pants.
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Old 06-14-2018, 09:07 AM   #27
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They are 2 sides of the same coin...more efficiency = moar powrz= less fuel consumed per unit of distance..
A lot of the time, performance is all about improving the volumetric efficiency, making more power from the same displacement. That isn't the same thing as overall efficiency, making more power with less fuel.
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Old 06-14-2018, 10:31 AM   #28
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individual cylinder timing is for people who need every last horsepower out of an engine most of the time it's drag and land speed people doing that.
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Old 06-14-2018, 12:08 PM   #29
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A lot of the time, performance is all about improving the volumetric efficiency, making more power from the same displacement. That isn't the same thing as overall efficiency, making more power with less fuel.
Manufacturers are making strides in getting more BTUs of energy to the road.

I hear rumors of 50% efficiency in F1. Coming soon to your driveway. Though not likely in our old Volvos.
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Old 06-14-2018, 12:19 PM   #30
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It's a heat engine, loads of energy are lost in trying to keep the engine cool enough to use things like 'oil' for lubrication, and tin/bismuth/lead based bearings.

If you could make it out of exotic materials (without, presumably, an exotic cost) and run it as hot as it wants to get, and not use a radiator to shed all those BTU's out into the breeze, that would probably help.
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Old 06-14-2018, 02:50 PM   #31
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It's a heat engine, loads of energy are lost in trying to keep the engine cool enough to use things like 'oil' for lubrication, and tin/bismuth/lead based bearings.

If you could make it out of exotic materials (without, presumably, an exotic cost) and run it as hot as it wants to get, and not use a radiator to shed all those BTU's out into the breeze, that would probably help.
Making better use of exhaust heat is a big piece of the puzzle. We are accustomed to roughly 1/3 in cooling system, 1/3 out the tailpipe and 1/3 driving the car; less assorted sundry losses along the way.
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Old 06-14-2018, 02:55 PM   #32
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Maybe something like a power plant that has several turbines running off the same source of steam, each turbine specialized to work efficiently in its place in the chain of expanding and cooling steam.

I'm sure it wouldn't work well in practice, but something like a larger, longer stroke piston shared between two pulse paired 'primary' cylinders. They each dump exhaust into it at TDC, and the exhaust gets to provide another power stroke down to BDC, when it dumps into the exhaust back to TDC, where it gets a new pulse of hot gas from the other paired cylinder.

Stuff like that isn't great from a volumetric efficiency standpoint (especially if you consider the 'child' cylinder as part of the displaced volume), but it could be from an overall efficiency standpoint.
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Old 06-14-2018, 02:58 PM   #33
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Quote:
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A lot of the time, performance is all about improving the volumetric efficiency, making more power from the same displacement. That isn't the same thing as overall efficiency, making more power with less fuel.
Picky picky.
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Old 06-14-2018, 03:01 PM   #34
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It's an EMPEEGEE thread, not an AITCHPEE thread!
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Old 06-14-2018, 03:52 PM   #35
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It's an EMPEEGEE thread, not an AITCHPEE thread!
For a given weight and drag CD there is a direct inter-relationship between fuel burned, gearing, revs, and mpg..>
Maybe not so common here in merikuh where gas is always so cheap but fairly commonly understood where the "normal" car is 1.3 or 1.6.

Many cases where a bigger engine beats a smaller in real world driving..The bigger one can be gear taller, and can be at lower rpm for a given speed..the smaller one to keep up with traffic needs to be revved higher all the time..and they're geared shorter...One that springs to mind is a Golf II with a 1800 had 3.7 or so final drive and the same car with a 1,3 (and that 1,3 was a bitchin-er-er motor than the 1,8 8v-----was geared stock at 4.47>.
The old MkII Escort did better mileage with a 2,0 Pinto than it did with a 1,8

I've built scores and scores of Saab 96 motors with 10,8 compression and a 2bb car with 38/38 carb that did better milage than the 8.0 comp 1bbl (34mm) carb---on long distance steady cruise or matched the poopy motor crusing at 55 when the nice motor was moving the car along at 75...
(around town blasting thru the gears and going up Seattles hills they did a little less but that because it was simply too much fun gassing it up and grabbing gears up up up.. but thats operator problems (I used to warn guys that MPG would suffer if they couldn't restrain themselves...none could) But cruise it make sense..to go 75 means 4166 rpm...One the low compression motor to make 4166 you had to open throttle this much....on the high comp motor you just had to crack it a little bit to make the same revs.

that hain't a hard concept...think of a typical turd 88 245 like that one sitting right in front of me about 12 feet.. choose say 45mph...It can do that in second at xxxx rpm, in 3rd at zzzz rpm, in 4th at yyyy rpm and 5th at #### rpm...What is the throttle setting for each of those? less and less as the gear goes up and the pedal does too. Same car, same engine les open throttle gets moar Em Pea Gees

Maybe I'm 'splaining it wrong...
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Old 06-14-2018, 06:11 PM   #36
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I just want a manual transmission to improve my highway fuel economy because I know the AW70 is the main contributor to my 24mpg at best. I commute in freeways where the traffic is going 80+ mph.

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decent MPG at 80+ mph.

24mpg at 80+ mpg is decent.


You'll get more MPG if you slow down than if you were to swap transmission.
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Old 06-15-2018, 01:05 PM   #37
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24mpg at 80+ mpg is decent.


You'll get more MPG if you slow down than if you were to swap transmission.
My 2004 E500 got 26mpg for the commute. Much of that was at 80 or more.

My current steed manages 22 at the same speed.

Something to be said for modern aero.
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Old 06-16-2018, 09:10 AM   #38
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My 2004 E500 got 26mpg for the commute. Much of that was at 80 or more.

My current steed manages 22 at the same speed.

Something to be said for modern aero.
My Insight gets 55mpg at 75mph so I would know about aero, light weight, and gearing.
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Old 06-16-2018, 10:22 AM   #39
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I cant find the picture of the two m45 transmissions welded together. 8 speed volvo stop messing around.

My wifes 89 244 with 2.4l m47 (perfectly tuned)got a consistent 26-27mpg in utah summers, driving normal. Winters dropped to about 21-22, also driving to work in sundance every day didnt help going over the mountain.

Your mpg sounds right, stop trying to underengineer your car OP.
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Old 06-16-2018, 11:36 AM   #40
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24mpg at 80+ mpg is LIES in a 240.


You'll get more MPG if you slow down than if you were to swap transmission.
Ftfy.
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Folks on here don't know a good deal when they see it.
how psi stock cna support?

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Old 06-16-2018, 12:32 PM   #41
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Ftfy.
When 2.2na(especially on the 7) is running lean how it likes to but everything else is good, its doable.
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