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Eco-Bricks - 35+mpg club

Pumping gas until it "clicks" at a random gas bar, and recording trip meter mileage, is not science.

It is actually fairly difficult to determine fuel consumption accurately.
 
sim said:
It is actually fairly difficult to determine fuel consumption accurately.
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Only if you do it wrong... but I do agree "it is actually fairly difficult to do it right"

I fill up with exactly ten gallons per tank : easy to get an average that way and no calculations involved.
 
sim said:
It is actually fairly difficult to determine fuel consumption accurately.
Click to expand...

Same fuel station, same pump....929 miles total with 30.3 mpg (avg) on 93-245...variations in mileage has gone hand-n-hand with number of stops and road conditions.

Yes, it is an art form to fill a fuel tank, some do it better than others.

Again, I live in a rural area...only a few other vehicles I encounter on rural roadways.
 
Over the last 80 days (ie. since installing a set of EV6 injectors) and 1,243 miles I've averaged 28.2 mpg. The 80 days before that I covered 1,611 miles and averaged 26.7 mpg. These figures are with UK gallons, which is nothing to write home about when converted to US gallons (23.5,22.2), but anything approaching a 30 mpg average is considered good going for these cars over here.

1997 945 CD, B230FK, M90L2, 3.54, 24.7" tyres, yadda yadda.
 
baggins798 said:
anything approaching a 30 mpg average is considered good going for these cars over here.
Click to expand...

Massaging the throttle plate consumes fuel...using an intake vacuum gauge can assist in increasing fuel mileage... a functioning O2 sensor is required.

If running in open loop (short runs) mostly, Gen IIIs are not worth installing. Only in closed loop mode can fuel savings be experienced. Hence, for city folks with short runs, its not worth upgrading to Gen-III.
 
baggins798 said:
Over the last 80 days (ie. since installing a set of EV6 injectors) and 1,243 miles I've averaged 28.2 mpg. The 80 days before that I covered 1,611 miles and averaged 26.7 mpg. These figures are with UK gallons, which is nothing to write home about when converted to US gallons (23.5,22.2), but anything approaching a 30 mpg average is considered good going for these cars over here...
Click to expand...
:-D
The previous engine in my 940 was giving me 31mpg(British) all day every day average over multiple 10-gallon fillups ...
Since swapping in a smoother engine I'm down to about 30mpg :-( which to me just isn't right!
Time to fit undertrays, which will be good fun.
 
Yeah, I run a wideband with integrated boost/vac gauge, and the fueling is spot on.

If running in open loop (short runs) mostly...
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The car is out of cold start enrichment and into closed loop within an 1/8 mile, our cities aren't that small. I live in more of a rural area anyway.

It doesn't enter open loop unless you go into boost (the switch point is about ~3 psi), so not sure what you mean by that.
 
My 240 with B230F+T gets 25-26 MPG with short trips (city-ish and rural) in the summer. Has been some time since I drove a longer stretch with filling up at the same gas station but it wont be bad. Not 35 MPG though!

edit, what helped:
-New front wheelbearings. Old ones were filled with sand-grease-water mix. Most of the enegry the old bearings dissipated was converted into sound so the car is a lot more pleasant (silent) to drive!
-Real alignment instead of me eyeballing.
-New air intake that does away with the cone and has a better placement of PCV return and AMM. The AMM was soaked with oil, now not anymore. Runs better, more consistent and slightly better MPG.

I've been running E10 fuel, stopped with E85 6 months ago. Last week I burned a new chip with modified injector constant and some other mods to get less rich startup and better mixture at WOT (was lambda 0.75, now lambda 0.80-0.85). Maybe makes the MPG slightly better as well.
 
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I'm getting 24.5 MPG in my 940 and my girl is getting 26.5 MPG in her 760. I do like using fuelly for tracking. Its easier to remember that way! I'm hoping to try a few upgrades soon to see if I can get a little closer to my 30 MPG target while still driving like a normal person.
 
letsgetsteve said:
see if I can get a little closer to my 30 MPG target
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YUR goal is too low...35+/- (if vehicle has AW71L) via upgrading injectors, and retraining foot.

UPDATE - 1993-944 NA Regina with rebuilt B23F, AW71L, Bosch 0 280 155 746 Injectors (cleaned/tested), No AC and No Cruise used, with one window down, and another cracked open.

Road-trip with mild/calm winds via mild/moderate terrain mostly

29.8 Overall MPG (US) (Includes about 50 miles within a larger city)

Interstate Driving Only with two stops

35 MPG with target speeds of 50-55 mph

32.6 MPG with target speeds of 55-60 mph

About 21% over EPA original estimate

City fuel economy - If few actual stops, its possible to come near 30 mpg with speeds below 45 mph via using AW71L's coast mode. In short, one has to anticipate traffic movements

35+ fuel economy - Its possible with target speed of 50 mph, with few stops, on flat-ish land, on calm days, or with wind to your backside.
 
yeah your right, 35 MPG would be cool... but not if I get passed by every single person with a 10 speed! I still want to have fun and get to where I'm going on time so for me 30 MPG is the real goal. That and 250ish HP so its fun and exciting AND economical. Balance is what I'm looking for.
 
letsgetsteve said:
I still want to have fun and get to where I'm going on time
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Update: 93-944 Rebuilt B23F-NA-Rex-I/Regina, 89-E10 Fuel, Bosch 0 280 155 746 Injectors, AW71L with new oil pump and rebuilt TC

Keeping up with city traffic flow - Larger City (20% with traffic light stops) Hwy (80%: 60 mph target)...192 total miles

26.1 mpg (US)


EPA Original -27 mpg Hwy at 55 mph with Regular Gasoline (no AC)
EPA Updated - 25 mpg Hwy

​
Bosch 0 280 155 746 Injectors - Its a no brainer with these Gen III injectors-Bosch DRI design (Deposit Resistant Injector)-on NAs with LH-2.4 & Rex, get a set cleaned/tested.
 
Update: Cold Weather Startup

18?F (-7.7?C) 1993-944 - Regina - Bosch 0 280 155 746 Injectors with rebuilt B23F

Key switch to on....wait about two seconds to prime fuel rail...key switch to start...normal quick startup

Fuel mileage has dropped down to 25-mpg hwy, due to ignition-fuel computer(s) not seeing speedometer

Footnote - Needless to say, when upgrading injectors, the O2 sensor must be fit for duty since fuel trims will be adjusted.
 
You forgot to mention the main reason your gas mileage has dropped... It's cold out and the engine takes longer to warm up, so it's in warm up mode longer(aka, uses more fuel).
 
27.5 MPG on last tank.

Midway tank I swapped to orange top injectors from a t5. the big 690 cc/min Siemens worked good but I want to get the tune as good as possible with (close to) stock parts.

Maybe they make a difference as well, various things werent properly set for the big injectors (like starting etc).
 
klr142 said:
You forgot to mention the main reason your gas mileage has dropped...
Click to expand...

I understand cold weather and fuel economy drop, but there is a speedometer code set by ignition/fuel computer, and I have not looked for ECM pinout to troubleshoot.

Those Bosch 0 280 155 746 Injectors are 19#, and OEMs were 18#; all the ECM sees is zero mph, and fuel trim adjustment function needs speedometer data





.
 
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