Fuel consumption...no not a tree hugger, just FMI

miller

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Anything i missed out on? Or other things to consider tracking for reference/changes?
Broader picture would be, to check basics, too.
Reason I mention it, as example, when I kept getting fouled plugs on a 383 I built. Results were new, but lousy plug wires. Had to visually watch the spark I was getting, real weak. Changed plug wires, good to go.
 

Wietse

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Good point!
I am thinking of changing them out anyway in the future.
They are brand new 8.5mm MSD plug wires but they came with the 90 Deg socket for on the sparkplug.
I've seen sets (MSD, Firecore) that come with a long, straight socket for same. (the sets you need to cut to size yourself and install the socket)

As now I have zip ties keeping my #7 and #8 plug wires away from the header to prevent them to burn up, and I am hoping that the straight plugs will give them some more clearance of the headers.
And hoping I can rearrange it a bit better so it looks more neat as these sparkplug cables seem to go everywhere now.
But for now I can just confirm the resistance again of the wires to see there are no faulty ones and worry about replacing them later. (I've seen some readings on MSD website regarding resistance in Ohm per feet/meter or so as a reference.)

My distributor is fairly new (MSD R.T.R. model) and the coil is same age (MSD Blaster SS) so it must still have a strong pulse. :)
All wiring harnesses have been renewed, new alternator (85 Amp) and separate wiring to ignition coil has been replaced with 0.75mm2 wiring.
Engine oil and filter have not done much miles after last replacement.
Carb has been stripped down to the bone and rebuild.
Fuel tank is clean, fuel pickup and inline fuel filters are new.
Air filter is new, fuel pump is new.
Last thing I need to check again is, the pushrod for the fuel pump.
The last one was shot big time and I replaced it with a new one (NOS) and measured it again after around 50 miles, but just to make sure this one is not wearing out again or my cam lobe is getting f*cked, I need to check it.
 

67Charger

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I just finished the Nevada Open Road Challenge. In the 130 target class, My actual average was 130.04mph for 119.78 miles, and I pulled 6.7 MPG with a 496 stroker using a Megasquirt 2 EFI setup holding me at about 13.8:1. Big engines use big fuel. 130 mph is about 4400 rpm. We were up at 152 for a while and that was closer to 5000. Pulled off a 2nd place in our class with 2.2 seconds error.
 

BSB67

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I just finished the Nevada Open Road Challenge. In the 130 target class, My actual average was 130.04mph for 119.78 miles, and I pulled 6.7 MPG with a 496 stroker using a Megasquirt 2 EFI setup holding me at about 13.8:1. Big engines use big fuel. 130 mph is about 4400 rpm. We were up at 152 for a while and that was closer to 5000. Pulled off a 2nd place in our class with 2.2 seconds error.

That is very cool
 

Wietse

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Home sweet home...back to work on the car :)

I went for a drive around town, when i came back i pulled all the spark plugs, which IMO look ok.
Not wet and fouled with carbon build up, heat range looks ok as well i guess.
All gaps were double checked and were at 0.035".
While i had all the spark plugs out i did a compression test as well which looks as follows:
(Engine was warm, air filter removed and carb at WOT, 8 compression strokes to take reading)

#1: 200 #2: 200
#3: 195 #4: 205
#5: 200 #6: 198
#7: 197 #8: 203

Deviation does not look bad i guess, i will do a cleaning session with some Sea Foam spray.
I set the idle screws back to basics and did some fine tuning with the vacuum gauge hooked up to the bottom connection of the manifold.
I got it at 10 Inch/Hg, when tranny put in Drive it drops to 5-5.5 In/Hg (pretty steady gauge)
Hopefully next week i will find some time and install the AEM A/F meter and see what it will tell me.
By that time i should have received my other sizes of jets as well....if i need them.

IMG_9540.JPG IMG_9541.JPG IMG_9542.JPG IMG_9545.JPG
 
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Wietse

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I double checked the ignition timing and was still at 18* @ idle.
After i've increased it to 20* just to try and found it runs better with that, if feels like it even wants more initial timing but i am a bit scared of going to far.
I starts well, idles well and is responsive on the throttle.
Did notice it sounds a bit different at idle when listening near the exhaust, don't know how to explain what i mean...
Mechanical advance is 18*, no vacuum advance, total advance is 38* reached @ 2500 RPM.

During driving coolant temperature goes up to around 210 Deg F, no pinging noticed either.

Very curious to see how far i am off once the A/F sensor is installed.
 

1967coronet

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Here i am buying RON 98 fuel for the Dodge.
I do have a few bottles of octane booster at home for any time i go for a long tour and might not come across a petrol station that sells 98 fuel.

According me, my fuel gauge is not showing really accurate so i had to do the math myself. (think it shows Empty a bit too early, or not?)
As the tank is 72 liter (19 US gall.), i filled it up full with 56 liter (14.8 US gall.) when the gauge was showing a hair of Empty, which leaves me 16 liter (4.2 US gall.) of backup.
After driving around for about 60 miles the gauge is almost showing half again and i was kinda shocked it burned 28 liters (7.4 US gal.) on 60 miles (96 km).
So in conclusion, it's not the consumption...it has a small tank :)
Same as with me, everybody always talks about my drinking, but never about my thirst. :p
After reading your post again , It sounds like your using the fuel gauge to figure the mpg.
To get a better idea on your miles per gallon go to your fuel stop and fill it up until it { the pump nozzle clicks off as in its full. Record your miles on the odometer.
Take a good long drive say 40 or 50 miles round trip, go back to the same fuel stop and refill using the same pump until it clicks off, check the miles on the odometer do the math along with the gals. it took to refill. May be better or may be worse but it will give you a better picture of the mpg.
 

Wietse

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On the next refueling i will follow up as you mentioned to get a more accurate reading and see how that works out.
 

Johnpat

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Running bored/ stroked Hemi,11/1 comp
approx 495 HP
Mix110/93 octane maybe 6-8 mpg
Dana 60 with 3.54 ,4spd
Who cares I'll still have more fun than the
20 mpg guys.
 

threewood

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On the next refueling i will follow up as you mentioned to get a more accurate reading and see how that works out.

Use an app that records speed via gps. The factory speedos are not going to be as accurate.
 

Wietse

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I did manage to get the AEM A/F sensor installed this morning.
I made it such to be a temporary setup to do the needed adjustments/troubleshooting, if not required i can remove it from the car and put a blank plug in the exhaust nipple.
Run the wiring through the hood scoop and secured with a strap :) very good visibility during driving==> safety awareness) :)

Noted the readings at idle, different speeds and near WOT situations.
I wrote down the average readings during constant speed.

Idle: 13.2 ("cold") / 12.8 after a drive with engine at operating temperature.
20 Mph: 12.0
30 Mph: 11.5
40 Mph: 11
50 Mph: 10.5

Several hard launches, mid sprints 30 ==>60 Mph i have not seen it go any higher then 13.5 (maybe 12.5 -13.0 average)
When speeding up normal it shows between 10.5 and 11.5 on average.
I think it could be leaned out slightly, or leave it as is?
Primary jets are #78, i just got my package with goodies which include the #75 and #73 jets to do any needed adjustments.
Also received my Firmfeel Stage 2 steering box!! :monkeyleft:

IMG_9556.JPG IMG_9557.JPG IMG_9558.JPG
 

miller

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Will not bother checking mine. Hope I have 8-10, but doesn't make a damn. Two fours...it is what it is. :popcorn2:
 

coloradodave

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I did manage to get the AEM A/F sensor installed this morning.
I made it such to be a temporary setup to do the needed adjustments/troubleshooting, if not required i can remove it from the car and put a blank plug in the exhaust nipple.
Run the wiring through the hood scoop and secured with a strap :) very good visibility during driving==> safety awareness) :)

Noted the readings at idle, different speeds and near WOT situations.
I wrote down the average readings during constant speed.

Idle: 13.2 ("cold") / 12.8 after a drive with engine at operating temperature.
20 Mph: 12.0
30 Mph: 11.5
40 Mph: 11
50 Mph: 10.5

Several hard launches, mid sprints 30 ==>60 Mph i have not seen it go any higher then 13.5 (maybe 12.5 -13.0 average)
When speeding up normal it shows between 10.5 and 11.5 on average.
I think it could be leaned out slightly, or leave it as is?
Primary jets are #78, i just got my package with goodies which include the #75 and #73 jets to do any needed adjustments.
Also received my Firmfeel Stage 2 steering box!! :monkeyleft:

View attachment 609313 View attachment 609314 View attachment 609315

This article might be helpful: http://www.hotrod.com/articles/innovate-air-fuel-ratio-meter/
 

Wietse

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Good info on that article.
As they mention, 12.8 - 13.2 is the ideal mixture for power.
Mine is near enough in that range, and i think this minor changes are not possible to be made by changing jets.
More likely this is stuff to change with air bleeds....which are out of my work scope :)

It feels good to know it's running good, i always worry after setting things up it leans out and i burn a piston or so.
To change anything on the fuel consumption will screw things up, which was not the plan in the first place.
Very happy to get a lot more sight and knowledge about these things to know what you are actually doing! :)
 

Wietse

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As everything was going well....something had to go wrong again...??
I just moved the car a bit on the drive way and was just sitting there at idle...suddenly start to run strange and dies.
Tried to start...nope...removed the air filter to look what is going on and i can see as someone else i cranking the engine the secondary is flooding like a bastard and dropping heaps of fuel in the intake.
Now the only thing i did was transfer some fresh fuel from a jerrycan to top up the tank, which was full till the cap!
Could that be a reason to make it flood?

I pumped out some fuel again and checked the needle valve and did not see anything strange but changed it anyway.
After that started the car, noticed a bit of excessive fuel coming from the primary as well when revving, re-adjusted both floats which were slightly high but have not been changed over the last 1/2 year.
After a little drive the carb stays dry during idling and when revving no fuel drops observed.

Very strange what happened here...
 

Wietse

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I've checked again, found 8 gallon to be filled up after 60 miles driving.
So settles out at 7.5 Mpg....not bad :D

Anyone some feedback on the numbers mentioned in post #52?
AFR acceptable or should i try a smaller size jet in the primary? (#78 ==> #75)
 

Wietse

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I went ahead and changed the primary jets to the #75.
During driving noticed at different speeds the AFR values are slightly higher, say i gained 0.5 at lower speeds and up to 1.0 at 50-60 Mph.
At harder launches and heavy speed increases on the primary's only it still ends up at 13.2 - 13.3, although i did see several times it peaks to over 14 but is not maintaining. (probably a lean moment at or after the pump shot)
A few times i did hear this "tingeling" sound coming from below the car, sounds like from the exhaust. Like there are small rocks hitting the exhaust pipe, not sure if this is engine ping. (would expect it to be better heard from the engine compartment.
I heard it before as well sometimes before the jet swap. (header sits close to the torsion bars as well, maybe the hit slightly during harder driving.)
 

Kern Dog

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I installed an AEM gauge several years ago. I chased the magical 14.5 number for quite awhile, thinking that was the right number for clean running and decent performance.
Maybe I am chasing a ghost. I have a 440/493 with 10 to 1 compression, Edelbrock heads and RPM intake, 2" headers, the MP 528 Solid cam with 1.6 rocker arms. The carburetor is a Demon 850 vacuum secondary. I have #83 primary jets and #92 secondaries. I have found that by adjusting my idle mixture screws to 1 turn out or less, it will idle in gear in the 14 to 14.9 range, cruising down the road at 13.5 give or take. It does hesitate off of idle and the gauge shows it goes off of the charts LEAN, 18.0+. Once past that stumble, it runs okay but is a little down on power. If I adjust the idle mixture screws to more than 1 turn out, say 1 1/4, the idle numbers go below 14. I took advice from others that the 14.5 number is the target for idle and cruise but I'm catching on that my car seems to run stronger with a richer mixture.
 
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