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| Fuel economy https://slantsix.org/forum/viewtopic.php?t=52072 |
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| Author: | valiant200kid [ Tue May 14, 2013 8:46 pm ] |
| Post subject: | Fuel economy |
i finally got the valiant on the road and im quite impressed with the fuel economy im getting 21 mpg average driving like a little old man lol and im 20 i feel i could get a little better though the timing is set at 12 degrees and the valve lash is set at the truck specs also the holley 1920 has a 58 jet in it with electronic igniton to back it all up other than that it has stock everything i would atleast like to get 25 mpg |
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| Author: | DusterIdiot [ Tue May 14, 2013 9:27 pm ] |
| Post subject: | Full timing...? |
At 12 BTDC what is your max mechanical timing and what rpm...also how much vacuum advance do you have? -D.Idiot |
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| Author: | ILMopars [ Wed May 15, 2013 2:13 am ] |
| Post subject: | |
My timing was at 12 which was too advanced. My car was pinging like hell and I could barely get 15mpg. |
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| Author: | FrankRaso [ Wed May 15, 2013 7:08 am ] |
| Post subject: | |
I think 12° advance is a bit much too. I would try going back to the factory setting and then advance the timing in 1-2° increments. It would be useful to know your advance curve like DI was asking. Sticking to a steady 60 mph, I the best I've been able to get so far is around 23 US mpg so you're not doing too badly. |
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| Author: | DusterIdiot [ Wed May 15, 2013 7:22 am ] |
| Post subject: | Yep... |
Quote: I think 12° advance is a bit much too. I would try going back to the factory setting and then advance the timing in 1-2° increments. It would be useful to know your advance curve like DI was asking.
Timing is very subjective, what works for one, doesn't necessarily work for another as Frank stated, in some cases 12 might work for some but 8 might be better especially if it's all stock and the distributor curve is unknown. I do know that if the curve is tailored to the vehicle and terrain it will do better. I know I have tailored better curves and been able to get at best 28 mpg out of a mid-60's dart...but that was all flat land/highway driving...(that also took some carb retuning and prudent driving). Sticking to a steady 60 mph, I the best I've been able to get so far is around 23 US mpg so you're not doing too badly. Some of your drive train options may limit this as well (axle ratio, automatic vs. manual transmission, engine build efficiency). -D.Idiot |
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| Author: | Aggressive Ted [ Wed May 15, 2013 9:18 am ] |
| Post subject: | |
One thing that has helped my mileage was a suggestion Doc had shared........get a vacuum gauge and drive like there is an egg under your foot. In town and local mileage average is still 22.5 mpg, freeway 25+ mpg. Timing is 10 degrees initial, 20 degrees mechanical and 22 vacuum for a 52-55 degree total depending on rpm 2500 vs 3000 rpm. Free flowing exhaust system using Flow Master mufflers, heat deflector under the carb, electric fans, cold ram air, fuel line mod., Carb rebuild: minimum new fuel inlet needle and seat, 2.76 gear ratio, 26" tall tires, more valve lash .012/.022, distributor recurve, alcohol/water injection, drop nose 2", front air dam, lighten car, synthetic engine and rear end oil, all help to improve mileage. |
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| Author: | ILMopars [ Wed May 15, 2013 12:25 pm ] |
| Post subject: | |
Mileage is back up to about 19-20 |
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| Author: | Aggressive Ted [ Wed May 15, 2013 12:39 pm ] |
| Post subject: | |
Awesome! No more engine knocking after you reset the timing? |
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| Author: | ILMopars [ Wed May 15, 2013 2:15 pm ] |
| Post subject: | |
Nope. No knocking. |
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| Author: | valiant200kid [ Wed May 15, 2013 7:57 pm ] |
| Post subject: | |
the distributor curve is unknown unfortunatly its a reman from advanced auto i'll have to check the timing after our mopar meet hear this weekend im currently in the middle of helping my dad get his big block duster back up and running on the plus side with the 12 degrees of timing i have theres no pinging at all i also forgot to mention my cam is advanced 4 degrees over stock so im at 102 degrees with my intake centerline instead of 106 |
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