Great mpg, mildly surprised.

rickwrench

rickwrench

Famous Member
Drove the 62 Squire to Carmel for the weekend, 240 miles total round trip on the odometer. The gas gauge still above half full when we got home last night. Went to the gas station to see how much gas we used... only 7.1 gallons of 89 octane gas (CA mid-grade).
33.8 mpg!
I knew it was getting a lot better mileage around town than I used to, but holy shtip.
I wasn't driving in any particular gas saving manner, just cruising along with the traffic (65-70mph?), stereo on, windows down, enjoying the drive with my wife. There were a few steep stretches (CA Hwy 17, 'nuf said), and a few small side trips around Carmel.
The car has a stock C5 200 block, stock C9 head, thick head gasket, DSII, stock exhaust, and a 1bbl autolite off a 78 Fairmont. The non-stock stuff is the big Al crossflow (195 degrees the whole way, even up steep 17), a 5 blade flex fan, big open element air cleaner, and the T5 tranny.
This is the first long trip I've made in the car since the T5 swap last year. Cruise rpms were around 2200-2300 in 5th (.72 OD, 3.50 rear, 205/70-14 @ 35psi).
Curious as to what kind of mileage are people getting with the T5s with stock(ish) and non-stock engines?
Rick(wrench)
 
lately...16MPG...pretty crappy actually. I'm not sure what's going on, but before I put the 'new' engine in and T5, was getting 27 MPG with a 2.77 3spd. I think my engine may be dieing. I also think one of my brakes is hanging up on the rear, causing more problems.

Slade
 
That kind of ecomomy is terrific. With my 4 man 250 2V Cortina if I cruise at 90kph at aprox 2200 rpm (bit less that 60mph?) I get about 13 litres per 100 ks in miles per gallon Im not sure as you measure your miles per gallon differently over there.
Is your cam standard
 
just did the math for mine...i use around 7-8 litres per 95-100 kms..got a 250 and drive anywhere from 100-160 kms/hr on the highway and whatever speed i can in the city... 100k's is about 62 miles and 13 litres is around 3 gallons (not sure if its US or canadian gallons though...)
 
With my carburetor dumping gas into the barrel after I shut off my car Id say give or take a two I get around ummmmmmmmmmmmmmmm, I dunno maby 5mpg......8 tops? :? lol Seriously Im not exactley sure...but it is quite crappy, but my carb is emptying out my wallet...errrr I need to figure out that measly thing.
 
That is good, mine must be a heavy drinker if your getting that out of your 250. Barinas get 7ltrs.
 
the engine is stock, but with a few impovements on it, there are few things that can be made to improve mileage...i am finding out exactly what..but my PCV gas condenser and well tuned engine are my first steps...i am hoping for better soon though, without needing to do anything to the engine itself...i used to get around 12-13 litres per 100 ks though so youre doing all right for a stock engine...
 
3.78 liters per US gallon.
4.55 liters per Brit gallon.
Hmm, I feel cheated somehow.
What octane is oz mid-grade gas?
Rick(wrench)
 
Ha! You guys must get you gas from us (California). 60% actual gasoline, 30% whatever toxic waste the refineries have too much of and decide to call an "oxegenate" that week, 10% fuel line disolver.
Rick(wrench)
 
I think it's 92 and 97 RON (but XE may correct me on the RON bit, da-doo, da-doo...) Whatever the numbers are, they're kind of dishonest in that our 92 is inferior to your 92 (and this is not some misplaced cargo-cultism; it's the different way of determining octane rating).

Frequently diluted with Ethanol up to 10% (officially blessed and advertised), also toluene and xylene as the proprietors feel comfortable with.

There are times when the car would ping less and have better emissions with a nosebag of barley chaff, I swear. Good fuel is found at the airport and in drums. :wink: Oddly enough, this is a civil offence and efforts to have an efficient, clean running motor will attract heavy fines if detected.

Adam.
 
yea i'm getting about 12 also...sometimes less than that!! what is going on?? I dont run it that hard at all. Even when i try to run it really easy, i will get no more than 13 or 14. How do i change my power valve or whatever?? Also, when i turn off the car it continues to run, where it continues to self ignite itself, called Dieseling?? It has a 2bbl Holley 350.
Anyway, any help here??
 
I get about 20.5 mpg after the T-5. I may have picked up 1 mpg after the trannny swap.

66Mustang 200: you might have a timing issue on your vacuum advance. Retarded timing will give poor fuel economy and will promote higher combustion temps that lead to dieseling. Also with inadequate vac advance, many people open the throttle plates to smooth out the idle. Problem is, if you have a dieseling problem, the throttle plates are not closed sufficiently to cut off the fuel.

I gained a few mpg when I finally got the vacuum advance straightened out on my car. It had been running in the 16 mpg range.
 
Fastback - my car does the dieseling thing too. Are you saying that advancing the timing may solve this prob? BTW - which way do you rotate the dizzy cannister to advance timing?
 
Advancing the initial timing could have a little benefit. But what I was saying is that often insufficient vacuum advance caused elevated temperatures. You can see what I mean by letting your car idle as normal. Then plug the vacuum line, and you should see the engine temp start to climb. Dieseling is a combination of the throttle plates not beiing closed sufficiently, and high cylinder temps, hot spots in the cylinder or spark plugs that are retaining too much heat. If your vac advance is not operating correctly, the temptation is to raise the idle speed by screwing in the throttle plate idle stop. When the ignition is shut off, the plates are open enough allowing air to carry more fuel into the engine, where it is spontaneously igniting due to the high cylinder temps.

I do not recall what direction the distributor rotates.
 
rotate it counter clockwise to advance the timing....my carb gives no vacuum ad the distributer port at idle and only 1-2 inces when i rev it up...i have the vacuum advance hooked up to the manifold right now...it deffinitely runs smoother and cooler with vacuum advance....
 
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