Gas mileage with BB
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,002
Likes: 0
From: Bay City MI.
Gas mileage with BB
I know that I should not be complaining about MPG with a BB, but around town I can watch the gas gauge drop like a rock. I am getting about 5 to 7mpg. My idle seems good, although a little wet sounding and WOT is fantastic. Should I mess with the idle screws to lean it out some. On my 850DP I am using 78 jets up front and 82 in back, and 6.5 power valves. Like I said I should not be upset about the gas but what is everyone else getting in there BB?
Safety Car
Joined: Jan 2001
Posts: 4,660
Likes: 3
From: South Central Louisiana
St. Jude Contributor
Re: Gas mileage with BB (467-Ratman)
I got 13 mpg on the hwy with my old 750 dp. I am not even gonna guess with the 850 till I get it tuned. Its running so rich right now my exhaust detonates like a potato shooter after some "spirited" acceleration. :yesnod: :lol: :auto:
By the way, rear gears believed to be 3:08's
[Modified by LAvetteman, 9:53 PM 6/24/2003]
By the way, rear gears believed to be 3:08's
[Modified by LAvetteman, 9:53 PM 6/24/2003]
Melting Slicks
Joined: Jun 2001
Posts: 3,281
Likes: 6
From: NC USA
Re: Gas mileage with BB (467-Ratman)
~10 around town and 13-14 mpg on the highway if I keep my foot out of it. Hwy mpg should improve slightly with the new Tremec but city mpg will suffer! :D
[Modified by Marks69BB, 10:10 PM 6/24/2003]
[Modified by Marks69BB, 10:10 PM 6/24/2003]
Pro
Joined: Jul 2002
Posts: 723
Likes: 0
From: North Port, FL
Re: Gas mileage with BB (467-Ratman)
I get about 9 or 10 MPG around town and 13 to 15 on the highway. I have 76 jets on the primary side and 84's on the secondary side of an 850 DP with 6.5 power valve. The last dyno run I did with an air/fuel gage showed that I am still on the rich side at wide open throttle with numbers runnig in the 12.1 to 12.3 range. With normal driving my plugs are a nice tan color so I think my primaries are about right. Have you checked your plugs? If they are black you can probably lean out the primary side and help your milage.
Drifting
Joined: Jan 2000
Posts: 1,612
Likes: 0
From: Phoenix Arizona
Re: Gas mileage with BB (467-Ratman)
467 Ratman,
I am planning on driving my '74 from Phoenix to the Cold Coast (San Diego) this summer and hope to get some mileage numbers.. I am figuring around 17 freeway with the overdrive.... We'll see....
Bob :cheers:
[Modified by Bob Turner, 7:56 AM 6/25/2003]
I am planning on driving my '74 from Phoenix to the Cold Coast (San Diego) this summer and hope to get some mileage numbers.. I am figuring around 17 freeway with the overdrive.... We'll see....
Bob :cheers:
[Modified by Bob Turner, 7:56 AM 6/25/2003]
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Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,002
Likes: 0
From: Bay City MI.
Re: Gas mileage with BB (Fevre)
No vacuum advance, my engine guy said he does not like it. I am sure that would most likely help the mileage. I have told people that I dont get MPG its called smiles per gallon! Whatch out Dinos here I come....
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Gas mileage with BB (467-Ratman)
I get an honest 12 mpg around town. I run 2 850 double pumpers with 80 jets all around and power valves. I lean out the idle alot, drill the throttle plates, all 8 of them to get the transfer slots closed. I am running leaner then 15-1 and my plugs look white. I hope for around 15 mpg on the highway but so far have not gone very far. Went 40 miles this morning in 93 degree heat and the vet never warmed up past 190 and the gas gage hardly moved.
