what's the MPG on your 428CJ?

[Raven R code 281]

I get about 16 mpg. Might look at a rebuild and see if new electronics (maybe Pertronics) can help and maybe a cam change. Although....I still need to kick but at the stop lights.

[maxum96 32]

16 mpg sounds about right. If you're wanting more mpg, use a lower gear ratio.

[Red Sportsroof 10]

Actually you would have to raise the gear ratio, to something like 3:50 or 3:25 to 1, fewer RPM's for fewer RPM's per mile, the CJ will handle it. A good motor and 3:50 gears will get you low 13's and High 12's with decent tires.

[Raven R code 281]

Got 3.50 gears in the back......ran 13.2 with stock tires in the 1/4.

 

;)

[DragPack69 0]

I get about 14 if I keep my foot out of it. gears, tires, and cam profile will play into it also.

I`m running a Comp cams 280 magnum cam, and 3:50 gears w/ 255/70 15 tires

 

 

John

[jholmes217 65]

Funny. Last thing I was worried about when I bought a 428 Cobra Jet was gas mileage!

[Raven R code 281]

w/ 255/70 15 tires

 

What size are your rims? I am ditching the styled steel chrome rims in favor of 15x7" Magnum 500's.

[Raven R code 281]

Funny. Last thing I was worried about when I bought a 428 Cobra Jet was gas mileage!

 

Same here.....but gas was about $1.10 gallon when I got this. Still.....no worries just A LOT of fun. It is really hard not to have a heavy foot while driving this thing!

[Powershift 19]

Fuel mileage, 428 CJ, DOES NOT COMPUTE........

 

HA HA!

 

It's like people asking me what fuel mileage my 1991 M931 A2 5 ton 6X6 gets too. I tell them it runs on destroyed hopes and dreams, with a sprinkle of crushed Prius.

[jholmes217 65]

Same here.....but gas was about $1.10 gallon when I got this. Still.....no worries just A LOT of fun. It is really hard not to have a heavy foot while driving this thing!

 

I hear you. Gas is hovering around $1.73 for the cheap stuff here in the Olympia WA. area.

[Raven R code 281]

I hear you. Gas is hovering around $1.73 for the cheap stuff here in the Olympia WA. area.

 

"Gas is"!? Let me get this straight....it is currently around that price!!!

 

This cheap stuff in upstate NY is $3.79!!! About $4.24 for 91

[shaun071 62]

I hear you. Gas is hovering around $1.73 for the cheap stuff here in the Olympia WA. area.

 

You guys have it easy on gas prices!! Try $6.00 a gallon here in Australia!!:taz::taz:

[Raven R code 281]

You guys have it easy on gas prices!! Try $6.00 a gallon here in Australia!!:taz::taz:

 

Holy crap!!!! Is that for a gallon or liter? Kinda takes the fun out of it.

[shaun071 62]

Thats for a gallon. Currently we pay anywhere from a low of $1.45 to a high of $1.60 per litre for 91. 98 is around $1.70 per litre. I'm out in the country so my wife does a 50 mile round trip to work each day and I'm doing about 30 miles per day as well. Gets expensive just going to work let alone doing any "fun" driving!!!!!

[jholmes217 65]

"Gas is"!? Let me get this straight....it is currently around that price!!!

 

This cheap stuff in upstate NY is $3.79!!! About $4.24 for 91

 

My mistake. I meant $3.73 for 87 octane.

[MustangBobby 28]

That must be nice. I'm on the east side of the state, and it's $3.63.

[70Mach03 12]

Wow, you guys sound like you have economy cars compared to my old 1970 428 SCJ with Factory Drag Pack and 4.30 gears. It was an auto and I got 5 to 7 mpg around town and 10 on the highway if I stayed under 60 mph. This was in the early to mid-70's. I sold it in 1977 when gasoline hit .75 a gallon. It was costing me nearly $15 to fill the tank. It was basically stock with F70x14 Goodyear Polyglass tires.

 

As a side note my daily driver today is a 2014 Shelby GT-500. The 5.8 Supercharged motor is rated at 662 net hp and the EPA fuel economy rating says 15 to 24 mpg. I don't normally drive it that hard and get 17 mpg in my normal commutes and recently got 25.5 mpg on a 200 mile all interstate trip by driving 70 mph (not as easy as it sounds, LOL).

[maxum96 32]

Actually you would have to raise the gear ratio, to something like 3:50 or 3:25 to 1, fewer RPM's for fewer RPM's per mile, the CJ will handle it.

 

 

You got it backwards, raising the ratio would be like going from 3.50 to 4.11 gears. But when you talk about "taller" gears, you are referring to lower ration. Like going from 4.11 to 3.50.

 

This web page explains it in detail.

 

http://www.badasscars.com/index.cfm/page/ptype=product/product_id=398/category_id=13/mode=prod/prd398.htm

[Mustangfan 2]

Heck the 428 runs on smiles per gallon

[BuckeyeDemon 211]

to me, gas mileage is highly dependent on the environment and the way a person drives (driving style, type of roads, duration, climate) which is probably the reason numbers vary so much on the internet. 

also, it's hard to say how a lot of people check their mileage too (did they have their car warmed up, jump on the highway, drive for a tank at a good speed, then check? or do they drive short durations, on roads with lots of stop signs with every stop includes a drag launch?). 

I seem to drive more conservatively when I actively monitor mileage on my truck, it's almost like a game.  

I believe the 1995 Mustang Cobra R (351W, 5 speed) was rated at 12 to 20 (15 average).  So if you were rating your car in the same way as they do on production cars, then it would seem you are doing unbelievably good.

In my opinion, if your plugs look good after a normal drive, then likely you are close enough, changes won't make much of a noticeable change in mileage.

[1969_Mach1 333]

I see this was an older thread.  But I cannot wrap my mind around why gas millage would be a concern on one of these cars?  With the little I use my car, I can still almost see my gas gauge needle move down while driving.  Spark plugs look good so fuel economy doesn't concern me.

[mach1cj 11]

If I remember back that far to when mine was running, it got about 9

[Brian Conway 264]

Once had a 74 Ford 4x4 Ranger that got 6 mpg freeway.  No reason to think the 69 428 does any better.  Never checked and don't really care.  I would like to get a better grade of gas without breaking the bank.  Right now in California 91 octane w/ethanol is about $3.35 and the racing 100 octane is $8.00.  Brian

[1969_Mach1 333]

I'm also in California.  I mix Torco Accelerator with the 91 octane pump gas from Union 76.  The pump gas in my area has 15% ethanol.  At 15% I haven't noticed any issues.   The Torco Accelerator raised octane but is advertised as concentrated race fuel and not an octane booster.  It has a long shelf life as long as it's not exposed to sunlight (UV light).  The mixture seems to work as well as when I mixed 110 octane race gas with the same 91 octane pump gas. 

[jmlay 80]

I can’t speak for my 428cj because it is still in pieces.... But all of the above is better that my Lightning @12.5-13 mpg. And I take it easy.