Mpg question?

[okie]

hey all , i have a question. WHat kinda mpg would i get for installing these on a 1970 fj40 ?

- msd ignition
- manafre headers
- new spark plugs and wires
- replacing radiator hoses and belts
- an electronic fuel pump
- skinny tires

So what kinda mpg are we talking about

like a 10mpg to 18mpg at all? hopefully?

what about if I added fuel injection?

 

[secretagent]

better

 

[lunap]

I had calculated for around 16 mpg during the summer. Once it got cold, I forgot to account for cold weather driving, warming up with the choke out, and stupidly ran out of gas. My gauge doesnt work so I was going by the odometer.

 

[ken_79-fj40]

Won't improve much, you are talking about pushing a brick through the wind with a tractor motor. That said, my 79 with 33's header, weber,desmogged, mallory, etc,etc, on a healthy 2f gets about 16 around town, and about 12 on the highway at 75. But my little acura I commute in gets 34mpg, so I average out pretty good.

 

[largenfirm]

Well, you're driving a car with the cross section of a brick, so that should pretty much cap your expectations.

IMHO, the new hoses and belts won't do squat - replace them because they need it, not to improve MPG. The electric fuel pump adds a non-road-repairable failure point, and won't help. New plugs and wires are a good idea, but won't likely help gas mileage, unless your existing ones are total crap.

Headers *might* help, or they may be a maintenance nightmare. They will screw up your cold idle.

Skinny tires that are bigger than stock may help, as a "poor man's overdrive." They'll hurt you around town, and help on the highway.

Best way to help your gas mileage is to change your oil regularly, keep up on the drivetrain lubrication, inflate your tires properly, and keep your foot off the gas as much as possible. Hmmm, no new parts - that's no fun!

If you are running the OEM carb, it is widely regarded as the worst of the Aisins. Upgrading to a newer Aisin might be a good idea. Particularly if the newer one is freshly rebuilt.

Fuel injection can help, but only if done right. And there are a lot of ways to do it wrong.

As a data point, my 82 FJ40, box stock, gave me 17 MPG on the highway, driving from Roundup, MT to Portland, OR, in June. It's out of tune, has vacumn leaks, and hasn't had a tuneup since 2001. I fiddled with it to get rid of the carbon in the cylinders, and blasted the carb with rattle-can carb cleaner, but that was it.

Driving style makes the biggest difference.

HTH

Kirk

 

[PabloCruise]

12-16 mpg

 

[Pin_Head]

Before: 12 MPG

After: 11.9 MPG

After fuel injection 12.1 MPG

 

[CruisinGA]

hey all , i have a question. WHat kinda mpg would i get for installing these on a 1970 fj40 ?

- msd ignition-may help a little
- manafre headers- same
- new spark plugs and wires -unless your stuff is bad, won't help
- replacing radiator hoses and belts-won't help
- an electronic fuel pump-won't help
- skinny tires-maybe a tad

So what kinda mpg are we talking about

s***ty

like a 10mpg to 18mpg at all? hopefully?

10-13 maybe.

what about if I added fuel injection?

maybe a little better-not too much.

Most of this stuff is just maintenence-type things. They need to be done, but do not improve MPG over what it should be, which is about 11-12.

Combined mileage from the factory is 12 mpg. It's going to be hard to coax more MPG than a stock cruiser from the factory got new.

 

[okie]

Did you guys know that the fj25s when they came out they had 15mpg? I think its just based on the condition of the engine exc.

 

[largenfirm]

Did you guys know that the fj25s when they came out they had 15mpg? I think its just based on the condition of the engine exc.

No PS, no AC, minimal electrical draw, 3 or 4 hundred pounds lighter, and no smog pump or emissions equipment...

Yeah, I can believe that number.

It's apples and oranges, though.

Kirk

 

[okie]

yeah a cruiser i was going to buy got 16 mpg it was a 72 fj40 and it was rewired , fine tuned, and had a flex fan in it. no joke

 

[IDave]

My 71 gets 17-18 mpg under summer conditions, most of my driving under 55 mph, as stock as I can get it.

 

[honk]

"As a data point, my 82 FJ40, box stock, gave me 17 MPG on the highway,..."

So as not to lead Okie into false hope it should be pointed out that a 1970 has 4.10:1 gearing if stock while a 1982 FJ40 has 3.70:1 final drive gears. All else being equal the '82 would achieve better fuel economy than the '70.

 

[okie]

hey honk, thats one thing i dont get about cruisers is the hole gearing thing. what is up with the numbers and all. How could i make an 70 fj40 get that gearing and get that gas mileage?

 

[poseidon]

If you change the gearing you will most likely get better gas milage on the highway because at the same speed, for axample at 55mph you will be at a lower engine RPMwith 3.70 gears than you would be with 4.11. I have a fj60 and they have the higher 3.70 gears. I am amazed at my milage given that I am SOA with 36s and get 14mpg. If I didn't have a lower first gear tran I don't thing the thing would be drivable though and I want ot get lower gears tat are going to bite into my milage. Here is a chart about gears tires and rpms if that helps:
http://www.intercotire.com/html/table.htm

If you want to spend money to save money on gas do yourself a favor and move closer to work. I live 1.5 blocks from my work and dont start my rigs for days. It takes me under 2 minutes to get to work and I save miles on my rigs and $$ in gas. Joining a carpool or using public transportation is also an great way for cruiser drivers to save money on gas even if it is just one day a week.

E

 

[okie]

thank you alot poseidon, i will check on that website. thanks for the info.

 

[Poser]

get a tdi jetta if you are concerned about mileage...

 

[Jman]

Best way to help your gas mileage is to change your oil regularly, keep up on the drivetrain lubrication, inflate your tires properly, and keep your foot off the gas as much as possible. Hmmm, no new parts - that's no fun!

My fully loaded, freshly tuned 87 FJ60 got 17 mpg on the highway using the above advice.

It's amazing what keeping your tires inflated will do.

 

[PabloCruise]

get a tdi jetta if you are concerned about mileage...

Yeah, just don't ever roll the windows down!!!

 

[okie]

hey thanks guys for the help. I think I can get it up to 16 though easy. They key is just to pretty much keep the engine in tip top shape, cooling and believe it or not the exaust is a big key thing.