Gas Mileage: Who's CS drinks fuel the quickest/slowest?

[gt bandit]

That even included a stint on the freeway with a late model Firebird that thought he had something for me.

Don

way to go Don - My brother is an old firebird man , this will make him cringe !!!

 

[davidathans]

Don`t we all have 16 gallon tanks?

yes

how often do you let your tank run sooo low that your actually filling up with 16 gallons? i ran out of gas one time in the gtcs and it burned up the mechanical fuel pump...so now i never let it run that low before i fill up..so when i fill up its usually 14 gallons-15 gallons...i've never been low enough to put 16 gallons in

 

[68gt390]

If I'm not mistaken, there is a feature built into most tanks that actually allow you to put a little over 16 gallons in. That is to allow for that very thing so you don't run out. This is actually the second time I've run it that low. Usually I'll stop when it's at a 1/4 tank. The needle was right on the "E" for a few miles from the gas station. Fortunately I've never run out in the CS yet. Think I better knock on wood. But, on the other hand that's why I have triple AAA. That way the gas comes to me if I need it. :grin:


Don

 

[p51]

There was an article in one of the MustangsPlus catalogs a couple of years back. They took a '67/'68 mustang coupe and put in:

- Ford crate engine (@300hp+)
- 3.5 backend
- 5-speed transmission
- Fuel injection

Made it into a track car (MustangPlus owner's son evidently takes it on the track and the street)

Then they took the modified stang and a stock (?) V8 automatic on a test drive from Stockton to Utah (?) and back and checked gas mileage. If I recall correctly the stock stang got an average of ~14.5mpg. The modified stang got ~21.

Unfortunately, this article is *not* on their website and is no longer an article that they put in their catalog anymore. I would have scanned/posted the article but unfortunately it looks like I threw out my old catalogs.

If anyone has this article and could scan it I think it would be interesting reading for this thread....

 

[68gt390]

Speaking about the 5 speed, that's the next modification I've thought about for my car. Don't really know with the engine mods I have and a big block if it would really be worth the cost. I'm sure it would save me some. Time will tell.

Don

 

[joedls]

I have a 5-speed in my 65 convertible and an AOD in my GT/CS. I love the overdrive on both cars.

 

[Mosesatm]

Resurrecting an old thread.

My aqua car is FINALLY back on the road after its engine and transmission rebuild. I've taken a couple highway trips so far and I am amazed at the fuel mileage. In fact, I keep double checking it to make sure it's correct.

Here are the general engine and drivetrain specs
Freshly rebuilt 1966 4V 289 bored .060
Engine also had the rods balanced
Melling 24212 cam Lift=288 Duration=298
Stock compression pistons 10:1 roughly
Premium fuel
Holley 570 Double Pumper with .054 primary jets.
Edelbrock RPM Manifold with an added 1" spacer
Stock vacuum advance distributor with single points
Stock coil
Rebuilt C4
3.00 rear gears
Stock exhaust manifolds with 2.5" magnaflow pipes and mufflers
Not sure where the timing is set. It's where the engine builder set it when he dyno'd the engine.

So far I'm averaging 18.5 mpg at a steady 70-75mph, with a few blasts to 100 (just to quickly and safely get around slower cars:wink.

I don't have a tach but 70mph should be right around 2700-2800rpm, and at those rpms the engine dyno'd at 275 torques and 150 horses.

What this says to me is that rebuilding an engine increases fuel mileage so for the good of the planet we should probably all get our engines rebuilt! Let us know if the spouse falls for that one.

 

[JohnnyQuest515]

13 is my average for my 390.

Anyone tried Octane booster or racing fuel to see if it helps in performance and mileage :icon_ecst?

Randy

 

[Mosesatm]

13 is my average for my 390.

Anyone tried Octane booster or racing fuel to see if it helps in performance and mileage :icon_ecst?

Randy

It should help a little in that it will let you advance the timing.

 

[Midnight Special]

...The C-code averages 16-18 mpg (22 on a long trip from LA). J-codes hover around 14 mpg and the S-codes around 9-10 mpg. I can't always say that I drive them in a manner to conserve fuel. I often zip up to cruising speed with the same "bursts" up to 70 or 80 to close whatever gaps on the highway. 'Keeps things clean and lets me constantly evaluate how they're running...

I've used octane booster in the past, but can't say I've noticed much difference in performance.

 

[robert campbell]

Racing fuel could make a huge difference if you tune the car to it, and then use it consistently. Octane booster could have the same effect to a lesser degree.

The key word is consistently. A perfectly tuned to 92 octane 10 to 1 compression motor would ping all over itself on racing fuel. Racing fuel is much more volatile, explodes more quickly, and produces much more “power per given explosion” in the cylinder. You would need to retard your timing, recurve your distributor, and maybe rejet on the carb. Octane booster will allow you more advance, but does little to nothing to convert pump gas to racing fuel. Racing fuel is a totally different blend.

If you did all of the above and then consistently ran the same racing fuel, you would notice a large improvement in performance. The crap they have at the pump today burns very slow and does not ping that bad in a high compression engine from yesterday. Tuning specifications are not all that different from the days of yore, the engines just have less performance. I am running 12.5 to 1 pop ups in my 289. Heads decked to a nominal 13 to 1 compression. Runs just fine with 38 degrees of advance. No pinging.

Now if I consistently used race rule in it all of the above would change. And it could make much more power.

Rob

 

[J.Bart]

Hey all,

I just wanted to thank all of you guys.

Every year, every resident of Alaska gets a dividend check based on the amount of oil we sell you suckers in the the "Lower 48". This year it should be around $1300 each! I have six kids and a wife, so that means my family gets over $10 grand! Woohoo! That should pay for my resto! :icon_lol:

Doug in The Great Land

do you have a guest room??? i'll move in next week lol.!!!!
go alaska!!! atleast one state has their act together

 

[J.Bart]

ok guy's
don't hate me, and i only read the first page or so.
but my 08 550 hp supercharged 5 speed stick, 331 rear end
18.5 mpg cold weather to 23 mpg warm weather at 75 to 80 mph

before the sc i had the cold air ford racing power pack i was getting
25 to 29 mpg at 75 to 80 mph and at 55 to 60 mph i was getting 35 to 39 mpg

 

[hookedtrout]

ok guy's
don't hate me, and i only read the first page or so.
but my 08 550 hp supercharged 5 speed stick, 331 rear end
18.5 mpg cold weather to 23 mpg warm weather at 75 to 80 mph

before the sc i had the cold air ford racing power pack i was getting
25 to 29 mpg at 75 to 80 mph and at 55 to 60 mph i was getting 35 to 39 mpg

Seriously, wow that is amazing, I should be able to upgrade from my Festiva based entirely on gas mileage to a new CS. So how much of an investment beyond the car in the cold air power pack did you have to get the 30+ gas mileage?

Still amazed. Cory

 

[davidathans]

Racing fuel could make a huge difference if you tune the car to it, and then use it consistently. Octane booster could have the same effect to a lesser degree.

The key word is consistently. A perfectly tuned to 92 octane 10 to 1 compression motor would ping all over itself on racing fuel. Racing fuel is much more volatile, explodes more quickly, and produces much more “power per given explosion” in the cylinder. You would need to retard your timing, recurve your distributor, and maybe rejet on the carb.
Rob

I dont know if you consider 100 octane VP gasoline as "racing fuel." I know i do, but i never have had a problem pinging with the 100 octane VP fuel with my car dyno tuned to CA 91 octane from the pump. I always race with the 100 octane VP fuel at the track, especially now for the Nitrous. I can't even run the nitrous on the 91 from the pump is what im told. I would tune the car to the 100 octane gas for the track, but then once i'm done racing, i have to put 91 in it to make it home because i dont trailer the car yet and then it would ping on me. So, i get the car tuned for 91 and then put 100 octane in it to be safe at the track, to make a little more power, and so i can safely run my Nitrous. Even though the car isnt tuned for 100, it feels stronger with the 100 on a CA 91 tune, but im sure i don't reap all the benefits as if i had it tuned on the 100, but i've never experienced pinging with a higher octane fuel than what the car is tuned for.

 

[JohnnyQuest515]

I saw several have 5 speeds and a couple AOD, curious who did the AOD conversion from a c6 and how much did it cost?

I want to put in a 3.50 traction lok rear end and the overdrive would make it a nice street cruiser.

Thanks, Randy

 

[J.Bart]

Seriously, wow that is amazing, I should be able to upgrade from my Festiva based entirely on gas mileage to a new CS. So how much of an investment beyond the car in the cold air power pack did you have to get the 30+ gas mileage?

Still amazed. Cory

my price sheet is a year old, but it shows under $1000.00

 

[hookedtrout]

my price sheet is a year old, but it shows under $1000.00

Now I just need to convince the wife that we will live long enough to see the pay back on the great fuel economy. ;-)

 

[J.Bart]

Now I just need to convince the wife that we will live long enough to see the pay back on the great fuel economy. ;-)

tell her it pays back quicker if you drive more...lol..

 

[GT/CS S Code]

Gas mileage?

Gas mileage? I've never bothered to take the time to work it out yet. When we take the car out for a Sunday drive, or take it to a "show and shine" event, we stop off on the way back home and I top off the tank and then go home and "put it to bed" in the garage. This car is just WAY too much fun to drive to be worrying about something as trivial as gas mileage!
On a related note, here in Canada right now our fuel is running about $1.01 Canadian per litre for regular gas. For 94 octane Super Premium (which is what I run in our 390 4V car) the cost is running about $1.22 Canadian per litre. There are approximately 4 litres to a US gallon, so we are paying about $5.00 Canadian for a US gallon. That equates to about $4.35 US per US gallon. I don't feel too bad though, as Laurie and I just got back from our European anniversary cruise trip, and in most of the European countries we visited they are paying about $1.40 Euros per litre, which is about $2.31 Canadian per litre. That converts to about $8.00 US per US sized gallon ...
There sure were a lot of tiny scooters, small "cc" motorcycles, and lots of Mercedes "Smart Cars" over there. Didn't see a single US mfg V8 car the entire trip. No surprises there! There are a few typical car, truck, and bike pictures from our trip posted below.