In building a MPG champ, what engine/body combo is recommended?
6/22/06, 06:45 PM
#1
Guest
Posts: n/a
In building a MPG champ, what engine/body combo is recommended?
I'm driving over 30K miles a year, mostly highway, want to build a Mustang
mileage champ, any V8 will have enough power, would a 4.6 DOHC, SOHC or
5.0 OHV get the best mileage?
I'm thinking a 1983-1993 Fox notchback would be the best since they are the
lightest vehicles but I'd like to hear others opinions.
Thank you in advance for the advice.
mileage champ, any V8 will have enough power, would a 4.6 DOHC, SOHC or
5.0 OHV get the best mileage?
I'm thinking a 1983-1993 Fox notchback would be the best since they are the
lightest vehicles but I'd like to hear others opinions.
Thank you in advance for the advice.
6/24/06, 11:01 AM
#2
Member
Join Date: February 6, 2006
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
I am no pro when it comes to these things, but I would go with a newer car. When driving distances like that you have to acount for more than the motor and gas milage; there is all the wear and tear on the running gear as well. I have a 89 fox and I would not choose it as the car to do what you intend to do. Unless you were going to replace and upgrade every single component before you start driving it those distances, I would go for a modern car - I think with a fox you will find your repaire bill climbing fast.
6/24/06, 11:08 AM
#3
Mach 1 Member
Join Date: November 20, 2004
Posts: 613
Likes: 0
Received 0 Likes
on
0 Posts
I wouldn't call a fox body unreliable, but the motor design was already decades old by the the time they put the fuelie version in the '86. Whereas the 4.6 SOHC has more of that technology stuff in it and is the new 3-valve mod motors even have varible cam timing. I would say your best bet is a 4.6.
6/25/06, 10:56 PM
#4
Legacy TMS Member
Hmmmmmmm.......mileage???????????
Weight is a critcal factor with fuel mileage - the best for that would be a nice light coupe with a 5.0 motor. Follow that up with a nice efficent motor that pretty much idles at freeway speed and you could get some good mileage. A high perf engine and a high mpg engine aren't mutually exclusive. The only real difference is operating range.
Weight is a critcal factor with fuel mileage - the best for that would be a nice light coupe with a 5.0 motor. Follow that up with a nice efficent motor that pretty much idles at freeway speed and you could get some good mileage. A high perf engine and a high mpg engine aren't mutually exclusive. The only real difference is operating range.
6/25/06, 11:09 PM
#5
Dethroned Nascar Guru
I would say go with a 96-98 4.6 SOHC with 2.87 rear end. It's more aerodynamic than the fox body and probably the 99-07s too. Before I added the supercharger I would get 19-20 city and 26-28 highway and I had the 3.27 gears, so a 2.87 should do better.
6/26/06, 09:05 AM
#6
Depending on your budget, consider building a car with an SVO/Turbo Coupe driveline. A hair dryer will provide enough excitement, and with 4 cylinders cruising mileage is great
6/26/06, 09:20 AM
#7
Guest
Posts: n/a
I appreciate all the advice. Definitely I need it.
Just personal preferences...
Because I'll depreciate the daylights out of anything I drive, I was going to
rebuild a Fox notch in a stealth style. I know I want to hear 4 cams whirring
around instead of a nice stereo, and I like the quad headlights for some
reason (probably 'cuz the first two Mustangs I ever owned had 'em),
but I'd like to put that style clip on the newest 4 cyl. notch (92-93) I can
find to help reliability.
I also want a 5 or 6 speed manual.
I know swapping a 32v in will require a lot of new
parts anyways, but at least I'll know I've got a reliable foundation.
As you all know, quite of few people have now done this swap
so I can avoid (most of I hope -
their trial and errors. I should end up
with a nice classic Stang that will save me $2000 yearly in fuel costs and I
shouldn't have a problem selling someday if I wanted to.
Or, drop the driveline into an even older classic rod!
That's the plan at least-
Just personal preferences...
Because I'll depreciate the daylights out of anything I drive, I was going to
rebuild a Fox notch in a stealth style. I know I want to hear 4 cams whirring
around instead of a nice stereo, and I like the quad headlights for some
reason (probably 'cuz the first two Mustangs I ever owned had 'em),
but I'd like to put that style clip on the newest 4 cyl. notch (92-93) I can
find to help reliability.
I also want a 5 or 6 speed manual.
I know swapping a 32v in will require a lot of new
parts anyways, but at least I'll know I've got a reliable foundation.
As you all know, quite of few people have now done this swap
so I can avoid (most of I hope -
their trial and errors. I should end upwith a nice classic Stang that will save me $2000 yearly in fuel costs and I
shouldn't have a problem selling someday if I wanted to.
Or, drop the driveline into an even older classic rod!
That's the plan at least-
7/5/06, 01:33 PM
#8
V6 Member
Join Date: April 11, 2006
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
In the money it would take to compromise performance to aid fuel economy, you could buy yourself a decent 4 banger beater car, and have the best in both worlds.
The late model engine/tranny/eec in the lightest body possible, for starters. Late model EEC has better potential fuel economy. However, the tradeoff is the increased weight of the 4.6 over a 5.0.
I suggest a 5.0, built for TORQUE. Small, good flowing heads (AFR 165's or similar), a custom cam for DAILY DRIVING duties. A 5 speed manual, possibly a T5Z with the .63 overdrive would be nice.
Coupe body would be ideal. Rear seat delete, manual windows, locks, etc. Lose as many of the creature comforts you feel comfortable without.
The biggest factor - how you drive it. Get a vacuum gauge hooked up, and drive it by that gauge. In other words, the more vacuum you are making, the better mpg you will get.
That's a log of mileage in a year, and you'll wear your toy out pretty quick at that rate. I still vote a 4 banger of some type...
The late model engine/tranny/eec in the lightest body possible, for starters. Late model EEC has better potential fuel economy. However, the tradeoff is the increased weight of the 4.6 over a 5.0.
I suggest a 5.0, built for TORQUE. Small, good flowing heads (AFR 165's or similar), a custom cam for DAILY DRIVING duties. A 5 speed manual, possibly a T5Z with the .63 overdrive would be nice.
Coupe body would be ideal. Rear seat delete, manual windows, locks, etc. Lose as many of the creature comforts you feel comfortable without.
The biggest factor - how you drive it. Get a vacuum gauge hooked up, and drive it by that gauge. In other words, the more vacuum you are making, the better mpg you will get.
That's a log of mileage in a year, and you'll wear your toy out pretty quick at that rate. I still vote a 4 banger of some type...
7/6/06, 12:02 AM
#9
Legacy TMS Member
Originally Posted by 93Cobra#2771
The biggest factor - how you drive it. Get a vacuum gauge hooked up, and drive it by that gauge. In other words, the more vacuum you are making, the better mpg you will get.
All the same, if you can reduce engine speed, not only do you reduce frictional losses, but at part throttle, light load, high vaccum operation. The pumping losses will also be reduced.
If you were gonna go the 5.0 route I'd build the engine like this;
- Efficient small port heads with a closed chamber design (or rather one that features a large quench area) - high velocity with an active chamber for good combustion.
- Big Bore x Short Stroke and long connecting rods - reduced operating friction.
- Flat top pistons with a high ring package and little to no dish (or a reverse dome if dish is needed) in the piston. Rings should be of the low drag variety - better chamber activity with reduced friction and reduced crevice volume.
- Run the absolute minimum head to piston clearence - increased quench area for more active combustion chamber with reduced area for unburnt fuel to hide.
- Consider thermal barrier, friction reducing, and oil shedding engine coatings - increased efficency with reduced friction.
- Use a roller valvetrain with the lightest springs which produce adequate valve control (think beehive springs, titanium retainers, hollow valvestems and nice stiff pushrods) - reduced friction while allowing for more precise and aggressive cam action.
- Free flowing intake and exhaust tracts (but not overly large so that velocity is compromised) - reduced pumping losses
- Limit engine operating range to the lower end (say idle to 5500 rpm) - reduced friction and wear.
- Underdrive pullies - reduced parasitic losses from the accessort drives.
7/6/06, 07:06 AM
#10
V6 Member
Join Date: April 11, 2006
Posts: 76
Likes: 0
Received 0 Likes
on
0 Posts
And, the lightest weight/road safe wheel and tire combo you can find. Think Bogarts or something like that. Big and littles would help even more. Add to that aluminum suspension components, such as lower control arms. Alum. Driveshaft couldn't hurt either. Avoid an overly wide rear tire/rim, and keep them inflated to the max pressure.
A flee flowing exhaust system, preferably ceramic coated would certainly be a plus as well.
To your point about vacuum - for whatever the reason, best fuel mileage happens at highest vacuum. Whether fuel injected or carbed...
A flee flowing exhaust system, preferably ceramic coated would certainly be a plus as well.
To your point about vacuum - for whatever the reason, best fuel mileage happens at highest vacuum. Whether fuel injected or carbed...
7/6/06, 06:55 PM
#11
Cobra Member
Join Date: August 20, 2005
Location: BC
Posts: 1,108
Likes: 0
Received 0 Likes
on
0 Posts
With my old engine (basically the same as the one in my sig, minus the cam) i would get 21mpg in the city and i think about 30 highway, and that was not taking it easy. Driving for fuel economy i think it should go up about 2mpg. Thats with a 5sp, and a 2.73 rear end. You really dont need to do much to a fox to get good mileage, just get the right tranny/rear end combo.
Thread
Thread Starter
Forum
Replies
Last Post