Looking to build a 28/29 full-fendered Model A roadster for a daily-driver. Been kicking around late-model EFI 4-banger (Ecotec or Quadfour maybe) but was wondering if the tried and true small-block Chevy would be the better bet. Something around 250 horsepower with an auto overdrive. I've been told the late 4-banger might return 30-plus mpg but I like the simplicity of the Chevy but want better than high-teen mpg. What are some of the similiar powered Model As out here getting on average? Around town and stop and go freeway.
This is no help-but I got 54.7mpg from my Prius on a trip from central PA to Plymouth,M*** and back-so I don't really care what my 350/350 '31 A is getting. Probably mid-teens to low 20's though.
My dad's '32 highboy roadster has a mild 350/350 with a 3.90 rear. A few years ago we ran to B'Ville and back in it, 1100 miles round trip. Averaged about 22 mpg with that short rear end, running about 70-75 most of the time! Motor was tach'ed around 3800-4000 most of the time... we were just keeping up with the other rods who were with us. Came back and put a 200R in the TH350's place. Although the engine RPM is GREATLY reduced, I was surprised that the mileage didn't change! The motor, as built, seems to have a real sweet spot right around 4000 rpm. I guess that's where it was built to run most efficiently. Don't know if that helps much, but just food for thought.
I'm going to throw something in on how big trucks accomplish fuel mileage better than several years back. Somewhat on topic. The truck engineers figured out that an engine runs more efficiently within a desired peak torque range/rpm range. Drop the engine rpms at the most used road speed or working rpms, more efficient. Clutch dampening technology has changed from that, beats per minute. It's like the old farm truck, don't shift the old stick down because the 235 can pull out of this noise after it comes back to rpm. Take a quick change and reverse the gears for about a 1.80 ratio for a long winded trip. No transmission overdrive or quick launches. A customer got a Pete C. thumbs up for some old Arkansas tin for his effort. Better than 25 mpg with a thumpin' SBC on carbs.
My sedan weighs 2440 lbs. with me and 11 gallons of fuel. I have a 12.3:1 sbc and a turbo 350 ****** with a 3:50 rear gear and 27.5" tall tires and a Holley 500cfm 2bbl. I usually get about 14-15 mpg on the highway. I think what's killing me is the 3300 rpm or so stall convertor. The engine/****** was built to move a 3400 lb. stock car, not a 2400 lb. hot rod. Not great, but slightly better than my Ford F150. Plus the race fuel that I run in the hot rod is $6.29 per gallon, ouch!
9.75-1 mid cam 350 with a pair of 600s tied together, th350 and 4.11 gears with a 28.75 tall tire all that in an 2000 lb package at 3000 rpm = 15-17 mpg
R&C Lee, I have a Ford Zetec in my lakes style roadster, probably only weights 1500 #, I have a BW 5 speed ****** and an early Hildabrand quickie, I run 5.20 gears (4.11 R&P with a 5A gear set) it runs around 2600 at 65 mph. I am slowly getting the mileage up last trip to Pleasanton I got around 25 mph, I think it should be over 30 but still need to lean on it a bit plus I am going to something around 4.80 for the rear end. I have attached a pic from Pleasanton. Rex
Rex, I saw your modified at a few shows this summer and it's killer. I definitely think you can have too much overdrive and hurt mileage. I'm hoping to get some clues to help find that sweet spot of power weight rpms.
On my 1660 mile roundtrip to England an back in August this year, my 34 Plymouth with 327 / Th350 got me 14,5 liters/ 100km that´s about 17 miles per gallon. Aslong as 1 US Gal are 3,8 liters that is... anyway, I always cruised @ 3500 to 4000rpm on 3.36 gears and L78-15 Cokers. That means we were cruising at 100mph most of the time, never less than 90mph. Best fuel economy is around 3200 rpm, but know you, we wanted to arrive Chris
I needed a daily driver and picked up a '91 T-Bird 3.8 V-AOD trans it is getting 27-28 Highway,I have seen some T-Bird Super Coupe 3.8 Blower motors and AOD'd pop up on craigslist in the $500 area with the computer and wiring have something unique and all FORD and get mileage,HP and light weight.??
If mileage were no object, what would you rather drive? The tried and true SBC, or the "different" Ecotec? Me, I'd vote ecotec
A touch OT on engine choice, but the lump-port-head, 600CFM 4-bbl 292 Chevy 6 in my Biscayne returned 20 MPG with "4/70 air conditioning", 4 adults, 2 kids and a whack of "miscellaneous child activity device" in the trunk; she turns about 2600 at 60MPH. I'd think a smaller carb and a taller gear might eek another 2MPG out of it.
Real world, Lee.....I drove my old 55 Olds all over the country back in the 80's-early 90's. Pretty much stock driveline, 324, hydro, stock rear (highway gearing, but unknown ratio) and got a solid 20-22 MPG. That's mostly highway speeds, usually a bit over the speed limits. My pal Manny drove his 56 Merc with me a bunch of times, and also got over 20 MPG. His was rolling on a Grand Prix frame, with a 455 Olds engine!!!! Proves you can get decent mileage, with a cool engine!
Ford V6 3 litre with EFI hooked up to 5 speed manual box, gets around 30 mpg if driven 'sensibly'. It can still pick it's feet up and run if needed, clearly not as fast as some but it's different. What do you want to be ??
I am convinced that "Bonneville gearing" is NOT the way to get the maximum economy all alone, but I have proven that efficient fuel injection, a decent overdrive that hits the correct torque peak at road speed. My heavy-***ed all steel 1935 sedan gets a consistant 25-26 mpg on the highway. I ruined it last year by taking my 3.70 ge****t out and using 3.25 gears.....the thing was awful, lost 3-4 mpg and the drivability was ****.....I had to change back to the 3.70s to make it right with the world again. My next project will be a roadster with one of these high-tech four bangers......even if not HAMB friendly under the hood it will still be a cool roadster built for DRIVING and having fun. I probably will run a full hood just to avoid the wagging fingers of the true "traditionalists". I plan to get close to 40 mpg in a fun, open roadster. See ya on the road!!!!
The roadsters running at B'ville don't have windshields....they do have tonneaus....I wonder how that relates to trying to get good highway mileage? also rearend gearing/overdrive has to work with the engine's torque curve. Late model larger GMs that get good mileage have gobs of off idle torque.
I think that Retrorod and squirrel hit the nail on the head, you need to get the engine sweet spot and the gearing right to make the best mileage and also performance. I have been ****ing around with the stack length on my injection, went from 6 inch stacks to 12 inch, big difference in the mid range pull and running. Still revs to 7K but the mid range has really picked up. Next is smaller ID stacks and a little shorter, should have the same affect without sticking my air cleaner out so far. Rex
I agree with the previous posts, having the engine built to work with an overdrive is key, I had a 200r4 behind a 350 that had a high rpm cam in it and it was a mess, always had to hit the throttle to get it to p*** on the highway, killed my mileage.
Thanks guys. It'll have a hood so I'm not worried about being trad nor am I wanting something that'll smoke the tires through 3rd gear. It'll be built to be reliable and get out of it's own way when needed and hopefully be easy enough to drive that the wife can take it for a spin if she'd like.
I drive the hell out of my 50 merc and consistently get 18 mpg. It does have the overdrive, but if you ran a S-10 ****** you might get even better mileage. Let alone in and A that is much lighter.
I'm averaging 24mpg. The HEMI shuts down 4-cylinders when not under load, so on the highway I'm driving a 4-cylinder!
Tough patooties. One,it's the most avdanced car out there. Two,it's fun to drive. Three, I was driving a 92 with 250000 miles. I drive 40 miles a day on really hazardous highways and I need the P's advanced safety features. Four, it's 55 PMG!! Five,it's 55 MPG! Six,-you get the picture. And, there's still the hot rod Model A
I've got a stock 350 with two fours (600cfm each) running progressive linkage, mated to a '87 T5 linked to a Ford 8" with a 2.79 ring/pinion. 2200# with me in it an a full tank. I went from Dayton, OH to Columbus, OH and back and averaged 18 mpg, almost all highway miles. Prolly would have been better, but damn if I can't stay out of that second carb. I also drove it from Dayton, OH to Louisville. The first tank of fuel lasted from home to the second day. read this as 165 miles on the highway and a LOT of too much horsing around in Louisville. That tank yielded 14 mpg. The second tank was the opposite; driving around in Louisville on the second half of day two and the trip home late on day three. Got 12 mpg there. So, I figure when I travel, the second carb will be disabled until I reach my destiation at which point I reconnect #2 and have some regulated fun. All this and my daily gets a solid 14mpg, seemingly no matter what. I'm convinced it's all about the gearing, both trans and ring/pinion. That and staying out of that damned second carb
Just as an exercise if one wanted to build, say, a carbureted 350 SBC that was exclusively dedicated to getting the best possible mileage how would'ja go about it? Virtually every aftermarket part is aimed at increasing power so just what parts, and what configuration would you guys go for? The gearheads natural tendency is always to try to squeeze as much power out as possible for any given budget. Thinking in completely opposite terms is tricky. What's gonna increase mileage and not power? They aren't completely at odds, efficiency is frequently power friendly, but channelling that mindset in the exact opposite direction doesn't come easy. I"ve got my own ideas but what say the HAMB?
I would use a 283 with a Performer 500 cfm on a Performer manifold, a mild cam that works with 9.5/1 compression at 1000-4000 rpm. 200r4 trans and a 3.55 gear would give decent/fun power and economy near 20. Can't say precisely 'cause my '31 Tudor went down the road b-4 I could really check.
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