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Are any of you considering building an "efficent" hot-rod?

Discussion in 'The Hokey Ass Message Board' started by decker, May 9, 2008.

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  1. Rudebaker
    Joined: Sep 14, 2007
    Posts: 1,598

    Rudebaker
    Member
    from Illinois

    Well, since mine is a '55 it doesn't qualify as a "hot rod" but I am reassessing my plans for it because of gas prices and fuel quality. This isn't going to set well with some of you but I have dusted off plans I had for a 355 SBC awhile back. It is basically a homegrown version of the 350 Ramjet crate motor but with a Q-Jet carb. It will run on 87 Octane, and a nearly identical engine got 25 MPG in a full size pickup with a 700R4 and 2.73's cruising 70 MPH on the interstate and dynoed 256 RWHP. My Stude will weigh in about 3100 with a SBC and 200-4R and is a whole lot more aerodynamic than that Chevy PU. With 3.73 gears and 28" rear tires I can cruise about 1900 RPM at 60 MPH, that's with tire diameter corrected to about 26.3" to compensate for weight. With that kind of RWHP it should run easy high 13's and with some strip oriented tuning low to mid 13's and I think I can still equal the MPG's of that PU. If I wanted to give up some ET bragging rights I could switch to 3.42's or 3.08's and drop my cruise RPM a little more.

    I don't see prices coming down, I think they'll just keep climbing and I believe the day is not far off where 87 Octane is the "good" stuff...........:( I intend to drive this car a LOT so I'm willing to give up being "different" for some fuel friendly performance. Yeah I could probably get the same mileage out of the Stude 289 and on 87 Octane but 256 RWHP too and on my budget? Not even close.
     
  2. Elfizzo
    Joined: Nov 12, 2007
    Posts: 12

    Elfizzo
    Member
    from Minnesota

    Talkin to one of my hot rod/fabricator friends yesterday and decided when it hits $5 we're buildin a still, already projects in progress are E-85 committed and we can convert our Harleys with higher compression pistons and a s&s super D alcohol carb. Several of us own some acreage and you can buy old farm equipment cheap, we'll do a coop kind of thing. This is what ol Henry Ford envisioned in the beginning. I know that there is prolly laws against this, but the southern boys did it, the government did this too us, and you can still buy ammo.
     
  3. denis4x4
    Joined: Apr 23, 2005
    Posts: 3,911

    denis4x4
    ALLIANCE MEMBER
    from Colorado

    Go dig out your back issues of HRM, R&C, PHR and CC from 1973 and 1974. There are plenty of tech features on building a SBC for power AND economy. Crower did cams for San Diego Gas & Electric Crown Vics that were running on propane. Offy did some special Dodge manifolds for the CHP that were designed to get better mileage.

    I find it very interesting that a lot HAMB'ers are caught in a time warp duplicating an era that they never experienced first hand. To those of us who were there, change was something we strived for all the time. Don't forget, we were paying nineteen to twenty nine cents a gallon for fuel and the minimum wage was eighty five cents an hour. I double damn guaranty you, if gas was $2.00 a gallon in 1955, we would have been massaging bangers, 850cc Austin engines and Willy's F-head motors.
     
  4. tjm73
    Joined: Feb 17, 2006
    Posts: 3,413

    tjm73
    Member

    I read this entire thread. I don't have much to add expect a little personal experience and thought.

    My non-HAMB 1990 Mustang GT convertible with a 5.0, T5, 3.73 gears and a B303 (224/224 duration @ .050" on 110 centerline) cam returned just over 23 mpg's over a 260 mile trip that was about 75-80% highway with the A/C on the entire time at 75-ish mph (~2400 rpm). The car is heavy. 3600lbs heavy. It also regularly went 13.78-13.85 in the 1/4. Not killer, but pretty good since it never 60' better than 1.99.

    I 100% believe a stripped 302 turning only an alternator with a 600-650 carb, a B303 cam and everything else stock, in a ligthweight car, will return upper 20's with a 5 speed all day long. And in a light weight car it'd go like mad.

    Car Craft cheap garage rebuilt a 100K '90-91 Mustang 302 with nothing more than a weiand Stealth intake and 650 carb they got ~275 hp/315ft-lbs with the factory roller cam. Later they added aluminum heads and made 405hp/380ft-lbs at the crank. STILL with the OE cam, compression, etc.... and i bet it'd still give at least mid 20's fuel milage with plain ol' 87 octane.

    http://www.carcraft.com/techarticles/116_0307_ford_302_v8_engine_buildup/index.html

    To me that is efficent. And as a nice bonus it still sounds and goes like a hot rod.
     
  5. theflame
    Joined: Jan 24, 2008
    Posts: 169

    theflame
    Member

    I've been thinking about this a lot lately. With gas prices here in the UK and the amount of cash I earn I'd HAVE to use whatever I put together as a daily driver. No way can I run two cars, so the one I do run has gotta be, if not as economical as my little eurobox, then sensible at least.

    Plenty of 2 litre Ford engines already set up for RWD available from scrap yards / classified ads, and if its a choice between compromise and have a rod or not and drive a Toyota forever, then yeah, I'll pop a little 4 banger in my car for now...
     
  6. Zerk
    Joined: May 26, 2005
    Posts: 1,418

    Zerk
    Member


    Right! We'd be creating better drivers. Also we'd be giving back something folks have lost, namely the ability to manage their time. The pace of a '30s-'40s car is a human pace, an invitation to sit back and enjoy the drive. You leave a bit earlier, drive a bit saner, get where you're going without putting your elbow in anybody's face along the way. How bad can that be for average people?:confused:
     
  7. Rudebaker
    Joined: Sep 14, 2007
    Posts: 1,598

    Rudebaker
    Member
    from Illinois

    Can't argue with logic like that.....:cool:
     
  8. Darwin
    Joined: Oct 14, 2002
    Posts: 505

    Darwin
    Member

    1975 VW Scirocco. 70HP. 32mpg. 100mph top speed. 1900lb. weight. No AC, PS, PB, MP3, ad nauseum. Vast wads of fun to drive. Current equivalent---nothing. Chances of anything similar appearing again---zero.

    Anyone given any thought to the fact that although modern 4cyl powerplants in small light rods will have excellent power to weight ratios they also might not get any better highway mileage, or even worse, than the aerodynamic vehicles from which they came? Virtually any early rod out there is an aero brick compared to any vehicle of recent vintage.
     
  9. krooser
    Joined: Jul 25, 2004
    Posts: 4,584

    krooser
    Member

    Take all of the crap outta the new cars and you'd get another 10 mpg. I read tha a new Porsche SUV weighs over 5,000 lbs. HUH?
     
  10. theflame
    Joined: Jan 24, 2008
    Posts: 169

    theflame
    Member

    Yeah, true enough, but I reckon the weight difference would be significant enough to work in your favour. Maybe?
     
  11. Darwin
    Joined: Oct 14, 2002
    Posts: 505

    Darwin
    Member


    Interesting idea except for the hideous cost involved. A Tesla is a $90,000 car with a $60,000 dollar drivetrain. The only really advanced thing about the Tesla, aside from the marketing, is the use of a very high energy density lithium polymer battery which is responsible for its range and acceleration capabilities at relatively light weight. Going to be a good long while before that battery tech is reasonably priced. It's true that electric motors develop maximum torque at zero rpms but that doesn't mean that they can't benefit from torque multiplication (gearing) or that they don't like to run efficiently at certain rpm ranges just as IC engines do. A solution to this is fairly close at hand---the wheel motor. Sometimes called in-wheel motors these devices can use the outer rim of the wheel itself as the electric rotor. This large diameter rotor means that the motor has a much greater inherent mechanical advantage therefore gearing is not needed and the motor will operate efficiently at revs that the wheel sees on the road. Very slick but naturally there are still bugs to work out especially in terms of brakes. What these devices will do is eliminate several hundred pounds of mechanical parts in the drivetrain which can be devoted to battery weight resulting in ranges that, well, dont' suck. And power from these devices is not a limitation especially considering they can be used at all four corners of the vehicle. An English outfit has built a technology demonstrator using a Mini-Cooper and it has an effective 600 plus horsepower with its four wheel motors. None of this tech is likely to find its way into a rod but stranger things have happened I guess.

    Anyone on this board who gives a teeny rat's ass about this tech as it applies to Hybrids can read a bit more about it in this post at my blog: http://oiukm32.blogspot.com/2008/03/hybrid-strain.html
     
  12. Darwin
    Joined: Oct 14, 2002
    Posts: 505

    Darwin
    Member

    Yeah the weight difference will likely be big factor in around town mileage but on the highway maybe not so much. Something like a really slippery track T or lakes car will do the best of course with something that looks like a Fab T with the aero efficiency of a garbage truck being a worst case example. An Ecotec in a 1500lb. track T will be a barrel of fun to drive pretty much everywhere and be damned efficient but most here would hardly consider that a trad setup--to say the least.
     
  13. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    Yeah, but when you talk efficient in terms of gas mileage, the rotary doesn't win. Still a neat & different engine that when worked on sounds like an angry chainsaw (I actually like it).

    Europe & UK in particular are really into putting these big street bike engines into kit cars and even retrofitting small cars - like older minis - check out zcars.com

    Honda VTEC is a popular swap into some of the kit cars - pretty good power & mileage combined - in something lightweight like an A, should do reasonably well.

    A perfect home for a 4-cyl. Anglias are small & lightweight, so can realize some of the mileage benefits w/o sacrificing too much performance when using them w/a 4-cyl.

    I think the 215 Buick/Rover is an overlooked engine. They're lightweight, compact, and plenty of parts available to tune them to any state of performance - in a light rod w/OD trans, they should return respectable mileage.

    Weight & engine size. Most mileage-master type cars are small to tiny engines in small, lightweight cars.

    There isn't any black magic here. Modern cars are weighed down with safety equipment, creature comforts, insulation, etc. Building something 500-1000lbs lighter than even the smaller cars should net a good 5-7mpg - maybe even more. EFI will help a lot by optimizing timing and fuel delivery over standard carb/distributor, but you can get pretty good mileage out of a carbed engine if you keep the formula right - small, lightweight, & overdrive.
     
  14. theflame
    Joined: Jan 24, 2008
    Posts: 169

    theflame
    Member

    Yeah, true enough.

    I got my eye on a 4 cylinder 60s Ford drivetrain of some sort I think - parts are easy to source, they're the right era for what I'm going for (even if it might not have been something that'd HAPPEN in that era...) and I've at least got a hope of being able to maintain it myself with out going on some kinda course. Pretty sure any kind of modern engine management set up would have me head-scratching quite a bit...
     
  15. Rudebaker
    Joined: Sep 14, 2007
    Posts: 1,598

    Rudebaker
    Member
    from Illinois

    Very good point although from my recollections of the 70's, and I'll be the first to admit there are some gaps "here and there" :eek:, the '75 Scirroco was no "bullet" in the wind tunnel. I know the "aero brick" thing was a general statement and while the Stude C/K Coupes don't technically qualify as rods they slice through the air pretty good for a 55 year old design so I'll let that one pass. ;)

    All funnin' aside, aerodynamics and weight have a large affect on fuel economy. It's a real balancing act to hit the right combination, even dropping cruise RPM too low can kill mileage. Just because X engine and trans got 30 MPG in vehicle A doesn't mean it can do that well in vehicle B. A heavy brick needs a little more power and more gear to overcome wind resistance and gravity. Some of the big GM cars of the 60's could easily pull 18-22 MPG with 400 to 455 cubes. Drop a smaller engine in them with the same trans and rear ends and the mileage would plummet. Smaller isn't always better................

    Take two identical '92 LWB S-10 2WD "bricks" with 4.3 TBI and 700R4's. One with 3.08 gears and the other 2.56 gears. The truck with 3.08's would run circles around the one with 2.56's as far as straight line acceleration but the 2.56 gears got better MPG's right? Nope, both trucks got the same identical mileage, 25-26 average. The 3.08 truck was mine and the other belonged to a co-worker. We drove the same distance to work over nearly identical roads with almost mile for mile the same type of traffic, he drove like his was made of glass and I beat mine like I stole it yet we got the same mileage. My theory is that mine turned more RPM at cruise speeds but at slightly less throttle opening because of the mechanical advantage of the slightly lower (higher numerically) gears in overcoming wind resistance.

    My old '94 LeSabre got 26-27 HWY cruising at 60 MPH, bump that up to 70 MPH on the interstate and mileage went to 29. Only explanation I can come up with is that even though the engine was turning higher RPM it was finally getting into it's torque curve and it wasn't working as hard so required less throttle opening. Maybe I'm all wet but I have seen it time after time with other vehicles. You just have to hit that magic combination and man is it hard to find!!!!
     
  16. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    There's something to this. Look at the '80s Ford trucks - most offered with either 302 or 351. Mileage in town favored the 351 (by 1mpg), but on the road, it favored the 302 (by 2mpg). More torque from the 351 required less throttle to move the heavy monster around town & get it going. But on the road, where you don't need that torque, just steady-state HP - with both turning same RPM for a given speed, smaller engine wins every time.
     
  17. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    I'm usually conscious of fuel mileage with any build or project, and tend to lean more towards that than towards all-out performance, although the two don't have to be mutually exclusive! An efficient engine delivers good preformance while saving fuel...and any mod that ups the efficiency a notch or two aids BOTH goals.

    That said, I've always wanted to build a lightweight car with a small motor to see what exactly IS possible in the realm of "fuel efficient hot rodding"! Given the funds and means to do so, I'd put together a small 'modifed' roadster powered by an old 1970s Datsun B210 engine and a five speed manual transmission. My dad's old 77 B210 got about 41mpg on the highway and it was kinda fun to drive, too! I just can't help but to wonder what the same drivetrain in a flyweight roadster project would be like?! The idea of a fun little hot rod runabout that could deliver in the neighborhood of 50mpg sounds very cool to me!

    Ha Ha...in the meantime, however, I'm applying my sinister "Econo-Rodding" techniques to a VW Bug! It's got the 1600cc Dual Port engine, but I got it with a carb that was FUCKED hard-core, so I started shopping for a replacement. My motor originally used a Solex 34mm carb with an air-valve abortion thingy, but I ordered an older style 30mm carb with no emissions provisions and a manual choke...smaller and simpler! (It requires the use of a carb adapter, also available mail order). The motor will still have a header, and an upgraded ignition system...giving it the classic "hot rod treatment"...but at the same time, I'm also cutting all the weight from the car that I can in an effort to make it as light as possible!

    So far, the stock fenders have been replaced with fiberglass ones, the stock hood was replaced with a 'glass one, the rear sheetmetal has been cut away (it's a Baja Bug!), the bumpers and brackets are long gone, the stock gas tank has been axed, the spare tire went away, the rear seat got tossed, and soon enought the front seats will go in favor of a single lightweight racing seat! Anything that doesn't serve a vital purpose is being removed (the car is sitting up high with all that weight gone already!) and vital components are being lightened up or replaced with lighter parts where possible!

    From past experience, I know that Vee-Dub boxer fours are far from fuel efficiency superstars, but they do halfway decent in stock form. I'm kinda eager to see how this one does with the header, hotter spark, smaller carb and a lot less weight to move around! I'd be stoked to pull 30mpg (or more?!) out of it!!

    (Problem being, it IS a VW...and thus, it is cursed with being flawed from birth by horribly ignorant unreliable design ideas...something I'm fighting to correct on a daily basis!!)

    Econo-Rodding is the future (I've said it before, but I think with regular unleaded up to $3.89 per gallon, it's gonna carry a bit more weight these days!!)

    :D:cool:
     
  18. Gemini EFI
    Joined: Jan 5, 2006
    Posts: 231

    Gemini EFI
    Member

    How many of us would'nt give the family jewels for something like this, with 700 HP?? Our projection for our 16 valve 2.3 project is that much with stock cams! and 890 HP with after market cams. In this car that would = more than 30 MPG. Hell my wife's Neon gets 33.Traditional does not have to be obsolete. The heros of our affliction used the best pieces they could beg borrow or steal. All in an effort to go fast The very basis of what we do is to go fast with things we've made or modified ourselves.
    Gemini EFI
     
  19. theflame
    Joined: Jan 24, 2008
    Posts: 169

    theflame
    Member

    Can the stock cam handle 700hp tho?
     
  20. jambottle
    Joined: Apr 11, 2003
    Posts: 564

    jambottle
    Member

    my pick for high mpg engine would be a 86-87 turbocharged buick grand national eng and 200 overdrive tranny with a good solid shift kit.then add a quickchange and play with final ratio to find the sweet spot at 70 mph.a tunable chip for the computer and your on your way to 30+mpg and in a light car ,enough power to light up the tires on demand.a bonus with this engine is a header system comes stock and straight pipes are quiet because of the turbo.a lot of regular regals also had this engine.if you live in the rust belt,there are lots out there.
    i think the total package of eng tranny and rear end is the solution to mpg and a quickchange ,would make tuning in a combo the best solution.used ones are aviable at swap meets in the $300-$500 range.
     
  21. TRUCKRODDER
    Joined: May 29, 2005
    Posts: 329

    TRUCKRODDER
    Member

    A friend of mine has 65 Chevy p/u with a 90 model Chevy truck chassis , 5.7 t.b.i. and 700r4 , he gets 21 mpg! I am working on a 51 Chevy pickup with the same drivetrain. I feel like If I can get that close to that on gas mileage and still run as good as it does I will enjoy the heck out of it!!:)
     
  22. Roothawg
    Joined: Mar 14, 2001
    Posts: 22,732

    Roothawg
    Member

    Yes, I am experimenting right now with a 283 I have on the stand.

    It is a 283 that had to go .060 over, I decided to run forged pistons and a small cam. I went with the 260H comp cams, the lift is .440 and the duration is 260 degrees advertised. I am going to run a hot electronic ignition . I am running a Weiand dual plane intake and a small cfm carb. That's the part I am hung up on. I am trying to decide the cfm that would be needed to fuel this small cid motor in the majority of it's driving. I figure that most of the driving will be in a 6 mile square from our house to my kids high school and maybe into town for a job. The average speed range should be from 25-50 for the most part.

    We are running a 350 turbo tranny and a 3.00 gear in a 2200 lb coupe.

    I'll keep you posted.
     
  23. repoguy
    Joined: Jul 27, 2002
    Posts: 2,085

    repoguy
    Member



    I'm a big fan of the 283. I had a 65 Impala with stock 2bbl / single exhaust 190 hp 283 and a powerglide, and I swear it was pulling down low 20's. I considered throwing on a few bolt-ons, but the damned thing ran so good I just ended up driving it and leaving the engine alone. I miss that car.

    What I REALLY, REALLY want to build is a 48-53 Chevy pickup, throw in a near-stock 283,
    bolt on an HEI, some headers, a small 4 bbl (you know, the typical bolt-ons), run a T5 and run it as semi-daily driver.

    As far as non-HAMB projects go, I'd really like to throw a Subaru WRX sti engine in an old bug (same boxer engine configuration). The way I see it, taking 300 hp engine that runs low 13's in the 1/4 and gets 20-24 mpg in a car that weighs just over 3200 lbs, and putting it in a car that weighs under 1600 lbs, would produce a ridiculous power to weight ratio and probably get 30-something to the gallon. All of this with the reliability of a stock late-model Subaru.
     
  24. gerrald meacham
    Joined: Oct 23, 2006
    Posts: 134

    gerrald meacham
    Member

    my shop truck is a 1931 ford econo rod with a 20r in it i keep the hood shut . not real prout of not being able to feed a hemi. but it does the job and gets the looks
     
  25. Rudebaker
    Joined: Sep 14, 2007
    Posts: 1,598

    Rudebaker
    Member
    from Illinois


    I vote for a 390 Holley with dual feed bowls off an old 780, make look like a hot rod engine at least ;) Actually, believe it or not, a Q-Jet is probably your best bet. One size really does fit all..........
     
  26. Gemini EFI
    Joined: Jan 5, 2006
    Posts: 231

    Gemini EFI
    Member

    Already been done several times.
    Gemini EFI
     
  27. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    You know what, I'd run a Carter WCFB - great little carbs & the vacuum controlled secondaries make it frugal as well.

    Otherwise, look at 500 Edelbrock or 570 Avenger...better venturi boosters than the 390, but a 390 Holley would work just fine too.

    4-hole phenolic spacer's help strengthen the signal to the venturis as well, so crisper response means less throttle to initially get the engine spinning.
     
  28. Chuckles Garage
    Joined: Jun 10, 2006
    Posts: 2,366

    Chuckles Garage
    Alliance Vendor

    last time I checked, hotrods werent economy cars.
     
  29. brewsir
    Joined: Mar 4, 2001
    Posts: 3,278

    brewsir
    Member

    Time for a new check.....if you can have economy and and ass kicking hot rod......what's not to like????

    I'm liking that turbo GN setup...may have to start looking for one. I rode in a grand national that had been tweaked a little and it was definately a fast kick ass car....I can just imagine what it would do in a car half the weight!
     
  30. turdytoo
    Joined: May 14, 2007
    Posts: 1,569

    turdytoo
    Member

    I got kinda bored before I read every inch of this thread so if somebody has already mentioned the virtues of a quick change rear end I apologize. I am very aware of the impact on performance or fuel mileage that comes with rear axle ratios. Are you?
     
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