just been passing BS with the guys and a subject got brought up which i thought was intersting enough to talk on here about. here soon i will enbark in a 28roadster build with 4cyl ford banger and factory 3spd trans. we were talking about how it would be cool if there was a GEAR BOX drive inwhich had input of 1 and output of 2. that way you could get higher speeds also be awesome to find an OVERDRIVE attachment to install behind the transmission. all of this would require extensive fabrication to even attach one another together but i thought atleast in theory it would be cool to do 80-100mph with a stock banger engine. lol
Mount two transmissions Ass to Ass and that would do it. There are industrial applications that do what you are asking however I don't think they are switchable.
Doug Nash and Hone-O-Drive both made assorted versions of what you asked about. Some were free-standing, others were integrated into the trans or axle. Others have made them too, but I'm not remembering any other company names.
It's unlikely that your banger could pull a 100% overdrive. If you could just keep adding gears to go faster, Bonneville cars would all be going 400. Maybe you could look for a Columbia two speed axle.
If you can quadruple (or more) the torque output of the engine, then that would be a good idea. Modern go fast cars like Vettes run a 1:2 overdrive.
There are a lot of overdrive units that mount either behind or in front of the regular transmission. One of my running buds has one on his big Block 4x4 chev that makes his cruising on the highway gas mileage half way reasonable. It only has a .75 or something overdrive though.
Ford, as well as most manufacturers in the up through the 60's offered 3 speeds with the Borg Warner electric shift overdrive unit. They were available for both open and closed drivelines and are 30% overdrive. Ford also had a top loader 4 speed that was used as a 3 speed + 4 was overdrive. They came in trucks back in the 70's and 80's. GM and Mopar had similar units made by New Process. Actually 3rd was the overdrive gear and the 3-4 shifter arm was inverted so that 1 to 1 4th became 3rd and OD 3rd became 4th. These were about 30% OD as well. 30% OD will turn a 4.11 rear ratio into a 2.88. Not 1 to 2, but readily available and pretty much a bolt in. Mike
get your wallet ready, this doesnt sound like a cheap option , but sounds good to me, keep us updated as to what you decide
Top speed on a Model A engined car with a 100% OD may be less than top speed with no OD. It simply cannot pull gears that tall unless it's putting out some very serious power. Plus, how will you engage and disengage this 1:2 box when you don't want it? If you are able to disengage it, how will the power flow through to the rear end? Ain't gonna work
http://macsautoparts.com/early-v8-f...-kit-ford-v7000/camid/F30/cp/JS0R3CHL1140749/ here is a price for you. -bruce
They will happily pull the 30%, and the price starts looking fairly reasonable compsred to machine work to custom insert an OD into torque tube or convert T5 to TT.
Go to the junk yard and find a small transfer case from a 4x4. Figure out how to mount it up backwards. Most have a 2:1 4x4 low range, if you can figure out how to spin it around it would be 1:2 100% overdrive
I have one of those Mitchell overdrive units sitting up in the garage. It's never been used as far as I can tell. I had no idea they were still available.
my heart skipped a beat when i saw the price. omg i think i might try a 4x4 transfer case like mentioned....
So you want to run a Model A at 65 mph or so? With everything else doing 75/80? Ambious but not a good idea...
You might find that it runs out of torque, at about the same speed that it runs out of rpm. I can see adding an overdrive to an early ford if it has a flathead V8, which has twice as much power as your A. But I think you'll be disappointed with the performance if you try it in the A.
well i guess ive been having a brain fart the past couple days. i forgot to tell yall that im not running the original rear end for the model a. im probably going to use a ford or chevy rear end from lets say an impala or ford f150. something like that. would that help me out on the highway or make the 0-60 any better just because of the gearing? then what would yall say be the best gears or rear end to use?
Why do you want to use a 9 inch? Out of a pickup? isn't it going to be kind of wide for your car? And heavy? And they do use more horsepower than most just to turn them. Your banger will never need the strength of a nine inch. And the gears were right for a 351 or larger engine. Not going to help you on 0-60. What transmission are you thinking about?
stock engine and trans. 4cyl model a . 1928 model. using a modern style rear end. the reason i use f150 rear ends sometimes is because they are cheap and plentyful. ford explorer is nice also because disk brake.
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