tranny adapter
Thread Starter
|
Senior User
Joined: Mar 2003
Posts: 183
Likes: 0
From: Utah
wow, sorry I created such a controversy. I'm still going to drop the 6 speed in my truck and I'll let you all know how it works out. How often do you see a '67 with a 6 speed, I think it'll be cool, so I'm going to do it. Of course it'll take about six months to save up the cash, oh well, you only live once
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
I'm not trying to boast about my car so much as point out that more gears will help with mileage and still allow you to have a high performance car.
20 MPG and 30 MPG are quite different in my book. I'm not exagerating either. I measured my mileage on a highway trip where I drove 75-80 MPH, but never let the engine get above 2000 RPM. I got over 30 MPG.
This cars does have some tech advances, but you'd be surprised how similar it is to our old engines. This thing is still a pushrod, single cam motor. It does have fuel injection, but a well tuned carbureted engine is not losing 1/3 gas mileage to EFI.
It does not take more power to maintain the same speed through a lower overall gear ratio. To move the same vehicle the same speed, requires the same power (provided all other factors are contstant). It does require that the power come at the lower RPM.
Take the same 60's Mustang. Keep the first 4 gear ratios and the same rear gear ratio, add 1 or 2 OD gears. The mileage will probably improve, the wear on the motor will probably be less. What's to debate here?
I'd like to apologize for having a bit too much attitude in my post last night. I'm dealing with a dying parent and I had 2 glasses of wine! I'm on the edge of a nervous breakdown!
20 MPG and 30 MPG are quite different in my book. I'm not exagerating either. I measured my mileage on a highway trip where I drove 75-80 MPH, but never let the engine get above 2000 RPM. I got over 30 MPG.
This cars does have some tech advances, but you'd be surprised how similar it is to our old engines. This thing is still a pushrod, single cam motor. It does have fuel injection, but a well tuned carbureted engine is not losing 1/3 gas mileage to EFI.
It does not take more power to maintain the same speed through a lower overall gear ratio. To move the same vehicle the same speed, requires the same power (provided all other factors are contstant). It does require that the power come at the lower RPM.
Take the same 60's Mustang. Keep the first 4 gear ratios and the same rear gear ratio, add 1 or 2 OD gears. The mileage will probably improve, the wear on the motor will probably be less. What's to debate here?
I'd like to apologize for having a bit too much attitude in my post last night. I'm dealing with a dying parent and I had 2 glasses of wine! I'm on the edge of a nervous breakdown!
Last edited by gtex; Dec 10, 2003 at 08:21 AM.
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
Originally posted by baddad457
The 67 Fastback Stang I had back in the 80's would get 20+ MPG out on the highway with a side oiler 427 and 2-4 bbl carbs ( this is at 70-80 mph too). And it would do it with a 4 speed Toploader and 2.50 rear gears. And it still would run 13 sec 1/4's. And I'll bet if I still had the car, it would do anything yours would, striaght line, corners, whatever.(Sometimes it's no the car you have to worry about, it's the driver) You don't have to have OD to get performance and mileage. The fact still remains that it takes more power to turn an OD gear than it does with a 1:1 ratio. A direct drive trans will also out last an OD trans too because of the simple fact that theres less stress on the transmission from the OD gears. How much did you pay for your 6 speed car? I'll bet it was a pretty penny, and I can buy a lot of gas with the difference in what you paid and what I've spent. If paying thru the nose for a 30mpg performance car or $3000 for a "performance" 6 speed transmission is what turns you on, then go for it. But it there's always more economical alternatives.
The 67 Fastback Stang I had back in the 80's would get 20+ MPG out on the highway with a side oiler 427 and 2-4 bbl carbs ( this is at 70-80 mph too). And it would do it with a 4 speed Toploader and 2.50 rear gears. And it still would run 13 sec 1/4's. And I'll bet if I still had the car, it would do anything yours would, striaght line, corners, whatever.(Sometimes it's no the car you have to worry about, it's the driver) You don't have to have OD to get performance and mileage. The fact still remains that it takes more power to turn an OD gear than it does with a 1:1 ratio. A direct drive trans will also out last an OD trans too because of the simple fact that theres less stress on the transmission from the OD gears. How much did you pay for your 6 speed car? I'll bet it was a pretty penny, and I can buy a lot of gas with the difference in what you paid and what I've spent. If paying thru the nose for a 30mpg performance car or $3000 for a "performance" 6 speed transmission is what turns you on, then go for it. But it there's always more economical alternatives.
BTW, at 2.50 gears, you are effectively running overdrive anyway. Run this car with 3.73 gears, improve the quarter mile times and add on overdirve to keep the same mileage.
Junior User
Joined: Nov 2003
Posts: 99
Likes: 0
From: Oregon
Having driven a '72 Ford my dad owned awhile back(the only 4 speed I've driven, as I'm still young), then now having driven a friends Corvette with a 6 speed T56, I would be under the impression that an FE engine, if built well and all, would have plenty of power in the low RPM range that is needed for an OD tranny. I mean, seriously...how much torque is a 390 putting out compared to the SB Chev 350?
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
Originally posted by gtex
BTW, at 2.50 gears, you are effectively running overdrive anyway. Run this car with 3.73 gears, improve the quarter mile times and add on overdirve to keep the same mileage.
BTW, at 2.50 gears, you are effectively running overdrive anyway. Run this car with 3.73 gears, improve the quarter mile times and add on overdirve to keep the same mileage.
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
You're arguing with a guy with a degree in physics.
Given the same weight and same drag coefficient, the motor is seeing the same load regardless of what gear or rear gear ratio is used. Unless there are substantial design differences between the gears, which is unlikely in a given transmission. Why would they design 6th different than 5th, except for the size of the gear.
The only thig that changes is the RPM at which the engine sees the load needed to maintain a given speed. Short of pinging from overload, I can see no disadvantage to running at a lower rpm. In the case of my car, it actually has enough torque at the lower RPMs to overcome the air resistance at highway speed and even accelerate in 6th gear.
Given the same weight and same drag coefficient, the motor is seeing the same load regardless of what gear or rear gear ratio is used. Unless there are substantial design differences between the gears, which is unlikely in a given transmission. Why would they design 6th different than 5th, except for the size of the gear.
The only thig that changes is the RPM at which the engine sees the load needed to maintain a given speed. Short of pinging from overload, I can see no disadvantage to running at a lower rpm. In the case of my car, it actually has enough torque at the lower RPMs to overcome the air resistance at highway speed and even accelerate in 6th gear.
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
While I don't have a degree in physics, I do have 30 years of practical real life experience. Try what I posted and you'll see that your theory about it taking no more power to turn an OD gear than a direct or under driven gear is wrong. There is nothing different in the basic design of the gears, it just takes more force to turn an OD ratio than a direct ratio. And some engines, do not run as efficiently at lower rpms than others. Most newer engines are designed to operate more efficiently at lower rpms that OD ratios offer. The engine in my Ranger is built to operate at a higher rpm than what Ford last built them to run. I didn't believe what someone else told me about my mileage going up instead of down when I swapped to 3.73's from 3.08's but now after the deed has been done, he was right. Sure I'd like to cruise down the interstate with my motor turning less rpms, but I also like the acceleration it has now with the 3.73's and the fact that, no matter what abuse I dish out to the Toploader 4 speed that I paid $150 for, it'll take it without a whimper.
Post Fiend
Joined: Feb 2000
Posts: 5,130
Likes: 8
From: Brea CA
Hi, mind if I jump in the off-topic conversation? 
Don't gear ratios give you torque multiplication? For example, if you started in 2nd gear it doesn't accelerate as fast as when you start in 1st. Seems like the engine is seeing less load in 1st. I'm trying to visualize what's happening to the load, am getting a headache.
Barry
Don't gear ratios give you torque multiplication? For example, if you started in 2nd gear it doesn't accelerate as fast as when you start in 1st. Seems like the engine is seeing less load in 1st. I'm trying to visualize what's happening to the load, am getting a headache.
Barry
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
I think he was referring to the final drive ratio, at the point where the tires touch the ground. But that still would be different because in OD you're trying to turn some components faster than they need to be then reducing the rpms down to get the same result. As much as I hate to think that I'd agree with what the europeans do as far as auto tech, they have it right when they avoid OD ratios to get the same effect. They geared the lower trans gears down to improve takeoffs and went with a higher rear gear ratio to acheive higher speeds out on the Autobahn. They know that OD geared components will not take sustained operation at high speeds or rpms.
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
Originally posted by BB
I'm trying to figure out what gtex mean't by "the motor seeing the same load regardless of what gear or rear gear ratio is used."
Still got a headache
I'm trying to figure out what gtex mean't by "the motor seeing the same load regardless of what gear or rear gear ratio is used."
Still got a headache
As long as we are moving the same vehicle the same speed! (Many other factors have to be constant as well). But the gear ratio (and total gear ratio) is irrelevant. What's magical about a transmision gear ratio of 1:1 , when we change the overall ratio by using different rear gear ratios and different tire sizes. At the same speed all components after the transmission spin the same speed (assuming we dont' change the the rear gear ratio or tire size). In OD, the engine and many of the transmission internals are turning at slower speeds as well. As aI said above, your motor has to be making enough power at that RPM to over come your load (load being, what power is required to keep this vehicle moving through the air).
If 1:1 is "ideal" ,then what rear gear and what tire size is "ideal" :-)
Last edited by gtex; Dec 11, 2003 at 07:29 AM.
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
Yes and no, I'm not saying anything about acceleration (getting a bike moving from 0-2MPH is acceleration). To mainatin 2MPH on a bike on a flat road, your resistance is from the air you move through and there is some friction with your bike components (a product of the normal forces, normal forces being primarily your fat **** on a bike:-) . In a car this friction is even more neglible compared to the air resistance at speed. Look at your car as a black box, your engine pushes against the air resistance. Does this force change when you change gears? No!
Now, going from a stand still or moving uphill and things change. I'm mostly looking at the "static" condition present when OD is used.
Now, going from a stand still or moving uphill and things change. I'm mostly looking at the "static" condition present when OD is used.
Last edited by gtex; Dec 11, 2003 at 08:20 AM.
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
You kinda confused me there Greg. When I am maintaining 50MPH down the road in second gear and change to third my engine is appplying more torque to the input shaft of the tranny to maintain the same speed. The engine is however doing less work (horsepower) and requires less fuel to maintain the speed. The engine is producing more torque at the flywheel to keep the same amount of torque at the wheels. The wheels require the same amount of torque to go 50MPH no matter what gear you are in.
Why would you downshift to go up a steep hill with a big load?(very big for your truck) The engine has applied its maximum torque to the input shaft of the tranny and has failed to produce the required amount of torque to the rear axles in the higher gear to maintain your speed.
Why would you downshift to go up a steep hill with a big load?(very big for your truck) The engine has applied its maximum torque to the input shaft of the tranny and has failed to produce the required amount of torque to the rear axles in the higher gear to maintain your speed.