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many of the smaller motors out there now are just hitting their powerband in the 3's; an engine that redlines at 6500 won't be hurt running at say 3500. If it's running in it's band it could be more efficient then almost lugging it lower.
As for swapping in a different trans; the cost you would go thru would not offset any fuel savings. I've seen my daughter's friends doing swaps in their cars, but as tuners it's common for them to do this. Resale isn't an issue and many of them do their own work.
If being a "tuner" or mechanic isn't on your resume, I wouldn't even consider this one. It's nothing like the old days with RWD where swapping rear gears was a somewhat common practice.
^yeah....I wouldn't even know where to start on a FWD little car like a Fusion.
But an old school RWD this was common practice to swap gear ratios. Had a buddy that had a model A streetrod with a quick change rear end. I was envious. It was litterally that....he could swap gears in a very short time. They made these types of rear ends for race cars back in the day but more recently they started putting them in streetrods because guys wanted to be able to easily adjust their gear ratios. As they were home built in our back yards we weren't engineers who had big budgets to go out and figure out the optimal gear ratio. We just had to fiddle around with them until we got them right. We weren't worried about fuel savings or resale value. It was all about performance.
Most cars I've ever owned turn somewhere around 2000 rpm at that speed. But they have been larger displacement motors than what you have in your Fusion.
The smaller the animal the faster the heartbeat.
The automatic 4-cylinder Fusion has a taller gear spread, and the final drive is in the high 3's.
Did you do an axle swap or true gear swap? The carriers in our axles are non-serviceable... and I can't find a single place that does any work on them. Not that I need it but its scary that there are no resources in case of disaster.
It was the carrier, so it was an axle swap.
I bought it via the Internet from an out-of-state '69 Limousine. As you said the axle are non-serviceable so 3.21:1 is the lowest ratio I can go. The only other option is to change the rear end with a 9" Ford, then I could have a wide choice of gearing... 3.50, 3.70, 3.89, 4.11, etc. But the 3.21s are the best compromise, I think.
Did you do an axle swap or true gear swap? The carriers in our axles are non-serviceable... and I can't find a single place that does any work on them. Not that I need it but its scary that there are no resources in case of disaster.
Are you saying that you can't buy new ring & pinion sets for the GM axle in 60's and 70's Caddys? Isn't it a GM 12-bolt, with maybe longer axles?
Gotta admit that I have never thought about changing the ring & pinion in a Caddy, but I always thought you could put just about any GM gearset in them. Not true?
I doubt the OP's car is really sucking down that much more fuel at 3500 RPM (as others have pointed out), and it would have to be quite a bit of fuel to warrant the expense of regearing it (if a mechanic would touch it, if it can't be done, and if the owner is willing to void the probably-long powertrain backing from the factory).
Ring and pinion swaps are normally done by drag racing types, or those who want more from a pull and of course by the off-road types (my jeep is regeared 4.56:1 on 32s :-) :-) )
I don't think that it would be an issue to go from the mid-4's to the low 4's.
Maybe I misunderstood. Do you have the Manual or Auto? If you have the manual then I think I'm understanding your issue based on the numbers above! The difference between the manual and auto on the top end gearing is significant.
When you say "Final Drive" are you referring to the gear ratio on the axle? Or is that the ratio of Engine RPM to Axle RPM in high gear?
Maybe I misunderstood. Do you have the Manual or Auto? If you have the manual then I think I'm understanding your issue based on the numbers above! The difference between the manual and auto on the top end gearing is significant.
When you say "Final Drive" are you referring to the gear ratio on the axle? Or is that the ratio of Engine RPM to Axle RPM in high gear?
Yes, final drive is synonymous with axle gear.
I have the manual, and you can see the difference in the numbers. My car turns at 3000 rpm at 65 mph, and the automatic turns at 2400.
Yeah....that's a sizeable difference. I just plotted up some stuff in excel because I'm a geeky engineer.
As you can see for any given gear the auto engine is rotating slower than the manual. If you drove both you'd be able to notice it pretty easily.
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