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gone-ot · 09-13-2012, 04:59 PM

I did something similar many, many, years (circa 1976) with my '72 Pinto with 1.6L engine, when I switched from stock 3.55:1 axle to 3.18:1 axle. That only lowered the engine speed about 300 rpm, from 2,810 rpm down 2,520 rpm, at 55 MPH. I would've needed a 2:50-2:53:1 axle, which wasn't available until 1977, to get under 2,000 rpm at 55 mph.

FE went from 27-28 mpg to 32-36 mpg -- but at the sametime I'd also added: (a) "tri-Y" header, (b) electronic ignition and (c) front spoiler -- so I can't say how much of that improvement was due soley to the lowered axle ratio.

Deja Vu: http://ecomodder.com/forum/156606-post3.html

09-13-2012, 04:59 PM	#12 (permalink)
gone-ot ...beats walking... Join Date: Jul 2009 Location: . Posts: 6,190 Thanks: 179 Thanked 1,525 Times in 1,126 Posts	I did something similar many, many, years (circa 1976) with my '72 Pinto with 1.6L engine, when I switched from stock 3.55:1 axle to 3.18:1 axle. That only lowered the engine speed about 300 rpm, from 2,810 rpm down 2,520 rpm, at 55 MPH. I would've needed a 2:50-2:53:1 axle, which wasn't available until 1977, to get under 2,000 rpm at 55 mph. FE went from 27-28 mpg to 32-36 mpg -- but at the sametime I'd also added: (a) "tri-Y" header, (b) electronic ignition and (c) front spoiler -- so I can't say how much of that improvement was due soley to the lowered axle ratio. Deja Vu: http://ecomodder.com/forum/156606-post3.html Last edited by gone-ot; 09-13-2012 at 05:19 PM..