MPG .... 5-Speed vs 4-Speed

[R.I.D.E.]

When I built my 76 280Z, I replaced the 4 speed with a 5 speed out of an 81 280 ZX. 5th gear was a .754 overdrive. The rear end was a 3.54. The car came stock with a direct drive 4th gear 4 speed.

That car would go 85 MPH at 3000 RPM in 5th gear.

I replaced the short block with a Nissan factory new short block, becasue they had a close out on them, when they started selling factory rebuilt engines. People were not buying the short blocks. It cost $375 and was brand new, not rebuilt.

It had flat top pistons that raised the compression ratio from 8.5 to 1 to right at 10 to one. Guage compression went from 160 to 190. It requuired some tweaking of the air flow meter and about 3 degrees less timing.

I was not hypermiling then, but even at 75 MPH on the Interstates I still managed to see as high as 28.5 MPG.

Depending on the engine size, my favorite configuration is gearing that gave me 30,60,90,120 in the first 4 gears. I foolishly replaced the 3.54 with a 3.90 later for greater acceleration.

The Echo revs at 2550 at 60 MPH. I wish it did that at 70 MPH.

One of the things I really liked about the VX was the tall gearing. It was almost the same as the 76 Z with the original differential.

I had a 59 Corvette that tached 2150 at 60 MPH. It would go 60 in first, 105 in second, 140 in third and god only know what in 4th. It averaged 21 MPG and that was before 1974.

regards
gary