Regear for lower cruising RPM

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Regear.jpg

Introduction
Lower engine RPM at a set speed means reduced friction losses and increased engine load to maintain a given power output. Higher engine load increases engine efficiency.

Note: This modification is much easier on manual transmissions compared to automatics. There are no reports of automatics being regeared at ecomodder.

A very easy way to improve efficiency with a change in ratio of engine RPM to speed is to install tires with a larger radius.

Contents

Instructions for mod

Information required: How do people perform this modification, pictures, problems, what to look out for
Information required: A listing for different ways to do this if its different on different types of cars

User experiences

Please enter your user name and any relevant data in the table

User data
User Name Car Make, Model, Year Cost of Mod Time to Perform Mod MPG Before Mod MPG After Mod MPG improvement guess Instruction Link
MetroMPG Ponteac Firefly 1997 65kph-72.9
75kph-64.95
85kph-57.9
65kph-79.9
75kph-70.3
85kph-62.85
65kph-9.6%
75kph-8.2%
85kph-8.5%
Ave-8.8%
Metro taller transmission swap thread: +5% efficiency gain (taller final drive)
Big Dave 00 F-350 XLT Mod= regear 20 MPG 23 MPG 15% (3MPG) data is tank to tank before/after mod [[1]]
Big Dave 00 F-350 XLT $4000 installed Mod= add 7th gear (overdrive) 26.7 MPG 28.2 MPG 7% (1.5MPG) ABA testing [Seventh Gear!]
cfg83 99 SW2 Wagon $240 ($140 parts, $100 labor) 41 MPG
steady state
49 MPG
steady state
20% (at steady speed highway) 21% theoretical gain (steady state highway) from gear ratio change. [Saturn S-Series 5th Gear Swap]

Problems / Consequences of mod

- Higher RPM required at speed before shifting into new higher gear and therefore lower efficiency at some speeds.

References

Forum thread links

Taller top gear makes a real difference (10%)

Metro taller tranny swap thread: +5% efficiency gain

Saturn S-Series 5th Gear Swap

External links

Regear how to

Personal tools