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Creating an Initial VE Table for Tuning

This is a tool for establishing a baseline VE table for your tuning efforts with MegaSquirt. It is designed to work in Internet Explorer 6.0, though it may work with other browsers.

Note that an improved VE table generator is built into all recent version of MegaTune, see:

The VE curve is assumed to follow the torque curve (which is not quite right, but close enough for a first approximation). This calculator is based on modeling your engine's wide-open-throttle VE with a quadratic equation of the form

VE = A*rpm2 + B*rpm + C
A, B, & C are constants.
These constants are derived from the:

An assumption has been made about the VE required to produced 1 lb·ft/ci as well as 1 hp/ci. A further assumption has been made that compressor efficiency=60% for kPa > 100. Finally, a scaling factor has been used to adjust the WOT VE to lower kPa. The factor is derived from examples of working VE tables.

A limit of 5% per rpm bin drop in VE has been applied to prevent the extreme drop-offs that can occur at high rpm & kPa when VE is modeled in this way. As well, all VEs are restricted to be not less than 25% of the highest VE, to prevent unusable idle values.

See the source code for this document for more details on how the calculator works.

This calculator has not been tested on all possible engine combinations and operating parameters.
Use it at your own risk.

1. Input:

Idle RPM is RPM 300 rpm minimum
Estimated idle vacuum is
(the most vacuum you expect from your engine)
~24 for stock
~15 for street/strip
~10 for race engine
RPM redline (maximum operating rpm) is RPM 12,000 rpm maximum
Peak flywheel horsepower is HP @ RPM
Peak torque is lb·ft @ RPM
Engine displacement is liters
Engine maximum boost level
(0 for naturally aspirated,
max. boost (psi) for turbo/supercharged)
psi 21 psi maximum
Click the "Reset" button to return to default form values.

2. Generate the VE Table in VEX format:

3. Verify and Load to MegaSquirt:

MegaSquirt® and MicroSquirt® controllers are experimental devices intended for educational purposes.
MegaSquirt® and MicroSquirt® controllers are not for sale or use on pollution controlled vehicles. Check the laws that apply in your locality to determine if using a MegaSquirt® or MicroSquirt® controller is legal for your application.
©2004, 2005 Bruce Bowling and Al Grippo. All rights reserved. MegaSquirt® and MicroSquirt® are registered trademarks. This document is solely for the support of MegaSquirt® boards from Bowling and Grippo.