[Diy_efi] VAF MAF

[Alexei Pavlov]

dave at ostat.com wrote:
> 
> Anyone had any success lately with the substitution of the signals from
> a type one VAF (l jetronic type, voltage positive logarithmic to flow)
> with a MAF?
> 
> I'm about to do this project, I realise that you have to do the
> following - transfer MAF response from linear to logarithmic, add
> overshoot to compensate for the flap spring overswing (otherwise no
> "accelerator pump"), and bias the signal with a ptc temperature sensor.

Hi,

You are looking for something like this:
http://www.milfordmicros.co.uk/home/default.asp


There is no 'accelerator pump' effects with the Bosch MAF (VAF).
The flap follows the flow rate, that's all. If you see spikes
on the MAF output, that means your intake manifold needs more air.

If you replace a flap MAF with a hot-wire/film MAF you need
introducing a temperature/ambient pressure compensations.

If you never go to mountains you can omit the ambient pressure
compensation.

Alexei

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