AFM differences? SD1 vs Jag

[gmw9666]

Car in with David Gerald (see my other thread)

If the Jag AFM is up the swanny do I "really" need to put a Jag AFM back in or would the normal one be more than fine

What difference does the two AFM REALLY REALLY make?

G

[hallsie]

Well, lets give it a try!

My AFM is still knocking about with the forum members somewhere and give it a go!

Stu

[gmw9666]

hallsie said:

Well, lets give it a try!

My AFM is still knocking about with the forum members somewhere and give it a go!

Stu

David Gerald have a new standard AFM to try to see what happens to the fueling to ID if its an AFM problem

[honestjohntoo]

gmw9666 said:

What difference does the two AFM REALLY REALLY make?

If the car is a Flapper, and the Two AFMs were originally set up to measure air for engines of different capacity then the spring innards would have been adjusted to suit.

Replacing one with another can start off as 'trial and error.

The replacement AFM, if not broken, will very likely run the engine OK-ish.

However, it is likely to be too rich or too weak across the range.

Initially one could monitor the result with spark plug condition. Too rich giving sooty plugs etc. You know how it works?

To correct the situation the flap spring can be adjusted accordingly.

Turning the adjuster wheel clockwise results in a leaner mixture and vice versa.

To make a more precise setting then a CO meter has to be used and/or a method of measuring fuel/air ratio.

None of the above is as simple as it seem but studying an excellent treaty on the Flapper AFM will reveal everything one needs to know about the AFM and how to adjust - IF NECESSARY.

Whatever one decides, bear in mind that careless adjustment of the wheel can result in in the spring whizzing undone in a millisecond, so one is urged to study the griff

[Wedg1e]

I've set up both types on my car using the Mk 1 seat of pants method; looked good on the dyno so my arse must be sensitive enough

I fitted the Jag unit together with uprated injectors but switched back to the original (actually probably not THE original but the one that was on the car when I bought it) after I had running issues that I thought might be AFM-related but which turned out to be a dying distributor pickup; one day I must switch back to the Jag one for a laugh...

[gmw9666]

See other thread got 2 going, my bad