Air Flow Meter Swap

H

halojm

True Classic
Being how the AFM on the X is rather small, has anyone swapped a 2nd gen RX7 unit for increased breathing. They are the same generation Bosch L Jetronic systems and should be plug in units. I know it wouldn't help on the low end, but at high RPMs it should help flow. Anyone?
Dave
 
The Guy Croft web site had a discussion about using a Datsun Z AFM on a Fiat 2000 with 40/80 cams. March 22,2007 date on the post.
 
I swear Dave

You know so much about parts interchangeability that I think you could build an X1/9 entirely from a 59 Impala.

Or, say, a Volvo. :whistle:

I'm just sayin.

Pete
 
Guy Croft Info

After reading the Guy Croft article about the possible use of a Z AFM, it seems that this could be the start of a great project. To do it properly, I'll have to hook the X up on a chassis dyno with a 4 gas analyzer, then run it up from idle, thru mid-range, to WOT and check my readings. By either swapping out the entire AFM, or internal pieces (such as the resistor board or flapper spring), it should be possible to "tune" the AFM to a specific vehicle. It should be especially interesting to see how it works with an X with a mild or hot camshaft.
Dave
 
Wide Variety...

My 86 had one off of an 88 MR2.

The Nippondenso (sp?) was leased technology from Bosch so tons of Corollas, Cressidas, Camrys, older BMW's, etc, have AFM's that will switch out with the X. Thing is, you gotta get extra air in there to take advantage of it. Also helps to have a slightly looser spring.

Here's what I did...which is a little more involved. I took the K&N unit from an MR2 and routed it to the trunk and let it suck air form the bertone vent.....it really worked and gave more 'bwah' to the car and more seat of the pants rev out. That combined with a higher flow exhaust helped it quite a bit....the K&N for MR2 is a huge unit. It was a very fun mod to think through and do, could be done much 'tidier' than this though. Uses the stock housing of the MR2 basically cut in half so that the open side of the K&N fills that space and takes in the air. I call this "Cooler Air Induction." Got all the stuff off of an MR2 in a junkyard, used some extra Fiat stuff laying around, some duct, total cost, about $35.

maf1.jpg


maf7.jpg


maf3.jpg


maf4.jpg
 
Lot of work

halojm said:
After reading the Guy Croft article about the possible use of a Z AFM, it seems that this could be the start of a great project. To do it properly, I'll have to hook the X up on a chassis dyno with a 4 gas analyzer, then run it up from idle, thru mid-range, to WOT and check my readings. By either swapping out the entire AFM, or internal pieces (such as the resistor board or flapper spring), it should be possible to "tune" the AFM to a specific vehicle. It should be especially interesting to see how it works with an X with a mild or hot camshaft.
Dave
Click to expand...

Might as well go for a megasquirt and do away with the AFM all together. I once ran my X with a Spider AFM as a straigh swap. It ran but barely. I sounded very lean, and I figured if I swap over the Spider injectors too, it might work better. Haven't tried that yet.
 
Pete Whitstone said:
You know so much about parts interchangeability that I think you could build an X1/9 entirely from a 59 Impala.

Or, say, a Volvo. :whistle:

I'm just sayin.

Pete
Click to expand...

Hmmm... Volvo never used this version Jetronic, unfortunately. If they did I'd have plenty of spares :grin:

I brought this thread back up because I'm getting a regrind & cam box from Bayless, and was looking for the thread on modding the AFM spring tension - can't seem to find it, obviously not using the appropriate search terms...
 
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