Would a cat-free exhaust require richer fuel mix?
Thread Starter
18 year old cars are cool
Joined: Jan 2008
Posts: 118
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From: Sarasota, Florida
On the two RX7's i have (see sig),
-Both have had the cats removed, and are just downpipe/header to straight pipe to mufflers.
-Both idle in a cycle between 250-600 rpm on the stock tach. The idle is like they are almost dying and then snapping up, then dying, etc. Both rev eagerly and when using the gas pedal they run great.
-Both have simple cone air intakes attached directly to the AFM's.
-Both have had the airpumps and ACV's removed, block off plates and vac caps.
-Both have the vac. nipple from just above and to the rear of the ACV blockoff plate running to their pressure sensors.
I've never looked into the AFR ratio. Does the (theoretically) higher flow of air through things require me to adjust for a richer mix to keep the idle solid?
Thanks for any thoughts here-
steve
-Both have had the cats removed, and are just downpipe/header to straight pipe to mufflers.
-Both idle in a cycle between 250-600 rpm on the stock tach. The idle is like they are almost dying and then snapping up, then dying, etc. Both rev eagerly and when using the gas pedal they run great.
-Both have simple cone air intakes attached directly to the AFM's.
-Both have had the airpumps and ACV's removed, block off plates and vac caps.
-Both have the vac. nipple from just above and to the rear of the ACV blockoff plate running to their pressure sensors.
I've never looked into the AFR ratio. Does the (theoretically) higher flow of air through things require me to adjust for a richer mix to keep the idle solid?
Thanks for any thoughts here-
steve
doesnt seem like anything is out of the ordinary. you just need to play with the idle adjustment thinger-majig. and the idle fuel mixer hickymadoo. search and you shall receive. check for regular tune up as well.
Besides adjusting the variable resistor, try putting in the stock airbox or rotating the AFM to sit more like stock. Gravity might be closing the AFM door a bit more than usual and suffocating your engine.
Thread Starter
18 year old cars are cool
Joined: Jan 2008
Posts: 118
Likes: 0
From: Sarasota, Florida
On the Turbo, it seems the AFM is a cone, not a door. And on the N/A, it's mounted as original.
The simple cone could be restricting the air?
So the answer is Yes, I need to adjust the AFR?
The simple cone could be restricting the air?
So the answer is Yes, I need to adjust the AFR?
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It's more likely the air/fuel mix though. Adjust the variable resistor, and don't forget the jumper wire.
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