• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

crank is back

Share this page

Out of curiosity, how much does your AFR fluctuate under a give condition? For example, if you are cruising, does your AFR readout bounce around between 14.5-14.8, or does it move smoothly between those numbers?

On my EFI car, it's pretty bouncey. But I don't know what normal should be.
 
On the 1500, being an older design, I don't think I would go above 15 for economy, and that would be pushing it. We don't like burned exhaust valves, do we?
You will find fluctuatuĂ­ons with rapid throttle movements. Sudden open gives a lean condition, unless correctly compensated for with the acceleration pump. Sudden deceleration will give rich condition. This "can" be conpensated by slowing the rate of closing the throttle, but that affects drivability.
And Scott, your readings sound right on the spot for my opinion. You should experience very good power, without wasting fuel when you don't need to. Better economy could be obtained, but that's not the exercise. I doubt much better performance could be obtained in it's current configuration, except maybe with cam or ignition timing. That is, if they aren't already spot-on.
 
Found that by eliminating the su fluid and using a squirt os penetrate spray instead it does richen out much faster when the pedal is depressed.

Morris. Mine is all over the map most of the, bouncing up and down probably by .30-.50 at any given moment.
 
With a wide band O2 sensor and EFI, I've set it up to cruise at 14.7:1 under low load, 17:1 for deceleration(high-vac), and 12:1 for 10lbs/boost accelerating. Thats one of the best things about EFI, you can tailor the AFR to the needs of the engine in a way no needle could ever do, and with a closed feedback loop to keep it correct at any air temp or altitude.
Ditto the timing control, 44deg BTDC at high vacuum, 32 deg BTDC mid-range, and down to 22deg BTDC at 10lbs/boost. No dizzy on the market to do that little trick.

Glen
 
Back
Top