Over Run Fuel Cut settings

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panel
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Over Run Fuel Cut settings

Post by panel »

What's everyone running in the 5 bins? I'm confused on the last 3 bins mainly. :?
'65 VW Bus with a Subaru EJ20 Turbo conversion , Air to water I/C , LS coils , 14Point7 Spartan 2 & Solid Air Fuel Ratio 52mm gauge.
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Masi_K
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Post by Masi_K »

-TPS lower than is setpoint just over closed tps. If your closed tps value is 88, then good for overrun is 89-91
-Coolant greater than is in what temperature (and above) overrun activates. I use this 71'c. Wich is same where warmup is off.
- After sec, is the time between tps in treshold and overrun kicks in. Too low short time cuts fuel when lifting gas for a gear change. I use 2sec.


- RPM is minimum rpm from overrun is activated(if tps, engine temperature and map are good to go). This depends very much of a car specs. I use rpm2000
- Map KPA is setting is setpoint where below it cut is online, and up offline. This setting should be low. In fact low as possible. I use 25kpa. I started from 40. This cuts fuel usually too often and when pressing gas again there is no smooth engine awakening :) This is what you should try and find yourself.
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jsmcortina
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Post by jsmcortina »

The key is to get smooth operation. I have mine set so that it only activates as I coast towards a junction.
If you set the kpa too high or the time too short it will activate too often and make the car jerky to drive.

To test it accelerate to high rpm in a low gear and lift foot off pedal, you will get a low kpa and see the PW drop to zero then as the rpms drop to the rpm limit the PW will come back on again.

James
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coyoteboy
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Post by coyoteboy »

While piggybacking my denso unit i have to use fuel-cut at 0 seconds as my idle valve is open >1800rpm. This means that if you cruise up to a junction without immediant fuel cut you get the car straining at the clutch and revving its nuts off when you press the clutch. With it on immediate cut I get perfect smooth operation.
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