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TOPIC: Not getting gains in mileage after the groove?

Not getting gains in mileage after the groove? 29 Jun 2021 20:01 #1

  • GregK
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Hey folks - here's an article I came across that might do us all some good, especially people who are disappointed that they're not seeing the gains they expected:

Food for thought, and an ancillary mod from Down under
Greg Kusiak
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Not getting gains in mileage after the groove? 15 Jul 2021 15:42 #2

  • Tracy Gallaway
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Driving style is a big factor in fuel economy. It's the biggest factor any driver can control for economy.
After watching the video Greg posted above, and some other research, I'm going to postulate some on driving style and it's effects on economy.

Ron Hatton, always encouraged the use of heavy throttle accelerations during the Groove's ECU re-learn drive cycle. When you look closely at his explanation of how the Groove works, you see that he said that the increase in man. vacuum during the intake stroke, causes more of the gas (especially the longer HC chain molecules) to vaporize than without the Groove. BUT HE ALSO SAID- that this increased vaporization results in a FASTER BURNING mixture. Vaporized fuel mixes much better with oxygen, and has an idealized surface area to speed combustion

An analogy to help understand it- compare how easily dry tinder and paper would ignite, compared to bigger chunks of wood. Ever see a dry grass fire?

OK, so, the Gadgetman Groove, enables MORE of the gas to BURN FASTER.. That also means, the engine wants less ignition advance timing. Because if the timing remains unchanged, the pistons will be trying to rise AGAINST that increased FASTER power pulse, BEFORE TDC.. You want that increased power pulse to peak, AFTER TDC, so it's pushing down on the POWER STROKE!:evil:

How to you get the ECU to retard timing? With heavy throttle! The knock sensor function--whether a stand alone Knock Sensor, or as incorporated as part of another sensor's functions--will sense knock and the ECU will back off the timing.

I've been advising people to use wide open throttle-WOT to get the ECU to both retard timing, and adjust fuel trims. That's Ok as far as it goes.

but a more sophisticated approach is needed.
So, I'm talking about more aggressive heavy acceleration to get to the target speed, and using WOT, when it's practical. There is something else to do.

When it's time to slow down, do like was shown in that video in Greg's post above. "Lift and Roll.". I don't know how universal this is, but I have seen this elsewhere, that when the throttle is cut to decelerate IN GEAR, the injectors are cut off. You need to look ahead in traffic and driving conditions to do this well. Not always possible to take full advantage of this- but we're playing Percentage Ball here!

To summarize: Re-think your driving style.
Use a harder acceleration to get to speed (takes getting used to).
Use WOT now and then, judiciously.
Once at desired speed, cruise steadily as possible, as conditions allow.
Look and try to plan ahead, to be able to decellerate IN GEAR, foot OFF the throttle,
Try to Lift and Roll more to slow down. Try to Conserve momentum, Remember the Brakes are disposing of the energy you got from burning your Gas!

Tire Pressure can really help in this strategy!

This will require practice, but can pay dividends in MPG'S!!

Tracy G.
Tracy Gallaway
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Last edit: by Tracy Gallaway.

Not getting gains in mileage after the groove? 18 Jul 2021 22:18 #3

  • GregK
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Tracy Gallaway wrote: When it's time to slow down, do like was shown in that video in Greg's post above. "Lift and Roll.". I don't know how universal this is, but I have seen this elsewhere, that when the throttle is cut to decelerate IN GEAR, the injectors are cut off. You need to look ahead in traffic and driving conditions to do this well. Not always possible to take full advantage of this- but we're playing Percentage Ball here!

To summarize: Re-think your driving style.
Use a harder acceleration to get to speed (takes getting used to).
Use WOT now and then, judiciously.
Once at desired speed, cruise steadily as possible, as conditions allow.
Look and try to plan ahead, to be able to decellerate IN GEAR, foot OFF the throttle,
Try to Lift and Roll more to slow down. Try to Conserve momentum, Remember the Brakes are disposing of the energy you got from burning your Gas!

Tire Pressure can really help in this strategy!

This will require practice, but can pay dividends in MPG'S!!

Tracy G.


quite right, Tracy - get off the gas sooner than later when you know that a stop is coming. when your alignment is right and tire pressure is optimum, you'll be able to coast like the proverbial grand piano across a greased stage.
The computer routine that is triggered when you do get off the gas is called "Deceleration fuel cutoff" - in the case of my vehicle, even though I haven't formally tested it. I suspect what happens is that the MAP sensor sees manifold vacuum going deep (with closed throttle) with an engine load and opens up the EGR valve to let whatever may not have been burned in the combustion event return into the manifold for re-burning - my instrument cluster has an instantaneous fuel consumption readout, and there's one long grade I travel regularly on the highway that I can take my foot completely off the gas and coast where that readout drops to 0.0L/100km at 100km/h! In my case in that instance, engine compression and the transmission keep things happening, but for all intents and purposes, I get infinite mileage at that time.
decel fuel cutoff - you dont give it a chance to work if you're constantly riding the back bumper of the car in front of you, and are hard on the brakes, then back hard on the accelerator to get back up to speed. it's all about feathering the gas pedal after starting from a stop, unless you have to REALLY get past someone. I'm certain it's one of the reasons Ron preached about making sure your intake gaskets were 100% and any other vacuum leaks attended to, regardless of whether your car was carbureted, port injected or direct injected - fuel vapourises better under deep vacuum, and only vapour burns in the presence of ignition spark.
Greg Kusiak
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