Inexpensive mods or equipment to help MPG?

I did once buy a quart of cheap engine flush for a really old Gen1 Prius that didn't have it's oil changed often enough and seemed pretty bad inside. But once I read the warning label I decided to only use a 1/3 of a quart rather than the full quart. Of course this flush stuff was different and was for running your engine to warm up and then flushing with oil change, not driving with it in your engine.

I've no idea if it helped but seemed like the least invasive and most responsible way to address engine grime on a poorly maintained vehicle... Never heard of Auto-RX, but in general these fall into the "pour & pray" category and gives you a feeling you put in extra effort without it taking much more time.

 

Yup. See the thread here:
Red Bullet Works! | PriusChat

 

Sadly, scam artists are still trying.

 

Have asked many people who have bought this what they think. Not a single one said it was useless and there was a noticeable amount, though minor, improvement in engine performance and if you study how it works, it makes sense.

And people who call stuff a scam before they do their homework on it don't get re-elected...

 

If I posted that reply, 10 out of 10 times it would be erased.

 

Most of the past hacks are covered above (grill block/block heaters/etc).

I don't think anyone has yet mentioned the "thermistor" hack which was semi-popular electronic hack among serious DIYers. This pulls the Gen2/3 Prius out of cold (low MPG) mode faster, by faking out the coolant temp.

I once considered buying a used 2012 PiP with thermistor hack, but the guy in WV was making a killing on asking price ($21k). He had bought it new for around $15k when WV briefly had a $7000 tax credit in 2012.

I would think Gen2 MPG benefits more from the thermistor hack, but never owned a Gen3 myself.

 

Even if painting your solenoid red helped anything, it and the thermistor trick would cause your Prius to pollute more, so I do not advise them.

While not something you can purchase, keeping your tires inflated, moderating your speed, and planning your braking well in advance are effective.

 

I haven't seen any reason to expect the red solenoid to increase pollution at all.

My favorite thing about that mod is that it is part of an active feedback control loop. There is a sensor that reports the degrees of cam advance back to the ECM. The ECM will use the red solenoid to position the cam precisely where it was going to position it with a non-red solenoid. I would expect that not to make any material difference in emissions.

 

Erased by yourself or someone else?

 

Well, yes, it would only emit more pollution if it worked in any way differently than a non red solenoid would, so we are probably safe from that.

 

@JimboPalmer

There is more than just the color difference here buddy, I have attached a photo of both the Red Bullet and the OEM solenoids next to eachother for you to see the actual difference in sizes.

This seems like it would not be a part you need anyway but it would help others who would use it if you did not bash or call ever product snake oil without even having facts on it.
Go check it out at RedBullet.net

Posted via the PriusChat mobile app.

 

I see ... it gets to the exact targeted, feedback-controlled cam position not just more redly than the old one, but also more bigly.

 

Thanks for posting that link. I hadn't followed prior discussions on this product. The descriptions on their website helped convince me that Jimbo and Chapman have most likely pegged it correctly.

The best I can tell is that this device might possibly allow a higher slew rate for VVT changes. Inside the servo control loop, this might get to a new setpoint quicker, but then won't change anything during steady or slowly changing conditions. So this might make a difference for aggressive PWR-mode drivers, but for slower steady-speed ECO-mode drivers like me, it won't do anything useful.

 

Interestingly enough this is similar to what's going on with @jacktheripper 's Lithium pack plan for Prius... The existing power curve doesn't change much and all the sensors and computers don't detect much of a difference, yet the electrons going into the battery pack are much more efficiently stored and very little is lost to heat compared to NiMH, which loses upwards of 30% of incoming electrons to heat. Likewise, when the electrons are coming out of the pack, the amperage levels are sustained at a much higher rate with much less fall off than faster draining lower amperage NiMH.

In general the both the lithium and the red bullet don't dramatically change overall power, but rather they significantly increase efficiency and overall performance which in some driving conditions give the sensation of significantly more power.

 

Red Bullet + Lithium = Difference



Posted via the PriusChat mobile app.

 

Indeed, that's the only opportunity for it to be of any effect at all.

When you were looking around the seller's site, did you happen on anything giving comparisons, with reproducibly documented methodology, of the slew rate with this device and with the original one? It would be a fairly concrete way to show that it does anything at all, with a lot fewer variables than butt-dynoing the car on a road.

I visited the site, but it's designed so if you visit with javascript filtering, it's an empty white window. I'm not interested enough to poke around it very long with my javascript pants down, or debug it for them.

 

Makes me excited for the kind of mods we'll be doing on our Classic Gen2 hybrids in a couple decades. I picked the right vehicle to show loyalty to that's for sure!

 

Not the DIY thermistor mod, but here is the @ccdisce ECT thread : A Prius ECT Spoofer MCU Controlled | PriusChat

And a gen3 install : ECT Adjuster on Gen3 Prius | PriusChat

 

I don't see the parallels.

I can easily understand how a better battery could possibly help efficiency. Lower internal resistance and improved coulomb efficiency (ratio of available elections out to charging electrons put in) both help energy conversion efficiency, improving mpg. These also reduce internal heating, possibly avoiding some protective current limiting at high temperature. It seems that Toyota did make use of battery improvements in Gen4, and it seems conceptually reasonable that modders could find a way to retrofit some of that into older models. But I haven't been following these mods closely enough to have anything to say about them.

I just don't see anything similar for this third-party solenoid. It merely changes a gain constant or slew rate limit inside a closed feedback servo control loop, something I worked with in my analog electrical engineering days. It isn't in any direct energy conversion process path. It doesn't change any control limits or operating points, only the settling speed and possibly trajectory of position changes. Since most driving involves holding this position steady or moving fairly slowly, there is little or no opportunity for meaningful improvement for those who already drive for efficiency.

As for aggressive drivers rapidly punching the pedal and feeling greater responsiveness, well, they aren't driving for efficiency in the first place.

Nada on that score, and no blank areas suggestive of anything of the sort failing to render on my browsers. That absence contributes to my feeling that this is equally effective as adding racing stripes.