Last post on Mar 16, 2010 at 3:20 PM
You are in the Toyota Camry
What is this discussion about?
Toyota Camry, Transmission, Sedan
#18 of 27 Re: packer3 
Mar 13, 2010 (7:13 pm)
I have sometimes wondered if our 1st gen Prius might get better FE if I modified it. Modification would consist of automatically "shifting" to neutral whenever the gas pedal returns to "idle". The Prius has no clutches to wear by shifting in and out of neutral for each coastdown period.
At the moment the Prius will always enter regenerative braking mode during coastdown as a simulation of engine compression braking. With the automatic shift to "neutral" the car would coast farther during coastdown periods but I would be losing the recharge affect.
6 of one, half-dozen of the other.
Your case is simpler since you do not have a hybrid battery to recharge and so shifting to neutral would not only extend your coasting distance but also reduce the wear on the transmission via less shifting.
#19 of 27 Re: thanks 
Mar 13, 2010 (7:26 pm)
"..hack to disable that.."
Heck, (Hack..) no.
Your dealer, as of ~'01, can set a C-best option that disables the defrost/defog/demist link that activates the A/C. I have both options set on my '01 F/awd RX300, the one above plus the one that allows me to disable the A/C indefinitely except during the summer when cooling is desireable.
I think there are even more C-best options now, for instance one that will prevent the system from automatically shifting into cooling mode once the cabin temperature rises to your setpoint or closely nearby. The newer systems, ~2010, will also actually revert to combined footwell and defrost/defog/demist mode if climatic conditions warrant.
My '01 Porsche C4 has a switch modification that opens the A/C compressor clutch circuit. Otherwise, going back to ~'68, I have always disconnected the A/C compressor clutch right at the clutch connection when cooling is not required.
#20 of 27 Re: packer3 [wwest]
Mar 14, 2010 (5:01 am)
So in other words. If I don't mind the hassle, shifting to Neutral during coastdown is good on a 2010 Camry because of below?
1. The fuel saved by the extended distance during coastdown should be enough to offset the small amount of duel feed to prevent the engine to stall when in Neutral.
2. Shifting to Neutral during coastdown actually reduce the wear on the transmission because it avoid a few down-shifting.
On a related note, many years ago, a mechanic told me shift to neutral will reduce brake distance and will not add any wear to the brake pad. Is this the same for newer engine with all the FE technology?
For your Prius mod... Is there a way to detect the charge level of the battery? If the charge level exceed certain threshold (i.e. near full charged), then the car will always goes to Neutral during coastdown? I assume it is best to keep a good charge most of the time to take advantage of the hybrid technology.
Does the Prius easy to mod? This is quite scary, I hope Toyota has protection on crucial modules (e.g. the protected codes of a Operation System).
#21 of 27 Re: thanks [wwest]
Mar 14, 2010 (5:08 am)
"...Your dealer, as of ~'01, can set a C-best option that disables the defrost/defog/demist link that activates the A/C..."
Good to know. Too bad it is something has to be done by the dealer. I had a 02 Civic and I could do that myself by pressing some buttons in specific sequence, but I have no luck to find similar hack with my 2005 Pontiac Vibe and my new Camry. Also my Vibe compressor seems quite noisy compared to other cars. http://a332.g.akamai.net/f/332/936/12h/www.edmunds.com/media/townhall/webxicons/- emotorcons/emo_blush.gif
#22 of 27 Re: packer3 
Mar 14, 2010 (8:21 am)
shifting to neutral during coastdown in the hybrid models will result in additional brake use. brakes will need replacement much sooner.
#23 of 27 Re: packer3 [acco20]
Mar 14, 2010 (8:49 am)
Unless we're talking "hyper-miling" in which coastdown distances are planned. In any case the Prius brake pad seem to last so long that a little additional wear might not really matter.
#24 of 27 Re: packer3 
Mar 14, 2010 (8:51 am)
Provided the extended distance coastdown is well planned, well thought out, yes.
#26 of 27 Note
Mar 16, 2010 (3:20 pm)
There has been some name-calling and other insults in this thread that is inappropriate. Let's leave those things aside going forward.