Spin9k

Can see you spend a lot of quality time with your gear box You mention you are doing all this 'playing with gears' at least in part to be efficient...so what is your typical city/highway mileage?

Personally, unless I'm at track, or in specific traffic situations, I shift automatically without thought when my subconcious tells my hand to do it. It's just 2nd nature. Too much thinking about things sometimes can lead to less than perfect results I found. But you're having a lot of fun I can see lol.
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BTW as far as I know, coasting out of gear is illegal most places (and should be everywhere). Not that you'll get a ticket, but mostly it's illegal to make you aware of the dangers of the practice.

Why would coasting out of gear be illegal you asked? For starters, you have little contol of the car except to brake, you can't accelerate if you need to quickly and moreover, and with potential far worse results ***when the engine is idling, you invite stalling at speed***.

How? Many actions can cause problems. When any electrical load causes the alternator to engage and/or power steering pump needing power to turn (not in an 8 of course) or power brake assist loads kick in during braking, for example. When load **on that idling engine**., happens, it can easily stall. So if your car stalls at speed, well, nothing good happens and it's very unsafe. Maybe you'll be ok coasting as you have been, but just like people who don't wear seatbelts...it only takes once when you really shoulda done the right thing...and you can be in serious trouble. Just saying

Razz1

Coasting in neutral plays havoc on the ECU of the RX8. Many members have reported problems with this.

Besides... if you have to think about shifting and when to do it..........

Get an automatic.

flashgordon91

Getting an Rx8 in an automatic is about as worthwhile as a handjob on your honeymoon. Manual or nothing.

DocBeech

iTrader: (1)

hey now you cant always just dive right in and bam your done:P its your honeymoon, you need to know what she still has to learn:P lots and lots of experimentation and favors are required.

xtremetreadwear

I disagree. The reason I even bought a manual transmission car was because of the control I have over shifting. The automatic provides almost no control and is quite boring.

Zolty, I drive my 8 a lot like you. I'm very conscious of exactly what the car is doing. I rev match as much as possible and my shifts are nearly undetectable, when I want them to be. Often I don't use the clutch for 2nd-3rd and 3rd-4th.

I don't coast nearly as much as you do simply because I love the feel and control of engine breaking. I've always lived in the city and am always in traffic jams and stop-and-goes so I use engine breaking to my advantage. I use a large following distance to allow me to, most of the time, stay in 2nd gear for miles, and rarely use the breaks at all. This does require precise pedal control, but I'm bored so I might as well. Not sure what the person behind me is thinking because they don't have my brake lights to tell them what I am doing. Oh well.

If there are 8 owners that say engine breaking will reduce fuel consumption, then I will do it more. I'm no expert, but I would believe at the most, the engine would only receive the same amount of fuel as if it were idling. If there's a possibility of it being less, hey, why not?

The theory of the engine delivering no fuel during engine breaking would make sense as I have seen some very good engine breaking while using the cruise control. I've seen no acceleration on very steep grades while still in 6th gear and can only conclude that if there was any kind of extra power being created in the engine, that I would gain speed.

In my opinion, use engine breaking as much as possible. Keep your vehicle in the gear that is necessary to go again at the rate you desire and you will feel like the 8 is an extension of your body. However, if you want to save your clutch, use neutral or hold the clutch after engine breaking below 2000 rpm because down shifting for more breaking will just wear out the clutch faster, and you'll only moving at about 15-20 mph anyway. I will never buy an automatic again simply for that reason. The feel and control of the manual Rx-8 is irresistible.

DocBeech

iTrader: (1)

automatics are an important way of life though. Look at the places some people live. Places I would never drive a standard like new york city, los angelos, or san francisco. I can remember taking more than 3 hours just to cross los angelos on a busy traffic day.

with that being said there are some incredible automatic and hydrolic shifting transmissions. look at the new corvette auto/manual. look at the indy car ones for that matter. I have seen some racing automatic transmissions that could shift faster and smoother than any of us are capable of.

jasonrxeight

if you rev match no clutch wear

jasonrxeight

driving manual isnt about having smooth and faster shifts, its about fun. no manual can be as smooth as automatics.
if you a kind of person who thinks shifting is too tiring, then get an auto.
I personally like driving a manual cuz it adds a bit of fun to my daily commute. its like why drive when you can take a bus? cuz driving is more fun.

xtremetreadwear

Fair point, but wouldn't that degrade his fuel savings?

jasonrxeight

no pain no gain.

Zolty.J

Thanks for all the comments.
LOL - I'm glad we made it to page two before this became a Manual vs. Automatic debate! I think there are a couple hundred threads on that topic, lets not waste effort on that here.

OK, So I've been driving and thinking, thinking and driving.
It's way more interesting than listening to the radio.
I do fiddle with the gearbox more than some drivers -
here in North Georgia, flat and straight don't exist in my daily driving.

I've logged about 1000 miles over 4 fill ups since my last post.
Unfortunately they are not really representative of my regular driving, but they are interesting.
The first tank is local driving and reflects the extra gear tweaking I've been trying based on suggestions here. It was much lower than my previous average of 18.5, at 16.1 mpg it was the worst tank I've driven yet. It was the first time I have worked against my 20 year habit of coasting as long as possible before my next stop. The RX-8 has lengthened those distances considerably, so shifting to neutral to coast has been a hard habit to shake. I had to re-accelerate on many occasions, and the engine bogged several times from being in to high of a gear. Not pretty or fun. It will improve.

The other three tanks reflect a weekend trip to Destin. About half Highway and half 55-65 mph back roads, with a little bit of town traffic here and there. Those were pretty stellar! I got 22.3 and 22.4 on the tanks that were pure cruising on the way there and back. Aside from a couple of 8000 rpm runs merging with traffic, these tanks were 95% in 6th gear at rpms between 2800-4000, 2% 6th gear below or above that range, and 3% gearing up to speed.

The middle tank of the trip was 21.1 mpg, and it was 13.5 gal vs. about 11 for the others. It included the driving around we did to dinner and shopping, but was still mostly 6th & 5th gear between 2800-4000 rpm.

Prior to leaving for our trip, I had my engine oil changed, as well as replacing the transmission and differential oil after 33K original miles. It will be interesting to see what effect this has on regular mileage.

I'm back home doing my regular drive for the next many weeks.
The techniques I am working with on this tank -
1. Keeping it in gear to decelerate.
I am finding that it is best to leave it in whatever gear it is in, not shift to 5 or 6.
2. Taking my foot Completely off the accelerator whenever practical.
Apparently this reduces fuel consumption to near zero.
3. Slowing almost to a complete stop in gear.
You cannot kill it, the ECU will start idling at 1000 rpm, and the car will roll.
4. Primarily keeping my revs between 2800-4000.
This looks like the "Sweet Spot".
5. Using only 1st or 2nd below 2500 rpm.
This or a little above seems to be where anything but super gentle throttle bogs the engine.
6. Target shifting around 4000-4200 most of the time.
Hits the next gear at 2800-3000 rpm.
7. Exercising the second and third fuel injectors occasionally with an 8000 rpm run, or redline.
Gotta have some fun and keep the driving tool functioning properly.


I'll finish with a question, or an observation worthy of comment...
I drove many hours cruising without the cruise control on this weekend.
I found many times that while at cruising speed, I could ease off the throttle a hair, then a hair, and another hair... and the car would stay at the same speed. Is this making any difference to the ECU? Did I tell it that I don't plan to accelerate? Am I reducing fuel consumption or merely noticing a sensitivity deficiency in my drive by wire?