TRZ750

Just over 12 months and now 12,000 miles so I thought I would write a report as many threads seem to be low time owners.

Summary I LOVE MY RX8. It is blue sport model with only a CD changer added. Yes I had a few of the minor issues posted here, like a cracked defroster button (only real part failure), M flash issues, and the mild break squel. But it is still a great car. I expected these issues as most new products have a few issues the first few years. I work for Yamaha so I know first hand the type issues that come up with a new product. I usually do not buy things the first year they are out for just this reason, but couldn't resist with the RX8.

I get 17.5~19mpg comuting back and forth to work on easy city streets. Usually shift 1-2-4-6 as trafic prevents hard accelleration. Commonly crusing at ~35mph or less in 6th. Fill up at 250 miles always as the fuel gauge hits empty a little early. Most I have filled up with is 15.2 gal. Always use 89 octane as it is both cheaper and produces better fuel mileage.

Freeway mileage is only 22 at 80mph. SO lower than expected. But I had 2 RX7s before and they only did 24~25 and were a lot smaller and lighter. The rotary has a large internal surface area so will never get the efficiency of a piston engine.

Best mileage was a drive in the hills of northern Georgia. With all the slow stuff, even though I was on and off the throttle, I got 25 mpg.

Add one qt. of oil at about 2500~3000 miles since the last change. Change oil & rotate tires front to back every 5000 miles. Easies way I found for the diff and trans oil was to use a presurized garden chemicel sprayer and modify the end to pass the thicker oil. Just pump it up and then hold the end in the hole. The Marine Industry has done this for years to add lube to the outdrive gearcases.

I have not exceeded 100 mph yet, but hit the rev limiter all the time in the lower gears. Prefer the windy roads to all out top speed. Feel there is good low end as I understand this is a small engine. Don't like the sudden power surge at ~4500 rpm. Accidently scared my wife once by hitting that point as I was exiting a parking lot and turning into trafic. I went sideways a little as the rear tires hit a wet center line at the same time the power hit. Nothing much for me, but my wife still yells at me because I scared her. Actually sometimes my right arm starts hurting when she keeps hitting me as I push to hard! She calls me "Mario" at times.

Again I LOVE MY RX8.

LBrx8fan

Nice post, but to really enjoy the car, take it out and find a nice stretch of road and get the car up over 100 mph. It is a very comfortable ride, you will be amazed that you are going 100+. I havent been over 130........yet!!

rx8wannahave

Nice post...the RX8 is a great car!

Dark8

It's amazing to think you are traveling almost half a football field a second at 100 miles an hour. And in our 8's it dosen't feel any faster then 70 mph. No wonder it takes a while to stop.....

irish8

TRZ750.....Nice post!! 35mph in 6th? Ouch!! My gas mileage is terrible if I go that slow in top gear!! Also, your mileage is good. I am getting about 17mpg, period.

- Irish

rx8van

Just curious.

I know there's a lot of talk on Mileage, but I couldn't find an answer to this question.

In any gear what RPM range in the 8 most fuel efficient? When I bought it the dealer told me to keep the RPM's between 4-5k. But I don't really believe that.

AvatarQAZ

4-5k? Nuts. Try to keep it below 3750. But really, there isnt a 'way' to improve fuel economy drastically. Driving habits are far and away, the only thing to do to improve economy. I know that I was getting right around 18 mpg no matter where I drove. From PA to GA, I got ~22. but with the mixed driving around here, I do around 18.

Recently, I started giving my 8 a workout (passed the 2k mark), and found her getting 15.5. Before, I would keep her below 4k, shift from 1-2-4-5-6, or 1-3-4-6, or 1-3-6 (city, mixed, highway). With the new fuel economy, I was doing 1-6 .

BTW 3750 is the point where the secondary ports open up... correct me if I am wrong

mysql101

The car easily zooms to 110-120 range, above that it starts taking too long to accelerate and so I've never hit 130.

TRZ750

Accelerationj is the big user of fuel not steady state at low speeds like my 35 in in 6th. I only do that when the road is flat or down hill and no way that I can go faster. I do always watch way ahead and plan my gear etc. So will push it all the way to red line at time and don't really drive like an old lady, but also will just glide along in trafic and not worry about being right up on the bumper of the car in front of me. I feel this type of driving makes a difference in my milage. Also I feel the oil consumption is a indication of the driver and fuel milage. If the driver is on the throttle and high rpm the oil pump will move more oil. So the hard drivers get ~1500 miles to a qt. and poor fuel mileage.

Check most cars and you will see that tall gearing, hense low rpm, is the best for best fuel milage. That is one thing Lindberg found out before his solo flight. He taught many WWII pilots how to increase their range.

jsh1120

Nice post, nice car, and given your handle, I'm guessing a nice bike.

TRZ750

Raced a TZ350, but was mainly a tuner for many types of racing. Originally boats, Then Yamaha racing MCs TZ250, TZ350, TZ700, & TZ750. Then a Mazda RX2 and a Yamaha F1 boat (~400hp V6). Now nothing!

My adult son has a R6 and loves it. I don't have anything as was able to borrow most bikes from Yamaha. Now was transfered to Atlanta and no MCs to borrow (darn).

jsh1120

Oh well. Do you get free pianos?

TRZ750

Sorry the Motor side is separate from the Electronic and Music side. We only share a credit Union.

1up5dn

Very cool, nice post.

I am quite partial to Yamaha myself. Of all the manufacturers I raced, I liked Yamaha the best. In fact it isn't even close. Yamaha paid the most, showed the most appreciation and IMO makes the coolest bikes! Suzuki actually did put forth a pretty decent effort also. Honda, bleh! I won't go there.

Chris....

TRZ750

Yamaha also treats their employees well. That is why I have been with them for 25+ years.

What kind of racing did you do? I have been in volved mostly in road racing, like Daytona. Since I have also been the Outboard expert, Eddie Lawson and Rick Johonson (when he raced for Yamaha) and others came to me for boat help. Eddie is a real nice guy and has actually let me use his Havasu home a few times.

fredw1

One dealer told me that 4-5K rpm was range of maximum efficiency for the rotary engine. Has anyone done any studies? This is my first rotary, but for a cylinder engine, the lower the better (2-4K rpm usually).

TRZ750

Same for almost all engines as long as the engine is not chuking. Match the gear to what you are doing. If going down hill in 8mph trafic I will use 2nd and no throttle. 1st will be too jerky as I need some throttle. When accelerating in 1st I always shift around 4K unless hot roding. When passing at 65mph I will use 3rd or even 2nd or 4th (depending on passing room). If there is no need for power then use the highest gear possible.

A engine has a brake specific fuel consumption curve that typically has a high point at idle and full throttle. This is typically done at full throttle and will change somewhat as the throttle is reduced. So you really need to now the required power to determine the corect settings on the BSF curve. If the power required is very low the best BSF is usually also very low as the required power to turn the engine parts around is lower. So as long as the engine is running smooth and stable use as high a gear and low engine speed as possible for the performance wanted.

jaedcem

A recent article in Road and Track addressed this issue and used the following statement, "RPM is the 900 pound gorilla of fuel consumption." There is no way to disguise it - more combustion cycles means more fuel is used. Ditto the last sentence above.