Last post on Oct 18, 2006 at 9:17 AM
You are in the Mazda RX-8
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Mazda RX-8, Coupe
#1235 of 1414 Squeeky brakes!!!!! NOT HAPPY
Apr 21, 2006 (8:56 am)
Hey all, I have a 2005 RX-8 sport, and I am at a loss with the squeeky brakes!! Been back to the dealer for the 3rd time to finally get "updated pads and shims". Will find out later today when I pick it back up. I has also started to pull right when you apply the brakes. Then to top it all off it more or less backfired last night when we got in the 5K rpm range. Told the dealership and said more than likly it was a fuel problem. I am an ASE mechanic so I do know just a bit about cars, the only reason I am getting the updated pads is because I talked with the tech and had him call the techline about puting Ceramic pads on. To also help with all the brake dust this car produces. The car is a blast to drive, but my wife is now very unsure about the car. Oh yea we bought it in FEB 06, and it has 3100 miles on it. So with this low miles and 4 trips to the dealer makes me worry. I have never been a big fan of Mazda other than the RX's. Any other imput would be great. Thanks all
Apr 22, 2006 (5:18 am)
The price of gas has forced my son to buy a motorcycle for his trips to and from work. I would like to know if the RX-8 is capable of running on a lower octane than the 93 premium which is now at a premium price. One man told us that he runs mid-grade in his vehicle with no problem. I am skeptical of this and do not wish to try it until I am assured that it would not hurt the engine. Any one out there tried this with success?
#1237 of 1414 Re: Gas mileage [baknpat]
Apr 22, 2006 (7:08 am)
Lots of owners even run 87 octane regular. In fact, the rotary runs -better- with lower octane fuel (until you reach the "detonation zone"). Reason is the large combustion chamber slows down ignition so fuels that burn with less "incentment" (heat from compression etc.) do better. If you do end up reaching the "detonation zone", don't worry, the RX-8 has an excellant protection mechanism and you'll notice it in action right away. It shuts down the engine to "limp mode" for a few seconds and if the detonation recurrs (three times in a short period I think it is) it retards ignition for 15 min as I recall.
We've experienced this effect while tuning with piggyback fuel computers - but only when we reached really lean conditions. The piggyback fuel computer (Greddy e-Manage) increases HP output by cutting back on fuel in the engine thus operating it much closer to perfect stoich. conditions which results in more power. Mazda can't do this as it overheats the cat. - we replaced the cat with a state-of-the-art metallic cat. As we are tuning for what is essentially racing conditions, we don't have to worry about the life of the cat. We found trouble started at HP outputs of 245-255 HP (stock is actually around 220 real world). We had to use "racing fuel" at these levels (octane ratings of 96-98). Lots of xylene and/or tolulene in the fuel.
I find running the gas with a little ethanol in it works best - burns very clean and resists detonation. 5-10% is what they claim they add.
#1238 of 1414 Re: Gas mileage [baknpat]
Apr 23, 2006 (6:25 am)
How much gas does he put in it when he fills it up? 13 gallons? How much cheaper is it per gallon for the lower octane gas? Your son might only be saving $2 - $4 per fill up. Getting a cup of coffee at home verses at Starbucks will make that up in one cup.
#1239 of 1414 duke15 ... no kidding...
Apr 23, 2006 (9:52 am)
I caught myself standing at the pump just last week debating - Premium or mid-grade? And then, I realized I've wasted more time thinking about it than it's worth.
Bottom line - the 8 does not get great gas mileage. If you don't want to pay the gas bill, get an Aveo or a civic or something boring.
I'm not happy about gas prices, but I still get a big smile and don't worry about it too much when I redline my 8. It's worth it!!
#1240 of 1414 Squeeky brakes are gone!!! (hopfully for good)
Apr 23, 2006 (4:10 pm)
Well we got the car back from the dealer with the updated pads and shims. So far not a sound and it stopped pulling to the right. What I was saying about the backfire was incorrect!!! There is a "rattle" noise coming from the engine or tranny in 2nd gear at 5K rpm. Any one with the auto trans have this problem?? Other than that no other issues Any how have fun in the RX's!!!
#1241 of 1414 Re: Squeeky brakes are gone!!! (hopfully for good) [fishnhard]
Apr 24, 2006 (5:05 am)
I've got an 2005 RX-8 AT Sports Package. I've got the squeaky brakes. I've always had the little rattle or popcorn noise which appears to exist on all auto trannies. I've also got a significant vibration in the LSD after drive on the highway.
After asking about these problems on this list many times, all the issues appear to be normal RX-8 privilege of ownership glitches. All the above issues have appeared over the entire history of the RX-8 model and should best be view as badges of honor for which owners need to be proud that they noticed, but should be left alone as mysteries to appreciate and theorize about.
Here are my theories.
1) The rattle or popcorn noise relates to the second firing of the upper spark plug. I think the auto-tranny RX-8 is quieter, therefore AT owners can hear more engine related noise details. The AT also is more complex from a fuel mixture vs auto gear shift computer calculation perspective. The complexity means that there is not as perfect of efficient fuel mix going into the engine at various moments at different RPMs. What we RX-8 AT owner hear in the way of the rattle or popcorn noise is the second spark plug burning the excess fuel. (PathStar will probably shoot me down, but I like my theory of the mysterious rattle/popcorn noise and I'm sticking with it, at least until PathStar shoots me down. Oh well.)
2) Break squeak is totally normal as confirmed by an official Mazda Service bulletin I saw online. Customers who ask about the squeak breaks, have the shims fix done as the corrective, but it's not a recallable or problem item. It's just a break squeak according to Mazda.
3) LSD vibration is normal mechanical function which just needs to be broken in over time. Since I can't drive to crazy here in the Boston traffic nightmare, it'll probably take 20K to break in my LSD. This is PathStar's advice and I except it totally until I reach 20K. Then if the LSD vibration is still bad I'll ask the the deal "What's up with that LSD?"
BTW, I'm worried my dealer over filled my oil on the last change. Are there any ways to check for over fill besides the dipstick?
#1242 of 1414 Re: Gas mileage [baknpat]
Apr 24, 2006 (8:35 am)
I've run some 10,000 miles on my rx8 using regular 87 octane gas--I don't notice any difference in normal driving conditions.Here in california all our gas contains oxygen[either ethanol or mtbe].I would certainly try regular gas in yours-- higher octanes are not required.
#1243 of 1414 Squeeky brakes!!!
Apr 24, 2006 (12:39 pm)
Well trispec, I am glad to know I am not the only one out here with an AT RX-8. The "rattle/popcorn" noise still bothers me. Due to the fact that the only time it will happen is if I put the shifter in the normal AT mode. If I use the auto stick or the paddles, it will not do it. The other thing I have noticed is Mazda likes to put a lot of blame for problems on the fuel!! I have been a mechanic for a long time and only on a few cases have I seen fuel be the problem. We have not had any problems with the LSD. Might be due to here in WA I have a lot of chances to get the RPM's and speed up over 60.
I forgot to mention that when the car gets to the point where the rattle happens, we have also been getting black smoke from the tail pipes from time to time, which is an indication of over fueling. I dont buy the fact that the fuel is the cause of all of that. I can believe the fact that the computer is allowing too much fuel into the engine. I am going to call and make yet another appointment with the dealer for this issue.
#1244 of 1414 Re: Squeeky brakes!!!!! NOT HAPPY [fishnhard]
Apr 24, 2006 (3:45 pm)
beware!!! i purchased a 2005 rx-8 in june of 2005, needless to say 12,000 miles later the engine died, it was running through oil like crazy, gas mileage is between 10-14, brakes started squeaking after 3,000 miles, now the car has been in the shop for over 60 days total in 10 months, mazda has replaced the engine 3 times, yes im on my 3rd engine due to these mechanical problems. i think mazda knows they have a major recall coming with these cars but is trying to put it off. there is alot more i could tell you if interested i can give you more info. keep an eye on your oil consumption.