OMG!! I was driving down the autobahn at around 240kph and all of the sudden... I started slowin down? @#$@# what is wrong with my car!! I brought it to the dealer and for a day he was arguing with me that the car was fine..... BS FLAG BS FLAG. I convinced him to check EVERYTHING or I was Calling Mazda Corp. He found a cracked Spark Plug.. swaped it out and Bingo! got my power back. This is the first time ive ever heard of a spark plug cracking. Just something to watch out for.

Originally posted by Rx8Freehk
OMG!! I was driving down the autobahn at around 240kph and all of the sudden... I started slowin down? @#$@# what is wrong with my car!! I brought it to the dealer and for a day he was arguing with me that the car was fine..... BS FLAG BS FLAG. I convinced him to check EVERYTHING or I was Calling Mazda Corp. He found a cracked Spark Plug.. swaped it out and Bingo! got my power back. This is the first time ive ever heard of a spark plug cracking. Just something to watch out for.


Maybe you should try a colder plug?

maybe your air/fuel mixture was too lean?

Originally posted by rotaryDemon
maybe your air/fuel mixture was too lean?

The computer should be looking after that, sitting on 240km/ph is pretty extreeme. I'd be trying colder plugs.

I can't help wondering if the cracked spark plug was merely a coincidence, and what you actually ran up against was the top speed limiter. I know that Japanese domestic market cars which are capable of exceeding 240km/h are electronically limited to that speed.

An acquaintance of mine once got his Jap-spec Toyota Soarer GT up to 240km/h on the banked oval at Ford's proving ground in Victoria Australia, and the engine basically went off song until his speed dropped below 200 again.

Just bizarre, never heard of such a thing. Bad luck perhaps?

Originally posted by eccles
An acquaintance of mine once got his Jap-spec Toyota Soarer GT up to 240km/h on the banked oval at Ford's proving ground in Victoria Australia, and the engine basically went off song until his speed dropped below 200 again.

Your mate is bullshitting you. All jap cars are limited to 180km/h by law. As well as this the speedo is not allowed to show more, even if it's a digital speedo.

I used to own a Japanese Soarer GT and it was limited to 180km/h just like all the others. That's not to say that you can't get them 'chipped'.

-pete

Originally posted by rpm_pwr
Your mate is bullshitting you. All jap cars are limited to 180km/h by law. As well as this the speedo is not allowed to show more, even if it's a digital speedo.

I used to own a Japanese Soarer GT and it was limited to 180km/h just like all the others. That's not to say that you can't get them 'chipped'.I guess it must've been chipped then. He wasn't really a mate, but rather a fellow competitor - this was during the Dutton Grand Prix Rally back in the mid-90's before the GP moved to Melbourne, and we were running an RX-3.

The test in question was held on the huge banked oval at Longford, and involved over a mile run-up to a 200-foot speed trap. The guy in question had high hopes for his Soarer, but came in at the end of his run beating on the steering wheel in frustration because of the behaviour I described. The car was still coasting down from 240 as it went through the lights, and if I remember correctly, his official speed was somewhere around 215.

<---- BAD LUCK lol ive been over 240kph, and my car is a U.S. Spec. but I have had my ECU flashed with the JDM spec.... (German Mazda dealer told me there are 2 spec's U.S. ... and Everyone eles..... Bastards) Any way... after I slowed down I had a Power loss across the entire power band. so there goes the limiter theory

A bit off topic, the Mazdaspeed RX8 will be fitted with special sparkplugs according to www.mazda.com I wonder whats the difference is?

Originally posted by Rx8Freehk
after I slowed down I had a Power loss across the entire power band. so there goes the limiter theory Yep, that puts paid to that one. :) Glad it was such a simple fix for you then. Was the crack on the external housing, or the internal electrode casing?

As far as I could see it was the external housing, didnt rip it apart. Oh Ya and in case yall are wondering..... A set of 4 Spark Plugs for Our 8's......... 170Euro!! thats like 200 bucks!! glad it was warrenty repaired :)

Originally posted by Rx8Freehk
<---- BAD LUCK lol ive been over 240kph, and my car is a U.S. Spec. but I have had my ECU flashed with the JDM spec....

I'm a bit confused here. Why is your car US spec? Germany is on the same euro spec as the rest of EU surely?

Also, am I right in saying you had the JDM flash in your ECU at the time you cracked the spark plug? That might be your problem :- What octane were you using at the time? Japanese ECU's are tuned for 100RON. Any less than that and you run the risk of detonating at full load. 240km/h for an extended period of time on lower octane is dangerous, cracking spark plugs is proof of that.

Eccles, if I'd taken a 2 tonne luxobarge to the Dutton rally, I'd be prone to exaggeration to cover my inadequacies too :) An rx-3 was a much better choice.

-pete

All jap cars are limited to 180km/h by law. As well as this the speedo is not allowed to show more, even if it's a digital speedo

Just today, my Service Manager told me he had the ability to turn off the speed limiter through the PCM, however it was illegal for him to do it. So there is a way to turn it off, if you knew how....

I had this same problem with a cracked leading plug. Don't know how it happened. My guess is a surcharge from bad ignition coils. Don't know how your coils are.

With regard to speed limiter - My 8 is JDM spec and was limited to 184 km/h which is Japanese law. I bought an AccessPort and took the limiter off myself. The fastest I've gotten it (on a closed road) was 248 km/h. It can do more but I didn't want to push my luck.

There are 3 diff specs as far as I know - Euro (limited to 146mph), JDM (Limited to 114 mph and US (don't think they are limited at all).

Holy 5 year thread resurrection Batman!

wooo for 5 and a half year thread revive!

ooooooookkk.......I FAIR didn't realise it was that old! :shocking:

Batman?? where?