DrGonzo

Hi all,

This is my first post and I have done a search on this but couldn't find the right answer. New to RX8 ownership as well, just picked one up on Friday and loving it

Anyway, I'm on my third tank of fuel - the first 2 fills were with BP Ultimate, but the third was Mobil PULP (95, not Synergy). Tonight I was getting a pinging noise. Would this be caused by the fuel? Considering the octane level of the fuel I would think (hope) not.

I didn't think rotaries could ping as my understanding of what causes pinging in a piston engine is piston slap. Is this correct or am I way off?

Any other thoughts on what the noise could be or what could be causing it? The car is also due for it's 60K service so the spark plugs etc will be replaced - but considering it wasn't making the noises on the weekend, I'd say it's not an ignition issue.

As for the car itself, my previous ride was an XR6 Turbo and they are like chalk and cheese. The XR's main pluses were it's power, straight line speed and the space (although the car was too big for my liking) but the RX8 trumps it in every other aspect. It loves a guzzle but I can live with that. Took it for a blast up to Yea and through Yarra Glen on the weekend and it handles and drives sooo beautifully! I don't think I will be wanting to give this car up for quite a while

Sorry for the long first post, I'll try not to make a habit of it :D

Vinnie.

myriadshalaks

iTrader: (1)

ping or knock can happen in a rotary. but that's not happening in yours. not with that gas. maybe you have something metal rolling around in there. check out my joke thread. Punchline 3 days in the making.
https://www.rx8club.com/series-i-tech-garage-22/ping-back-cat-111888/

Revolver

Welcome Vinnie.

Glad you're enjoying the car.

I also agree you're not hearing pinging. Some have complained of something similar when running 91RON (and others have run that octane without a problem) but you shouldn't have a worry with 95RON.

This may sound silly, but you're not hearing the rev limiter beeping are you?

Otherwise, not sure what it may be. Suggest you get your local service centre to check it out if it continues.

DrGonzo

Thanks for the replies.

It's definitely a pinging/knocking sound, and it seems to be coming from the front of the car. It may just be a similar sounding vibration? Maybe it's a coincidence that it started when I changed fuels.

Definitely not the rev limiter beep, they are 2 completely different sounds and the one I am hearing starts from around 3500RPM.

I'm due for a service as I said earlier, so I'll get them to check it then. Anyone had experience with Penfold Mazda in Hawthorn?

takahashi

Welcome to the family Vinnie

Yes any car could ping but it is unlikely it will in a unmodified car. I don't think it will ping even if you have put the 91 RON fuel in. They have margin for error for those things.

I, however, think that the engine mount is the culprit. At least the service guy that does these car think the engine mount we used to have is pretty ordinary. Do you think the engine mount has been changed before Vinnie?

Also if there is hesitation on power, the plug is definitely need to be replaced. The rotary use oil to lubricate the chamber and it is not friendly for old plugs. I suggest to change them if they have not been touched for $60K. I have a habit to swap them in 20K max (if not earlier).

Enjoy the car mostly.

If has not resolved, I can come out and have a look at it. Just that I am interstate atm.

DrGonzo

Hi Takahashi,

Thanks for the offer, much aprpeciated! Seems like a good community over here

There's a recall sticker in the door jam but I am unsure what it is for - whether it's for the engine mount, cold start, or something else. I'll have to ask when it goes in. It's still under warranty so I'll make sure everything gets up to date.

There's no hesitation in power. It actually pulls a bit harder and just as smoothly as other RX8s I have driven. I'll be asking for new plugs anyway.

fatmarco

hi,
I've been told that the metallic pinging sound is when the second set of extra ports opens up...that is the sound of the engine at those revs. You only hear it when you have a light throttle and linger at those revs. When you rev higher it goes away

DrGonzo

Ah, that makes sense, it only happens at half-throttle. I didn't want to go to WOT just in case it was actually pinging. I'd be better off getting it checked out at service anyway.

Thanks again guys, much appreiciated!!!

Mazurfer

All gears or mainly third at 3500? BTW...........hello from Melbourne.............but Florida!

DrGonzo

All gears otherwise I probably would've suspected a synchro or something.

Go Heat!!!

auzoom

Ping is just pre detonation, hence it can definately happen in a rotary engine.

Remember this is 95 RON not US 95 (PON I believe?). 95 RON is about 91 in the US.

I ran 91 RON for a while with no issues, even on he track. The only time I have had any issues was during a Dyno day where I used Mobile 8000 and the dyno operator refused to continue due to excessive pinging.

Cheers

Andrew

DrGonzo

Maybe they just don't like Mobil fuel?

auzoom

Well I was trying to be diplomatic but heck From a constant complaints of friends with high powered cars, its more that mobil fuel is @#$%.

Try sticking some octane boost in it.

Cheers

Andrew

DrGonzo

My XR6T loved the stuff but then again it doesn't exactly have a high revving rotary under the bonnet, does it?

I won't ask what fuels you guys all use because I'm sure it's been covered in the millions of threads about fuel and mileage etc

Octane booster sounds like a good idea.

auzoom

I use BP ultimate or if I am tracking, VPower Racing.

msydd

Dr Gonzo - I had a similar problem *souded like pinging and a bit down in power) around the 60k mark... turned out to be dirty spark plugs and was fixed when they were changed ... so maybe it will go away after the service???

DrGonzo

A tank of BP Ultimate seems to have fixed the pinging. Looks liek I'll be sticking with this fuel from now on
Still needs a service of course. Should be running very nicely soon.

Once I get some time I'll make a proper intro post with pics etc.

auzoom

Cool. I would make sure you let the service techs know about your probs. msydd has a point that you could have fouled plugs as a result.

lordjay

Fortunately, I've never heard that Pinging noise in my RX. Although the first night I was driving my RX-8 and I was low on fuel and money, I filled up with 91 octane and it was alright. The next day I filled up with BP 98 and I've never filled up with anything lower again

Next time I pass by a Shell I'd like to fill up with that 100 Octane V-Racing Fuel, that would be a special treat for my RX-8

auzoom

With VPower racing, while my car performs fantastic, I get the most horrid fuel economy. In the vacinity of 1/4 to 1/3 less than normal.

Cromax

I find that I get the same economy but with better responsiveness.

I premix though remember.

On another note, something I've noticed noticed recently is that Mobil Petrol has improved in quality substantially. They seem to give better economy and it's much smoother under throttle. I've noticed it since they've been refurbishing all their service stations ... the petrol from the corner of waverley rd and springvale rd service station burns cleaner than the petrol from the corner of ferntree gully rd and springvale rd. I've only really been using Mobil over the past few months (as Kall can vouch for) so I'm a pretty good yardstick. Reason I have been using mobil is every time I fill up with Shell V-Power my car runs rough and doesn't accelerate as well. I have a feeling Shell's turning into a budget petrol provider due to their dockets (look at how much V-Power Racing costs compared with normal Optimax) so their quality on their lower range stuff is reducing.

I don't get it though ... adding 5% ethanol to a fuel mix shouldn't cost as much as what Shell are expecting us to pay! Looking at United (who are the budget version Mobil) they charge noticeably less for their ethanol blends.

Cromax

That was on BP Ultimate though. I imagine any good economy you did was undone by the mountain driving though.

enforcer

Thats good k's Kal...you're doing extremely well on the economy stakes.

My needle seems to move very quickly the first half of a tank....and it makes no difference if its Shell Optimax or BP Ultimate...but to be fair to Mazda 8/10 its city driving...

Sometimes I wish we had a bigger fuel tank capacity but I figure the extra weight would burn extra fuel, which would off set any savings between refills anyhow...