anyone who experiences engine knock (sounds like marbles hitting sheet metal) upon acceleration, call 949 222 2638. this is Mazda's consumer compliance line. Voice your concerns, otherwise this problem will never be remedied!

I like how one person has a problem with a car, and immediately assumes it's a widespread defect.

Hey there have been enough posts on the board about this to warrent this particular post, myself included.

I know of several, including one from England, and it's on both Auto and Stick.

The real trick is getting it to reoccur for the Mazda techs, and thats a whole different ballgame.

Back to reality guys... in case you don't know... this marbles in can rattling you talk about has been around for some DECADES with all rotaries to the best of my knowledge.

MY RX-2 did it many moons ago and my RX-8 does it today, and it has NEVER hurt anything, or changed my love of the rotary in any way.

All your spouses and/or girl/guyfriends don't sound the same, why should all cars sound the same. After all you are taking your 'piston' knowledge and trying to apply it to a 'non-piston' engine. You need to accept new realities, i.e. the rotary reality... and it is not the 'piston' reality.

Forget it and drive! :)

PS there are many newbie threads about this noise, and the answer is mercifully the same... forget it and enjoy the ride and the new noises!!! :D

I was not surprised when I heard my engine knock using 87 octane. I would be concerned if my engine knocked using 91 octane.

Is this your first rotary engine? I'll bet $50 it is....

THE SKY IS FALLING THE SKY IS FALLING!!11!! OMG!!

Originally posted by Psylence
Is this your first rotary engine? I'll bet $50 it is....

THE SKY IS FALLING THE SKY IS FALLING!!11!! OMG!!

Do you want me to PM you my address so you can send me the $50.:)

It's hard to say without actually hearing the noise.

I know if I heard appreciable knock from *any* of my rotaries I would be seriously concerned. Knock/detonation is definately not good for a rotary and it's not normal.

The above, however, assumes that what the writer is describing is actualy detonation - which is impossible to know without actually hearing it first hand.

The '8 does have a raspier exhaust note than my FC or FD and I could imagine how someone might mistake the sound for knock. BUT - if I actually did experience detonation in the '8 I would most definately be very concerned.

hmmm...seeing all these threads maybe we should get some of our senior fellows with old RX-7s(and prior!) to get a sticky or something to act as a Rotary engine Primer for all of us first time rotorheads.

Something very simple as in noises, sounds, common strengths and weaknesses. This way we can point them to a common article. I have learned a lot about newtorking and stuff like that through other tech forums that have had primers.

just a thought for some of our more ambitious owners!

Originally posted by sferrett


The '8 does have a raspier exhaust note than my FC or FD and I could imagine how someone might mistake the sound for knock. BUT - if I actually did experience detonation in the '8 I would most definately be very concerned.

The reason I was not suprised to hear knock from the 8 is because others have said they heard it. I stopped using 87 octane because I was concerned .I am 98% sure the sound I heard is knock. The Knock is very loud and can be heard over the raspy exhaust note. I heard it a few times on separate fills but ONLY when using 87 octane.

Originally posted by Rick
The reason I was not suprised to hear knock from the 8 is because others have said they heard it. I stopped using 87 octane because I was concerned .I am 98% sure the sound I heard is knock. The Knock is very loud and can be heard over the raspy exhaust note. I heard it a few times on separate fills but ONLY when using 87 octane.

One of the reasons I stick with 91 octane is that I don't want to push the envelope and have detonation due to insufficient gas octane. The description of marbles being dropped into a tin or popcorn sounding are fairly accurate ones.

One thing though - if you continue to experience knock, you will damage the engine - so it might be wise to change to 89 if you're steadfast against going with 91 as recommended in the manual.

I've heard it using 87 octane also. I've since then use 89 and I hear it once in awhile when I'm on full throttle. I cant say I've heard it using 91 because I dont use 91.

Originally posted by sohcpunk
I've heard it using 87 octane also. I've since then use 89 and I hear it once in awhile when I'm on full throttle. I cant say I've heard it using 91 because I dont use 91.

That's enough for me to think that using less than 91 is just asking for disaster. Perhaps if you're never hard on the gas you might get away with it, but for me that's just not how I drive.

IMO the money saved by using 87 or 89 just doesn't justify the possibility of damaging the engine.

Originally posted by sferrett
That's enough for me to think that using less than 91 is just asking for disaster. Perhaps if you're never hard on the gas you might get away with it, but for me that's just not how I drive.

IMO the money saved by using 87 or 89 just doesn't justify the possibility of damaging the engine.

Are you implying that using anything lower than 91 octane will damage the engine? The manual states you can use 87 and higher. What is your claim based on?

My claim is that continued knock will damage your engine.

Others have stated that when using 87 or 89 they have experienced knock.

I'm not saying that you will damage your engine by using 87 or 89 - however, in my opinion, by doing so you are increasing your risk of engine damage based on people reporting that they have experienced knock using 87 and 89 octane.

Just my opinion - feel free to take it with however much weight you wish.

Also remember that the effective octane is lower in places that use oxygenates, especially in the winter.

That said, I don't see why anyone would use less than 91.
I use 93, 94 when it is convenient.
The difference between a tankfull of 87 and a tankfull of 93 in the DC area is about $1.
That is $500 for every 100,00 miles.
Go find an insurance policy with those kind of terms.

FYI - I ONLY use Shell Super Unleaded Premium (93), and always have, BUT the detonation (pinging) has begun on my car!

They replaced my "standard" spark plugs with the hotter plugs last time it was in the shop being looked over. Now, when the car is cold or first driven, it's fine. As soon as it warms up, though, it begins.

Anything over half throttle between 3000 and 4500 rpm will cause detonation (in ANY gear) that can be heard over the radio being on! It was warm in Houston over the weekend (80 degrees), so I had the air conditioner on ferrying the boy to basketball practice, and the car was detonating almost constantly during any type of acceleration.

I ordered the "standard" plugs, picked them up yesterday ($80 just for the two), and am going to install them tonight. I'll report back on the results, but if any of these "complaints" are after the install of these plugs (and you live in a warmer climate), it might have nothing to do with octane.....

Originally posted by dunno
anyone who experiences engine knock (sounds like marbles hitting sheet metal) upon acceleration, call 949 222 2638. this is Mazda's consumer compliance line. Voice your concerns, otherwise this problem will never be remedied!

hi dunno,
I use Shell 87 and have never heard this on my car. Do you hear it during light acceleration, say from when you're accelerating from a traffic light during heavy traffic, or is this hard acceleration as in racing?

thanks,
rx8cited

i have an auto 8 and use only 93 oct. and still hear this engine knock. took it to Mazda service and they say it is "detonation" and is normal. however, for a new vehicle this is hard to accept since the noise is even louder than the engine itself. i will call that number.

Originally posted by sferrett
That's enough for me to think that using less than 91 is just asking for disaster. Perhaps if you're never hard on the gas you might get away with it, but for me that's just not how I drive.

IMO the money saved by using 87 or 89 just doesn't justify the possibility of damaging the engine. I use 87 exclusively and never get knocking. Please don't generalize from your experience and expect it applies to all of us. I am quite happy with my driving experience. If and when I ever hear knocking I will increase the octane level of my gas. Until then, 87 it is.

I'm not going to be convinced that it is indeed "knock" until someone actually proves it. Show me the output from the engines knock sensor at those throttle positions.. Show me EGT increases. Show me something other than "I hear a funny noise in my engine."

Until I see that, or my engine itself expires while making said noise, I remain unconcerned.

My 2¢ -

My RX-8 has been making a pinging, detonation-type noise for quite a while.
It is more pronounced in some RPM ranges than others and at different load levels.
Having heard that type of sound many times on various vehicles, I was concerned that it is pre-ignition so I investigated it more carefully:

1) The spark plugs show no indication of detonation.
2) My compression remains the same, showing no indication of engine damage.
3) A datalog of the knock sensor shows no activity.
4) The noise is clearly coming from the right side of the engine.

The last point is significant because the spark plugs are on the left side of the engine. Combustion chamber noises would have to be on the plug side.
The exhaust manifold is on the right side, however.

I suspect that there is some kind of post-exhaust combustion going on in the exhaust manifold making this noise.

Also important to note -
The manual tranny makes a terrible racket. It grinds and whines and rattles. This is true in all of the RX-8s I have driven.
It can be heard clearly under acceleration at all times.
At some point I will try some Redline MTL or MT-90 to see if it quiets that component of the unpleasant noise. This adds to the noise at all the right (wrong?) times making it sound more "centered" in the engine bay, so a careful listen from the passenger seat is necessary to really hear where this "detonation" noise is coming from.

Originally posted by 8_wannabe
I use 87 exclusively and never get knocking. Please don't generalize from your experience and expect it applies to all of us. I am quite happy with my driving experience. If and when I ever hear knocking I will increase the octane level of my gas. Until then, 87 it is.

As I reiterated in a later post - I don't expect anyone to do anything based on my opinion - I can generalize if I want, it's up to the reader to feel compelled that it applies to them or not. Everyone, please feel free to place as much or as little weight in my generalizations as you see fit. If you want to use 87 - excellent - but I'm not going to because I deem it a risk.

The good thing about free will and such is that we can all do whatever we want.

For those using 93 and higher: Mazda recommends 91 "for optimum performance" as they say in the owners manual. Using higher octane than recommended offers zero benefits. Oil companies, auto manufacturers, and petrochemical engineers all say this. Check their websites. Using lower than recommended, I understand there is a debate, but using higher is a waste. You will get no greater performance, no less knocking, no cleaner engine, no nuthing. It's your car and your money and obviously you can do what you want; just be aware you have succumbed to hype and you are the one they saw coming a mile away.

Also for the record, CA or at least San Diego, does not offer octane greater than 91. At least I've never seen it; perhaps some specialty shops might offer it. From some of your posts it seems like higher octane levels are more widely available in other states.

Originally posted by 8_wannabe
For those using 93 and higher: Mazda recommends 91 "for optimum performance" as they say in the owners manual. Using higher octane than recommended offers zero benefits. Oil companies, auto manufacturers, and petrochemical engineers all say this. Check their websites. Using lower than recommended, I understand there is a debate, but using higher is a waste. You will get no greater performance, no less knocking, no cleaner engine, no nuthing. It's your car and your money and obviously you can do what you want; just be aware you have succumbed to hype and you are the one they saw coming a mile away.

True, and I'd add the the potential to loose power is there since higher octane means a slower flame front and harder light-off.

However, since there is the idea that pre-ignition is possible on this motor in stock form and that oxygenated fuel will often have an actual octane that is lower than the rated octane, it is not a bad idea to use 93 since it is only marginally more expensive than 91.
Add to that the fact that I am running even more advanced timing and leaner mixtures and 93 is a logical choice.

The "premium" fuel from most refining companies also has the more expensive detergent package, but that is of little concern in a properly tuned motor, especially one without a valve train.;)

I've not experience any knocking, I only use 93 octane, 91 is not available here and it goes from 87, 89, to 93 with about $.10 a gallon difference between each one. I did have to buy 89 once because the 93's handle was ripped off, I experience extra vibration in 6th gear, same speed in 5th and 4th produced no such vibrations.

Originally posted by 8_wannabe
It's your car and your money and obviously you can do what you want; just be aware you have succumbed to hype and you are the one they saw coming a mile away.


We should probably keep the emotional slants out and attempt to continue this as a technically interesting thread - it would be very easy for someone to interpret the above as a personal attack.

People see me coming a mile away because I'm overweight, not because of the gas I use. I use 91 because that's what the owner's manual recommends, which doesn't qualify as hype in my book.

Maniac's comments on the noise possibly being afterburn rather than knock is interesting - as I said, I've not heard this noise first hand in the '8 so I don't know for certain what people are describing is detonation. Either way, I will continue to go with the recommendation in the owner's manual.

Simon.

sferrett, well said, I have to admit I was feeling a little out of sorts with some of the earlier comments.

This is our first Rotary and it's NOT a normal noise. I don't know if it's detonation, I don't know enough about the engine. All I do know is that I floored the accelerator and somewhere around the 6000 rpm mark a horrible rattling sound occured, like the engine was about to trash itself, along with a loss of power.

I immediately backed off the throttle and it went away. I haven't been able to duplicate it since, thogh it happened the next day to my wife, but thats the last time it has occured, it's been running for the last 5 days without a problem.

Sorry to all you folks out there who consider this a waste of time as it's a "Normal" occurence, but you can imagine my alarm as someone who has a brand new car and is not expecting it.

My take is this, If it doesn't do it often, then why should it do it at all?

I am not overly worried myself, however my wife gets all freaked out if she hears something she is not expecting, heck if the check engine light comes on she pulls over and calls me. Trouble is, we bought the car for her, not me... Otherwise it would be a Stick shift, not an Auto! :)

Still, that said, even negative type comments have a place here as it does lessen my concern. Still engineering and materials in general has come a long way since the RX-2, and consumer expectations are that much higher.

My S2000 has 50,000 miles on it and is constantly redlined to 8900 rpm, but as yet has not given ANY odd noises.

Whew, there, thats off my chest now. :)

Originally posted by sferrett
We should probably keep the emotional slants out and attempt to continue this as a technically interesting thread - it would be very easy for someone to interpret the above as a personal attack.

People see me coming a mile away because I'm overweight, not because of the gas I use. I use 91 because that's what the owner's manual recommends, which doesn't qualify as hype in my book.

Simon. Nothing personal, Simon. My post started out as "For those using 93 and higher..." That doesn't apply to you as you're following the manufacturers recommendation. I didn't know you were fat so no slight intended there. I meant what I said and believe this is totally factual: Gasoline companies have created a myth that somehow increasing octane is good for your car. They make a lot of money off those who have succumbed to this myth. It is nothing but hype, but those who have fallen for it seem perfectly content because they "believe" they are doing something positive for their car. All hail the power of marketing! :D I am talking about those who exceed the recommended octane rating for their car, not those who simply comply with it.

Originally posted by 8_wannabe
I didn't know you were fat so no slight intended there.

haha - actually the overweight bit was actually meant as a joke.

"no worries"

Simon

Originally posted by Maniac
My 2¢ -

My RX-8 has been making a pinging, detonation-type noise for quite a while.
It is more pronounced in some RPM ranges than others and at different load levels.
Having heard that type of sound many times on various vehicles, I was concerned that it is pre-ignition so I investigated it more carefully:

1) The spark plugs show no indication of detonation.
2) My compression remains the same, showing no indication of engine damage.
3) A datalog of the knock sensor shows no activity.
4) The noise is clearly coming from the right side of the engine.

<snip>


The knock sensor log is very interesting along with the engine right side location. If abnormal rotor pressure happens from some kind of pre-combustion in the intake phase then maybe the noise is rotor gear rattle :eek: This would cause a power loss but would likely look ok to O2 sensors. Maybe the inertia angle sensor used for misfire detection would pick up on this?

Originally posted by Maniac
My 2¢ -

My RX-8 has been making a pinging, detonation-type noise for quite a while.
It is more pronounced in some RPM ranges than others and at different load levels.
Having heard that type of sound many times on various vehicles, I was concerned that it is pre-ignition so I investigated it more carefully:

1) The spark plugs show no indication of detonation.
2) My compression remains the same, showing no indication of engine damage.
3) A datalog of the knock sensor shows no activity.
4) The noise is clearly coming from the right side of the engine.

The last point is significant because the spark plugs are on the left side of the engine. Combustion chamber noises would have to be on the plug side.
The exhaust manifold is on the right side, however.

I suspect that there is some kind of post-exhaust combustion going on in the exhaust manifold making this noise.



You describe exactly what I hear and never under load; only while cruising in 3rd or 4th. With the passenger window down and driving alongside a sound-reflecting wall or concrete divider, I can't hear the sound coming back from outside the car like you can with a piston engine that's detonating. My guess is it's elsewhere in the exhaust system, but it is disconcerting. My 3rd gen has never made that sound (altho its tranny is also noisy like the RX-8). Thanks.

listen up all you prior rx-7 owners, if you think this "detonation" noise upon acceleration in the new 8 is normal then rotary engines are a piece of crap. bottom line here is i do not think it is a normal noise and will take legal action against mazda if needed. a new car should never make than kind of noise whether it be a rotary or regular piston engine. 949 222 2638. that is the number all you prudent fellows should be calling right about now.

Originally posted by dunno
a new car should never make than kind of noise whether it be a rotary or regular piston engine.

suggest you'll do better if you lose the attitude ...:( nevertheless...how about a sound clip? Let's us hear this noise, collectively we may be able to help.

Originally posted by dunno
that is the number all you prudent fellows should be calling right about now. What should we tell them? That we heard of a guy who is hearing noises? I don't think they'll be too interested in 2nd hand reports. I suggest that we don't call out of prudence, but if your car is making funny noises then by all means call.

It. Is. Not. Detonation.

But by all means, please get rid of your RX8, Dunno. I don't want "certain types of people" ruining the reputation of my car. ;)

Oh, and for the 91 and under octane crowd. GET IT THROUGH YOUR SKULLS. Not all of us live in godforsaken Cali. We don't get goat-piss 91 octane as "high-test" on the east coast. Premium is 93.

i was only referring to those people who are experiencing that particular "detonation" noise. if your 8 does not have that problem, then don't waste your time calling !

I agree.. post a sound of this noise if possible, I've never heard a rotary knock before.

Originally posted by Psylence
for the 91 and under octane crowd. GET IT THROUGH YOUR SKULLS. Not all of us live in godforsaken Cali. We don't get goat-piss 91 octane as "high-test" on the east coast. Premium is 93. That is probably me you are responding to, but you got it backwards. Cali is God's country; where else do you get great weather, great beaches, free "shake and bake" from our earthquakes and fires, plus Ahnuld all in one!?

My point about gas is, Mazda does not recommend "premium." Mazda recommends 91. If 91 is midgrade for you, then that's what they recommend you use. Any higher grade is a waste. What perceived benefit do you think you're getting from the extra octane, and what studies/reports back up your assertion?

correction to above, call 800 222 5500. that is mazda's consumer hotline in regards to the rattling / pinging noise that some 8 owners are experiencing. again, if you do not have that problem, do not call. the other number posted is only reserved for written complaints about mazda vehicles.

Originally posted by dunno
the other number posted is only reserved for written complaints about mazda vehicles.
Oh, so you call them to give a written complaint. ;)

Originally posted by jonalan
Oh, so you call them to give a written complaint. ;) Yeah, I thought that was pretty funny too.

seems like we have a few sarcastic members here ! you first send in a written complaint then they will contact you about your specific concerns. that is how i got the number in the first place. but that won't apply to either of you, obviously.

isnt this just the sound of the intake ports opening? as it spins open it makes a sort of rattling noise. as for the loss of power at WOT could it be lag time between the moment the rpms pass the specific point and the time it takes to open? i have never experienced any sort of power loss in my 8 nor knock. also perhaps there is some "sticking port" issue that we all heard rumours about on pre-production vehicles.

Originally posted by zoom44
isnt this just the sound of the intake ports opening? as it spins open it makes a sort of rattling noise. as for the loss of power at WOT could it be lag time between the moment the rpms pass the specific point and the time it takes to open? i have never experienced any sort of power loss in my 8 nor knock. also perhaps there is some "sticking port" issue that we all heard rumours about on pre-production vehicles.

I like your theory a lot for the high power engine. If the rotary barrel valves sometimes stick, rattle and not open fully this covers the observations. However, the low power engines do not have 3rd port barrel valves so maybe there are 2 different noise/power issues? Here is an Australian pic of the barrel valves.

do any of you rotary engine enthusiasts know if a rotary engine has something called an egr valve? (exhaust gas recirculation)

Originally posted by JCC
I like your theory a lot for the high power engine. If the rotary barrel valves sometimes stick, rattle and not open fully this covers the observations. However, the low power engines do not have 3rd port barrel valves so maybe there are 2 different noise/power issues? Here is an Australian pic of the barrel valves.

wow great pic thanks.

Originally posted by dunno
seems like we have a few sarcastic members here!
No, there's quite a lot, actually. It's all done in fun, though (hence the ;) ). Please don't take it too seriously.

Well, I just started to hear this light knocking (marbles in a can ) sound at aroun3,000 - 4,500 RPM under light acceleration in the first few gears. But I don't feel a loss of power at all under full acceleration and I also don't hear the knocking either. It just seems to be in that 3-4.5K rpm that it happens or is most pronounced.

This happen to me once before a few months ago but it went away. Now its back.

Here's a theory to take into consideration: The buggers at the gas station mixed/blended the gas octanes or filled the "premium Tank" with regular fuel. Basically, you think your pumping 91 octane but its either 87 or something in between because they screwed up or tried to save a few bucks by blending octanes.

When the car was new, I could use 87 octane. Then at about 4000 miles, I started having detonation underheavy acceleration at high RPMs. I switched to 89 octane and it's all gone. I do have other noises - probably a loose cat or at least the shield on top of it, and some wirl noise proportional to the RPM when just touching the acceleration (water pump? other bearing? the air pump? dunno, dealer mechanic says it's normal... though 3000 miles ago it was not there). So.... it is somewhat a noisy car, but if it runs fine and no CELs are there, why bother?!? Oh well.....
But if it is detonating using 91 or 93 octane I would take care of it for sure. No engine would possibly like detonation....

I had a high RPM rattle since the day my 8 was new. I ran nothing but 93 octane, and the noise happened every single time I ran it to redline. You'd hear a "Bzzzz! Bz bz" noise around 6K, then it'd dissapear until around 7200 when it'd come back steady until I shifted. (And don't tell me it's normal, I own a 72 RX2, and used to have an 85 GSL-SE. I know what a rotary sounds like)

I spoke to my long time mechanic friend at my Mazda dealer (who is Rotary Certified) and he told me it is detonation, and there's nothing you can do about it. I had a theory regarding the ports on the S-DAIS opening, but never got around to testing it before I traded the car.

Perhaps someone would like to unplug the wires that operate the S-DAIS and run it through the gears disconnected? I believe that may be the cause of the noise.

I have noticed the same noise at 6000rpm. But what I did notice is the noise doesn't happen if you slowly accelerate up to 6k and beyond. Get on the throttle and there it is. So doing this a few times did lead me to believe it is the ports opening.

Whoever experiences this noise try accelerating slowly and see if it is still present. I didn't hear it when I did it, but when I stepped on it I heard it.

Yep, mine behaved exactly the same, which is why I was suspicious of pre-ignition. I believe the S-DAIS operation is not affected by throttle, only by RPM. If that's the case, it's knock, or just a resonance caused by the rush of air at WOT. If the S-DAIS is throttle position sensitive, I'd say it falls into the range of normal operating noise.

I just read the entire post and I’m feeling much better now. I run 87 octane, it is winter and we have oxygenated fuel in Maine. I have 2500 miles on my car and get 18-21MPG. I shift at 4K normally but have heard it beep a few times too and I haven’t heard a sound that has caused me to worry yet!

Has there been a poll done yet that correlates octane to knocking? If not maybe there should be so we can get some real data. I’d think there should be 8 options:
I use 93 and have no knocking
I use 93 and have knocking
I use 91 and have no knocking
… And so on.
I use 87 and have knocking

Good idea?

I just read the entire post and I’m feeling much better now. I run 87 octane, it is winter and we have oxygenated fuel in Maine. I have 2500 miles on my car and get 18-21MPG. I shift at 4K normally but have heard it beep a few times too and I haven’t heard a sound that has caused me to worry yet!

Has there been a poll done yet that correlates octane to knocking? If not maybe there should be so we can get some real data. I’d think there should be 8 options:
I use 93 and have no knocking
I use 93 and have knocking
I use 91 and have no knocking
… And so on.
I use 87 and have knocking

Good idea?

Yes. Set it up! I'll post my experience as well.

From hagar852 "But what I did notice is the noise doesn't happen if you slowly accelerate up to 6k and beyond. Get on the throttle and there it is."

Yes I noticed this today as well. I don't get, or take, the opportunity to get on the throttle often and thought I heard something in the in the past, but today the above behavior was pretty obvious.

Kind of a "clacking" noise? Hmm... it sounds sort of like the noise under the hood when I shut the car off, which only started happening after the "M" flash.

I forgot what causes that noise, something to do with a gadget that releases the fuel pressure or something to prevent flooding. Sorry, I'm too damn lazy to do a search.

Obviously there is enough of this going around (mine does it too). Has anybody had engine failure do to this. I just hit 4k miles when I started noticing my sounds.

Whats the latest flash? I had one done 2 months ago.

I have an april o4 build date with manual trans. Notice the ping nearly since purchase, now have 2,700 miles. Still happens at times. I notice it at low speeds, 2nd and 3rd gear at low rpm and moderate throttle. Car runs great, though. No hesitation. No knocking and plenty of power at higher rpm. Will continue to monitor the engine and check back on the forrum. Any suggestions are appreciated.

Ryan

To add my 2 cents worth, I have been very patient with my RX8 and it has been back at the dealer twice now. It is very easy to duplicate the knock - either find a nice piece of highway and run WOT in 1st, 2nd to the redline then change to 3rd and keep your foot flat - at about 80mph the knock will start - sounds just like things are going to explode.

Now for the guys who say, one email and it's panic, I live in Denver so the next acid test is go up into the mountains and find a really steep grade and hit that full throttle in 2nd then 3rd - as I told the dealer, when you need the big dogs Zoom Zoom runs for the kennel plus really want to expolde (you have to back off the throttle)

I love the car but after the last visit to the dealer, 3 days of trying, they retuned the car to my wife saying they could find nothing wrong so give it a try and see what it's like.

This is going to sound VERY wierd but Zoom Zoom has been great untill this week end when i checked the oil and founf the oil cap lying loose in the engine bay - put the cap back and guess what - the noise is back.

Any ideas or feedback is welcome.