This is just the darnest thing I've ever witnessed. I had a MTH file tuned for:
- Alta 15% Pulley Reduction
- Alta Cold Air Intake w/Silicone Hose
- OBX 4-2-1 Header Manifold
- Factory Limited Slip Differential
- DSC
- 91 octane

After adding a 2% oversized crank pulley, I started experiencing some pre-ignition detonation at WOT over 3500 RPM. Volker was kind enough to supply me with a new MTH that lowered the timings. Once I uploaded that, it helped to alleviate some of the pinging, but it was not completely remedied.

Shortly thereafter, I installed some Denso IK24 spark plugs. The pinging disappeared completely. Quite pleased with the results, I decided to upload the original MTH file (the one that came before I had the file tweaked for the 2% crank pulley). The pinging returned, so I re-uploaded the newer file (the one that came after the 2% crank pulley). Now, I'm getting the same amount of pinging as after the 2% crank pulley and with the newer MTH file.

Anyone have an idea of what might be causing this?

 

Firstly, i wouldnt upload old files when you have newer mods ie 2% oversized crank pulley. Always use the right file for the mods you have

Are you running the new file in ? Strange that the pinging wont go away, despite it not being theyre before. Have you spoke again to volker to address this ?

Additionally are you using the correct fuel RON, has the file been set right to the fuel your using? Here in the UK ive only known pinging/pinking when a customer used 95 RON despite them asking for a 98 Ron file. Once they went to 98 RON pinging/pinking never returned

Si

 

hmmm, that is weird.. i dont have any problems with pinging with my set up..(our cars are very simular) maybe its the winter gas? (bad gas?) i use shell and cheveron only.. arco and some of the other cheap gas makes my car get bad gas milage and performance.. have those colder plugs and better maps should have stopped the pinging. (why did you upload the old file?)

 

Thank you for helping, Cooper_Si and BMDoubleU!

No, I should probably contact Volker, but with the turnaround time on files these days, I figured I wouldn't get it back in time (I'm leaving the country for three months at the end of next week).

Volker did suggest before that I use 93 octane fuel, but then I explained to him that in CA we can only obtain 91, so he tuned the file accordingly.

These days, I'm running Chevron or 76 - before the pinging began, I was running Shell. Just trying to experiment with different brands of petro to see if that might be the case, and even with octane boosters, the pinging is still there. The only thing that did make the pinging go away completely was when I first put in the IK24 plugs.


I figured that the older file had more aggressive timings that the stock spark plugs could not run without pinging, and so once I had the colder plugs in, I thought I'd try out the more aggressive timings to see if I could get an increase in performance. D'oh.

 

Maybe you just need to allow time for the ECU to adapt?

 

that is a possibility.

 

octane boosters dont work. they only make your octane rating go up a few points.. (like: .1 or .2 points. not a whole point like 1.0 or 2.0)

you might want to take a trip to sears point and buy some 100 octane..(unleaded ofcourse).. buy a full tank of 100 octane. drive it until you have 3/4 of a tank left. fill your tank with 91.. drive some more until 3/4 of tank again and so on. this will allow your car to adapt with the octane rating droping slowly over time. you will eventually hit 91 octane but not for atleast 1000 miles. (this is what i did to prevent any issues with my car when i installed the crank pully..)

let me know how it goes. (my car is still pulling strong with no pinging or knocking)

 

boosters do work.

Are the people that have experienced pinging 100% sure it is pinging. I have two mcs's one completely stock and one with mth, pulley, cat back, etc... and they both make that clicking noise. I ask because based on a talk with with a bmw tech instructor, the dme senses pinging and retards at inaudible levels on a regular basis. Also, when on the dyno my tuned car see coolant and air temps much, much higher than on the street without any sign of pinging, yet on the road I will hear that clicking noise in the 3-4k range.

people have mentioned the crank pulley as the source and I recently took the belt off to inspect it. I found that there was enough play in the pulley to create a clicking noise against the block.

I'm not saying your wrong or that the pulley is to blame, but maybe were barking up the wrong tree.

It's is killing me to know, just not enough to put other projects aside to find out.

 

One more thing, there is another post where someone data logged the timing changes between 100 octane and 91. They could cleary see the retard taking place, but when I asked, he said he could not hear anything different.

 

To be honest, I am not absolutely certain it is pinging - I took it by my local tuner shop to get it checked out, and after they listened to the sound, was informed that since the 2% overdrive crank pulley was installed, more air is going in, and hence is most likely preignition pinging. The owner was a little perplexed, as the shop's Mini also pings a little after a cold start, but ceases once the engine warms up. There is another Mini owner on this board who frequents the same shop, is experiencing pinging, and has the stock crank pulley. If the shop is incorrect in its diagnosis, there could be a lot of misinformation being passed around.

The sound I'm hearing is like poking a stick into a whirring computer fan. I thought it was something caught in the PS fan until my shop diagnosed it as pinging. While it may not be pinging, I can't figure out why a new MTH file would cause the sound to somewhat decrease, go away completely with colder IK24 plugs, then return again when I upload a MTH file with more aggressive timings. I would be very interested in your findings once you have the time to investigate your crank pulley to see if that might be the source of the sound. Thank you for your help!


BMDoubleU, thanks for your input - I just might take a trip to Sears Point this weekend to score some 100 octane gas. It couldn't hurt (except for the wallet).

 

and sometimes I do hear it. Right now, I'm running a new set of IK24s and things are better, but I don't have my data logging stuff to make sure the timing retard has gone away....

There's a thread on this called "What mods giveth, timing retard takes away..." you can find it here....

https://www.northamericanmotoring.co...ad.php?t=62870

Seems like we're hunting the same thing....

One thing I'd love to do is get files that don't advance timing as much as work on A/F ratios...

Matt

 

https://www.northamericanmotoring.co...ad.php?t=61328

Matt

 

Latte, I don't believe the shop is incorrect in their diagnosis...they have diagnosed the fact that we are experiencing detonation due to increased boost, although the increase is coming from different sources. Yours is coming from your 2% crank pulley and mine is coming from my 15% SC pulley. If there is a solution (other than race gas) we will all benefit from it. I have been playing around with different plug materials (other than iridium) and different heat ranges, although it has improved, it hasn't been silenced completely.

 

for this is something that can measure your timing. One nice thing about the 100 octane is I got to map what my timing vs RPM at full load is, so anything that logs timing can let me know if it's retarding.

But if it's very sever, you do hear it before the electronic mother in law can pull it back.

But slight timing retard isn't a curse, it's just the motor optimizing for conditions. Better gas will give more power. Cooler days will give more power. But what sucks is that here in CA, you're never going to get full benefit from power adders without using good gas, or doing a bunch of stuff to make the combustion chamber run cooler...

Matt

 

I'm not saying anyone is wrong or that it is mis diagnosed. It's just that saying that you know it is pinging because you have extra boost doesn't convince me as my completey stock car does it too. Also, I can accept a severe ping getting through once, but the dme will retard 3 degrees every cycle until it stops, so I find it hard to believe it would keep happening after the first audible sign, let alone after what the dme can sense.

I should add that I have never had pinging issues before so I have no reference for what a legitimate ping would sound like. The thing that is pushing me towards something else is that at my last dyno visit I asked the operator specifically to watch for pinging. He said he and the computer did not detect any. The dyno has so much more heat and sustained load on the car that I find it hard to bleieve that it happens on the street, but not the dyno.

One more possible source of noise is the cv joint. While working on the car recently I noticed that moving the shaft back and forth caused an obvious ping noise at the end of tavel.

Again, I'm not tyring to impose my idea, just add to the collective concious. It really is erking me to know what the cause is.

 

here. There are times when it sounds like bbs on glass, and times when you don't here it because the timing retard is less severe. This shows up to 11 degrees of retard. Believe what you want.

Matt

 

I absolutely believe there is timing retard. My question is if the cause is extra boost and dme sofware changes, why does it happen with stock car too. And if the dme can sense pinging before a human can, then how could it get loud enough (on a regular basis) to be heard by the driver.

Again I did not say it wasn't pinging. I'm saying how do you know it is pinging? Having extra boost, low octane, or extra timing CAN be causes, but they are not quantifying proof that a noise IS pinging. And charts that show timing retard show that the dme is working. If I didn't see any retard I would be more inclined to believe it was pinging.

I'll stay out of this topic from now on.

 

but be open minded. Why is it that you think that all the drivers that have reported pinging, and find that it goes away with high octane fuel, or other things that effect ignition timing, don't know what they're talking about? To tell you the trueth, when it first happened to me, I couldn't understand why... I've come up with a few guesses, but really have no clue...

1) When the amount of retard needed is large, a 3 degree step may not be enough. So the first one gets real hammered (audibly so), and the next few may as well.

2) Looking at the curves, it doesn't look like the retard is to an absoute level. So if it's pulled back a certain amount, and the revs are changing, going to more advance, then the total timing can be going up more than what would still be inaudible.

3) Who knows what the map hackers are doing, maybe they're changing the retard thresholds to squeeze a few more degrees out, no matter how unwise that would be!

So even though the systems is supposed to prevent it, I can see a few ways that it may not provide so much supervision as to prevent any audible ping....

But you are correct in pointing out that the observed phenomina are not well explained, mostly due to the black box nature of the ecu...

But really, it's present with standard pump gas, go to high octane gas it goes away. Also the knock signal is pretty high even with retard, and goes to zero with high octane gas. Data looks pretty conclusive to me.

Matt

 

what u mean by 'pinging'

 

but you know it when you HEAR it!

If you floor the car, you hear slight tapping sounds as the RPM climbes. Can be some or all RPMs...

Matt

 

I guess my position is a little misunderstood. My first thought is of course pinging, my open mindedness (?) and lack of pinging experience is what made think maybe not. I don't know either way. It seems reduced with booster or higher octane, but I can't tell for sure. It seems to come and go either way. I'm still not sure why it doesnt happen on the dyno.

Another thing I tried was carbon deposit cleaners. Again I can't really quantify anyhting. I have just ordered the 180* t-stat. Who knows.

As for staying out, I'm not pouting or anything, just trying not to take any focus from the thread.

 

There are various conditions that make the detonation seem better or worse (come or go). ambient temp can have a lot to do with it, as well as air density. When I drive at night I notice I don't ping as much as during the day.....after I've been driving a bit I don't ping as much as when I started driving. Personally I am covinced that the noise I hear in my engine is detonation, directly related to the quality of octane that is available to me. The only way I was able to prove this was to run a high octane (50/50 blend of 91/100 octane) and log data before and after. Not only could I tell an audible difference, but the data clearly showed a much smoother timing progression under WOT. just my 0.02....hope the 180 t-stat works for you, as I too have been wondering what effect that would have on this condition.

please don't feel like you need to stay out of the thread. continued open minded discussion is how we eventually find closure to some of these frustrating issues..........

 

I'll let you know what I find with the t-stat. At my next dyno session I will try to get runs at different temps to compare the various parameters.

Haulins, are you the one with the lovestunrz plate? I asked before, but didn't see an answer.

 

nope, that ain't me.....