Discussing LSPI (Low Speed Pre Ignition)

[greggles]

If you want to see what active LSPI looks like, visit a first gen mazdapseed3 forum. If you wailed on the car all day, perfectly fine. Try to boost up a hill in a high gear, watch your rods fly out of the block in protest.

 

[toledospeed]

I want to add bit of detail to my oil experience in case anyone looks through the archives. It might be hard to follow, but if you're concerned with LSPI, it's probably worth it.

I was on an APR Stage 1 91 High Output when I was hearing knock. It wasn't there when stock under the same conditions and inputs. And by stock I mean '16 GTI S DSG Non-PP with ultra all-season tires (competition killer? not exactly), and that's it. I always use Mobil premium 91 gas.

So the knock was present at incline and WOT starting from the very first day it went tuned. I switched to OEM Beru RS7 plugs, 1 step colder. The frequency of WOT incline knock was about the same. At that point my local APR dealer analyzed the car via VCDS. Nothing. During that visit I opted to install the TCU DSG software, but that didn't remove the knock (the optimized shift points are reassuring though). Shortly later I found out generic oil was used by a non-VW shop at the last oil change - hence this thread.

So when I replaced the generic oil, the problem was reduced from 60% occurrence of incline road, WOT knock to about 20% when I counted up all the times I did a hard pull. Again, all the while I'm not getting codes. And it's worth noting that vehicles are not ordinarily equipped with pre-ignition knock sensors. That's where I left off in this thread.

Since then...I switched from OEM Beru RS7 to OEM NGK RS7 plugs. I would very unscientifically say it reduced incline and WOT knock occurrence from 20% to 10%. It still wasn't a satisfying experience though knowing a single peak compression event very well could finish my joy ride for good. So I went back to my local APR dealer, now outside the 30 days refund window, and just had them switch the car to the 91 low output file for the price of labor (which was free - it's their '1 time charge' deal). Let me tell you, it's an interesting experience to have a DSG tune with the low output file, but so far so good. Back on point, what's the occurrence of undetected but audible knock? Big 0% (zero)!! I couldn't be happier.

Mind you, at that point I had NGK RS7 heat range 8 plugs in giving no pre-ignition knock. I then decide to not let well enough alone and switch to the Golf R NGK plugs which are heat range 7. (I'm thinking - GTI stage 1 low output is so close to stock Golf R numbers, right? Why foul the plugs early?) Mistake! I ended up with the same 10% or so occurrence but not as intense, and by that I mean that the duration of the inharmonious knock was shortened drastically. But for me that just wasn't going to cut it. So back in go the NGK RS7's and wallah - engine symphony!! I've been giving it all the beans lately and it just isn't going to happen.

Here's hoping the best for it, and for you too if you've had this ordeal. I know not everyone would have this experience - every car is different even if technically the same. For those of you with high output *joy* and then some, I"ll just say I'm a wee bit jealous but low output gains aren't all that bad. I'm satisfied, all things considered.

Did you ever experiment with different fuels/octanes? From your description, if they were available, one of the first things I would have tried would have been different brands of gas, ethanol mix, octane booster etc. The different plugs had an affect on the combustion process due to their heat transfer properties, but it just sounds like the car just didn't like the tune/fuel/environmental conditions. I noticed you are in the SW US. When I was in Tucson a couple years ago, I had a turbo Mercedes CLA rental, and I noticed that there was only 91 octane available. It would be disappointing to live in that heat with a tuned turbo and not have access to 93 octane. Might want to look into an upgraded IC or w/m if you haven't. That would surely help your odds of running the higher output file.

If you want to see what active LSPI looks like, visit a first gen mazdapseed3 forum. If you wailed on the car all day, perfectly fine. Try to boost up a hill in a high gear, watch your rods fly out of the block in protest.

Haha, had an '09 MS3 in a prior life. I used to frequent the forum and remember the horror stories.

 

[Crud_muffin]

Appreciate the feedback everyone. It really is hard to limit variables as I'm sure we all try to do when diagnosing.

Also to add, there is such a thing as low level preignition knock that is not catastrophic. GM discussed the challenges of LSPI in modern DI turbocharged cars in a 2015 conference. I think you'll find their vetting process interesting. That part starts at 00:22:52.

https://youtu.be/0B6SHa4qv60

 

[Crud_muffin]

It would be disappointing to live in that heat with a tuned turbo and not have access to 93 octane. Might want to look into an upgraded IC or w/m if you haven't.

So true about the heat! I'm in Nevada and 91 is all there is unless you go mad scientist - which I'm not opposed to.

Comments about an IC has me thinking. I read up that the Golf R IC is a tad larger than the GTI's and swaps over. Seems like a no brainer upgrade. The strange thing about it is that I've had highs of 60-80 outside temps during the 2 months of diagnosing this thing. That said... the knock most often would rear its ugly head after extended runs where oil temperature was 200+ for a while (and the knock noise would occur in the 2800-3000 rpm range as described earlier).

I know there are less aggressive tunes with less compression in the LSPI zone, but I'm in love with the down low power that APR offers. I'll find a way to regulate the addiction, haha.

 

[greggles]

Skip the Golf R intercooler. As more and more data comes in, it is a relatively minor upgrade. Go for the unitronic when on sale or wait for the burger motorsports option (Which is supposed to be budget friendly).

It takes 4-5 hours to install the intercooler, so the main issue is install cost or time, not the cost of the intercooler.

Golf R Intercooler on IS20 GTI, Eurodyne tune

66F ambient
Starting charge temp 96F
Ending charge temp 105F
http://www.datazap.me/u/phsycomatt89/log-1495149947?log=0&data=1-2

88F ambient
Starting charge temp 105F
Ending charge temp 123F
http://www.datazap.me/u/phsycomatt89/log-1495149947?log=1&data=1



Unitronic Intercooler on IS20 (ED Stage 2)

77F ambient
Starting charge temp 91F
Ending charge temp 86F (at end of acceleration)
http://datazap.me/u/defining/ed-stg-2-adj-93oct-27psi-70-degrees?log=0&data=1-4



This one 81F ambient, stays really low. Freaktune
http://datazap.me/u/georgiatechme/freektune-rev-e-3rd-gear-3k-65k?log=0&data=6-13-15

See intercooler thread for more data.

 

[Crud_muffin]

^ love the data and links. Thanks!

 

[Narako]

you sir, might have just solve the unanswered question about the little gremlin in my car. THANK YOU!!! My car has always been making this weird knocking noise (kind of like someone flicking a metal sheet) for some time now. I can always recreate the situation, putting load on the car while at low RPM. I'll try to get you guys a video of this mystery phenomenon happening if it happens to more of you guys.

 

[Crud_muffin]

^ Good to hear! Can't wait to hear/see your video. Please tell us too about your setup.

Here's my little video. You'll have to turn the volume up and listen for the click at the end. It wasn't a great example to give to APR because it's so limited, but it was hard recording with one hand and not hitting​ a light post.

https://youtu.be/1hFrSBZx5dM

One guy on YouTube posted a similar MK7 GTI knock noise too. It looks like at the very least he had a DSG tune and probably didn't know it (gear selection in D mode was visible). He said switching from 87 octane to 93 fixed it. So I suspect he wasn't aware the ECU was tuned in the first place because stock software would pull timing. His case was probably traditional pinging from the wrong octane, not 'abnormal combustion events' like from LSPI.

https://youtu.be/bYdnhsnX2fs

 

[Narako]

Hope you guys can hear it, but this is what I've been talking about (knock during load at low RPM)

https://youtu.be/6wohRwfnjkM

This is a complete break down on what's on my car:

APR Stage 2
MK7 R Intercooler
Denso IKH24 Spark Plugs
CTS 3'' Turbo Back exhaust
CTS Turbo Inlet
034 Dog Bone Insert
K&N Drop in filter
ECS Catch Can
Michelin PSS
P3 Gauge

Planning on adding BFI stage 2 mount and larger rear sway bar. Also I'm open to suggestions for other stuff to add on my car

 

[AtlantaDad]

Hope you guys can hear it, but this is what I've been talking about (knock during load at low RPM)

https://youtu.be/6wohRwfnjkM

This is a complete break down on what's on my car:

APR Stage 2
MK7 R Intercooler
Denso IKH24 Spark Plugs
CTS 3'' Turbo Back exhaust
CTS Turbo Inlet
034 Dog Bone Insert
K&N Drop in filter
ECS Catch Can
Michelin PSS
P3 Gauge

Planning on adding BFI stage 2 mount and larger rear sway bar. Also I'm open to suggestions for other stuff to add on my car

My car is doing this around 3k rpms in 3rd. Tried to log the other day and was afraid to stay on it. MAPerformance stage 1 93 octane.

Sent from my SM-G955U using Tapatalk

 

[Crud_muffin]

Hope you guys can hear it, but this is what I've been talking about (knock during load at low RPM)

That's the exact same noise. At 7 sec. in the video and 3300 rpm I definitely hear it.

I've been digging and digging on this topic and came across something that might point to the answer. Basically, in my case, I'm going to need a performance intercooler. I just pulled the trigger on a stock fitment upgrade.

https://www.carthrottle.com/post/w96gzom/

"Known as 'heat soak,' the amount of heat energy being pumped into the intercooler is greater than the amount it can shed to the air or water passing through it’s core. Eventually the boost temperatures will rise. You could see 130° F turn into 230° F rather quickly with some stock intercoolers. This is when detonation is more likely to occur."

"You’ve been stuck in stop and go traffic for 30 minutes, but suddenly you reach your exit and you go for it. You drop the hammer in 2nd gear and the EJ257 goes to work. Problem is … the 180° F air your turbo is ingesting is coming out of the turbo at over 400° F. That hot air is being fed to a heat-soaked, top-mounted intercooler (TMIC), which hasn’t had time to cool after being cooked under the hood. The result is feeding your engine 350°F air at 15 PSI of boost pressure."

 

[Narako]

My car been doing that for some time now. I think it started doing that around 5k (It did it when it was Stage 1 and at Stage 2). The funny thing about it is that when i ran it through some diagnostics(dynos, that fancy expensive diagnostic tool from Snap-On, and OBDEleven) it comes out as "nothing is wrong"; Power is good, ride is good and MPG.

This car is weird, every time i hear that noise i let go of the pedal and reengage it, and it'll go away.

 

[Crud_muffin]

My car is doing this around 3k rpms in 3rd. Tried to log the other day and was afraid to stay on it. MAPerformance stage 1 93 octane.

I suspect this happens to more people but Justin Bieber through high amp speakers drowns it out - kidding!

I have this theory after reading the Car Throttle article. He said for a 7k redline, don't go WOT until 3200 rpm because of LSPI. Our cars have a higher redline, right? I believe going stage 2 and beyond also mechanically creates a possible higher redline (assuming fuel pressure, etc. supports it). So could it be that the LSPI zone grows in proportion to the added power? Not sure. In any event, I did find that with the APR 91 high output that consciously waiting until 3000 rpm and beyond before putting the hammer down did 100% prevent any of the knock. Strange thing is, and maybe you feel the same, the onset of the knock can happen not 100% mashing the pedal.

 

[AtlantaDad]

I suspect this happens to more people but Justin Bieber through high amp speakers drowns it out - kidding!

I have this theory after reading the Car Throttle article. He said for a 7k redline, don't go WOT until 3200 rpm because of LSPI. Our cars have a higher redline, right? I believe going stage 2 and beyond also mechanically creates a possible higher redline (assuming fuel pressure, etc. supports it). So could it be that the LSPI zone grows in proportion to the added power? Not sure. In any event, I did find that with the APR 91 high output that consciously waiting until 3000 rpm and beyond before putting the hammer down did 100% prevent any of the knock. Strange thing is, and maybe you feel the same, the onset of the knock can happen not 100% mashing the pedal.

Lol! I'm just glad we've finally moved on from the Frozen soundtrack. Took way too long to let it go... wah wah waaah

You make a good point. I don't typically mash it under 4k unless in first and just hooning a bit. But everyone says to log in third from 3k to redline. I'll watch my IATs like a hawk, and stay away from that situation. This is my daily after all, so I don't need to be saying "who's there?" to cylinder 2. [emoji14] Intercooler will be the next major upgrade for me, but that's probably not until next spring. So until then, constant vigilance!

Sent from my SM-G955U using Tapatalk

 

[The Fed]

You all worry too much. Your warranty is 5/60 or better if you bought a mechanical breakdown contract.

You don't want higher cylinder temperatures and pressures? Don't tune.