Fuel property effects on low-speed pre-ignition

[RamFan]

Originally Posted by weasley
It has come about through down-sizing engines, running small engines with high boost at low speed and high loads. The effects can be devastating in only a small number of revolutions.

I have to say it is years since I last heard any pinging or knocking.



Other markets have been using small displacement turbo engines for decades now. Shouldn't LSPI have reared it's ugly head by now? These markets also typically recommend higher octane fuels more often than U.S. manufacturers, I suspect that's a big factor.

To the second point, I'm in my late 20s, I honestly don't know if I've ever heard combustion pinging/knocking. I don't know if I'd even be able to tell what the noise is if I heard it. Marbles in a can is the best description I've found, is that accurate?

 

[wemay]

delete.

 

[StevieC]

Originally Posted by RamFan
[To the second point, I'm in my late 20s, I honestly don't know if I've ever heard combustion pinging/knocking. I don't know if I'd even be able to tell what the noise is if I heard it. Marbles in a can is the best description I've found, is that accurate?


Yes that is a good description for pinging. Marbles in a can.

 

[Bryanccfshr]

All of us who were around in the late 70s early 80s when leaded gas was phased out, we heard it a lot. My dad had a 4x4 truck with a SBC and it would rattle when taking off, it had a granny low gear that was too low for street and 1st gear was too tall to not ping and knock the engine. I have not heard that noise in along time.
Originally Posted by RamFan
Originally Posted by weasley
It has come about through down-sizing engines, running small engines with high boost at low speed and high loads. The effects can be devastating in only a small number of revolutions.

I have to say it is years since I last heard any pinging or knocking.



Other markets have been using small displacement turbo engines for decades now. Shouldn't LSPI have reared it's ugly head by now? These markets also typically recommend higher octane fuels more often than U.S. manufacturers, I suspect that's a big factor.

To the second point, I'm in my late 20s, I honestly don't know if I've ever heard combustion pinging/knocking. I don't know if I'd even be able to tell what the noise is if I heard it. Marbles in a can is the best description I've found, is that accurate?

 

[Virtus_Probi]

I found it really fascinating that the researchers actually turned the injector in the cylinder under test to wet the walls more as they felt that would increase LSPI occurrence.
I guess details like that could help account for some engines apparently being more susceptible to LSPI compared to seemingly comparable engines of different makes.

Originally Posted by Whimsey

I've not heard that Ford Ecoboost engines are prone to LSPI. I've heard of some GM, hence Dexos 1 Gen 2 being required, and some Subaru engines being prone to LSPI.
Whimsey

The Hyundai Veloster Turbo was the first car I heard about having LSPI trouble, seems like a lot of the vehicles that were damaged were modded but not all of them.
The 2.0l DIT in the WRX and the Forester XT was recalled for LSPI.
The GM 1.5l DIT in the Malibu was also recalled, and some of the same recommendations for that engine were later applied to GM's 2.0l DIT...but I don't know if the latter engine was also recalled.
It does seem like the Ecoboost engines have been relatively LSPI-free, but I have found stories about engines blowing up and LSPI being suspected while poking around on various Ford fora.
Maybe Ford did the best job of aiming their injectors?
;^)

 

[StevieC]

We have a first generation Veloster in the family and 0 issues with LSPI, but it's not modded, just to support what you are saying.

 

[dailydriver]

Originally Posted by Virtus_Probi
Maybe Ford did the best job of aiming their injectors? ;^)


I am hoping that you are correct about this

(IF it is even a factor any more so than the other 'tweaks' they could do with any other systems to prevent LSPI from occurring.)

Eventually, after the power train warranty is up, this car will get a piggybacked PORT injection system added (as some manufacturers are doing at the factory, currently), and tuned in, to help prevent not only this, but any IVD problems as well.

 

[wemay]

Originally Posted by StevieC
We have a first generation Veloster in the family and 0 issues with LSPI, but it's not modded, just to support what you are saying.


The only one's that had the issue were the 1.6Turbo models. The naturally aspirated ones were trouble free. Which one belongs to your family member? Also, Hyundai performed an ecu tune to rectify the situation that became standard on the models after the initial release year. I'm not sure how successful that's been.

 

[StevieC]

TGDI 1.6 and it had the tune. It likes to produce valve gunk so it had one cleaning when it was first new and thereafter we've been doing CRC's GDI/Intake/Valve cleaner regularly. It also has a catch can. But it had 0 issues before this as well in terms of LSPI.

She may have gotten lucky and didn't provide the right conditions for it to happen.

 

[wemay]

Originally Posted by StevieC
TGDI 1.6 and it had the tune. It likes to produce valve gunk so it had one cleaning when it was first new and thereafter we've been doing CRC's GDI/Intake/Valve cleaner regularly. It also has a catch can. But it had 0 issues before this as well in terms of LSPI.

She may have gotten lucky and didn't provide the right conditions for it to happen.


I doubt she was lucky. The one's who've been bit by the LSPI bug are the unlucky ones...all makes and models. I'd wager the vast, vast number of vehicles are trouble free and we greatly exacerbate the issue on these forums.

 

[StevieC]

Originally Posted by wemay
Originally Posted by StevieC
TGDI 1.6 and it had the tune. It likes to produce valve gunk so it had one cleaning when it was first new and thereafter we've been doing CRC's GDI/Intake/Valve cleaner regularly. It also has a catch can. But it had 0 issues before this as well in terms of LSPI.

She may have gotten lucky and didn't provide the right conditions for it to happen.


I doubt she was lucky. The one's who've been bit by the LSPI bug are the unlucky ones...all makes and models. I'd wager the vast, vast number of vehicles are trouble free and we greatly exacerbate the issue on these forums.

She also has our family looking after it and we are anal on maintenance. We were also quite interested when she got it, in seeing what the latest tech from Hyundai was. She had bought it a few years after I bought my Santa Fe.

 

[MParr]

There is so much out there on LSPI. There are some that think certain motor oils will combat the problem. I am not going to buy into that thinking. You have Consumer Reports and other media mockingbirds saying consumers don't need to buy any other gas but 87 octane. I call Bovine Scat on that one. This isn't the 1980s where all domestic engines have 8:1 compression ratios. Today's engines are way more complex with all sorts of sensors and computer controls. The compression ratios have increased, displacement has decreased, forced induction and direct fuel injection has been added.
https://www.roadandtrack.com/new-cars/car-technology/news/a18008/premium-fuel-futures/

 

[Bryanccfshr]

I do wonder how many of these had a "tune"

 

[CR94]

Originally Posted by wemay
... I'd wager the vast, vast number of vehicles are trouble free and we greatly exacerbate the issue on these forums.
More likely form members exaggerate it than exacerbate it, I hope.

 

[Kql]

Typical bob is the oil guy, 3 pages in and EVERY poster is using lspi and detonation synonymously when they are 2 completely different things.

 

[PimTac]

Typical bob is the oil guy, 3 pages in and EVERY poster is using lspi and detonation synonymously when they are 2 completely different things.

Then again, going around digging up older threads seems to be your MO.