LSPI engine damage

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Originally Posted By: bigunz

Yep my head is spinning
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I was thinking about this and it could be endless with what it could be.

The problem could be caused by a multitude of different or linked things and everything inbetween when it comes to fuel, from it been just a change in the octane from 98 to 95 and the ecm removing timing with 95 etc to stop it happening or from particles of unburnt 98 fuel hiding in the ringlands (being more resistant to burn) to excesses of soot caused by the extra octane booster been uses or even the claimed 25% extra detergents from 95 to 98 ( I have read some detergents can cause carbon too) or even too much of a particular solvent in the fuel and most probably a lot more other things as well.

I agree completely. It looks like they are going to have to do a lot more research.
It kind of drives me nuts
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Just don't buy a Direct Injection, Forced Induction engine & you'll be fine.....HaHa Buy a big ole V8 & pass everything on the road except a gas station
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Originally Posted By: bigunz

It turns out it was 98 Octane (93 AKI) that was the cause, changed to 95 (91 AKI) and it stopped within 50 Km's (done it once) and hasn't done it since.


Myself and some friends have had trouble with 98 RON in Australia with a multitude of vehicles. In the end we found it was the 98 at certain petrol (gas) stations that caused problems, but the same brand 98 at other petrol stations was OK. I hear 98 RON is more susceptible to age and contamination issues. Those fuel stations that sell less of the expensive 98 will have older stock and more issues. When I got the same fuel from a high turn-over station, no problem.

Not many people buy 98 PULP, most get 91 ULP or 95 PULP. Both PULP have lower sulphur limits than the regular ULP.

I've settled on 95 RON myself. My motorcycles would ping on 91 but not 95 or 98. Plus I've never had a bad batch of 95.
 
Originally Posted By: SR5
Myself and some friends have had trouble with 98 RON in Australia with a multitude of vehicles. In the end we found it was the 98 at certain petrol (gas) stations that caused problems, but the same brand 98 at other petrol stations was OK. I hear 98 RON is more susceptible to age and contamination issues. Those fuel stations that sell less of the expensive 98 will have older stock and more issues. When I got the same fuel from a high turn-over station, no problem.

Not many people buy 98 PULP, most get 91 ULP or 95 PULP. Both PULP have lower sulphur limits than the regular ULP.

I've settled on 95 RON myself. My motorcycles would ping on 91 but not 95 or 98. Plus I've never had a bad batch of 95.

Have said in the past that I reckon something is "up" with the fuel in Western Australia. Used to live up North, and never had an issue with pinging on 98, and even 95 in some instances (that said, my knock sensors were on the way out). Pop down to Perth for a visit, fill up with 98 from a high-turnover station and BANG, pinging. Fill up with 98 on the way back home further up the coast; no issues. Then I moved down here, and the same thing happened

Theoretically, most of the fuel in W.A. should be coming from BP in Naval Base. Maybe fuel has to be formulated different for very hot, arid areas? I always wondered whether the 98 pumps down here were ripping me off and giving me a tank full of 95 - there was just no other reason why Caltex 98 in the city should be different from Caltex 98 in the middle of nowhere!.
 
I've read about issues related to that on l83 chevys also direct injection, a lot of Silverado owners due to our compression ratio are running mid-grade now at least the ones in the know because regular sometimes causes knock.engine compensates obviously but since I've made the switch about 2k miles ago it runs much smoother.
 
Nuttin quite like dredgin' up old threads, eh?

Originally Posted by Solarent
... they say that one of the way that OEM's have been combating LSPI up to this point is by programming the engine to pump excess fuel into the cylinder, which has a cooling effect to prevent the issue.


If that's the case then it should add credence to me splash ethanol boosting.

Originally Posted by OneEyeJack
I've had a 2017 Sonata rental that would pull hard at around 1,200 rpm under load and not shift if you were steady on the throttle. Driving that way and holding it in 6th gear in cruise control by moving the shift lever to the left taking it out of the "D" position would get highway mileage from 37-43 mpg. It felt like a struggle but I drove it that way for the mileage thinking the engine control system would take care of itself. Still, you only get mileage like that driving carefully and paying attention to the flow of traffic on the freeway. This car did the rest. I was really impressed.


Might that be the 2.4 or the 2.0T? Either way it's interesting none the less. That's less than 500 rpm over idle. I lug at 1500 rpm & cruise at 1750 rpm toolin' about on two-lane.
 
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Originally Posted by PimTac
My theory is just plain old lugging the engine.


Perhaps though in my case the 2.0T has 9.5 static CR, 17.4psi,& 269ftlb starting at 1725 rpm. Combined w/relatively light curb weight & C/D of 0.28 what is lugging?


Originally Posted by dblshock
run the TCW-3 640:1 to control deposits.


I always wondered how the figure came up to be 640:1. Why not 512:1?

Would that change for differing fuel delivery systems?
 
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Carburetor, throttle plate, multi-port or direct injection would all be the same, eh? The high pressure of the DI is claimed by some to wash the cylinder walls of crankcase oil. Yet, if that's the case then perhaps less is needed or even more depending on how one assesses the situation I suppose.

I'm still wondering how the ratio of 640:1 was decided. For decades 2-cycle outboards have run 100:1 though some manufacturers recommended 50:1 for commercial/constant high rpm use. If 100:1 synthetic provides enough lubrication for the marine application how was 640:1 determined to be the proper ratio for keeping 4-cycle combustion chamber deposits to a minimum and provide additional top end lubrication?

Was there some kind of study about how much synthetic 2-cycle oil could be burned w/o clogging up a wideband O2 sensor?
 
Originally Posted by Sayonara_Sonata
Carburetor, throttle plate, multi-port or direct injection would all be the same, eh? The high pressure of the DI is claimed by some to wash the cylinder walls of crankcase oil. Yet, if that's the case then perhaps less is needed or even more depending on how one assesses the situation I suppose.

I'm still wondering how the ratio of 640:1 was decided. For decades 2-cycle outboards have run 100:1 though some manufacturers recommended 50:1 for commercial/constant high rpm use. If 100:1 synthetic provides enough lubrication for the marine application how was 640:1 determined to be the proper ratio for keeping 4-cycle combustion chamber deposits to a minimum and provide additional top end lubrication?

Was there some kind of study about how much synthetic 2-cycle oil could be burned w/o clogging up a wideband O2 sensor?




As I have said a number of times before, I'm not a engineer. You mentioned the high pressure of DI. I take that to mean the high pressure delivery system. Yes they are high pressure but they have to counter the pressure within the combustion chamber. Someone correct me if I'm wrong here.

Mazda runs a 13:1 compression ratio in their SkyActiv engines. I have not experienced any extreme fuel dilution by the nose test. I'm too cheap to get a analysis done. I do run 92 premium fuel though. There has been a number of discussions here and elsewhere regarding decreased fuel dilution with higher octane gasoline.

The computers control the fuel injection very precisely. They inject fuel at varying and multiple times into the chamber depending on what all the sensors tell them. It's not the old one shot and done scenario from the past.


I had to re-read my responses. This is a old thread. It seems every weekend we have these resurrections
 
Me apologies for the Lazareth thread raised from the dead. In the course of research this was the thread that popped to the top.

Originally Posted by PimTac
... regarding decreased fuel dilution with higher octane gasoline.


Thought never crossed me mind. I've read that high octane non-ethanol can be 25% aromatic in the blend.

I've run E-free 87/92, E5 92, E10 91/93 and played w/splash blending ethanol at various points from E15 the low to mid E20s.

Some, w/2.0T engines, that only have E10 91 available splash blend to kick the octane up to 93. That requires one run E30. In this instance the additional timing advance trumps the lower BTU of the ethanol & as a plus cooler combustion via higher latent of heat vaporization, more volume, ethanol vs petrol, at a modest mpg penalty.

The TCW-3, at whatever ratio, is the continuation of the MMO or A/T blend at fillup as top end protection/insurance/Owner's own version of extended warranty. In modest amount it surely wouldn't hurt, but why 640:1? That ratio has most certainly achieved, if naught else, urban legend status.

Mariners will argue over 100:1 Vs. 50:1, or the ever popular split 75:1 enabling them to stand on both sides of the fence simultaneously/ I'm at least half right though can only be at most half wrong in the optimist Vs. pessimist struggle, but that little discussion involves 98%-99% petrol.

Math isn't me strong suite though the diff as I see in 640:1 Vs. 512:1 or even 768:1 comes to 0.04% evah so roughly. Six point four times leaner than 100-1 isn't much, but neither is 5.12X. Why not 576:1?

How would any ratio of TCW-3 play into LSPI?

Enquiring minds wish to know.

Perhaps a thicker crankcase oil as 5W40, compared to the lower viscosity mileage blends, would help stave off the rare LSPI occurrence.
 
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Originally Posted by Sayonara_Sonata
Me apologies for the Lazareth thread raised from the dead. In the course of research this was the thread that popped to the top.. . .

Lazarus was dead only four days. . .
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This thread has me literally cracking up. If taking off in a cold car resulted in blowing an engine then half of Ohio and Michigan would be riding bikes. I have ripped my kids, took keys and still watched them start their cars in zero degrees and gone in 60 seconds. I'm not proud but at 46 I guarantee I did it at least a hundred times growing up. My grandad owned big rigs and drivers would be fired for doing it yet they still did and not one catostrophic failure. With age comes patience and not liking a cold car, I let it run for a good 10 minutes now but didn't used to.
 
Originally Posted by Sayonara_Sonata
If that's the case then it should add credence to me splash ethanol boosting.


I doubt it does add credence, because any measurable cooling effect also means you're adding enough ethanol to affect the energy content of the mix as well. Since ethanol has roughly 30% less energy per volume as gasoline, if your injectors can't supply enough additional volume to bring the A/F ratio back where the ECU expects it, the engine will run lean. Which means it will run hotter, and offset any "mythical" gains you're trying to convince yourself of. And running hotter will create hot spots with more opportunities for pre-ignition, which will result in... wait for it... LSPI.

There's a reason "gas" engines specify a maximum of 10% ethanol and not more. Why splash boost it when you can just fill up with pump E85 for $0.30/gallon cheaper, then footbrake boost it for about 5 minutes or so. Just be sure to record it and post it to Youtube, and have a spill kit ready to clean up the mess.
 
[/quote]

I always wondered how the figure came up to be 640:1. Why not 512:1?

Would that change for differing fuel delivery systems?
[/quote]

620:1 makes measuring easy.
2 gallons (US) per 1ounce.
 
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