Dboyizmlg

+1

Big turbo, with engine block being mostly stock can deff be the culprit

Kingtal0n

Keep in mind two things,

A: The rod bearing is a mechanical part, i.e. you can spin an sr20det by hand (crank it over with a start, spin it with the rear tires, or if you invented a device to spin the engine electronically all of that is possible without the turbocharger or even gasoline) And at some point, the oil pump / provided oil will be insufficient at some XXXXrpm. Also, there are mechanical limits imposed by valvetrain parts (but for the sake of this example, lets assume the valvetrain is invincible to 999999rpm). and piston velocity speed limits, and other mechanical problems with ultra high RPM. What I am getting at is, running engine or not, there is some mechanical limit imposed by the rotating assembly, its design/clearances, the oil you have chosen, and the variables associated with a running engine: temperature, frequencies, pressure settings such as oil pressure relief, and even the alignment of structures within the engine and all of the places oil is expected to slip from between parts.

That said, how fast do you think we can spin an sr20det engine with an invincible valvetrain until it spins a rod bearing? and why would the lubrication fail, is it the pump? the weight of the oil? the clearances of the engine? The type of bearing? None of this can be known, even with a full tear-down and inspection you are still making a "theory" of why the engine failed. It does not necessary have to be the real reason it came apart. The main point of A: is this then: There are many situations that can cause a rod bearing to fail which have nothing to do with the turbocharger or even combustion of gasoline, and everything to do with lubrication facility of the engine.

With this main point in mind, we will come to B:

B: there is only one way that gasoline (i.e. the turbocharger aspect of the engine) can cause a rod bearing to spin, (whereas there are several lubration aspects) and that is pre-ignition (for zealots I am being more specific: on-set of combustion pressures too rapidly, too soon) and that way is very specifically due to insufficient octane and/or too much timing advance. Ill repeat it: these are the only two aspects of the turbo that can cause rod bearing failure this one way.

One of them is due to the gasoline you put in your car, the other is due to the guy with the laptop.

Praxis

That timing table is terrible. The Power FC over reports knock, but it can be used during dyno tuning.

380rwhp, on a legit, un doctored Mustang Dyno is a lot of power for a stock bottom end.

Most common detonation failure I see is due to oil in the intake. Either pcv, or turbo.

Praxis

Number one cause of detonation in a street type car is oil.

Pcv, or turbo, rings etc. Ive even seen valve stem seals do it.

On tear down, look for oil in the intake, intercooler piping, and piston tops for burnt oil residue.

Croustibat

We do, in France, because these come with stock S14

It depends on what you call "good power" of course. I missed one when it went on sale, built by my tuner, 450WHP+ , z33 gb, had done 1 pro drift season, owner wanted a V8.

This was a dyno run done with a JASMA restrictor welded in the exhaust, that was removed later. 2 years ago, still running and taking abuse

TheRealSy90

So for example where I live, our coldest time of the year is high 60's, and the hottest part of the year is between 105-115 for a couple months. This would make sense to run that 10/15w50 oil even with a good condition oil pump, correct? (I don't really take the "lows" into account, because I'm not usually driving my car around at 3-5am in the winter.)


This is our yearly averages.

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civicej8

Thanks codyace. My car probably was at your cars power level.

I've read even enthaplys suggestions for built motors and he suggests stock bearings for the mains and rods. I even talked to my tuner after and he reassured me we were running a super safe tune. He said my knock count on the fc was at 19 at the highest. He said you need to be in the 70s for engine damage. Although my motor didn't seem to last long after that.

Kingtal0n

words

With OEM cams the knock high is 12 on the PFC, and I see an occasional 14. The number itself is not as valuable as the consistency with which it appears. For instance, when I install HKS 272 camshafts with VTC, I would see 19 on about 1/3 to 1/5 of every wot pass. If I disable the VTC, it goes back to a consistent 12 (PFC can turn off VTC at 1300rpm so it is off the entire time you drive, or just unplug the vtc solenoid). the fact that vtc can be picked up in the engine knock number should tell you that other such similar situations exist of which we are unaware which undoubtedly result in the random number that appears.

For what it is worth, it may not be apparent if you never operated the data-logit with an PFC, the default setting in the power FC for knock count to warn the driver is around 65.

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5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240

Croustibat

No, it does not make any sense to base your oil choice on anything else than pressure when cold and at operating temp. Temperature has an influence on oil viscosity and therefore pressure, which is why the oil choice needs to be made depending mostly on oil working temperature.

The temperature VS oil thickness choice graph is something for people with no engine knowledge (nor oil pressure gauge) and standard car use.

(and i don't know how to use °F, there is an international standard, use it )

Basically, on these engines, if your oil working temp is around 100°C, you should be fine with 10w40 in summer and 5w40 in winter. If you are more around 110°C , 10w50 would be fine. If your oil temp reaches 120° or more... there may be something wrong, so find what and/or get an oil cooler .

Again, if you ever need 15wX oil or Xw60 on these engines, it mean something is seriously wrong, or you are living in an extremely hot country, or the engine is giving everything it has for prolonged time and can't cool correctly (like 600+ WHP)

TheRealSy90

It's just not the standard here, sorry I don't think to use it.



Well I do live in a very hot country, we average over 40°C in the summer time during the day, and no less than 18°C in the winter to put it in perspective, we only have a couple "winter" months. Wouldn't 10w50 and 15w50 have the same effectiveness when the engine is at operating temperatures?

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Kingtal0n

Croustii, do you have any charts or diagrams of oil flow vs pressure in an engine? I've been trying for 3 minutes to find one for any random engine; it is proving more powerful than my attention span

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5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240