Fixed my boost issue.....but spun a bearing this morning

Quote:

Originally Posted by donniekak

Closer to 500. Turbo was fully spooled by 4500 rpms.

Think his car made 640 ft/lbs

Quote:

Originally Posted by keo92stealth

Think his car made 640 ft/lbs

That was corrected.

Quote:

Originally Posted by donniekak

That was corrected.

Yep. 20-25% correction I believe. And that was at higher boost than what he was running when bouncing off the fuel cut (19psi).

I ran king bimetal bearings....so did max, road course use. I think Wayne may have used them also in his 600+hp single turbo car. You are really over thinking what is going on here mershad. If everything else is happy you can have soda cans for bearings and the engine won't lunch itself, remember, in normal operation the crank never makes actual contact with the bearing while running.

The oil is just a lubricant for wear resistance and does a little cushion but the bearings have to still be able to take the load. There is a reason they make trimetal bearings with stronger back plates.

Quote:

Originally Posted by mehrshadvr4

The oil is just a lubricant for wear resistance and does a little cushion but the bearings have to still be able to take the load. There is a reason they make trimetal bearings with stronger back plates.

tri metal bearings have been in use since, hell, well before the 1930's. FWIW, the backing plates are the same between bi-metals and tri-metals.

The link I embedded on post #70 has this discussion for question #3. This is a discussion from MAHLE, King Engine Bearings, and Federal-Mogul. Worth a read since it addresses some questions being raised here...

http://www.enginebuildermag.com/Cont...0000032275.pdf

Quote:

Originally Posted by KOPELIOVICH (King Engine Bearings):

Question 3: What other engine factors, including the parts do you have to take into
consideration when you are designing bearings and when selecting a bearing?

The engine parameters determine the loads applied to the bearings. The load is the resultant force created by two sources, one of them is combustion in the cylinder and then the other is inertial forces created by the moving parts of the engine. The load applied to the bearing at any angle of the crankshaft may be calculated and so too can the hydrodynamic bearing parameters, like minimum oil film thickness and energy loss and oil temperature rise and oil flow, etc. We at King are using our calculation software for proper bearing material selections. But we can determine several main parameters that influence the load applied to the bearing. The parameters are as follows:

Compression ratio –The higher the compression ratio, the higher the pressure of the
gas in the top dead center and the higher the bearing load.

Displacement per one cylinder – Larger displacement means larger amount of fuelair
mixture is taken into the cylinder. It means that the larger energy is discharged in the
one cycle and the larger load is applied to the bearing.

Fuel type –Gasoline fuel with higher octane number allows working with higher
compression ratio without detonation, so the higher-octane fuel produces higher load.
Methanol fuel may be used with even higher compression ratio, about 16. So they load
even higher than gasoline fuel.

Engine type – Diesel engines, especially diesel engines with direct injection,
produced highest pressure in the combustion cylinder, which may reach 220 bar, and of
course highest load applied to the bearings, mostly connecting rod bearings, upper
connecting rod bearings.

Aspiration type – Turbo and supercharged engines use compressed air in the air-fuel
mixture. And compressed air allows to intake a larger amount of air and larger amount of
fuel in one cycle so the larger energy discharge is formed and the larger load is applied to
the bearing.

Bore diameter – The same cylinder pressure produces higher absolute load in the
cylinder with higher bore diameter.

Piston and conrod weights and the rotation speed – Inertial forces developed by
the moving piston and the conrod decreased the resultant force acting on the upper
connecting load bearing. And at the same time they increase the force acting on the lower
part of the connected rod bearing. The inertial forces are proportional to weight of the
moving parts, and therefore, the effect of inertia forces is particularly high at high RPM,
such as 6,000 to 10,000 RPM, which is realistic for racing cars. In the same question
there was a question about the shaft material. I will add that, regarding the crankshaft,
nodular cast iron crankshafts work better with aluminum/silicon material because of the
ability of silicon to polish the ferrite peaks. And tri-metal bearings are recommended for
steel crankshafts.

This was the first paragraph in the 20 page discussion in the subject matter and is worth a read if you have 30mins to burn... There's lots of good bits in there.

In the previous question #2 the TT gas engine was raised and it was tied to having a bearing fit for a Diesel application. Lot's of information about why bearings fail, how they are mfr'd, selected, and expectations were discussed in the post 70 link. The underlined above is pretty much the consensus of all MFR's. From what I gathered the primary reason for the Bi-metal aluminum is embedability and longevity, not power, although there are new composites being tested and developed of bi-metal bearings that have higher compression strength than traditional bearings. When you get shit in your oil the bi-metal bearings take up some of the oil debris. The tri-metal are so strong they don't embed and you lose oil film clearance and create hot spots.

Anyway, never the less, the fact is, the bearings used in Mike's engine were not performance bearings.

And he had no idea how to tune/use an AEM, and was dicking around with it multiple times.

I think all we are trying to say here is it everything else was right the engine would have lived with those bearings. I don't think they are a smoking gun.

I just think everyone should quit being so matter-of-fact with their opinions of the cause. Seems pretty obvious to me that we're all here trying to learn from the failure.

Are oem bearings bi or tri? Clevites? I've used oem (91-92) and std clevites in my engine making at least as much power as sin and inspected them regularly. I've seen scuffing and shit, but nothing awful. The quickest damage I've ever seen occurred when the oil became contaminated with fuel.