BE Bearings In-Depth: Oil Flow, Oil Pressure Analysis

[8k4]

Why was throttle modulated just after start? Every graph has throttle modulation, baseline should be included

[Green-Eggs]

Originally Posted by 8k4

Why was throttle modulated just after start? Every graph has throttle modulation, baseline should be included

There's a bunch of reasons. The most common is to leave a full parking lot or garage ASAP as a courtesy of the guy waiting patiently for your spot.

Doing cold start analysis was an afterthought. I think the program that searches the database for them is going to get tweaked to see if we can remove these types of entries.

[Sneaky Pete]

Originally Posted by BMRLVR

The strength of the wedge is not reliant on system pressure, the strength of the wedge is a result of the journal spinning against the wedge of oil. Actual pressure on the wedge is much higher than system oil pressure.

Indeed...but increasing the clearance has a detrimental affect on the oil film pressure, which is pretty much key in keeping the moving surfaces apart.
Out of interest do you have an idea what is the oil films' peak pressure?

[SVH]

Originally Posted by Sneaky Pete

Indeed...but increasing the clearance has a detrimental affect on the oil film pressure, which is pretty much key in keeping the moving surfaces apart.
Out of interest do you have an idea what is the oil films' peak pressure?

I don't see it as "detrimental". Any data that indicates that it is? Indeed the clearance in BE's bearings might be perfect

[Green-Eggs]

Originally Posted by SVH

I don't see it as "detrimental". Any data that indicates that it is? Indeed the clearance in BE's bearings might be perfect

When BMW changed the rod bearing clearance on S54 to what BE is now using on S65, and using the same oil, I don't think we saw any of these concerns or engines blowing as a result.

[aussiem3]

Wealth of information and data to absorb. Hope all these lead to one thing - a solutions is afoot to put an end to the BF saga. Thank you for sharing.

[AutoTalent]

Originally Posted by Redd

Generally it takes less than 3s to reach 90% pressure for both BE and BMW bearings. But why is there such a spike at the 60-80degC and 90-96degC temp ranges, up to 26s to reach 90%?. This seems very anomalous.

Is it a characteristic of the oil?

Originally Posted by 8k4

Why was throttle modulated just after start? Every graph has throttle modulation, baseline should be included

I'm told changing the programming to find samples without throttle modulation wasn't a simple programming fix. Apparently it was difficult enough that it turned into an all day project. A few temperature ranges got erased in the process because there weren't any samples in those ranges without throttle modulation. Anyways, here's the results. They've been updated in post-1, and post-2 as well.


Testing Results: BMW Factory 702/703 Bearings

Overview

Cold/Warm Start Analysis

Cold/Warm Start Data

The following chart amd graphs will show what it looks like from the time you press the "START" button to 30-seconds later. The chart shows how long from “START” until 70% and 90% oil pressure is attained.

Cold Start Graphs

Warm Start Graphs

Testing Results: BE Bearings SP1527HK

Overview

Cold Start Analysis

Summary Oil Pressure, Oil Flow Tests

Once you start your car, have you ever wondered how long it takes for oil pressure to build and oil flow to start? This is the section that shows what it looks like.

The following chart amd graphs will show what it looks like from the time you press the "START" button to 30-seconds later. The chart shows how long from “START” until 70% and 90% oil pressure is attained. After analyzing some of the data, it appears the throttle input might have been influencing the maximum oil pressure and flow. Had I known this, I would have not introduced any throttle until 30+ seconds after starting the car.

BE Bearings


BMW Factory 702/703 Bearings

• Most likely outlying data caused to throttle input

Summary
According to this chart, the BE Bearings take less time to reach 70% and 90% oil pressure compared to their BMW OEM counterparts. Not only is it less time to reach full oil pressure, it seems significantly less time to reach full oil pressure. This is a bit of a shock to me and something I never expected to see.

Cold Start Graphs

Summary
These graphs show both BE Bearing and BMW Factory bearings (as lighter colors). It's very clear from these graphs, that the oil pressure comes up faster with BE Bearings than BMW Factory bearings. Having oil pressure come up faster and lubricating the bearings is a huge benefit to reduce bearing wear and increase bearing longevity. This was an unexpected surprise that we didn't anticipate. The graphs also show no decrease in oil pressure over factory bearings. This should allay fears that increased clearance would decrease oil pressure, especially during this critical "Cold Start" time period.

Oil flow does seem to modestly increase as well. This was an anticipated outcome, but it's good to see it on the graphs.

Warm Start Graphs

Summary
The trend with continues from our Cold Start graphs to our Warm Start graphs. Oil pressure comes up faster with BE Bearings than BMW factory bearings. Oil flow shows modest increases as well, but we'd say this is fairly inconclusive -- especially above 80c. Those graphs contained too much throttle input, and we think that contaminates the results. Now that we know this, we will see if we can filter out the results containing too much throttle, and moving forward will capture results without any throttle until 30-seconds has passed since starting the engine.

[Leonardo629]

Will you guys be conducting similar data gathering on a 0W40 oil? With BE bearings of course?

[undecided]

Originally Posted by Leonardo629

Will you guys be conducting similar data gathering on a 0W40 oil? With BE bearings of course?

As temps in the northeast can dip into the 0 degree Fahrenheit (-17 Celsius), running 10w60 in the winter doesn't sound wise regardless of which bearings you 've got.

[Redd]

Thanks for the hard work!

[Sneaky Pete]

Originally Posted by SVH

I don't see it as "detrimental". Any data that indicates that it is? Indeed the clearance in BE's bearings might be perfect

Oil Flow: The most significant change between factory and BE Bearings is the oil flow. We were hoping for a modest increase in oil flow to offset a modest decrease in oil pressure. But the resulting oil flow is nearly double with BE Bearings over the BMW 702/703 bearing counterparts.

Looking at the 50% throttle oil flow graphs and picking the data point where the oil flow rate does indeed appear to have doubled from 21 GPM to 42 GPM with the increase in bearing clearance.
With the OEM bearings the 21 GPM covers the oil flow to the Vanos, main bearings, rod bearings, camshafts, piston cooling, chain tensioners etc.
So lets say of that 21 GPM, 7 GPM flows through the rod bearings.
With the increased clearance bearings the total flow increases from 21 GPM to 42 GPM, which can only be accounted for by increased flow through the Rod bearings (as nothing else has changed).
So by increasing the RB clearance we see the oil flow though the rod bearings increase from an estimated 7 GPM to a total of 28 GPM (7 + 21).
A quadrupling of oil flow though the rod bearing may initially seem appealing but its due to the increased clearance allowing the oil to haemorrhage out of the bearing at a greatly increased rate.
Increasing the ease of escape of the oil from the bearing will naturally also negatively affect the pressure of the oil wedge and the loaded oil film.

Having double oil flow over the bearing surface increases the wedge strength

There is zero data to support this.

[SVH]

Originally Posted by Sneaky Pete

Looking at the 50% throttle oil flow graphs and picking the data point where the oil flow rate does indeed appear to have doubled from 21 GPM to 42 GPM with the increase in bearing clearance.
With the OEM bearings the 21 GPM covers the oil flow to the Vanos, main bearings, rod bearings, camshafts, piston cooling, chain tensioners etc.
So lets say of that 21 GPM, 7 GPM flows through the rod bearings.
With the increased clearance bearings the total flow increases from 21 GPM to 42 GPM, which can only be accounted for by increased flow through the Rod bearings (as nothing else has changed).
So by increasing the RB clearance we see the oil flow though the rod bearings increase from an estimated 7 GPM to a total of 28 GPM (7 + 21).
A quadrupling of oil flow though the rod bearing may initially seem appealing but its due to the increased clearance allowing the oil to haemorrhage out of the bearing at a greatly increased rate.
Increasing the ease of escape of the oil from the bearing will naturally also negatively affect the pressure of the oil wedge and the loaded oil film.



There is zero data to support this.

"So let's say that.....".
Conjecture. Where's your data.
You also presume that the flow over the bearings is enough to start with. Most data to date indicates
differet.

[BMRLVR]

Originally Posted by Sneaky Pete

A quadrupling of oil flow though the rod bearing may initially seem appealing but its due to the increased clearance allowing the oil to haemorrhage out of the bearing at a greatly increased rate.

If the oil were haemorrhaging out of the bearings as you state, system pressure would drop...... You need to brush up on your knowledge of hydraulics.

Oil being lost out the side of the bearings is the only way for additional oil to get in, it is by these means that a journal bearing is cooled. It is less desirable for the bearings to not allow some oil to escape, under these conditions bearing temperatures increase and as a result the oil in the bearing loses viscosity and the oil film could break down allowing metal on metal contact.

[Green-Eggs]

Originally Posted by SVH

"So let's say that.....".
Conjecture. Where's your data.
You also presume that the flow over the bearings is enough to start with. Most data to date indicates
differet.

When I showed the oil flow data on BMW 702/703 bearings to my engine experts, they all thought 2-4 GPM at 8000 RPMs from 100-103c oil temps was a dangerously low value. The summary graph which is all oil temperatures above 98c, was also dangerously low in their opinion.

So funny to hear a guy argue against the same spec BMW used on a revised S54 rod bearing is now dangerous for S65. I wonder if anybody else finds that pretty funny.

[Green-Eggs]

Originally Posted by Sneaky Pete

Looking at the 50% throttle oil flow graphs and picking the data point where the oil flow rate does indeed appear to have doubled from 21 GPM to 42 GPM with the increase in bearing clearance.
With the OEM bearings the 21 GPM covers the oil flow to the Vanos, main bearings, rod bearings, camshafts, piston cooling, chain tensioners etc.
So lets say of that 21 GPM, 7 GPM flows through the rod bearings.
With the increased clearance bearings the total flow increases from 21 GPM to 42 GPM, which can only be accounted for by increased flow through the Rod bearings (as nothing else has changed).
So by increasing the RB clearance we see the oil flow though the rod bearings increase from an estimated 7 GPM to a total of 28 GPM (7 + 21).
A quadrupling of oil flow though the rod bearing may initially seem appealing but its due to the increased clearance allowing the oil to haemorrhage out of the bearing at a greatly increased rate.
Increasing the ease of escape of the oil from the bearing will naturally also negatively affect the pressure of the oil wedge and the loaded oil film.

This particular oil flow sensor was chosen after consultation with Dinan, Van Dyne, and Nascar guy. All three companies use the same Flow Technologies 0-15 GPM sensor on their engine dynos. The fact you think you see 42 GPM from a 15 GPM sensor, and didn't question it, tells me you're not at all familiar with the oil flow of car engines.

The 0-15 GPM oil flow sensor specifications are listed in the opening of post-1. The fact you missed this, and think you saw 42 GPM readings, tells me that you didn't read this article very closely, or didn't understand what you read.

There's two different scales on the summary graph: one in blue, the other in red. They're color coded for a reason to match the lines in the graph. The oil flow graph is in red, and corresponds to the scale on the right of the graph (also in red). That oil flow scale runs 0-15. It's impossible to read 42 GPM from that scale when it maxes out at 15 GPM. The fact that you didn't catch this tells me you're not familiar with reading technical data, charts, etc.

There is zero data to support this.

You have a long history of making comments without any supporting data. If you had any data to back up your claims, you could have presented them already. I'll trust the white papers by Clevite and King over a random internet guy with a long history, personal vendetta, and no SME credentials.

Pete, it's time to give this a rest. This article and the data is the worst case scenario for you and your agenda. You hoped oil pressure would be dangerously low. It wasn't, and barely changed. It's still well within BMW specifications. You didn't believe oil flow could be measured attributable to bearing clearance. You now seem to concede that point as well. Face it Pete, no oil pressure drop and double the oil flow, and using specs equal to BMW S54 rod bearings is about the worst case scenario for you and your agenda. Time to pack it up and find a new target for your energy.

[Green-Eggs]

Originally Posted by BMRLVR

If the oil were haemorrhaging out of the bearings as you state, system pressure would drop...... You need to brush up on your knowledge of hydraulics.

Oil being lost out the side of the bearings is the only way for additional oil to get in, it is by these means that a journal bearing is cooled. It is less desirable for the bearings to not allow some oil to escape, under these conditions bearing temperatures increase and as a result the oil in the bearing loses viscosity and the oil film could break down allowing metal on metal contact.

S54 rods for example, have a channel cut into them specifically designed to allow oil to "hemorrhage" out. I know one race shop who machines S65 rods to put that same channel in them to allow the oil to "hemorrhage" out of them as well. Pete should know this...right?

[Sneaky Pete]

Originally Posted by Green-Eggs

There's two different scales on the summary graph: one in blue, the other in red. They're color coded for a reason to match the lines in the graph.

Its a fair cop guv....I was inattentive when I pulled the numbers from the wrong side of the graph.
It changes nothing though, the principles remain the same.
Increasing the RB clearance does allow an easier escape for the supplied oil such that the flow out of the bearings increases approx some fourfold (not double as you mistakenly noted - but I won't go on about it). The consequence being a 4% drop in oil pressure for the whole lubrication system.
Equally it remains correct that increasing bearing clearance will change (non-beneficially) the distribution of pressure over the bearing surface and increase the peak pressure.

[BMRLVR]

Originally Posted by Sneaky Pete

Its a fair cop guv....I was inattentive when I pulled the numbers from the wrong side of the graph.
It changes nothing though, the principles remain the same.
Increasing the RB clearance does allow an easier escape for the supplied oil such that the flow out of the bearings increases approx some fourfold (not double as you mistakenly noted - but I won't go on about it). The consequence being a 4% drop in oil pressure for the whole lubrication system.
Equally it remains correct that increasing bearing clearance will change (non-beneficially) the distribution of pressure over the bearing surface and increase the peak pressure.

The peak film pressure will not be an issue at this clearance level. With the development t of the BE Bearings for the S65, no one reinvented the wheel and did anything that was experimental or risky. BE Bearings put the S65/S85 at a clearance level that is recommended by mechanical engineers, engine builders, bearing manufacturers, and is used by a vast majority of OEM's

The only concern with BE Bearings from the beginning was, how much of an oil pressure drop would be seen once the bearings were installed? With this data we have answered this question and the results are even better than what we expected.

You can keep prodding and poking all you like but all it is doing is making you look silly. You are suggesting that a rod bearing set at best practice clearance could cause some serious issue in an ICE.

[Green-Eggs]

Originally Posted by BMRLVR

The peak film pressure will not be an issue at this clearance level. With the development t of the BE Bearings for the S65, no one reinvented the wheel and did anything that was experimental or risky. BE Bearings put the S65/S85 at a clearance level that is recommended by mechanical engineers, engine builders, bearing manufacturers, and is used by a vast majority of OEM's

Also no different specs than BMW themselves on updated S54 bearings. Those are 0.0010 inch clearance per journal-inch diameter. BE Bearings for S65 are 0.0011 inch clearance per journal-inch diameter. That's basically the same spec.

The only concern with BE Bearings from the beginning was, how much of an oil pressure drop would be seen once the bearings were installed? With this data we have answered this question and the results are even better than what we expected.

With more data to come on a monthly basis.

[Green-Eggs]

Originally Posted by FogCityM3

Agree with this point, thx. Would be interesting to look at the underlying data itself to determine median, mode, std deviation and other measures/relationships.

I'm told BE dudes were able to find a statistics add-in to their SQL server. I have no idea what that means lol. I think they're planning to re-run the analysis with median, and mode and then post the spreadsheets for download. Not sure when that will be done...but probably in the next few days.

[Leonardo629]

Let me ask again, possible 0w40 testing? It will add a lot of insight to why BMW chose 10w60.

[BMRLVR]

Originally Posted by Leonardo629

Let me ask again, possible 0w40 testing? It will add a lot of insight to why BMW chose 10w60.

Not sure if it will happen, but with the clearance now at what it is with BE bearings a 10W60 can actually be used and taken advantage of. I can't see there being an issue with 0W40 with the looser clearance either.