FA20 Engine Oiling, Bearings, and Starvation

[Element Tuning]

Ok so I'll try and just get this on track and talk specifically about pressure relief and the pump on the FA20 since we can't debate every application. So the FA pressure relief is different than many I've seen and I can't totally say why it is that way.


Don't hold me too this because I've got more important things to do, like come up with a solution, vs. debating it. From what I remember there are two stages to the relief which is why the spring is so long and the piston has to travel so far. You can also see the differences with the OEM FA20 and the FA20DIT



So these oil pump are not dinky oil pumps, they are quite high volume, so the problem is in the motor itself (volume demands). Twin springs vs one spring, long piston vs. short piston, long spring vs short spring, and preloaded bolt vs. unpreloaded bolt.

I have tested both the 12mm and the 14mm on this engine and the 14mm wasn't even enough. I have shimmed the pump until my pressure gauge can't even read the pressure it's so high at start up. Nothing done to the pumps alone was enough to get the pressure high enough under operating temps.

So we sprinkled pixie dust on our Element Tuning motors and we can get the pressure we need on the street to just about any power level you need up to 9k RPM but on the track we are still to low to get over the 400 whp mark safely. Now if the math is correct with the Remax gear, add all our internal engine mods, add the massive oil cooler, add the accumulator, and continue with 50 weight race oil, I'm hoping we'll have enough for 500 whp under racing conditions.

Maybe the Remax gear can get people without our engine build up some but I'm really not optimistic it's going to be enough for you guys on it's own. We have with our build 85 psi to 8k and about 80 psi to 9k RPM at operating temps (dyno and hard street) and most OEM engine builds are lucky to see 55 psi to 7000 RPM. I'm asking the Remax gear to give me plus 20 psi under racing conditions but many are hoping it will give them what we already have (+30 psi) along with what we need for racing (+20) which would total +50 psi more oil pressure. It's a long shot!

[rice_classic]

Originally Posted by Element Tuning

I have tested both the 12mm and the 14mm on this engine and the 14mm wasn't even enough. I have shimmed the pump until my pressure gauge can't even read the pressure it's so high at start up. Nothing done to the pumps alone was enough to get the pressure high enough under operating temps.

So we sprinkled pixie dust on our Element Tuning motors and we can get the pressure we need on the street to just about any power level you need up to 9k RPM but on the track we are still to low to get over the 400 whp mark safely. Now if the math is correct with the Remax gear, add all our internal engine mods, add the massive oil cooler, add the accumulator, and continue with 50 weight race oil, I'm hoping we'll have enough for 500 whp under racing conditions.

That part in bold is what was missing from earlier in your thread (at least I missed it) and it satisfies my curiosity.

Thank you sir.

[EAGLE5]

Originally Posted by D K

WTF???

Did I stutter?

[rice_classic]

Originally Posted by jsimon7777

Did I stutter?

You're not necessarily incorrect.

But to this community it's a HUGE design flaw!

[Decay107]

Haven't checked back in a while, but unless my limited understanding of how oil pumps work is incorrect.

And using the measurements provided for the reimax and stock oil pumps here
http://www.gt86.org.uk/forums/topic/...details/page-2

Are my calculations correct that the stock oil pump is flowing around 92 lpm of oil at 7000rpm? Perhaps a lot of the pressure drop we see comes from improperly chosen oil coolers.

Some calculations from setrab are located here,

http://www.setrab.com/media/28769/Se...nce-graphs.pdf

To me it seems that to optimize pressure drop to thermal efficiency one should really shoot for right around 2lpm/tube. So someone running a series 6 13 row oil cooler would be flowing nearly 4x that amount which would lead to significant pressure drop (my guess is around 12 psi just across the core) at 7000 rpm. Has anybody tried a 50 row series 1, I bet that improves things.

[EAGLE5]

I don't think that's exactly how fluid dynamics works. An overall pressure drop comes from taking liquid out of the system, like when pouring into the oil pan, not from flowing into a large, pressurized pool in the cooler. Friction and other constrictions would create pressure drop. Physically pushing more liquid can do it, too.

[Ultramaroon]

Originally Posted by jsimon7777

I don't think that's exactly how fluid dynamics works. An overall pressure drop comes from taking liquid out of the system, like when pouring into the oil pan, not from flowing into a large, pressurized pool in the cooler. Friction and other constrictions would create pressure drop. Physically pushing more liquid can do it, too.

no.

If you have 70 psi at the output of the pump then the overall pressure drop is 70 psi.

How much of that 70 psi budget is left to lubricate the journals after the oil cooler? This is the question. Unfortunately it's not a fixed value. Among other things, it's a function of mass flow rate. This is what I tried to explain earlier in this thread.

Both you and @Element Tuning are making the same mistake in your consideration of the overall mass of the system. Whether flowing through several oil coolers in parallel or through only one, the mass flow rate is the same.

Resistance to flow is an inherent part of the system. But why?

The total flow resistance of the system is the sum of all the series resistances encountered. Among other things, resistance to flow is a function of fluid velocity. Anywhere the fluid has to speed up is a place that place that takes away from the total pressure budget.

A radiator can exchange thermal energy 2 ways. It can take a lot of energy out of a few long thin tubes, or it can take the same amount out of those tubes all chopped up to shorter pieces and running in parallel. The effective surface area stays the same but in the second solution, the fluid velocity is slower. That's precisely why the Setrab series-1 with the same power rating has a lower pressure drop than the series-6.

Another clever arrangement could be to run a couple series-6 in parallel. The same amount of oil at half the velocity through a fatter pipe.

[cdrazic93]

Originally Posted by jsimon7777

I don't think that's exactly how fluid dynamics works...

Originally Posted by Ultramaroon

no.

Both you and @Element Tuning are making the same mistake in your consideration of the overall mass of the system. Whether flowing through several oil coolers in parallel or through only one, the mass flow rate is the same.

lol I would interject but alas I am not smart enough yet not of graduate level fluid dynamics courses. Ultra mistakenly thought I knew something about fluid dynamics

[Ultramaroon]

Originally Posted by cdrazic93

lol I would interject but alas I am not smart enough yet not of graduate level fluid dynamics courses. Ultra mistakenly thought I knew something about fluid dynamics

Oh, stop. You don't give yourself enough credit. See, I didn't use a lick of math.

...but my textbooks are right here on the coffee table. ...just in case.

[cdrazic93]

Originally Posted by Ultramaroon

See, I didn't use a lick of math.

oh, automatic failure to show your work, F!

[Andreas83]

Installed the motor with the reimax pump gears.
Started it, and it runs fine NA at the moment.
Had to go back offshore, so I did not have time to finish the supercharger install and wire up the pressure and temperature gauge.

[Element Tuning]

Pretty much everyone has an opinion, a theory but I have facts since I have physically tested so many tweaks to the oiling system.

We have already visited the cooler vs no cooler pressure differences. Without the cooler the temperature increase and the resulting decrease in viscosity results in less pressure than without the cooler. Therefore any minor pressure drop the cooler causes is offset with an actual gain in presure due to the increase in oil viscosity

[LS1M]

What about a cosco or forester-style oil cooler? That wouldn't cause pressure drop, but from what I read, it also doesn't cool enough. So, how about an independent loop similar to an air/water intercooler, to feed it colder water. Best of both worlds? Cold oil w/ no pressure drop?

Another thought: using an electric scavenger pump to bring oil from the pan, through a cooler and into a sump tank, then another to bring it from the sump to the oil pump pickup? Like an electric dry sump setup.

Not sure how practical either of these ideas is...

[EAGLE5]

There are many ways to cool the oil. It just gets into issues of cost, complexity, and effectiveness. As far as I know, Element has done more than anyone to solve the issue, and for all but high-hp builds on the track, most solutions will work fine.