Oil Line Length

[av8rirl]

While having a pint or two after testing at one of our races last season, I got discussing the length of oil lines from the block to filter to cooler and back to block.

The guy I was chatting with (and who I would assume to be well more knowledgeable than me) was telling me that the shorter the oil lines, the better. When I think about it, it does make sense... it should sap a little less power from the engine to pump the oil thru 2 feet of pipes than it would to pump it thru 5 feet of pipes.

So assuming I can package the filter and cooler in such a way that I still get sufficient cooling... Am I better off shortening the oil lines?? Or does it make an actual difference? Looking for opinions from people that know more than me... or fact from people that have done something similar!

Cheers in advance

[Al Weyman]

Right I tell you from some recent personal experiences on this. I have two more or less identical spec Small Block Chevy engines in each of my cars both have the identical Mellings performance oil pump fitted and both have around 2 to 3 thou bearing clearance, both have solid roller cams so statistically the pressure should be identical. Then we come to the differences, on the 2nd gen car I have removed the cooler, Accusump and all the lines and am just running a stock oil filter, on the 3rd gen car I have the full Monty, remote filter, oil cooler and Accusump. This engine is a clear 15 to 20 psi down across the range, hot, cold, ticking over or revved than the other engine. Both have good steady oil pressure so not a problem but the remote lines and filter etc definitely supped oil pressure from the one engine.

BTW the lines are not particularly long and I did once run the same engine in both cars and saw a similar oil pressure drop when installed in the car with the remote filter etc.

[Zoltarc]

With positive displacement pumps a fixed volume of fluid is displaced during each revolution regardless of static head (i.e the restriction causing the pressure).

However, pumps must overcome frictional losses, so reducing the line length will reduce the amount of energy required to do this.

[GORDON STREETER]

Having a long and too small a delivery pipe to a pump in a dry sump set up will result in lower pressure and will sap more power, but I can't see it reducing it on the pressure side.

[Al Weyman]

According to Vizard it will especially if using 90 degree elbows. Also I have found by personal experience as I have outlined above that it will.

[av8rirl]

Thanks for replies so far guys.

I'm not looking to increase or decrease oil pressure... just wondering if having a longer oil line saps some power from the engine?

So I'm thinking 2 things from the replies:
1. Reducing the length of the pipe will make it easier for the pump to overcome frictional losses so thereby lowering the amount of power being sapped?
2. 90deg elbows should be avoided in oil lines?

I'm not expecting any of this to increase performance significantly but we already have a race winning fast car so any increase (small or not) is a gain that might give us an extra .05s... and that may be the time diff between pole and second!

[Al Weyman]

On the subject of power losses on my small block chevys I have always used a 20/50 mineral basedoil like Valvoline racing 20/50 but when I built these last two engines because I am using all roller cams so figure I do not need the ash qualities of the mineral oils I have gone over to 100% synthetic 10/40. Well on these engines I prime the oil system with an electric drill prior to fire up and I can tell you with the 20/50 it nearly burns the drill out, with the synthetic its noticibly less strain on the drill so I figure worth a few BHP.

[neiltb]

sap power, no, reduce pressure, depending on application. with a fixed speed (to engine speed) pump power losses will not increase but flow will suffer, if you pumped to achieve a flow power would be lost.
All bends are bad but the better radiused the better, pressure is lost in bends (with flow loss) and in fittings where diameter goes down (think venturi). Pressure could be recovered by increasing pipe diameter but would only be true at that spot.