Does the Thickness of Your Oil Matter? | Engine Masters FULL EPISODE | MotorTrend

what is oil viscosity what does it do in your engine can it make power and why all of that this time on engine Masters [Music] [Music] all right [Music] our new sponsor is driven oil and they're letting me do something I've always wanted to do which is a test of various viscosities of oil they said you know we're not sure what you're going to find out on the dyno but hey let's go for it so what we're going to do is look at a couple of different viscosities and we're going to do horsepower we're going to do temperature over pressure and we're going to compare the two viscosities to see if there's a difference in temperature over pressure to sort of get an idea of the viscosity index the viscosity index being the oil's ability to maintain its viscosity over a broad range of temperatures all right this can get kind of complicated and so let's go over some oil Basics first of all what is viscosity it is a measurement of a fluid's resistance to flow a higher number is thicker a lower number is thinner so therefore a 520 oil is thinner than a 2050 oil the thing you need to understand which I didn't and a lot of people don't is that the viscosity test for the high number for example the 50 and 2050 is handled completely differently than the W number the low number the winter number here's what that's all about let's say you got a 2050 oil the 50 is measured at 212 degrees and to simplify it they basically put it in a test tube with a metered orifice and they time how long it takes to flow out of the tube that's how it's measured but on the W number the lower number the 20 and 20 50. it's totally different that is the measurement of resistance to spinning they take sort of a vein and put it in a bath of oil and spin it and the lighter the oil the faster it spins therefore they can sort of extrapolate the oil that will flow best at the coldest temperature and they kind of then adjust that to rate for an SAE viscosity rating it's fairly complicated the main thing that you need to know is that the W rating the 20 is there because oil manufacturers wanted to be able to have a thinner oil on cold startup so that it gets all through the engine as quickly as possible they just didn't want to have wear and tear on Startup there's a whole lot of other stuff in oil that is tuned for your specific application next let's talk about this gp1 which they recommend is like their ultimate hot rod oil the gp1 is a semi-synthetic and they admitted to me that you know the way the oil industry works it can have a very very low percentage of synthetic in it to be called a semi-synthetic apparently the thing about the gp1 here is that it's good for hot rods because it has the potential to make Power because the additives in it and it's really good for fuel contamination like if you're running methanol or if you're running E85 or if you like us run your gasoline car way too rich and you get a bunch of fuel in the oil they've got additives that prevent that fuel from breaking down the oil and causing it to be thinner it will stay thicker longer with contaminants in it in the hot rodding world a big one is main bearing and rod bearing clearance let's say you've got three thousandth rod bearing clearance which is fairly big and you're doing that because you've got like a supercharged application another application could be really really tight like perhaps the new LS that is 1.8 thousandths and the thing is you need a viscosity of oil that matches what that clearance is thinner for a tighter clearance thicker for a bigger clearance that's one of the main things because you want to maintain what's called a hydrodynamic wedge which is the lubrication that is between the crankshaft journal and the bearing to separate the two of them so they don't touch and so they don't Shear the oil wow that's a lot of stuff and honestly it's real basic because there's a lot more to it now the two oils that we're going to be testing here are a 5W20 and a 20 w50 I want to find out does one make more horsepower than the other but what's really interesting is looking at the different temperatures you can run at remember how the high end of the SAE rating is based on 212 degrees we're going to run these oils at 212 degrees but we're also going to run them down at 100 degrees and what I want to look at is how pressure and power changes when you have different temperatures but the other thing to do is to compare the two oils to see if one of them diverges and has a bigger problem maintaining that viscosity index than the other one so that's the oil test what's the engine we're going to use honestly it's kind of a weak Chevy 454 Big Block the bottom end is a Mercury Marine crate engine it's got like seven and a half or eight to one and that's the problem with it making big Power we're guessing that the camshaft in it based on the power curve probably has 224 duration of 50 000 tablet lift it's probably a Comp Cams xr276 HR hydraulic roller it's got the GM performance cylinder heads on it which were made by Edelbrock and the intake manifold is an Edelbrock RPM air gap up top we have a 750 Holley on there and it's got a product that isn't available anymore which is Percy's jet plates you can just turn a screw and adjust the jetting so that's what the engine's all about now I'm going to sit down with the Steves and then we'll have a little bit of a discussion start to make noise and see if there's really a difference between different viscosities of a really good quality oil we don't even know what we don't know we're going to find out as we go isn't that normally the case I guess so this time more than ever maybe because totally yeah this kind of information just can't come by that easily now you know this is one of those tests to me that sounds so easy but the more you think about it and the more you figure out how to get it done it becomes really complex well that's going to be on you because the big thing is well it is is going to be the control of oil temperature and water temperature and the reason for that is the water temperature affects horsepower and if we're trying to look at different horsepower between two oils then we need the water temperature the same but we also need the oil temperature the same so that's going to be hard but you can do it I think we're going to do is start with our thinnest oil go to the thickest one so the first one going in is going to be the 5W-20 driven gp1 I'm in the control room here with Steve because we're keeping an Eagle Eye on these two Fields right here which is oil temperature and coolant out we really need to keep that stuff repeatable which is difficult and so we're going to kind of look at this first test and agree on where we should start pulling the engine uh based on what we think we can duplicate with the other oils yeah you know it's not unusual at all when we're testing this stuff that we kind of figure out some of our test procedures during the first set of testing that way we know that we can duplicate it through each of the tests and be accurate so we can compare back to back foreign [Music] [Applause] [Music] heat up the oil by running it at about 3 500 RPM under a fairly big load and then we'll try and cool the coolant temp back down and run it again turn red there we go right now we shut it down and wait for the coolant to cool and hopefully the oil stays fairly hot foreign as a reminder this is with the driven 520 oil and I'm going to start by giving you what's actually the least important data at this point which is the horsepower and the torque the torque is 541.4 3500 RPM and we made 468.8 horsepower at 6 000 but before we have another oil to compare that with really I think the story is in the oil pressure yeah I think so too here's our oil pressure curve cold with a peak of 66.9 PSI and a nice curve beautiful curve no windage garbage or anything like that happening up at the Top If we have a windage problem we often see the pressure just you know do this and then yeah how about hot our Peak with hot oil is 50 53 PSI you can see that the hot oil has lower oil pressure everywhere because it gets thinner and what's interesting is that hot oil is honestly where the spec is for the 50 weight because it's at 212 degrees which is what we ran it at yeah so that's right at that number the question is does the hotter oil make more horsepower so now we go back to the power curve and compare those two things pretty good the black lines are the cold oil which was about 100 degrees and then the red lines are 212 degrees and you can see that the hotter oil makes a little bit more power as we've seen time and again it's no mystery you know ask any drag racer hot oil cold water that's how it's going to make the best power with the hot oil our Peaks are higher the torque is 544.7 also 3500 RPM just like it was before and the horsepower 472.4 at 6000 RPM so yeah up a few numbers everywhere the thing I'm really curious about though is what happens when we pour the thicker oil in if we see any difference or you know trends that are not the same as far as how quickly it gets hot what the difference is in pressure all those things I'm curious too because I can't tell you how many times a drag racer will opt for a thinner oil because he can't heat it up like we did so instead of a standard oil that's got 212 degrees he's going to go to a zero or 10 weight oil at 100 degrees and it's going to have the same sort of viscosity looking for that power what's interesting is I was speaking to Bill at Driven oil about exactly that and he was working with the guys who run in the nmra where it's coyote stock it's ostensibly a stock engine he said a bunch of the people were running that zero weight oil but they were actually losing ring seal and what they would do is they would pour in an additive that would make more power and then go hey I make more power and he's like well you could have just run the thicker oil to begin with so it's not always about the thinnest oil to make the most power it's not it really is a combination I mean when you look at the higher levels in Drag Racing comp Eliminator Pro Stock those sorts of things the ring technology is way out there I mean they're like 1.2 millimeters Pro Stock stuff is even as thin as 28 thousands they're gas ported in a ring seal yeah they've really gone to a lot of extremes to get great Ring seal so they're able to get away with that a regular stock Eliminator car not so sure that that's beneficial to start running zero or ten weight oil interesting so the next test is going to be with thicker oil and I hope that we can derive things about whether the thicker oil is hotter at the same coolant temp than this is because that's what the theory is but that's not what your real world experience shows my going back to what you said before one of my fears is running a really thin oil under a high load situation like a lot of power a lot of pressure on that contact interface you know squish that really thin oil out especially when it's very hot the hydrodynamic wedge that's why you want a thicker oil with a larger uh bearing Journal clearance and also why guys with superchargers tend to run heavier viscosity so you you're not displacing the ultimate example there would be a Top Fuel motor 70 weight straight is what they run in top fuel engine but I'm going to be curious when we put the heavier weight oil in the engine I mean how much of a penalty are we really talking about in power if any well you can go burn your hands and drain it out and I'll go ahead and pour the new stuff in and then I'll find out let's change the filter too that makes sense I'll take a nap okay okay all right changing oil for power and pressure [Music] thank you [Music] [Applause] [Music] there's our cold oil run just to observe it looks like the oil went from 100 degrees to about 119 on that pole now our chore is to get the oil up above 212 like 225 degrees shut it off and cool the coolant back down to 125. there's 225 or 220. yeah it took longer and it took a hotter coolant temperature to get there [Applause] [Music] this will be interesting let's go sit down with dulcich and discuss first up we've got the 2050 cold the peak numbers here are 539.2 pound-feet of torque and 464.4 horsepower but now we're going to Overlay it with the same oil run at a higher temperature and after looking at the last test with the thinner oil this shouldn't surprise you too much sure enough the hot oil makes more power to the tune of 548.5 pound feet of torque and 478.5 horsepower that's big that's a huge difference yeah I like it a lot now what we're looking at is oil pressure Cold versus hot with the 2050. so the peak oil pressure when it was cold was 73 PSI and the peak when it was hot was 60 PSI once again the hotter oil gets thinner sure right but that doesn't necessarily mean that it's not 50 weight when it's hot that's the thing that I think is sort of a mind boggler we ran it at 212 degrees that's where oil is rated so that's where it's a 50 weight not out of the bottle I got you right poor viscosity is different no yes compared to the thin oil is what I'd like to know uh let's have a look what we're looking for here is to see if the viscosity index is different between the two oils the black lines are 20 50 cold the red lines are 20 50 hot the green lines are 520 cold and the blue lines are 520 hot and it looks to me like the Gap is about the same pretty similar if I remember it was 14 and change pressure differential on the thin oil and 13 and a tiny bit on the thick oils of and of course the reason that the thinner oils lower pressure is just because it's thinner to begin with sure yeah yeah all right so I don't think that's very instructive that's not really teaching us that there's any big breakdown based on temperature between these two oils no it's just kind of what what you would expect as things heat up dinner is going to have less pressure thicker is going to have more and the thin oil versus the thick oil didn't do anything differently that's what we're deriving from that the last thing that we should look at is the temperature gain between the two which I'm going to assume is going to be the same because the pressure was the same right that would follow yeah our next graph is showing us if one of the oils gets hotter during a Dyno pull than the other and by the way the scale here from here to here is one degree so it might look drastic but it's not it's one degree the red line is the 520 the thinner oil the black line is the 2050 the thicker oil and basically wherever it starts dictates where it finishes that's what this Gap is and it kind of train tracks it's the spread is the same basically throughout the run it's one or two degrees difference throughout yeah so it see any significant change or variation on how fast it's heating up not at all and maybe we're just dealing in a Range where both of these have a viscosity index good enough that they just don't care we don't know there's a lot of data here more than I thought we really had initially and you know not a surprise we always learn more as we go but there's a lot to sift through here there's what's happening and what's going on and why but wait the most interesting thing is coming up right now all the rest of this is just stuff that doesn't affect your life the next one makes dulcich and I really really happy and there's the myth buster that is going to change your world the red lines that made more power are the thicker oil that's the 2050. the thinner oil made less power right because most people think you pour in really thin oil because then there's less resistance to pumping there's less windage loss you know less professional loss all that all of those things are correct but that's not the story it is overcome by the fact that the thicker oil contributes more to ring seal all right let's conclude I think the first thing I've got to do is walk back my enthusiasm for the 2050 because honestly the whole ring seal Theory and the more power the thicker oil is unusual at best like the guy at Driven told me thinner oil will always make more more power up to the point of it compromising ring seal yeah and we've seen that in plenty of testing thinner oil makes more power yeah over and over again this Energy may be a little bit unusual you know it's got wider Rings a ton of laps on it um and in this case maybe this is a bit unusual just because it did help ring seal that's the only explanation for that Divergence in the curve it still opens up a subject I had never considered I didn't know that that oil could contribute to ring Steel by a pretty dramatic margin when you look at the horsepower gain up at the top yeah so that's my big takeaway from the episode is that it has that potential but it doesn't mean it's going to happen every time as a matter of fact it's probably going to happen in rare occasions the other thing I think we have to admit here is that through all our struggle to look at temperature over pressure and viscosity index and everything else I think honestly the dyno doesn't have the capability to push the oil to the point where we can really conclude on that oil testing becomes a huge volume of information I mean this is only just a piece of it you know when you look at the lab testing you know we've done oil testing in the past where it goes to the lab it goes to the dino it goes to the race team and then makes that Circle two or three or four times before they actually settle on a blend that everyone is happy with so it goes on and on there's a lot of depth to it so I think more talking and thinking than hard data here an unusual result with the power I learned something every time and this was one of them ring seal from oil once again yep maybe we can dig up more freakish power gains that's kind of what we do on future episodes of and disasters

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Id: DWblUriIwhg

Length: 21min 51sec (1311 seconds)

Published: Tue Aug 01 2023