S197 Boss 302 in Chile Build Thread Profile - S197 Mustangs

[Mad Hatter]

It was basically to exemplify that fittings and oil line have a cost, and that' cost is Oil pressure.
Back in the day the rule of thumb was one 90* bend was about the same pressure drop as 8 feet of empty tube that same size. Obviously the exact amount depends on the specific fitting type etc. and you could easily scrutinize that 6 ways to Monday but the message is the same, fittings and hose cause pressure drop so plumb with that in mind.

True! Very much on my builders mind as he went out of his way to make sure we did not have any 90 degree uncurved angles. Oddly enough, the same 925/915 combo had higher oil pressure in the previous motor then the new one. Again, most likely because we spent way more time porting the block and heads. Some of the oil entrances/exits were really quite horrible on the stock block.

 

[Coz]

The 172 is tempting as for size, but the price to BTU ratio is not that great (its US$595)

True, but only if you're getting the full BTU potential from the 915 & 925. Won't the portions in the shadow of the bumper loss some of that potential?

FWIW, I wouldn’t choose the 172 for lots of reasons.

Inquiring minds want to know at least a couple of the main reasons.

 

[Grant 302]

Worst oil temp was 300F on a hot day with some 30 deg C ambient temp. But that coincides with the full splitter past the oil pan. Actually, that was with just the with the 925. Next time out was with the 925/915 combo and the engine blew up. Was also having high temps at around 290. Not much data am afraid to say.

But it’s enough to point to a cooling capacity problem. Consider the OEM cooler to be worth in the 45,000-60,000 range and that there are (old) examples of running hot with it in addition to either a 925 or 934.

Keep in mind that the squirters put a higher heat load on the oil because they remove it from the pistons directly.

I suppose you could just pull the spitter extension and hope for the best.

Inquiring minds want to know at least a couple of the main reasons.

Proximity of inlet and outlet. I’d really like to see how the far end (away from the fittings) of the cooler is working.
Ratio of end tank area to tube/fin area
Short tube length
Cost efficiency

I’d have to look for it, but I recall an example of it not performing well on a car with the OEM cooler removed. I think that owner ended up adding a second cooling core also. Don’t remember what size.

...

Regarding oil pressure and fittings...I agree that adding restrictions/pressure drops is a cost. One that costs a bit of HP and potentially requires longer warm up times.

But I think it’s often misunderstood. Adding pressure drops like a cooler or fittings or hose length...will increase observed gauge pressures when tapped upstream of the added restrictions. It seems people often expect such addition to cause observable gauge pressure drops.

The other misunderstood thing is that nominal increases don’t affect flow in normal operation or any time that the pressure relief valve isn’t open. And as far as I know, that’s not an issue with our cars once up to operating temps.

 

[Coz]

I’d have to look for it, but I recall an example of it not performing well on a car with the OEM cooler removed. I think that owner ended up adding a second cooling core also. Don’t remember what size.

That sounds vaguely familiar.

However, I was not recommending the 172 as a stand alone replacement. Only as a replacement for Mad Hatter's lesser rated 915 that he has in conjunction with the 925. While the 172 has a smaller oil pressure drop, this may be offset by the additional fittings & plumbing that will probably be necessary to integrate it with the 925.

 

[Grant 302]

That sounds vaguely familiar.

However, I was not recommending the 172 as a stand alone replacement. Only as a replacement for Mad Hatter's lesser rated 915 that he has in conjunction with the 925. While the 172 has a smaller oil pressure drop, this may be offset by the additional fittings & plumbing that will probably be necessary to integrate it with the 925.

Understood about the combining...as well as some of the advantages. But for the cost (without checking current prices) and the space, I’d still consider other options/combos.

 

[Fabman]

Yes, observable pressure varies depending on where you sample it from.
Up stream the pressure increases because it is ahead of the restriction and the more restriction the higher the reading will be.
After the restriction (which is what the bearings see) pressure is less, and the more restriction, the more the pressure drop.
Its like stepping on a garden hose, one side the pressure goes to the moon while it barely trickles out the other side....extreme example but the principle is the same.

 

[Dave_W]

What if he plumbed the existing coolers in parallel, with Y fittings, instead of in series? In theory, wouldn't that turn the system from being equivalent to a 2-pass into a larger 1-pass? Just trying to save him some money. (I know, blasphemy for this site.)

 

[Grant 302]

Yes, observable pressure varies depending on where you sample it from.
Up stream the pressure increases because it is ahead of the restriction and the more restriction the higher the reading will be.
After the restriction (which is what the bearings see) pressure is less, and the more restriction, the more the pressure drop.
Its like stepping on a garden hose, one side the pressure goes to the moon while it barely trickles out the other side....extreme example but the principle is the same.

Except that the system is using a positive displacement pump and that the flow doesn’t go down at the bearings. So barely trickling out at the end of a garden hose isn’t a good example. Flow stays the same - that’s the important part most people don’t get.

One example is to look at the 2 dinky holes in the OEM cooler. That restriction is much like stepping on the hose, but stock systems using it don’t have a problem with flow.

What if he plumbed the existing coolers in parallel, with Y fittings, instead of in series? In theory, wouldn't that turn the system from being equivalent to a 2-pass into a larger 1-pass? Just trying to save him some money. (I know, blasphemy for this site.)

...approximately the equivalent of a ‘940’... or somewhere between the 934 and 948 that’s available...still not enough capacity. And less cooling than in series.

 

[Mad Hatter]

But it’s enough to point to a cooling capacity problem. Consider the OEM cooler to be worth in the 45,000-60,000 range and that there are (old) examples of running hot with it in addition to either a 925 or 934.

Keep in mind that the squirters put a higher heat load on the oil because they remove it from the pistons directly.

I suppose you could just pull the spitter extension and hope for the best.

I think you are right and now with all the modifications that are on the motor it will mean more heat then before. Will start with the following,
1) Reduce the length of the splitter so it does no go past the oil pan.
2) Cutting two tunnels to improve the downforce and at the same time get some air on the headers. Even got some NACA ducts to put on the splitter to help improve air flow to the headers.
3) Maybe should have wrapped the headers.
4) Box the radiator and coolers so the air goes through them no around,
5) The drop in oil pressure from the ported oil ducts in the heads and block should improve things. At least it makes it easier to add more cooling.


Test the above, and see what temp we get. If still a problem, look at either a second 925 cooler or a 948.... maybe the setup we already have and the Boss OEM cooler, though the plumbing will be a pain.

 

[Grant 302]

2) Cutting two tunnels to improve the downforce and at the same time get some air on the headers. Even got some NACA ducts to put on the splitter to help improve air flow to the headers.

^ I wouldn’t do this. Any air kicked upwards between the fender liners will ‘compete’ with the air trying coming out from the radiator and engine bay. The only place I’d vent a tunnel is into the gap between the fender liner and wheel/tire.

5) The drop in oil pressure from the ported oil ducts in the heads and block should improve things. At least it makes it easier to add more cooling.

Biggest drop is likely from adding the squirters. They use some of the flow volume discussed and reduce the observable gauge pressure.

Test the above, and see what temp we get. If still a problem, look at either a second 925 cooler or a 948.... maybe the setup we already have and the Boss OEM cooler, though the plumbing will be a pain.

I think testing first is a good idea. Should be getting warmer weather there now?

I like the OEM cooler for thermal performance, but don’t like the risk for leaking coolant on track. I’d only go back as a last ditch effort.

Maybe adding a 948 to the 925 parallel would be a prudent solution. Like a ‘973’ if they ever made one! Not sure if there would be room to mount the 925 any more forward sine the two would probably need to overlap some.

 

[Grant 302]

If you do go to an oil/water setup, I’d consider something like this teeing off some of the cold side coolant flow.

Inline Engine Oil Coolers | PWR Performance Products

The PWR Performance Products Inline Oil Coolers consist of a complex internal core to provide high heat transfer design in a low pressure drop configuration. The internal core is made up of complex aluminium extruded tubes to carry the water through the shell, whilst a...

www.pwr.com.au

 

[Fabman]

Except that the system is using a positive displacement pump and that the flow doesn’t go down at the bearings. So barely trickling out at the end of a garden hose isn’t a good example. Flow stays the same - that’s the important part most people don’t get.

One example is to look at the 2 dinky holes in the OEM cooler. That restriction is much like stepping on the hose, but stock systems using it don’t have a problem with flow.


...approximately the equivalent of a ‘940’... or somewhere between the 934 and 948 that’s available...still not enough capacity. And less cooling than in series.

Let me see if i understand this, so you're saying that if I put a ball valve in a pipe (big restriction) and closed it off almost completely it would still flow the same amount of fluid? At some point it would dead head and hit the bypass valve or blow something up or just bypass at the pump. You cant flow more fluid through an opening than there is opening. At first pressure would rise just like it does with a sprayer on a garden hose, but the more you close that hose the less that comes out of it. I don't see how this is any different, just on a different scale.

 

[Mad Hatter]

Yes we are basking in 25 C all these last few days. Dam hate those prudent.. and expensive solutions. Lets see what the first temps are, but I fear a 948 is on the list. With the 925 and leave the 915 for the gear box

 

[Grant 302]

Let me see if i understand this, so you're saying that if I put a ball valve in a pipe (big restriction) and closed it off almost completely it would still flow the same amount of fluid?

Start with the ball joint open. You can start closing it and flow will stay the same and gauge pressure will rise all the way up until the bypass pressure is reached and the relief valve opens.

And yes, the lever would likely be past half way on a 90° ball joint before that happens.

At some point it would dead head and hit the bypass valve or blow something up or just bypass at the pump.

Yes. At some point. Look at the orfice in the OEM/Boss cooler. Dinky, like I said. And that doesn’t cause any use of the bypass at normal operating temps.

You cant flow more fluid through an opening than there is opening. At first pressure would rise just like it does with a sprayer on a garden hose, but the more you close that hose the less that comes out of it. I don't see how this is any different, just on a different scale.

No. What I think you’re missing is that velocity goes up too. Flow rate stays the same when driven by a positive displacement pump. Which isn’t in your household plumbing. It’s only regulated to a certain pressure, which is why you can stop it with your thumb.

 

[Fabman]

Start with the ball joint open. You can start closing it and flow will stay the same and gauge pressure will rise all the way up until the bypass pressure is reached and the relief valve opens.

And yes, the lever would likely be past half way on a 90° ball joint before that happens.

I think I alluded to this so we are in agreement here.

Yes. At some point. Look at the orfice in the OEM/Boss cooler. Dinky, like I said.

I have no reference for this since I do not own a boss and haven't seen said orifice.

No. What I think you’re missing is that velocity goes up too. Flow rate stays the same when driven by a positive displacement pump. Which isn’t in your household plumbing. It’s only regulated to a certain pressure, which is why you can stop it with your thumb.

I get that, I build Piping and various types of pumping systems including PD pumps on a regular basis in commercial plants and a major R&D facility here in the bay area. Things are frequently blowing up because somebody tries to put more through the system than it can handle. I'm aware that velocity increases with restriction (Bernoulli principle) as I think I alluded to, but at some point volume decreases. Fluid is non compressible, That's what sends the pressure up on the outlet side of the pump. It has to go through the hole or bypass somewhere or stuff blows up. A side effect is that the restriction heats the fluid, negating a portion of the coolers efficiency.

 

[Grant 302]

I think I alluded to this so we are in agreement here.



I have no reference for this since I do not own a boss and haven't seen said orifice.



I get that, I build Piping and various types of pumping systems including PD pumps on a regular basis in commercial plants and a major R&D facility here in the bay area. Things are frequently blowing up because somebody tries to put more through the system than it can handle. I'm aware that velocity increases with restriction (Bernoulli principle) as I think I alluded to, but at some point volume decreases. Fluid is non compressible, That's what sends the pressure up on the outlet side of the pump. It has to go through the hole or bypass somewhere or stuff blows up. A side effect is that the restriction heats the fluid, negating a portion of the coolers efficiency.

I know you understand the concepts. I think there’s small differences in the finer points and details. And some of that matters with the actual effects of oil system changes.



I don’t have one loose or I’d take dimensions. But oil goes out those two ports and maybe a dozen times each since it’s stacked plate design.

Sometimes, I think people pick the ‘wrong’ parts because of incorrect analysis. Like the published pressure drops in the 172 vs. 948. I know that stat alone has made many choose the 172, when examples here show that the 948 performs better.

 

[Fabman]

I know you understand the concepts. I think there’s small differences in the finer points and details. And some of that matters with the actual effects of oil system changes.

View attachment 58372

I don’t have one loose or I’d take dimensions. But oil goes out those two ports and maybe a dozen times each since it’s stacked plate design.

Sometimes, I think people pick the ‘wrong’ parts because of incorrect analysis. Like the published pressure drops in the 172 vs. 948. I know that stat alone has made many choose the 172, when examples here show that the 948 performs better.

Boy those are pretty small. I imagine though with the number of plates the total combined area must equal the size of the inlet...at least I'd expect that.

 

[Dave_W]

How is the venting behind the radiator? Can you cut the hood for extractors? Take a look at post #238 in the Vorshlag build thread for ideas. They should have "kickers" at the front edge of the vents to increase the low pressure area the extractors vent into. Also see how they completely boxed between the bumper cover openings and the radiator. As important as getting air into the coolers is getting the air out.

 

[Mad Hatter]

How is the venting behind the radiator? Can you cut the hood for extractors? Take a look at post #238 in the Vorshlag build thread for ideas. They should have "kickers" at the front edge of the vents to increase the low pressure area the extractors vent into. Also see how they completely boxed between the bumper cover openings and the radiator. As important as getting air into the coolers is getting the air out.

Yes, have been looking at the Vorshlag Big Red car for a long time. Like the slanted rad with the custom CAI as well. Have the track spec hood setup, but am thinking of adding a bigger front lip ( on the grill, before some one says something funny..). Boxing in the rad will be at the top of the list.

Looks like we Log the car tomorrow! Will report the oil pressures and temps.

Seriously thinking of getting a 3D printer to make some cool aero add-ons, any body tried one?

 

[Mad Hatter]

Well, we finally got the car out of the shop and on the road for a clandestien logging trip (the computer kind). It got a little cold so it was funny to see that the engine took for ever to get warm.... On the highway, the temps would not go above 120 max. Oil pressure stayed stayed at 35psi at idle and during logging went to 70psi at 7000 rpm. We took the car out without the long splitter on so that might be part of the reason.

Logs are off to Shaun and am checking the email every 15mins. Logs was ok, but the measured AFR was reading 0.91 while lambda was at 0.83. To my basic cave man understanding, that means the car is breathing more then the tune was set for, leaving it lean? Hope it means that more is to come.

Car felt a little flat above 6000rpm.But its a base tune so just have too wait for tuna magic.