Does anyone have any experience running steel oil lines to a front oil cooler VS running braided lines?

My concern is oil pressure losses.

Has anyone tried one VS the other in their car?

ALSO! Does anyone have a good bench mark for how much oil pressure was lost when a front cooler was installed with something other then steel lines?

THANKS!

wow, what kind of oil pressure do you plan on running????

-16 (7/8") hose is good for 300psi (smaller diameters hoses has even higher ratings, almost double) (there is some "racing" -16 that is good for 900+ psi)

I don't understand what the concern is using steel (rigid) tubing vs hose (flexible).

The pressure losses due to hose/pipe size will be very similar for the same size.

A pressure drop across a cooler is best determined by contacting the different cooler manufacturers. You would obviously want one with a low pressure loss, and very high delta T. (difference in temperature)

When you keep mentioning pressure loss, are you meaning pressure in your engine?

The oil pressure in the oil passages inside the engine should remain the same or possibly be slightly higher with the addition of a front mounted oil cooler. (It may be higher due to running cooler oil through the oil pump).

What application are you asking about?

The application is for my 2.3L 4 banger, but will be the additional cooling required for my 3.2 project.

Using rubber lines will cause expansion of the tube diameter and then subsequent loss of oil pressure. Because we are talking about maybe 16 or more feet of hose I wasn't sure how significant the losses would be.

I am running Mobile 1 5w-50w synthetic performance blend right now. With the cooler I have now mounted under the trunk and about 6' of high quality (Aeroquip FC332-08)1/2" hose, I've observed about a 0.5 to 0.75 bar drop from stock. The oil cooler is nothing fancy but one that is just tube with fins attached to the tubing externally.

Does that make it as clear as mud?

-16 is 1", as they are measured in 16ths of inch...

so -16 = 16/16" = 1"

-10 = 10/16 = 5/8"

I guess JR is assuming there is preasure lost due to all the new hardware. But as for myself I wanna know if there is any substantial oil preasure lost with the A new cooler and EXTRA hosage? Does one need a high volume oil pump?


What say you?

The loss in pressure will stop once the hose stops expanding. If your engine is fresh enough to be holding at the pressure relief valve cutoff, it will be the same with rubber lines. If not, it will be lower until the lines have expanded, and then it would be the same. That period of time won't be much, maybe a few seconds. But the lines are elastic, so they will contract again... Therefore the lines will be acting like an accumulator, keeping your oil pressure up longer than it would with infelxible lines. (only for a few secons at the most). In the real world i doubt it matters at all, and may not even be measurable.

The 911 engine is dry sump and the scavenge side of the oil pump feeds
a cooler and then to the tank. There is no relation to the engine oil pressure (fed by the pressure side of the pump)unless something drastic goes wrong in the return (scavenge) section.

Dunno much about the T-4 oiling system except there is one single stage pump doing both jobs when a cooler is used. I can see a engine oil pressure drop. Big lines would help with this a bit....less back pressure, but most CSOBs use little stuff. I think the sandwich adaptor has small fittings which would serve as a flow restrictor anyhow....

Save yourself a big hassle, and go with braided AN-12 or -16 lines to start with. It's enough to snake them to the front without worrying about trying to measure and bend pipe.

I used -12 with my 2.7 liter conversion, and it never has a pressure or temp problem using a front cooled. Just be sure to put a thermostat (I used a -12 Mocal unit) so you're not trying to pump cold oil through 20 feet of oil line when you don't have to.

If the car is for street, -12 should be fine. If it's a race car, go with the -16. Be sure to sit down before ordering and pricing the lines and fittings. It's not going to be cheap, but you only have to do it once.

I've always been schooled that front coolers require high VOLUME oil pumps.

I tried it once without and lost the motor.
not proof that this was the reason, but you can bet I went back to high volume when I replaced that motor.

auntie

I run all -12 except the run from the tank to the motor which is -16.
Good stuff.


JP nailed it.
Pressure is in the engine as long as there is a gravity fed supply of oil from the tank.


KT

I would like an opinion of a slight variation of this theme. My 240Z has high pressure rubber or silicone hose to the oil cooler. A mechanic I asked said that this is what all of the over-the-road trucks use and that they go many thousands of miles without problem. If I had been the one putting the oil cooler on the car I probably wouldn't have even thought of the high pressure rubber hose but it is there and it is rated well beyond the pressure it sees. I have not compared price but the mechanic says the price is dramatically lower.
What gives? Why use braided line over the blue high pressure hose?

i would use blue in a heartbeat! i used SS b/c A ) it is bling and B ) i got a killer deal on it....

blue is great....

It certainly seemed to be hefty and it has been on my Z for years. On my Submarine the oil lines to the cooler and the cooler would never be seen as they would be under the shroud that has been constructed around the fuel cell. So no bling factor needed. I noticed the cooler on the Z after a year or more of owning it and it never gave me trouble or apparently the previous owner trouble.

Seems to me that it would be easier to run from the back to the front as well...

Aeroquip socketless blue hose is cheaper by the foot, and each connector is about half of the blue/red AN ones... and they do not require hose clamps! puch onto the barb and go!

.... unless you are trying to use a cheap rubber garden water hose

Where are you measuring the pressure?

How is it routed?

Not measuring it anywhere right now as nothing has been installed or routed.

This question line also rises in part by my new motor. I put 800 miles on it with some 10-30 oil and now I have gone to the Mobile 1 synth 5-50 and I've got 1200 miles on that oil now and have been observing something...
Oil pressure seems to be steadily dropping off. At an idle of 1200RPM and 190F my VDO gauge is falling to 0.3 Bar or about 4.5 PSI. I have a dual pressure / idiot light sensor mounted in the stock hole for the idiot light. The idiot light is also lighting as well. *I DO have a high volume oil pump installed as well. I am also sure I have the correctly matched gauge and sensor combo.

I'm not very worried about it yet as what I've read on previous posts this seems to be normal. However my pressure does seem lower then usual but I am also running 5-50 oil which is lighter then most. So the fact that my oil pressure is so low at idle maybe understandable. This I imagine might also be partly to blame that I have an external oil cooler.

-JR-

When I added my front cooler with the -10 aeroquip blue hose mentioned above I noticed no pressure drop at all. I have the raby modified T1 pump and a sandwich adaper. I have ~20psi at idle and a max of about ~45psi after the oil is warm (using the aftermarket vdo gauge), but I do run 20x50 royal purple full synthetic.

steel might be a tough one to work with ...why not use a refrigeration grade copper and a good silver solder, in conjunction with high pressure lines
plus you get the bonus of having a good heat disapation through the copper lines....

Starting to think I should switch to a 20-50 blend oil.

I also found that on the 916 cars, Porsche used brass lines. In retro spect the steel might be hard to work with but metal lines sure would look sexier I think.

Probably use steel or copper for most of the length and then use the Areoquip hose to make the transisions for ease of installation. But I'm about a year away from that project.

That seems WAY low. Try using the right weight oil (10W30 or straight synthetic 30W). With SAE 30W you should have roughly 3 BAR (48psi) at 2500 RPM, a minimum of 2 BAR (28psi). There is no specific oil pressure listed for a type 4 at idle in the 914 Technical manual but you should have at least 1 BAR (14psi) oil pressure at idle. Less than 6 PSI and the idiot light will come on to tell you something is wrong.

Also, if you're not measuring it currently, how do you know for sure your oil pressure is low? Other than the idiot light coming on at idle that is.

20/50 is optimum for most TIV engines with stock clearances (that are rather loose) and my oil pump.

45 PSI is **perfect** oil pressure, more than 50 PSI will route a portion of the oilo BY the oil cooler and make for higher oil temps. We turn engines 7,500 RPM with 40 PSI oil pressure and they make better power with lower oil temps.

Seeing a huge number on the gauge only costs you power and running temps. Volume is key, pressure is secondary.

[/quote]
I also found that on the 916 cars, Porsche used brass lines. In retro spect the steel might be hard to work with but metal lines sure would look sexier I think.
Probably use steel or copper for most of the length and then use the Areoquip hose to make the transisions for ease of installation. But I'm about a year away from that project.
[/quote]

It might be worth doing a bit more research before ANYONE decides to go with a rigid line.

here are a couple of realities:
-many types of copper or other rigid lines will work harden and crack
-in the event of a lot of twisting or an impact, rigid lines are more prone to crack than flex lines
-running a rigid line in the cockpit where the impending crack sprays hot oil onto you in an accident is a bad idea.


I have a partial rigid ALUMINUM line in my 1st race car (old black car)
I ran it outside of the cockpit under the rocker. I did it as an experiment and to shed more temp. It cost MORE money because each end of it (leaving the motor, and entereing the cooler) I convert back to stainless due to the concerns with the above problems that come from rigid lines.

an automobile (especially a 914 with stiff suspension or "poly" bushings) is going to create an awfull lot more vibration than a refrigerator.

brant

word

i dont wish to know how a lobster feels... (hot bath )

The rubber lines used by OTR trucks is probably similar to high pressure hydraulic rubber hoses. These have MINIMAL expansion due to pressure (even at hydraulic pressures 10x what you will see in a car).

The main thing to watch for and make sure you get is high pressure hoses and fittings that are rated for the type of fluid you are using. (Make sure it is compatable with engine oil at 400 degrees and you should be fine.)

High pressure fuel lines (rubber) also exhibit minimal expansion due to pressure which is why they are rated as fuel injection fuel hoses.

I would not choose hard lines over flexible hoses for fear of pressure losses. The largest pressure loss you would see would be if you were to use too small of hose for the application.

With a 911 3.2, you should be safe using -12 lines to the front cooler. Some swear by -16 but I know from 18 years of driving the car on the track with 2 drivers, that -12 is sufficient.

If you are using a front mounted oil tank, the feed line (suction) should be a minimum of -16.

Coleman racing has some finned aluminum lines. They website doesn't show a picture but the print catalog does. If I had known about these when I was plumbing up my car I would have given them some serious consideration. I'd think in terms of running the finned lines along the longitudenal under the rockers (outside the cockpit) and then converting at each end to AN braided stainless for the engine and cooler connections. If you then added some airflow under the rocker cover you might get some useful, albeit uncontrolled, cooling. Flow and pressure loss would not have been my reason to run hard lines...

Regards,
Kevin

I'm thinking that there has to be something to solid oil lines.

Porsche used this method on both the 911 and the 916 as opposed to any other method of moving oil around the car.

I wouldn't mount the lines on the inside of the cabin in any scenario I'm considering. My car won't be a dedicated race car so I want the cabin to look nice without carpets installed. IE: Glossy painted floors.

But check this out...
916 setup that were made apparently from original 916 rails.

I can see a couple obvious advantages to having solid oil lines over flexible lines (rubber, SS braided, Silicon).

Rigidity for one: If they are damaged by an impact they may crush but won't break without substantial force, whereas a rubber line would shear and your vehicle would be inoperable.

Heat Dissipation: The early 911s with a remote cooler up front had the steel lines coiled up, they called it a "trombone cooler". No radiator, and it was enough at the time to keep the oil temps down. The metal lines transfer heat better than rubber which is an insulator.

Cost of manufacture: It's another part you can sell at retail price (2-3 times cost of production) as opposed to running a rubber hose.

With rubber lines I think the advantage you get is that it's cheaper to run as opposed to fabbing up solid lines. Any other ideas please contribute.

I respectfully disagree.
those rigid lines will tear
in 70 when those were factory used, I don't think SS lines existed yet.

SS lines are going to give you the most safety in the event of an impact...
and rubber is just one step below that in its ability to flex.

Rigid lines can crack even without an impact.

hopefully others will chime in here .

my opinion is that the factory did it because they didn't have the technology to do better.... not because it was superior.

and as far as using the line for more radiant cooling.
yes it will..
I know...
I've done it...

but its not necessary.
you can achieve all the cooling you need up front with out spending the extra money on radiant cooling.

In fact I have TOO MUCH frontal cooling on my car.
so gaining more is not a needed option.
brant

I believe that there were 3 reasons that the factory race shop chose the steel/brass lines in the GT cars similar to what is shown in the pic of a clone of a 30-some year old factory prototype.

1. They were cheap for the factory race shop to produce (as they probably already had all the parts and made them up themselves).

2. They were easy (as they probably already had all the parts and made them up themselves).

3. That is how they ran oil lines before.

None of those reasons had anything to do with oil pressure losses.

One can run lines like those, but Caveat emptor (some of the dangers/warnings are listed in the above thread).

Just because the factory did something 30+ years ago, it is not always the best way to go, unless you are just trying to duplicate 30+ year old technology.

Best of luck with your oil lines.

I've been hearing this a lot, with solid lines cracking and fracturing in this post. I find this strange because steel lines have been used extensively in automotive circles since the 1930's. Brake lines, power steering lines and trans cooling lines are just to name a few applications. The only time I've heard of these failing has either been a crash, extensive corrosion or damage from incorrect installations. If steel lines were so bad then I don't believe a modern braking system would rely on such a setup.

In the crash scenario, the last thing I'm worried about is if my oil lines are intact. All though I suppose a case could be made if you are concerned about igniting the oil on the exhaust manifolds or something along those lines. Then a flexible line might resist certain types of hits better. That said though, a piece of sheet metal would probably rip right through a braided line much easier then a steel line.

-JR-

yea....from the 1930's

why don't you look at MODERN applications...the technology for hoses (all types) has gotten better with lower prices in the last few decades...back in the 914/6 GTs day, I know rubber hoses had been available, but the low cost and technology wasn't there, the ends had to be crimped on instead of using -AN fittings (steel tube cheaper and easier to deal with the end fittings)

the point is moot 'cause you are going to do what you want to do, why even ask??

Did you bother to see what that car looks like in the interior with the carpets removed?

Did you see the two oil lines routed right at the drivers feet next to / below where a dead pedal should go?

While carpeting can be placed above the oil lines in this location, there will still be a lump where the oil lines protrude into the passenger compartment.

It was not just 916's (11 or so) that had these rigid lines running from just under the oil tank to inside the cockpit (where flexible rubber lines ran the rest of the way), the GT cars (and GT kits) also ran this setup.

Oh, it looks like the silver one switched to SS braided lines.....

The same can be said about rubber lines. They are used in the automotive industry in all these applications without ill results.

Brake hoses - rubber
Power steering lines - rubber
trans cooling lines - rubber

Without the rubber lines for flexability, none of those steel lines would survive.

I just don't understand the original question about pressure losses due to the rubber hoses.....