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Discussion Starter #1
I would like to hear some opinions on oil pressure on some NA deals. How much is to much? How much is to little? What do the NHRA Pro Stockers run? Wet sump engines with high vacuums.
 

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Not sure what the Pro Stockers run for oil pressure... but I've always gone by the minimum 10lbs per 1000rpm as a safe start.

My N/A 588BBC uses a Moroso Billet Pump.. along with their Pro Eliminator Fabbed Pan (Wet sump)... Cold with 15w-50 Dominator Synthetic Racing Oil I will see about 85lbs... 1200 rpm idle.. Hot, I'm at about 35lbs.

At a real quick glance, looked to be mid to upper 80's across the line at 7600rpm.. hard to see.

My 2.

Cheers -
 

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Just dynoed a race engine that had 58-60 psi at 7k using 5w-20 wetsump 14" vac.. No problem

A pro stock car has scary low pressure when you see what theyve got at idle. 20 psi sometimes.
 

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I would like to hear some opinions on oil pressure on some NA deals. How much is to much? How much is to little? What do the NHRA Pro Stockers run? Wet sump engines with high vacuums.
You can run as low as around 25-30psi if you take the time to control all the internal bleeding, generally people don't take the time to think about all the unrulliness taking place within the crankcase. Gun drilled rods for the high vac .
 

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I generally don't run high pressure in my NA engines. 40-ish peak. Just no reason for more. I haven't been focusing on that area though lately to be honest.... I believe if you put attention to detail on oil Control, 25-35 would be fine for 9500+ engine. If you felt that is what your program needed.
 

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I generally don't run high pressure in my NA engines. 40-ish peak. Just no reason for more. I haven't been focusing on that area though lately to be honest.... I believe if you put attention to detail on oil Control, 25-35 would be fine for 9500+ engine. If you felt that is what your program needed.
X2
 

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I know that 500" NHRA Pro Stockers are running under 20 lbs and have been for 2 or 3 years. I know about dyno runs with only 12 lbs on same engine. Slight power increases but at what cost. I just can't see how low pressure combined with using snake oil isn't a recipe for disaster.
 

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I know that 500" NHRA Pro Stockers are running under 20 lbs and have been for 2 or 3 years. I know about dyno runs with only 12 lbs on same engine. Slight power increases but at what cost. I just can't see how low pressure combined with using snake oil isn't a recipe for disaster.

Depends on the goal with the engine. At what cost? I would say at zero cost. Certainly it is a disaster if you're not designing the engine for it.

I have to ask the question, Why do I want 65 pounds of pressure at 7000 rpm in a given engine?

I think most folks out there are simply using what they have been taught is the norm, and what they have read in magazines. That is good for folks who have that depth of engine skills.

But folks who are building an engine like Tim is in the original post, he is deciding to put focus on the oiling system and there are gains to be had. 5 hp for him is a big deal.

More is not always better. Sometimes less is more.
 

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Discussion Starter #11
Depends on the goal with the engine. At what cost? I would say at zero cost. Certainly it is a disaster if you're not designing the engine for it.

I have to ask the question, Why do I want 65 pounds of pressure at 7000 rpm in a given engine?

I think most folks out there are simply using what they have been taught is the norm, and what they have read in magazines. That is good for folks who have that depth of engine skills.

But folks who are building an engine like Tim is in the original post, he is deciding to put focus on the oiling system and there are gains to be had. 5 hp for him is a big deal.

More is not always better. Sometimes less is more.
Your right Chris. Right now I have 50-60 PSI with 18-20 inches of vacuum. #9 oil. My issue is not with pressure I can turn it up or down a bit Im more concerned if I have to much oil pump. I have a SCP 1.450 Pressure section. Seems I have to run some pretty tall pullies to keeep it down. My runs start @ 75-80 PSI and as vacuum increases it pulls it down. Im also concerned with cavitation going on with that big pump. What do you think?
 

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Chris, I agree with your post. The "at what cost" I was referring to was at what point is there diminishing returns power wise and having to freshen the engine (bearings) frequently. My experience with real light oil is that you must pay particular attention to rod and main bearings and oiling the rockers arms if the engine has sat for more than few hours. The little bit of power that lower pressures and light oil can provide may be great for the Pro Stock car, but for an All Motor car at Milan it is not advised.
 

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Discussion Starter #14
I'd limit the section to 1.1-1.2 max what is the pulley sizes?
18-19 Crank 44-46 Oil pump. I have never been able to get the oil pressure down were it could see a difference. But again I think the 1.450 Pressure section is just to big for a 302 Main Honda rod deal. Like you said 5 HP is a big deal. I have had this pump for over 8 years,just wondering if it is time to go?
 

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I saw a dyno sheet of a Mopar NHRA Pro Stock engine that was in the low 50s for oil pressure at 10,200RPM with 0w oil:shock:. That was dry sump though with the best oil control possible sitting on a dyno stand.

I see in Reher Morrison's books he talks about they like to stay on the looser side of tolerances and thet they have seen more engine failures due to running tight tolerances. Does anyone else agree with this? I mean if you are running 0w-10 oil, low volume pumps, and 50PSI max at 9,000+RPMs on a max effort deal are you guy's running everything as tight as can be or is looser better?
 

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I deal with Titan pumps quite a bit, as per them, you can run one of their High Volume Pumps at low pressure and still have plenty of volume to prevent engine damage. As it has been said in the past, clearance will allow for lower pressure at a high volume. I would contact someone like Titan and see just how low you can go and still have a safe margin with volume. Companies like them have tested over and over again.....
 
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