SCARY31

Why Do I Not See Many Dry Sump Systems On Perf.boats? I Know
There Is Alot Of Hp To Gain From An Oiling System. I Used To Race A Super Late Model Stock Car With A 355 Small Block, And Had A Dry Sump System With A 5 Stage Oil Pump, And Would Spin The Motor At 8,000 Rpm.

Reed Jensen

The expense... a cam driven oil pump from Melling is about 30 bucks... The cost of a pan is about the same for a windage tray.
Factor in the cost of the pump... the hoses... the tank... mounting brackets... etc etc...
One of the second reasons boaters don't have dry sump systems is boats don't generate the kind of sustained "G" side loads autos get. So there isn't the worry about cavitation at the pump pick-up... But I agree with you... they are a neat system to go with if you can afford the cost... I've seen some cats at the boat shows that have a dry-sump system on the engines.

Lmarth

You'll get better worded responses than mine, but there are in my opinion a number of reasons you don't see many dry sumped marine motors. You have first hand experience with the first and that's the significant cost penalty over a wet sump system. Most marine motors don't spin more than 5200 rpm or so and usually don't simulate the lateral g forces you get with cars where there's the risk of uncovering the oil pickup and sucking air (not a great lubricant). Dry sumps with their much bigger oil resevoirs together with an oil cooler are better at cooling oil than a wet sump. Obviously, if you're turning high rpms, you'll have less windage losses with a dry sump. Having said all this, the high end stuff from Merc have dry sumped motors and drives. The top marine engine builders also offer dry sumped motors. If you're turning 8000 Rpm in a stock car with super wide tires, I too would want a dry sump with one pressure and four scavage pumps. I bet it worked the nuts---as long as the belt stayed on. You're reminding me why I enjoy boats more than I enjoyed racing cars. With cars, it was a constant struggle to cool the water, oil, brake systems. With boats, a lot of that goes away. From a cost/benefit standpoint the average high performance boater probably wouldn't spend the extra money to gain a few horsepower at 5200 rpm.

articfriends

iTrader: (1)

Dry sumps are the ultimate but not neccesary in most applications,plus the belt wearing out,breaking etc would be one more thing to worry about,Smitty

The Menace

With dry sump you will not have that potential of a dry fraction of a second at high sustained R's resulting in scaring a bearing etc and a blown engine etc.

Without a dry sump you can't sustain those high r's for long. I turn 6000 r's.

My Ferrari is dry sumped. Lambo's are dry sumped. The new Ford GT's are dry sumped.

Dry sump system: cheap insurance for a $50m engine.

The Menace

I had a stock 502 that the pick up tube dropped.

It is not uncommon for a wet sump shaft to break or pickup become plugged.

dodsonartic1

Its Not So Much The G Force To Worry About At 5000 Rpm Oil Wrapping Around The Crank Robs More Than Just A Few Horse Power And A Dry Sump Would Stop That But You Guys Are Right It Is Very Costly But What The Heck I've Seen Guys Spend More Money For Less Hp

Reed Jensen

My Ferrari is wet sumped... and the fugger cavitates if I put it through a long hard right hand turn...... That is something I need to change......

The Menace

"Git R Done" Reed. Mine was factory installed.

KNOT-RIGHT

This is a good description.

A dry-sump lubrication system has four major advantages over a wet-sump system: increased power, improved reliability, better cooling, and enhanced safety.

As piston displacement increases, so does the volume of air displaced inside an engine's crankcase. A piston displaces an equal volume of air both above and below itself with every crankshaft revolution. For example, a 632-cubic-inch big-block running at 8,000 rpm moves more than 2,900 cubic feet of air per minute inside its crankcase. As one piston moves downward in its cylinder, another moves upward, so the total volume inside the crankcase and oil pan remains constant - but this rapid movement of air from side to side and front to back, combined with the rapidly spinning crankshaft assemble, creates a hurricane of incredible intensity inside the engine.

You can imagine the effect this hurricane has on the oil in a wet-sump system. Even with baffles and windage trays, the oil around the pickup is constantly buffeted by the air displaced by the pistons. The gale forces created by the rise and fall of pistons No. 7 and 8 can literally whip the oil in a wet-sump reservoir into a froth. The large counterweights that are required to balance a stroker crank also act as huge fans that churn the oil like a blender.
Thus we have the potentially deadly combination of extreme bearing loads and marginal lubrication. Consider that each piston in a 1,250-horsepower engine produces 156 horsepower. That is more than four times the output per cylinder of a production big-block - yet the crankshaft bearings that must withstand these loads are no larger than the bearings in a low-rpm stock engine. With the high surface speeds and the huge centrifugal forces generated by a long-stroke crank, the rod bearings can be stressed beyond their limit unless they receive continuous lubrication.
Removing the oil from the pan and storing it in an external reservoir solves these problems. First, a properly designed dry sump tank will de-aerate the oil before returning it to the pressure pump. By removing trapped air, a dry sump ensures that the pump supplies only pure, liquid oil with its maximum lubricating qualities intact.