horsepower increase w/ dry sump and vacuum pump

[sledpuller]

what hp increase would you guys realisticly get on this motor by adding a dry sump and how much more for a vacuum pump with the dry sump?475cu in truckpulling motor turning around 9000rpm.living good on a wet sump,has good windage tray,lifter bore bushings,restricted oil on top end to cut down on windage. only consider spending money for hp increase of coarse xtra reliability is a bonus!!also im useing exhaust vac on headers are they really pulling much vacuum?has anyone ever measured it?do they make hp?thanx to everyone that answers!!

[Ed-vancedEngines]

A vacuum pump could help if you have much blow by. I used to think that a good dry sump was worth appx 40 hp but now I am doubtful. We have over the past year changed a few guys into good wet sump systems for the purpose of weight removal and they did not slow down any. Most went a little quicker.

I have not any dyno facilities to run any bck to back tests with. I imagne that some of the guys here that do will be able to give you a more complete answer .

Ed

[hsutton]

My son's engine picked up 26 RWHP with the vacuum pump although he still has the wet sump oil system.

[PackardV8]

Greetings, sledpuller,

Today's better dry sump pumps, when correctly installed are better than a vacuump pump. The five and six-stage pumps pull so much vacuum, special seals and a vacuum break are required. The Cup cars were running into problems with the piston pins not getting sufficient oil and had to install spray bars to both cool the bottom of the pistons and lubricate the pins.

Having said all this, they are only necessary for extended high-rpm use. One can make as much horsepower in a drag engine with a well-designed wet sump and vacuum pump.

A properly designed header vacuum system is better than nothing, for reducing crankcase pressures. However, you should realize a noticeable horsepower increase with a vacuum pump in your application.

thnx, jv

thnx, jv.

[Ron C.]

Back in the 80's I flogged a pan exhaust evacuation system on the dyno. The motor was a 394" SBC and I tested up to 8K RPM. After trying different angles and depths in the collector I did find the best spot. But could not find any measureable power gain with that system. It must have been worth something or Jenkins wouldn't have had it on his SBC's. But he was turning a lot more RPM's. So maybe it was futher up the scale.

But the vacuum pump is another story. It is worth measureable power gains and that of course varies a lot depending on engines. The largest gains are in the first 10" of vacuum and unless your class racing I would hold it in the 14-15" range for less troubles on pin lube.

That's my experience anyway.........blessings............Ron Clevenger.

[bigjoe1]

On an 1150 HP Big block (632) the vacuum pump was worth 56 HP at 7500 RPM. On a very racy SB Ford I did. the vacuum pump was good for 51 HP at 8500 RPM.. To get these big gains, the engine should have narrow rings( O$#) and very low tention oil rigs. It is true, If the engine does NOT have some blowby, there will be little or NO gain at all. JOE SHERMAN RACING

[PackardV8]

Greetings, bigjoe1

Do you subscribe to the theory some horsepower gains come from pistons finding less resistance descending into a vacuum? Or is the converse contained in your statement that

If the engine does NOT have some blowby, there will be little or NO gain at all.

and thus would have a pressurized crankcase and removing this pressure is what frees up the horsepower? Or. is it from better ring sealing.

Bottom line, what makes the 51 horsepower plus, as the vacuum pump takes a few to pull the vacuum?

thnx, jv.

[bigjoe1]

The reason I know that some blowby is when the pump will work it best is, when I was doing a test for GZ Motorsports, I installed a pump on a well seasoned SB Chevy. We saw almost NO gain with the pump, BUT they brought a very slick blowby meter that you connect to a valvecover vent whole. it said the engine was very well sealed up, almost NO blowby. . We I put the pump on an old engine, there was a gain of 25 or 26 HP at max revs. This engine had moderate blowby, so the pump worked pretty good. Whenever I build an engine from scratch, I always consider if it will have a vacuum pump when I select the ring package. I like to use very low drag ring stuff for serious dragrace engines. JOE SHERMAN RACING

[383Malibu]

Jack - IMO, the power gain doesn't come from the increased vacuum per se (unless the motor is already in need of freshening). The power comes from reducing the internal friction generated by the rings by using thinner rings and low tension oil rings in combination with gas ports and vacuum to maintain the seal and keep oil out of the combustion chamber.

[PFC1]

Always search for that edge!!!?

[s/c 266]

I did not see anyone mention the vac pump and pan vac gains associated with windage. I'm pretty sure THAT WHNE you pull a vac on the BBC pan youR lessening the air friction losses.

I measured 2 to 3% HP across the rpm band on my 565 with a small 10" vac

[sledpuller]

so who makes and sells the best setup for my application?bbf 475 cu in truck pulling motor turning around 9000 rpm,wet sump?what will i need to produce 10 -12 in vacuum.i dont want to go anymore if i will have oiling pin issues in this wet sump motor.wont the increase in vacuum cause a loss in oil pressure from fighting the oil pump its a mellings hv pump?will i have to have a regulator or due they figuire your rpm and tell you what size pulleys to use to obtain such vacuum you want?thanx to all that replied!!

[Stocky]

And what's the best exhaust evac design ?

[Ed-vancedEngines]

Best exhaust vac design is a remote vacuum pump. Next to that was one that was made by Shogun Industries. It was not great if you had restrictive mufflers though, None of them are, except external vacuum pump. Some guys have modified the late model Ford Vacuum pumps and made them work on Chevys, Those who have tried the late chevy pumps have been disappointed.

Sledpuller,
I suggest if you can to buy a good Gerotor Pump from Titan or even from Morosos, and talk with any of the custom pan builders, Stef's , Billet, Canton, Moroso, etc, and explain your application. I also like to ise Oil Accumalors.

In Wet Sump engines I do not like to see more than 12 to 14 inches of vacuum. I am concerned for rist pin oiling and don't want to pull oil from them.

Ed

[EngineTech1]

so who makes and sells the best setup for my application?bbf 475 cu in truck pulling motor turning around 9000 rpm,wet sump?what will i need to produce 10 -12 in vacuum.i dont want to go anymore if i will have oiling pin issues in this wet sump motor.wont the increase in vacuum cause a loss in oil pressure from fighting the oil pump its a mellings hv pump?will i have to have a regulator or due they figuire your rpm and tell you what size pulleys to use to obtain such vacuum you want?thanx to all that replied!!

Moroso #22641 would work great for that application. If your engine is assembled nicely and sealed up well then you shouldn't have any problem pulling more than enough vacuum. If it's not sealed up well then you may have a problem pulling vacuum. To control your vacuum level you can drill a hole in your filler cap and and tap it for a small pipe plug and drill the center out with different size holes for a pressure bleed to regulate vacuum. Moroso has rpm limits for the pump and sells pulley assemblies for it. Pulling more than 12 to 15" Hg with a wet sump can be dangerous to the engine unless it is built right and all the clearances are perfect. It will cause a little loss in oil pressure but shouldn't cause any problems. We have built 950hp small blocks with internal wet sumps that routinely pulled 18"+ Hg and ran at around 40psi or slightly less without any problems whatsoever.
It is correct that the biggest power gains with a vacuum pump come from running lower tension, thinner rings that can't properly seal without at least some crankcase vacuum. It does also reduce aeration of the oil and reduces windage losses somewhat.