Chip

iTrader: (3)

Ive never seen one, why is that?

I dont believe for a minute that none of the tuners have heard of them, so why dont any of them fit them?

GARETH T

the gains are so small

rsnissan

iTrader: (9)

This was OE on my datsun sunny but never really seen anyone fit one aftermarket

Chip

iTrader: (3)

Quantify "so small" please if you know any figures mate?

GARETH T

i was just guessing at it,, but as another guess single figures at peak HP,

Fudgey

iTrader: (4)

not being thick here - i just dont know lol

what does a vac pump do?

suck the crank pressures out the block etc and back into the inlet or something?

Chip

iTrader: (3)

Yes mate, thats spot on, although dumping to atmosphere makes more sense from a performance point of view, putting it back into the inlet would mean adding oil to your charge which is never a good idea!
(although is what manufacturers HAVE to do as they arent allowed to dump it on the floor, lol)

alistairolsen

normally sucks it out the block and blows it into a catch can and the air out of a filter. Meant to reduce blowby and windmilling losses

Chip

iTrader: (3)

You are correct (as always!) mr olsen

GARETH T

i think it would increase blowby as there would be a higher pressure differential

AlexF

Never heard of one being used for performance gains!

Alex

Chip

iTrader: (3)

It reduces blow by on the cylinder on the induction stroke at the time, on the cylinder thats firing its going to make naff all difference as you are talking about a tiny percentage difference anyway.

Chip

iTrader: (3)

That surprises me, thought you would have been one of the people with useful input TBH!

Stavros

Seen one on a foriegn Supra once, if they were to be belived they gained a suprisingly silly amount, over 30horse or summat.

Cant remember the details now

GARETH T

ya i guess your right

Fudgey

iTrader: (4)

cheers for the answer guys

Chip

iTrader: (3)

Thats a similar amount to what some of the yanks are making on V8's doing the same thing.

In my mind, if it gains you 5bhp for basically bugger all effort and bugger all expenditure (second hand pump) then it seems like a very worthwhile modification.

Might cure my valve stem seal smoke as well

Deleted by Request

Will increase power due to less drag on crank...BUT positive crankcase pressure primes the pump and helps to ensure a steady flow of oil into the pickup...when you dabble with the vacuum pumps there is less pressure to push the oil thru the pickup.

Chip

iTrader: (3)

Phil, interesting theory, but the oil pump is a displacement pump, its really not going to be effected very much by a few psi more crank case pressure or not, and anyway the same differential in the crank case RESISTS flow from the places on the engine that oil is used and ultimately released from, so means that you need more pressure anyway to get the same flow of oil through the mains etc.

Ie you are basically removing the same pressure from both sides of the oil system.

Stavros

And that wasnt a fancy setup, it was a conventional old skool V8 style straight into the exhaust one, using a slash cut exit to create the vacumn, no fancy pumps at all.

Some testing, albeit on Hondas, here...

http://www.honda-tech.com/zerothread/1199935

Deleted by Request

What about an oil accumilator?...a sealed cylinder with a floating piston. Pressurized air on one side of the piston forces a reserve supply of oil into the engine if the flow from the internal oil pump is interrupted...this apparently works better than your idea Chip on a wet setup.

Chip

iTrader: (3)

Oil pump is easily solved Phil TBH, just go dry sump, which is better than any alternative that im aware of and solves many other problems too such as surge.
But like I said, im not actually convinced that reducing crank case pressures will have a significant effect on the pump for the reason I mentioned about it taking pressure from both sides of the oil system.

Chip

iTrader: (3)

Interesting reading, the upside of the exhaust ones is that they dont ever create too much vacuum, but if I used an electric pump I would monitor the case pressure anyway and only turn the pump on in circumstances where it was acceptable to do so.

Deleted by Request

...well my 348 is a dry sump...scared the shit out of me when i first got it to see no oil in it from hot (my mistake) one morning

Chip

iTrader: (3)

And you saw inside it how exactly phil?

Deleted by Request

....from dipping the dip stick you dip stick

ian sibbert

Where is the dip stick on your dry sumped engine Phil?

Not being smart i'm genuinely interested....

Chip

iTrader: (3)

you have a dipstick into the sump of your dry sumped engine to tell you that the sump is dry?

Deleted by Request

....you have to bare in mind 2 years ago i had no idea it was a dry sump setup..even though it has a seperate tank in the engine bay with a dipstick ...it was a dizzy Mike R moment

..you ever get a feeling that you have to watch what you say cause haters are everywhere?

Chip

iTrader: (3)

So, anyway, moving away from Phil and his usual off topic crap, and back onto the subject at hand....................

SillyFezzaMk1

iTrader: (1)

your the dipstick for trying to dip a dry sump engine

Dan

ian sibbert

Ive tried on a couple of occasions to promote the Accusump concept, we have had a couple of cars, N/A high revving 1.6 and 1.4 vauxhall engined rally cars with accusump's, engines had been built by John Hardman race engines,

Looks to me like an neat an simple solution, i'd certainly give one a go...

http://www.accusump.com/

And I defo dont hate you phil, you lush handsome B**tard

GARETH T

ian i guess you could use a small hydraulic accumulator, and avoid the aftermarket car tuning tax

Deleted by Request

How is my dry sump off topic?

Seems to me you are always looking for a scape goat when YOU start on me..get over it and chill.

Chip

iTrader: (3)

Because wether or not your dry sump scared you actually has got nothing to do with wether or not power gains from crankcase vacuum pumps are useful on a YB or any other engine.

Just stay on topic or butt out please Phil.