mactaylor Custom Title Time!
1,005 posts · joined Aug 2007 ·
any body running a vac pump? we used to in our speedway car and made good gains!
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vacuum pump tech
dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
Rodney does. His came from $hawn Geer$
the yanks claim 20 hp.(probably 10 in Australia)
Even 10 would be worth the money spent.
...although you can spend couple of grand pretty quickly depending on whose you buy,
and what you spend on braided hoses and catch cans,
or how much stuff you want to make and experiment with.
the yanks claim 20 hp.(probably 10 in Australia)
Even 10 would be worth the money spent.
...although you can spend couple of grand pretty quickly depending on whose you buy,
and what you spend on braided hoses and catch cans,
or how much stuff you want to make and experiment with.
westi wrote:That's mad Alan.
mactaylor Custom Title Time!
1,005 posts · joined Aug 2007 ·
I thinkl a gemini diesel had a pretty good pump on them, any other cars you know of?
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greedy53 Bishop of Volkswagenism
3,062 posts · joined Mar 2006 ·
early commadors
👍👍😂🙅🥷😬🤓
Judsons4eva Officially Full-On Dubber
270 posts · joined Oct 2004 ·
Vacuum pumps on diesels are for a different purpose. As many diesels don't pull any vacuum from the intake they require a vacuum pump to operate the brake booster. The vacuum pumps used on drag cars supposedly are meant to give a power boost by creating a vacuum in the crankcase and relieving blowby pressure.
While the proponents of vacuum pumps claim HP increases but I seriously doubt 10 to 20hp increase (if any) - Frankly I wouldn't waste my money. They were original put on drag cars that had large amounts of blowby out of ultra HP engines. The claims somewhat defy the laws of physics as to create the vaumm you need to put energy into driving the vacuum pump so how can you get more power out than you put in.
Ken
While the proponents of vacuum pumps claim HP increases but I seriously doubt 10 to 20hp increase (if any) - Frankly I wouldn't waste my money. They were original put on drag cars that had large amounts of blowby out of ultra HP engines. The claims somewhat defy the laws of physics as to create the vaumm you need to put energy into driving the vacuum pump so how can you get more power out than you put in.
Ken
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westi what the
1,610 posts · joined Aug 2005 ·
18 bhp on a fontana.also picked up a bit up a bit in mid range.
well worth the money if you are chasing an edge.
every engine is different so gains will always vary,but you can always play with pulley ratio's.
me personally,i have a million other things i can grap power from before i go down that road.i already have a full engine bay and don't need anymre headaches.
well worth the money if you are chasing an edge.
every engine is different so gains will always vary,but you can always play with pulley ratio's.
me personally,i have a million other things i can grap power from before i go down that road.i already have a full engine bay and don't need anymre headaches.
down sharon.
Judsons4eva Officially Full-On Dubber
270 posts · joined Oct 2004 ·
18 hp in how much? can you explain why there is a hp increase?
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modulus Veteran Volks Folk
2,009 posts · joined Jul 2003 ·
Not quite. Superchargers, for example.Judsons4eva wrote:The claims somewhat defy the laws of physics as to create the vaumm you need to put energy into driving the vacuum pump so how can you get more power out than you put in.
Ken
I think the 10-20 hp gains are probably on 6000 hp top-fuel engines (or, as dangerous pointed out, 3000 hp on an Australian dyno). That sort of gain *might* be possible by the simple reduction of pressure on the underside of the pistons, 'though I haven't done the math.
hth
dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
I think the reduction of
windage,
and
Pressure,
allows the components to rotate and reciprocate easier.
A dry sump pump with a large scavenge stage/stages,
can do the same.
It seems that vacuum creation does produce more power,
but the gains are actual,
not imaginary like with criogenics and coatings....😂
windage,
and
Pressure,
allows the components to rotate and reciprocate easier.
A dry sump pump with a large scavenge stage/stages,
can do the same.
It seems that vacuum creation does produce more power,
but the gains are actual,
not imaginary like with criogenics and coatings....😂
westi wrote:That's mad Alan.
Judsons4eva Officially Full-On Dubber
270 posts · joined Oct 2004 ·
Ok physics can explain superchargers. Forcing air through a restricted intake system gets more air in the cylinder and the engine behaves as if it is a bigger displacement.
Vacuum in the crankcase makes it easier for the pistion to go down (in on a flat 4) but conversely makes it harder for the piston to go up ( out on a flat 4) so the net gain is zero. The only reason I can see is a greater pressure diffential accross the piston rings - so the rings seal better with less blowby - but 30 hp in 3000hp as a ratio is not worth worrying about on a 200hp engine and the loss with belt friction etc will probably offset any gains.
It does have the effect of lower oil pressure and that may give some gains
The only reference to vacuum pump gains on the web is from those selling them - there is nothing in the technical literature from the SAE etc.
Vacuum in the crankcase makes it easier for the pistion to go down (in on a flat 4) but conversely makes it harder for the piston to go up ( out on a flat 4) so the net gain is zero. The only reason I can see is a greater pressure diffential accross the piston rings - so the rings seal better with less blowby - but 30 hp in 3000hp as a ratio is not worth worrying about on a 200hp engine and the loss with belt friction etc will probably offset any gains.
It does have the effect of lower oil pressure and that may give some gains
The only reference to vacuum pump gains on the web is from those selling them - there is nothing in the technical literature from the SAE etc.
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dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
Judsons4eva wrote:The only reference to vacuum pump gains on the web is from those selling them - there is nothing in the technical literature from the SAE etc.
I feel the same about cryogenics.
I think that there is a gain from vacuum pumps by the evidence I have seen and heard about from parties that do not sell them.
I think the key is not the vacuum so much as the "lack of pressure".
Perhaps it is purely due to better ring seal alone,
although you could argue ,I suppose, that if there was no problem there to begin with,
it would not be needed, or have less return of lost power.
Even sanctioning bodies feel it is an advantage,
and some classes have banned them.
I know a fellow with a moden engine dyno,
so will ask him if he has found particular number for the gain.
westi wrote:That's mad Alan.
VWCOOL 23 Windows of Awesome
5,158 posts · joined Jun 2003 ·
yeas a bloke I know fitted one to a Holden V8 years ago and there were gains in engine dyno power and times at the strip.Not sure how much - but it was the basis of an article in Street Machine; I think it was a Holden 2.8-litre 'Blue' six (VH series) exhaust pump
Pay your debts, CxxT
mactaylor Custom Title Time!
1,005 posts · joined Aug 2007 ·
gains are made not from the vacuum itself butyou can run lower tension rings and that there is less oil in suspention floating around for the crank to run into. ang a lovely by product is that you get almost zero oil leaks!!!!
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Judsons4eva Officially Full-On Dubber
270 posts · joined Oct 2004 ·
The only thing that can explain a slight power increase (20hp in 3000hp!) is the advantage of lower tension rings and the greater pressure differential across the ring pack giving better ring sealing and less blowby. You are right about the oil leaks too as the first use of them was to stop rocker cover and sump gaskets blowing out on nitro cars!
On most of the VW engines we drive I can see no advantage and a lot more hassle cluttering up the engine bay, with another drive belt.
On most of the VW engines we drive I can see no advantage and a lot more hassle cluttering up the engine bay, with another drive belt.
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mactaylor Custom Title Time!
1,005 posts · joined Aug 2007 ·
yes but we arnt talking about a 1600 dp!!!!!!!
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Judsons4eva Officially Full-On Dubber
270 posts · joined Oct 2004 ·
20 hp in 3000Hp is 0.6% so even on a 300hp super hot VW engine this is only 2hp and I guarantee the losses in the belt drive of the vacuum pump will probably exceed 2 hp - so the net gain is Zero - so forget it!
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dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
The gains are outright.
Net, not grosse.
The gains, wether 10, 20 or 30hp, are seen on engines from small to big, and not just 1000hp prostock V8s.
The fontana above that Westi mentioned was probably a 250 to 300hp inline 4 cylinder that is used for speedway.
The figure I was told for a V8 speedway engine was 20hp on a 700 hp 370 ci engine.
If the gains on a volksy were 10hp,
net
I think it may be worth chasing if you have exhausted all other avenues.
In my case I think I would go for a big dry sump pump to get some gains and improve the oil system at the same time.
Most engine builders and dyno operators in the racing world claim just going to a basic drysump system
reduces windage enough to show a net gain in power and torque despite the extra power needed to run them.
Net, not grosse.
The gains, wether 10, 20 or 30hp, are seen on engines from small to big, and not just 1000hp prostock V8s.
The fontana above that Westi mentioned was probably a 250 to 300hp inline 4 cylinder that is used for speedway.
The figure I was told for a V8 speedway engine was 20hp on a 700 hp 370 ci engine.
If the gains on a volksy were 10hp,
net
I think it may be worth chasing if you have exhausted all other avenues.
In my case I think I would go for a big dry sump pump to get some gains and improve the oil system at the same time.
Most engine builders and dyno operators in the racing world claim just going to a basic drysump system
reduces windage enough to show a net gain in power and torque despite the extra power needed to run them.
westi wrote:That's mad Alan.
Judsons4eva Officially Full-On Dubber
270 posts · joined Oct 2004 ·
I guess we'll have to agree to disagree - just can't see anyway a 5% gain in power can be had by having a vacuum pump attached to the sump. If it helps you go faster then good luck - I'll be proven wrong.
Ken
Ken
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dangerous 23 Windows of Awesome
5,901 posts · joined Jan 2005 ·
I would not say I disagree with your reasoning Ken,Judsons4eva wrote:I guess we'll have to agree to disagree - just can't see anyway a 5% gain in power can be had by having a vacuum pump attached to the sump. If it helps you go faster then good luck - I'll be proven wrong.
Ken
but would like to try something like this, since reducing windage may be worthwhile in MY understanding of the way things are.
It may prove to be of little value, but I WILL know for sure,
not just think it might.
westi wrote:That's mad Alan.