changing displacement??

[SIBILANTx]

:uh: changing displacement by way of vacume........if i evacuate my block would i get any gains in performance or horsepower?
i could use a brake booster vacume pump from a early model "CADI". I know for shure it would change the displacement.but would i get any benefitsfrom doing this???? give me some feedback.
:uh:
greatly appreciated.
87 DX hatch

[NXRacer]

what are you smoking?? How can that possibly work??

a good exhaust upgrade could give you much more power i'd imagine then what you're trying to do.

[SteveDX89]

:wtf: Engine displacement depends on cylinder bore and piston stroke. I don't have any idea what your saying but I believe the flaming will begin.

[SIBILANTx]

the amount of air the pistons moves in the block not the head
in the crank case

[SIBILANTx]

i know drag cars use c02 to displace the air in the crank case, what is the advantage of doing this?

[thegreatdane]

:huh: umm, in the crank case? you want to suck out air from the crank case?

[SIBILANTx]

yes

[NXRacer]

i think you'd only want to worry about sucking air out of the crank case if you were a top fuel dragster. Other then that, i think the air and any 'resistance' it has would only be a problem if you've already done every other possible thing there is to do to the motor.

do some basics first, worry about the nit picky things later.

[A20A1]

Don't flame it's just over thinking how the process works...

To evacuate the head you need an exhaust system properly tuned... the exhaust itself creates some of the vacuum... the rest is from the movement of the piston.

Any vacuum pump would have to be located on the exhaust side of the head and be able to take the high heat of the exhaust... so that means turbo... it's not really a vacuum pump, but it does force in more air on the intake end.

There has been a few exhaust tip and muffler makers that use certain designs to try to increase exhaust velocity to help pull out more exhaust, and in turn pul in more air. But I haven't used or tested any of them.

[AccordEpicenter]

drag racers have been using moroso belt driven vacuum pumps for years, it helps the rings seal better... If you use one be sure you dont suck in all the seals...

[SteveDX89]

That may or may not be something worth doing but it has no effect on displacement.

[k-roy]

Ok I kinda get what you are saying.
Those old AMerican V8s did not always create enough crankcase pressure, mostly because of high lift and low rpms that people wanted. GM added an air pump as an accesory to help out with things like windshield wipers, flip up headlight covers, washer fluid squirters and even power locks because all that was vaccum powered.

What you need to understand is that on our Honda's the setup is backward, outside of the emissions system the car does not ned much vacuum at all. Let me make a list (Mike correct me if I am wrong)
Vaccum Secondary on the carb, Choke, AC Idle Boost, cruise control, idle boost, and the distributor advance. All of that can run off vacuum from the stock intake manifold without a problem. Honda in their infinite wisdom also added an air suction valve to the mix, it runs in a metal hose from the exaughst manifold to behind the valve cover to help out with extra vacuum. There is another tube there that runs alongside it, thats for the exaughst gas recirculation, emissions crap. Ok now im sure you are lost but oh well, time to press on. What I assume you are looking for is more power, and thats a good thing. There are 2 questions you need to ask yourself. One, does my state require me to have the emissions in my car check regularly? Second, so I want to do some crazy ass modifications for next to no money all in the search of more power? If the answer is yes to both of those its a good day my good friend, you came to the right place.
Ok here is how to make power from the mess of lines under your hood. First you can start by removing a lot of the mess.
Read this: http://www.3geez.com/showthread.php?t=11067
After you do that you can really tap into newly found power.
I reccomend you rig up an intake, mine is like the one in the 4th and fifth pic.
http://www.3geez.com/showthread.php?t=15496
After that your car will idle smoother and pull harder. Time for more power adders on the cheap. Get an aftermarket coil, and a new set of sparkplugs. http://www.3geez.com/showthread.php?t=114
If you are feeline froggy you can even rip out the powersteering and air conditioning systems, they take away power.
All that is pretty caheap and can ber done for around $100.
After that you can work on Exaughst for some decent power gains.

[A20A1]

Oh so he's talking about upgrading the PCV system...

[SIBILANTx]

SO it dont make no sence?? slap a turbo on and BUYAKKA! killed two birds with one stone. ive done a lot of work on this car, the whole vacume removal stuffs done. 2.5" pipes to nice muffler. Got the intake P&P, waiting to find some exhaust manifold diagrams to make a turbo manifold, and a nice weber.
3geez has helped me AND I HOPE WILL CONTINUE TO HELP ME.
THANKS

[SIBILANTx]

yes, upgrading the PCV, IS IT POSSIBLE??

[A20A1]

lol, hook the as valve to venturi vacuum, then hook the air suction port to a Y coming off the crankcase ventilation hose somewhere between the block and the PCV valve...

as throttle increases the valve opens and starts sucking out crankcase fumes into the as valve and then to the ehxaust...

that should work...

If the as valve was indeed intended to be a vacuum pump and not just a way of injecting air into the exhaust to clean up emissions.

I have no idea if that will disrupt the PCV system or if oil will get into the exhaust even though there is the oil seperator before the PCV valve...

Hopefully no fuel can enter if the valve sucks in more air as manifold vacuum drops...

You have the valve still?

I could be thinking of this wrong... anyone have any insite?