Shining some light on the EVAC system, technical reasons

[RX-Dave]

I hope this may help some to think about why exactly the EVAC may help. I have yet to run filters, so I have yet to experiment with it.

I do know, origonally used to control oil leaks and blown gaskets in NHRA ProStock racing, that vaccum pumps have been used for years. Large, HP draining vaccum pumps!!! These things require HP to turn em, so for these guys to bolt one on and turn them off the crank, there has to be something beyond that.

By using a pump big enough to make 10+" of vacuum, they found that 2 things would happen. The vacume would pull all un-neccesary oil from the cylinders (just leaving enough to seal and lube the rings) would greatly help combustion with "dry" un-contaminated air.

Secondly, the crankcase vacuum, when used together with low tension cylinder rings, would make HP!!! SUBSTANTIAL HP. Several places note as much as 30hp on a 500hp sportsman engine could be gained.

I am not saying that the EVAC is right, but controlling that under-piston pressure is.

Here is a link to Moroso's web site, and some tech info on why they use vacuum pumps.

http://www.moroso.com/catalog/categoryd ... code=17200

 

[SUPERTUNER]

I do know, origonally used to control oil leaks and blown gaskets in NHRA ProStock racing, that vaccum pumps have been used for years. Large, HP draining vaccum pumps!!! These things require HP to turn em, so for these guys to bolt one on and turn them off the crank, there has to be something beyond that.

I know some if not all the current Pro Stock cars and ALL of the Pro Stock bikes are using electrical vacuum pumps. It doesn't take much power to turn those as they are not turned by crankshafts. When I ran Pro Stock bike, we used to know when the rings seated by the vacuum draw on the guage for the evac pump. I also built a custom exhaust system for my PSB that had a siphon tube down between where all 4 primary header tubes came together in the collector. If you position the correct I.D. tube about .750" past where the primaries end in the collector, you will get that siphoning effect with absolutely zero horsepower loss. Only thing with this design is that you don;t begin pulling a negative vacuum until your off the line about 50 - 60 feet or so. It added literally 5 ounces of weight too!

Freddie

 

[RX-Dave]

Fred - My association was that in order for these guys to give up some crank HP, it was to gain some. That vacuum was a good thing.

 

[Turbo Tim]

The header collector solution of removing crankcase pressure would be a better way because it doesn't put oil mist into the air /fuel charge .Oil mist in the intake charge WILL cause intake valve deposit buildup.

 

[Frostbite]

I guess the question that needs to be asked is this:

Is there enough of a vacuum created with the ECP evacuation kit to adequately evacuate the crankcase?

If not, do we need an inline electric pump to boost the evacuation levels?

Frosty

 

[Bossman]

At this point i would have the same opinion as RXHALLER on the issue of putting warm damp air charge into the intake. What are going to be the long term effects on the motor of that? Is there any other way to create the vacuum and deposit the oil.

 

[DC5]

At this point i would have the same opinion as RXHALLER on the issue of putting warm damp air charge into the intake. What are going to be the long term effects on the motor of that? Is there any other way to create the vacuum and deposit the oil.

The stock system works the same way as the EVAC.

 

[Bossman]

With the stock system though it dumps in the side of the large airbox not directly into your intake charge. Don't get me wrong though this is just my in theory thinking, I am still up in the air about if I would use it. I don't know if there if enough of a gain to risk possible long term effect on the motor. But then again I problably shouldn't worry about it because I don't keep sleds long enough for that to happen.

 

[DYNAREX]

with all the talk about the evac setup i thought i should chime in
yes the benefits of negative pressure or vacuum in the crankcase do increase power,this is undisputed and proven many times in different fields-including myself and freddie on a dyno with my evac kit.
the factory system is fine as long as the stock airbox is in tact-and yes the oily film inside the airbox is mainly engine oil so the engine is ingesting a slight amt of crank oil with every breath-longterm problems i can only sumise to be minor -nothing a little seafoam wont cleanup every season as far as the carbon on the valvestems-the system i designed also draws the slight bit of oil mist or vapor from the crankcase so its no worse off than what yamaha originally designed-
the main reason for this system is that when riding at high rpm in extreme cold the crankcase vapor will freeze in the filter that is supplied with the air filters and the positive pressure in the crankcase blows out the valve cover gasket {namely the one on the clutch side} and oil soaks the clutches-not many have experienced this but it does happen.
in my system,should the "trap"fill with moisture and freeze,the airflow will not get restricted and crank evacuation will still occur-an added bonus is that the frozen moisture can be removed with a simple drain fitting-any questions feel free to email me
thanks
dynarex

 

[Turbo Tim]

I ran the ecp kit all last winter and loved it , I had all around improvement including Topend . I saw the Posts about adding a crankcase vent system but never did it because I did not have any reason to and did not want oily ,warm, moist air injected directly into the throats of the carbeurator . Just my 2 cents worth ..........I have a turbo now and still have the same k&n filter on the vent tube ........No problems and no oily discharge at all.......................I guess the best of both worlds would be to install a filter of some kind in the tubes to make sure the air is clean going into the carbs ..............