95wht6spd

Were you running a crank case breather too?

spoon98hatch

No I wasnt- that would negate the effect of the RX style catch can

CamminC5

Can the discussion continue on crankcase evap????

JMBLOWNWS6

I keep using my mexican setup that has been working since 07

The Bat Car

Someone ask any questions on the crankcase evac & I will answer them.....the breather from RX/Colorado Speed has a integrated one way flow controlling checkvalve that is configured for the size of the engine. It is not to vent vapors out, that is done via the evac suction from the intake manifold while under boost, or the inlet side of the head unit while in boost. The checkvalve breather provides filtered fresh make-up air for the crankcase (an essential part of the evacuation & flushing process) but only lets in the correct amount that the ECU will be able to adapt for if running a MAF tune. If running a SD tune then that is not an issue. If running a breather that is unrestricted then the unmetered, uncontrolled air entering w/out being measured by the MAF will confuse the ECM and you will see your fuel trims all over the place as it tries to make sense of the conflicting data it is recieving from the MAF, MAP, and upstream O2's.

Most over 600-700 rwhp have a SD tune so the MAF is a non issue at that point and a open breather can be used.

Spoon, it is impossible to pressurize the crankcase w/the dual valve system....each valve will only allow flow in one direction. Your pressurization I bet is due to a piston/ring/cylinder issue. You and the other haters seem to be ignoring those posting here using the system installed properly and curing all issues they experianced with the vent only method. If you doubt this, just ask any reputable engine builder if they see this when tearing down another builders engines (most wont admit that their engine had an issue even though it is rarely the builder, but the tuner going lean while doing the dyno tune damaging the piston) and see how often they see this on big boost motors. Just as I have posted the links to other posts where they found that to be the case.

Treat the problem & fix it, don't just deal with the sympton.

Again, those who don't care about proper evac and longevity of their engine should be ignoring all this anyway instead of just posting insults.

Ask tech based questions and I will answer them.

Most here are still confusing crankcase pressurization

MVP'S ZO6

So the RX cans are based on engine size? Did I understand that correctly?

02402ramair

I would think there is some kinda mathematical formula that X bore at X ring gap under X amount of boost would produce X amount of CFM needing X size of hose for proper venting. Is there such an equation? I am no mathematician. I go off what works and then go 1 size bigger. lol

Vince99FRC

"Someone ask any questions on the crankcase evac & I will answer them.....the breather from RX/Colorado Speed has a integrated one way flow controlling checkvalve that is configured for the size of the engine."

Where did you get RX can?

Tact

The Bat Car

The flow through a oil separating can must be regulated. On the OEM setup GM assumes the same CI and cylinder fill, etc. so they use a sized PCV valve or in the case of the vallet cover, a fixed orfice that controls the amount of flow through & out of the crankcase. When you veture outside of that parameter then the flow must be matched to the engine build and FI or NA and the amount of boost run if FI. The RX system has matched flow control checkvalves to ensure this and do not use the valley cover vent as it is far to restrictive if it is a big cube or FI application. On a stock cube NA motor the valley can still be used but it does not allow the entire crankcase to be properly flushed since the entire drivers side bank is left stagnant. The drivers side valve cover has a nipple on the rear of the valve cover that can be uncapped and used allowing the integrated checkvalves to work properly.

If you have a monster FI build then there is another model with -8 outlets, and app 30% more capacity and the flow controlling checkvalves are a greater flow and are moved inline allowing the amount of evac needed. But, what we see far to often is there is a piston/ring/cylinder damage/sealing issue allowing more blow-by than any system, belt driven vacuum pumps included so if your blowing the dipstick out or oil seals you may still have a motor ecent power, but your blow-by issue can only be addressed by tearing down and replacing the damaged pistons and correcting the bore where there will be metal transfer & scouring. Doubt this? Ask any reputable engine builder if they see this in other builders engines they tear down (most wont say they have issues just as most tuners that cause the damage during dyno tuning by going to aggressive w/Air Fuel and/or timing) and you will se how common this is. Even the best forged pistons will suffer from detonation in a few short seconds. The most common is the top ringlands soften enough to pinch the compression ring and then the seal is compromised.....#8 is usually the cuplrit as it runs leaner than the rest in the LS based engines with 5 & 7 also subjet.

That is why we see so many come in with the evac system deleted and huge lines running to vented cans or just open lines. That will release the pressure, but the underlying problem causing this amount of blow-by is damage and it wont go away.

Keep the questions comming. This is back on track thanks to the mods.

ANYthing you don't fully understand, and the oil analysis is still what I will go back to for any that want proof as to the amount of harmfull compounds contaminating the oil due to not having proper evacuation, not just venting. And again, if you change your oil after every outing/track event to avoid this and can get away with just venting.
:thumbsup:

dsmlights

what do you guys think about this,

http://www.racetronix.biz/customkiti...sp?kc=CEPH&eq=

robert miller

not showing up at the moment...

tirecraft

That will not work IMO . That Air pump "Modified" will not remotely come close to what a True Vacuum Pump can do .

The Bat Car

tirecraft is correct. We have tried using the electric pumps for years and allthough they do pull decent vaccum we have got them to last very long for street use, and yes, they are not close to the capacity of a belt driven pump. They DID work well for intermitant use on some of the track cars though.

baezi z06

Hi great thread

i´m installing a GZ motorsport vacuum pump kit "belt driven" and it has vacuum control valve included, the pump is susposed to draw atleast 15" and the contol valve is adjustable from 12"-19"
but when do you know when to much vacuum is to much vacuum for the engine. ?
i was thinking of installing a vacuum gauge in car so i can monitor the vacuum , can i log it threw my HPT if i get for example auto meter gauge?

i have a 404ci LS2 NA engine built whith nitrous in mind whith whith wider ring gap .

thanks
Baezi

tirecraft

GZ Motorsports makes a good Ls vacuum pump we ran one on Kyles car for years with good "suckcess" . We didn't log pressure we got the engine hot and revved it to 6k and set it At 8 inches of vacuum . We calculated the rate of raise every 1000 rpm and figured we had about 10 inches at max RPM. Too much Vacuum will start taking oil away from the pins and cause some problems. We ran a ton of nitrous through that motor and it was pretty happy .

baezi z06

ok i see

did you guys run a vacuum gauge incar always ?

What is too much vacuum and how can i monitor that, just not go over 10" ?
i saw here earlyer in this threat they where talking about 14-15" not higher, maby that´s for bigger engine.
I would´t wante to suck the oil from the pins first time out

thanks
Baezi

dascorcha21

on my engine i just ran a hose to my mity vac from the valley cover rev the car to 6k and set it at 11" and done! you only need to set it once not soo much needing a dedicated gauge to monitor it all the time as it pretty much stays constant once you set it.

tirecraft

We did run a in car vacuum gauge .
I would keep it around 10 " to be safe
I believe pro stock guys run 20 plus " but those motors are built for that.

a/c man

can a vac pump create more HP?