Crankcase Evacuation System on Stock Engine

[RDY4WAR]

Do you consider headers a bolt-on modification?


viewtopic.php?t=59218#p836083

Yes, headers are included. Going by the GMHTP rules which includes roller rockers and valve springs as well. The heads, cam, intake manifold, and entire bottom end must be stock from the OEM. Rebuilds aren't allowed, must be OEM short block. Must have at least 18" vacuum at 800 rpm.

Current record stands at 11.48 @ 118 mph. I have done currently....

1-3/4" headers to mini-bullets dumped
Ram air from the foglight hole
52mm TB
1.6 roller rockers
O2 sensors deleted (tuned open loop only)
Electric WP
AC/HVAC deleted
PS deleted
Underdrive pulley
160°F stat
TH350 with a high STR 9" 4000 stall
4.10 gear in the fragile 10 bolt
M/T 28x9 PBRs and skinnies
Sunoco EXO2 fuel

...plus a bunch of suspension work and weight reduction. I'm trying to get it under 3000 lbs race weight. It's at ~3150 lbs currently. I even got what is essentially a copy of the oil used by Elite Motorsports PS guys in a slightly more viscous 5w-20 grade (lots of friction modifier). The lubrication at every point has been catered to maximize friction reduction.

That's why I'm looking at crankcase evac. I'm going to need every bit of power I can get from it.

Are you pushing oil past your seals/gaskets?

No leaks or excessive blow-by. Compression and leakdown numbers are excellent given the mileage. It has a clean bill of health.

[Old School]

How fast are you at this time?

[cardo0]

Here's a 3rd Gen camaro using exhaust evacuation and he only gets 2 or 3 inches of vacuum at 4000rpm:
You exhaust system may be different but its fairly easy to measure with a vacuum gauge.

To aid ring seal you want closer to 12" Hg vacuum.

[FC-Pilot]

I'm getting ready to add this to my street car. Have a few customers that say they work great. Can only expect 4-5" @ 12.5 volts. More with more. I'm going to run it through the PVC.

We use that same thing on our dyno for street type engines. It saves us fiddling with pcv valves and somebodies poor crankcase ventilation getting the floor all oily (“I did not want a breather in my polished valve covers! I paid good money for them and I don’t want to cut a hole in them!”). We have an oil separator after the pump. Maybe if we put it before the pump we would still be on our first one.

Paul

[SpeierRacingHeads]

Mine is a AC Delco 215-425.

I'm putting a separator before the pump and then a push on breather on the exit of the pump.

[Kevin Johnson]

Here's a 3rd Gen camaro using exhaust evacuation and he only gets 2 or 3 inches of vacuum at 4000rpm:
You exhaust system may be different but its fairly easy to measure with a vacuum gauge.

To aid ring seal you want closer to 12" Hg vacuum.

This is why it is important to read the earlier citation.

David Vizard reported on the care that had been used to select the sweet spot in the exhaust system. I imagine that if a spot had been chosen for convenience then less optimal results could be expected. Granted that the Moroso tube has a modification to help smooth some of this over.

My point is about incremental improvements in power due to lower parasitic windage and pumping losses: [My emphasis]

As discussed in Chapter 3, Lubrication Decisions, creating or “pulling” a vacuum on the pan produces power both directly and indirectly. Pulling a vacuum causes the oil to drop out of suspension quicker and, as a result, it reduces windage. That same vacuum also allows the use of a lower preload on the rings, thus lessening ring-to-wall friction. Mechanical pumps cost money and use power to drive them so the full gain of the vacuum is not realized. An exhaust-driven pan-evacuation system is inexpensive and doesn’t create parasitic losses. That makes it worth looking into.

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[RDY4WAR]

How fast are you at this time?

Only 1/8-mile numbers before the pandemic lockdown happened. That was 7.72 @ 90 mph with a lame 60ft. That was before the 4.10 gear (was on stock 3.23s, crossing 1/8-mile in 2nd gear) and was on 93 pump fuel. It's going to take some more work and some mineshaft air later this year to get there.

[ptuomov]

What’s the best crankcase evac system that has been designed that uses the manifold vacuum to pull a crankcase vacuum at low rpm and exhaust collector vacuum to do the same at high rpm WOT?

[BobbyB]

What’s the best crankcase evac system that has been designed that uses the manifold vacuum to pull a crankcase vacuum at low rpm and exhaust collector vacuum to do the same at high rpm WOT?

I have wondered if peak manafold vacuum could be stored in a big "can" then applied to the crankcase for a drag strip run. This could be in addition to an exhaust or electric system that could provide a few inches all the time. Just a thought. No design, never saw such a thing.

[leahymtsps]

Kevin if you can post a speedtalk topic from 09-10 titled Exhaust evac. questions, Bill Jones gives allot of detail
including a picture of where it worked best. I tried but couldn't get the picture for some reason.

Tom

[Kevin Johnson]

Kevin if you can post a speedtalk topic from 09-10 titled Exhaust evac. questions, Bill Jones gives allot of detail
including a picture of where it worked best. I tried but couldn't get the picture for some reason.

Tom

viewtopic.php?t=16468&start=30#p237013

welded in center cloverleaf area.JPG

[Kevin Johnson]

What’s the best crankcase evac system that has been designed that uses the manifold vacuum to pull a crankcase vacuum at low rpm and exhaust collector vacuum to do the same at high rpm WOT?

I have wondered if peak manafold vacuum could be stored in a big "can" then applied to the crankcase for a drag strip run. This could be in addition to an exhaust or electric system that could provide a few inches all the time. Just a thought. No design, never saw such a thing.

That's kinda like using your spare tire as your window washer fluid pump.

Maybe your roll cage.

[RDY4WAR]

Kevin if you can post a speedtalk topic from 09-10 titled Exhaust evac. questions, Bill Jones gives allot of detail
including a picture of where it worked best. I tried but couldn't get the picture for some reason.

Tom

viewtopic.php?t=16468&start=30#p237013


welded in center cloverleaf area.JPG

Thanks for the link. I'm going to check it out.

[Superstock]

Is it possible for you to email me?

[bentvalves]

I'm getting ready to add this to my street car. Have a few customers that say they work great. Can only expect 4-5" @ 12.5 volts. More with more. I'm going to run it through the PVC.

We use that same thing on our dyno for street type engines. It saves us fiddling with pcv valves and somebodies poor crankcase ventilation getting the floor all oily (“I did not want a breather in my polished valve covers! I paid good money for them and I don’t want to cut a hole in them!”). We have an oil separator after the pump. Maybe if we put it before the pump we would still be on our first one.

Paul

Hi Paul,

where exactly is the vac pump plumbed to ?