Crankcase Blowby Flow Rate - Screwcharged Methanol

Looking for some rough numbers here......

Either on the dyno, or at the track, has anyone ever measured their actual crankcase blowby air flow rates while under power? IE: Have you ever hooked up a flow measuring device to actually measure the crankcase blowby air flow rates while under boost with a typical PSI C or D methanol type deal?

If you have, I'd appreciate any feedback that you can provide.

Thanks.

 

Nobody has done this before ???........

 

If you leak the motor down and its sealed up why would this matter? You are basically controlling and minimizing windage after that.
Dale

 

Not if a person wants to draw and maintain an amount of vacuum in the crankcase.

 

I read crankcase pressure in the lifter valley and made laps to evaluate my puke tank venting. It would produce over 2 psi on a 45psi chevy D rotor combo.
I doubt you'll ever maintain a vacuum in the crankcase of a screw engine.

 

Vacuum

Hi, There was a european company at PRI that made a billet pan and oil pump combo, they showed me the data logger showing vacuum up to about 3.5 seconds into a run on a pro mod car though I cannot remember who they were, it may have been Autoverdi. I know this doesn't help a lot but but it may give you a rough idea of what is possible. Also this may have been a roots car.

Best wishes,
Trevor Sherwood

 

Curious, what was your total vent area? With the area and pressure I could guesstimate the flow....

 

I can see all this mattering on a Super Stock engine with a 283 cu in engine. Vacuum matters then. Not on a screw blower than can put out 50+ psi. Way more gains than that in my humble opinion. 10 to 14% leak down and it will run 5.60's on alcohol or nitro. Thats a fact
Dale

 

I don't know anything about them but Performance Trends sales one for about $500 they maybe able to tell you if it will do what you want it to do.

http://performancetrends.com/prices.htm#Blow_By_Blowby_Sensor_Prices

 

Back in 2006 Moroso designed a Vacuum Pump that was put on two Blown Pro-Mods and run for a while.

These two cars where running 6.0's to 6.1's consistantly, and produced 16" at the hit, and by the time they shifted into 2nd, would drop to 6" to 8" and maintain it down track.

If the engine showed any signs of a missed tune up or had just been thrown back together after a between rounds thrash, it would make 3" or so.

First and for most, inline "flapper valves" had to used to block off the burn down lines. You can make vacuum with two open 1" i.d. lines.

The oil was really clean, and both teams felt they gain a mph or two from it. The biggest down fall was all the extra plumbing taht was involved. Flapper valves, equalizer lines, and lots of inline "t's' made a lot of extra stuff that had bee maintained and always buttoned back up after a run. People have told me it can be simplified, but our experiance say otherwise.

The Vacuum Pump is #22643, and it flows right at 99 CFM free flow. Its the biggest flowing pump on the market.

Right now, we are working with some teams that looking for more moderate vacuum results, but enough that oil life, and some power can be made.

Scott Hall
Sales Engineer
Moroso Performance

 

Scott , what was the details of the oiling system on these test engines you ran your pump on ?

 

I've heard of some of the 100-250 psi boost tractor pullers measuring cfm out the blow by tubes trying to watch detonation and/or when to change the rings

 

Both engines were KB Blocks with Veney heads and a Plueger Oil Pump Dry Sump System. Standard Stuff......

 

Thanks Scott. Two questions...... How does the displacement of that pump compare to the displacement of the Star vacuum pump and how much RPM will it tolerate? Also, I'm a bit confused by the yellow line in your post above. Could you expand a bit on that?

 

I think he meant to type, "you *can't* make vacuum with two open 1" i.d. lines", hence, the flappers. The flapper allows pressure to escape when positive and closes back shut when subject to a vacuum condition.

 

Can't.............

 

OK, I got it. That makes sense.

 

Good Morning,

Sorry about that......CAN'T..........its amazing what one mispelled word can cause...lol....

The Star Vacuum Pump that most people see on the Nitrous and Turbo cars is similar to our #22843. The free flow numbers are in the mid 70's and work on most everything.

We built that #22643 to be the biggest thing on the market, and could keep up Blown and Turbo stuff.

 

Thanks Scott. What RPM will it tolerate and what sort of drive ratio do most run it at?