Vacuum pump on a dirt late model?

[Krooser]

Don't see much of vacuum pumps on dirt cars. Why use one? Why not?

[In-Tech]

Don't see much of vacuum pumps on dirt cars. Why use one? Why not?

Depending on vacuum amount, can suck dirt past the seals.

[Krooser]

Don't see much of vacuum pumps on dirt cars. Why use one? Why not?

Depending on vacuum amount, can suck dirt past the seals.

Are you talking crank seal, oil pan seals and such? Just wondering... I've only seen a couple guys use them in the last 40 years.

[MadBill]

Years ago a pal of mine bought a hot-rodded VW engine literally dirt cheap. The seller thought it had been sabotaged with a handful of grinding compound, but it turned out he'd spent hours blasting around a tiny dirt track engulfed in his own dust and the fine thread labyrinth crank seal VW used in place of a conventional design had wound a cup of ultra-fine grit into the engine.

[Ks Fats]

It just adds another variable to an already complex platform; if you are talking open class racing where you have to play with timing and restrictor plates to keep the car hooked up and drivable the gains are nullified before you hit the track. We are still allowed dry sump systems for open engines so it would be redundant. If you are talking about a limited series requiring wet sumps and other restrictions there might be some gain with the right ring package; even then chassis dynamics under race conditions might kill the system. Time and money could be better spent improving other areas for bigger gains.

[englertracing]

Pretty sure some run 5 or 6 stage dry sump and no breathers and they get a vacuum

[Racing68]

I've only done a few of those but they would pull at least 6" of vacuum with 4 scavenge stages.

[MadBill]

With Gapless top rings, low tension oil rings and a 3 scavenge stage Aviaid pump, a 380" SBF road racer I consult on pulled 20" before we cracked open the vacuum break and dropped it to 12-14". When it lost vacuum due to an intake manifold leak, it turned into a total bug-fogger.

[englertracing]

With Gapless top rings, low tension oil rings and a 3 scavenge stage Aviaid pump, a 380" SBF road racer I consult on pulled 20" before we cracked open the vacuum break and dropped it to 12-14". When it lost vacuum due to an intake manifold leak, it turned into a total bug-fogger.

Iron or aluminum?

[MadBill]

Iron Dart block.

[racinnut15xm]

Pretty sure some run 5 or 6 stage dry sump and no breathers and they get a vacuum

This, and I think somewhere in the million page rule book it says no vacuum pumps.