Converting Wet Stump Engine to Dry Stump

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Discussion Overview

The discussion centers on the feasibility and implications of converting a wet sump engine to a dry sump engine, particularly in the context of building a low-budget, street-legal car suitable for drag racing. Participants explore the technical challenges, costs, and potential benefits of such a conversion.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the difficulty and worth of converting a wet sump engine to a dry sump engine, noting potential benefits in weight distribution.
  • Another participant argues that the conversion is tough and slightly expensive, suggesting that the minimal returns do not justify the effort for casual use.
  • A participant inquires about the benefits of a windage tray in a wet sump engine and the implications of having negative crankcase pressure, especially in boosted applications.
  • It is suggested that the primary advantage of a dry sump system lies in maintaining full oil pressure during startup and under various g-loads, rather than weight distribution.
  • Discussion includes the potential horsepower gains from a windage tray and the role of crankcase pressure in relation to oil leaks and PCV valves.

Areas of Agreement / Disagreement

Participants express differing views on the practicality and benefits of converting to a dry sump system, with some emphasizing the high costs and minimal gains, while others highlight specific advantages related to oil pressure and engine protection. No consensus is reached on the overall value of the conversion.

Contextual Notes

Participants mention various components required for the conversion, such as windage trays, external oil pumps, and hydraulic accumulators, but do not provide detailed specifications or assumptions regarding their effectiveness or necessity.

Who May Find This Useful

Individuals interested in automotive engineering, particularly those considering modifications for performance vehicles or drag racing applications.

guitarrc6
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hey everyone, i was wondering if anyone knows how to convert a regular (wet stump) engine into a dry stump engine? Is it hard to do, and is it worth the gain? My goal is to make a low budget, street legal car that can do drag strip duty on the weekends. I know that a dry stump would be better because you can repositon the weight of the oil to make the car have better weight distrabution, but that's about all i know. any comments would be helpful.

thanks, brian
 
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The long and short of it is it's tough, and slightly expensive for minimal returns.

You need a windage tray, crank scrappers, An external oil pump, a resevior for the retorn oil, and a hydraulic accumulator (to act as a surge volume). Add in the AN fittings, braided hose, and the hassel associated. It's not worth it for a weekend warrior.
 
ok, i got another question, would a windage tray be benificial in a regular wet stump engine? and also, is it good to have a negative crank case pressure? If its good to have a negative crank pressure, is that more benificial in a car that has boost?
 
Dry sumps are expensive, don't kid yourself. The gain isn't in weight distribution, the biggest gain is in having full oil pressure at startup and at any g-load on the motor. As said, very expensive for gains, but when you have 10K in the motor its worth it to protect your investment.

I've read that a windage tray can be up to maybe 10HP along with knife-edged crankshafts, and both reduce the chance of oil foaming should it puddle and become agitated. Some trays can also help tie the main caps together, I think in top fuel its cross-bolted as well.

If you had positive crankcase pressure, you would likely have oil leaks around your main seals. Hence the PCV valve...

Cliff
 

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