I didn't know how they worked either.... but once explained it sure seems simple enough. I thought maybe it was a bladder type deal inside the cylinder.

The pre-charge sets the "spring rate" and the air inside the backside of the piston behaves as the spring. That would be one way of thinking of it.

Hydraulic accumulators come in two basic varieties. Bladder and piston type. I am not aware of one marketed for auto racing that uses a bladder. The bladder type fits the description of what you were envisioning.

In hydraulic system design I have used these to act in the same way a capacitor behaves in an electric circuit. It absorbs spikes and allows the pressure to vary less in a system that has a large volume actuator.

It's funny -- because my Lotus 2 Eleven came with the accusump... and I have one in the Mustang (manual valve). Everyone on the Lotus forums talks about taking them off because the "leak" or they have some other BS issue with them or because they add weight.....

On PT forums - we're just now "discovering" them. This and dry $ump$.....

So I de-bodied the Lotus on Friday because I want to do some minor things on it... and my buddy that also owns one - came to the shop on Saturday so I could show him how easy this was to do.... (his is brand new). And we discussed the Accusump. He is thinking he'll take his off and toss it as an unnecessary part since he's going to upgrade from the stock pan and go with the baffled version I have.... But I said I use mine as a pre-oiler in both cars because they sit so long between running them etc.

Personally -- I think they're good insurance... and that if a guy is going to seriously TRACK his car - they're cheap and easy to add and just might save you an expensive rebuild.

I agree, unless you are looking for the last .01 percent in performance. I'll take the $300 insurance policy on my $25,000 engine, regardless of the oil pan.

^^FACT^^

Improved racing now makes a trap-door baffled pan for the Holley-302 pan that wasn't available 6 months ago when I installed my motor. I'll be dropping my sub to pull my motor and install one of those too now!

Good insurance.


Here's what people kind of don't think about --- we start putting big ass wide super sticky tires on these cars -- thus RAISING the G's forces they can pull in the corners.... Then we do out and begin to track them - pushing the boundries way beyond the "street" scene... and that oil is just begging to climb the pan and block walls ---- and leave the pick up dry as a bone....

I put a 7 quart road race pan with trap doors on mine 11 years ago when the only sticky tires it had were on the rear! Now, with RT615k tires and the bigger brakes the car is going back together with an accumulator also.

Some people claim that the sump shouldn't be mounted in a horizontal position. I think this video proves that wrong.

I was worried about that also and was trying to determine how to mount it on a little bit of an angle. It looks like if there is little to no air in the tank initially (which should be the case if there is a precharge) then air shouldn't be a problem...