How to test opening PSI for oil filter bypass?

[SuperBusa]

 Originally Posted By: chunky

It's a spring loaded valve. I cut the filter in half and it takes almost no force to open the valve. It's still a bit of a concern for me as the valve appears to bottleneck flow a good bit. Whether it's more restrictive to flow than the engine, I couldn't tell ya. However, I'd rather use a filter that's more similar in construction to the OEM Honda filter construction.

Yeah, I doubt it restricts the oil flow at all (or is so small you'd never really see it) when fully opened. From what Gary mentioned earlier, it sounds like it's just a check valve to prevent any oil from leaking down the center tube when the engine is turned off. Think of it as a filter with two "ADBVs" in it. Must be some kind of "Porsche spec" (?). Porsche must have asked Purolator to design that filter that way ... first time I've seen or even heard of an ADBV in the center tube of the filter.

 

[chunky]

Yeah, it must be to keep oil from leaking out the center. Man, that would make for such tidy oil changes. Maybe after I get the 2nd oil pressure sensor put in, I'll try one out to see if oil pressure drops at all. If not, then I'm in business.

 

[chunky]

Bosch just called me back. The 3312 filter for the S2000 has a bypass spec of 12-15psi.

 

[SuperBusa]

 Originally Posted By: chunky

Bosch just called me back. The 3312 filter for the S2000 has a bypass spec of 12-15psi.

Obviously, without knowing what the actual (measured) PSID is across any given filter in your car while operating at track conditions, all you can do is try and find the largest sized, best flowing filter (with adequate filtering performance) with the highest bypass setting you can find. This would give you extra insurance that the bypass valve would not open under racing conditions. But, it might actually be easier for you to rig up the pressure gauges across the filter to do some actual measurements on filters that might not meet the criteria above. It could very well be that they would be working fine ... but you'll never know without actually measuring the PSID and comparing it to the bypass valve setting.

 

[Gary Allan]

The Chevy OEM's that I've looked at run in the filter circuit ..which is dictated by the in block bypass valve mechanism. The thought being that as the fluid thinned, the flow would breach this threshold less. Some install a 30lb in block bypass spring (it comes as a unit, iirc). The mid 80's Ford auxiliary coolers used something similar, but due to the bypass mechanism being in the filter, they used a sandwich adapter with a lightly sprung ball and seat setup. The same theory applied. The thinner the oil got ..the higher the flow rate though the cooler. What couldn't make it ..just got shunted to the normal pathway. Permacool does this the same way. They assure that, under most conditions, no more than 2PSID is seen across the cooler circuit. The only exception that I recall is a Hayden sandwich. It used a bimetal spring that closed over the bypass port as the oil temp warmed. I never determined if the bimetal spring also acted as a bypass valve. That is, I don't know how much tension it placed on the port. It may bend like a reed in the wind ..or be rather fixed, regardless of the pressure differential it saw. There are also some that use the bi-metal spring sorta like a rail changer. The oil flows on one side or the other of the bi-metal spring. The spring is fixed on the exterior of the housing when hot ..and the interior of the housing when cold. The oil flow hits it and is channeled in one direction or the other. The force of the oil flow would kinda make it want to stay were it was. It was a rudder on the front end of the ship (if you see what I'm saying).