Basically the checkvalves should open in one direction only and also at very low cracking pressures, close to 0psia so that the manifold vacuum can provide vacuum to the rest of the system.

Also you need to ensure the valve can handle the pressure differences between the inlet and the outlet to ensure it can hold when under boost.

I plan to use these for those checkvalves when I replace the plenum. They are made of kynar with viton diaphrams. Should withstand the temperatures of the engine bay better.

http://www.usplastic.com/catalog/ite...6844&catid=489

 

Ah, now that looks like it has potential! Looks like pretty good specs too, please keep us posted if you try them. Might be good to try on a working setup too just to see if they effect operation at all. Billet sounds good of course but I'd wonder if you could find something with as good a spec...

 

at that cost i ordered 10 of them! w/ shipping it was under the cost of a single pcar check valve. ill install a few when i get the car back

 

http://m.ebay.com/itm/5pcs-3-8-10mm-...119?nav=SEARCH

I'm pretty sure this is the style my buddy installed. I recently ordered as well.

 

I looked at those too and the only thing that made me not order those is because they don't specifically say that they are for air. No mention of cracking pressures also or any specs.

 

I hear ya but I figured he has been running them for a bit now and I want to get away from the plastic. Will see how it goes.

 

Does your SRM plenum have 3 vacuum ports on the top as the factory one does? Mine has two...

 

its billet aluminum. drill and tap for any port you need. ezpeazy

 

I know, But was curious if others had two ports and capped the oil reservoir?