PCV mod.

[fastback4]

I've been running this mod on my 1997 3100 Monte for 300 miles or so with no oil loss or new oil leaks, smooth idle, easy starts with cold and warm engine temps. The picture will show the original pcv line has been capped at that end only. Now both the front and rear valve cover ports are drawn into the intake before the throttle body opening. Been hearing that performance will increase if you can free up manifold vacumn usage not to mention no dirty internal walls of the UIM with oil residue. I'll pull the UIM next week and see if the UIM is cleaner than when i had it off 3 months ago when i had to replace a bad injector wire lead.....Tom

[Superdave]

um.. lol

the PCV needs manifold vacuum to vent the crankcase pressure properly. There is no performance gain and possibly a performance loss by doing this. Manifold vacuum usage is not something that is in short supply, as long as the engine isn't at WOT it's always going to make vacuum.


I'd hook it back up the way that the GM engineers did ASAP. Sure you might get a little oil mist in the UIM but as long as your PCV is good you won't have a problem.

[AaronGTR]

Way to modify a system without understanding how it works at all.

[GrandAmGTTT]

what about if he used an oil catch can to help draw the moisture out.? in line with the pcv system, not changing anything but adding the can in line with it. It wouldn't really give any performance gain but might draw out the moisture if anything?

[Superdave]

what about if he used an oil catch can to help draw the moisture out.? in line with the pcv system, not changing anything but adding the can in line with it. It wouldn't really give any performance gain but might draw out the moisture if anything?

still a waste of time on a stock engine.

[GrandAmGTTT]

well ya thats what i was saying, but its something he could do if he wanted to mod the pcv system lol, i think it may help it out some

[AaronGTR]

If he put a catch can in the line from the front cover, with the system set up like stock, then it might cut down on a little bit of oil inside the intake manifold. Nothing significant, and no real performance gain from it, but it wouldn't hurt anything. The way he has it set up right now though, the system is doing absolutely nothing. The only time the crank case will vent to the intake is when he's at WOT and it can build significant enough pressure in the crank case.