what are those things?

[hankthecrank]

I just took the carb off my 307 VIN Y last night, and I noticed two nipple looking things in the bottom of the intake manifold, just below the front/primary holes. What are these things and what are they for? Seems like they could restrict air flow pretty good.

 

[RITTER]

If they are on the base of the manifold, they are probably designed to give the air/fuel flow direction. The keep the mixture from just blowing straight into a flat surface :idea:

 

[tc1959]

EGR Ports

 

[hankthecrank]

Are you saying that exhaust gas is flowing through those things?

 

[RITTER]

I am going to have to agree with the EGR system. Your exhaust crossover would be directly under those fittings

 

[tc1959]

Are you saying that exhaust gas is flowing through those things?

Yes when the egr valve is open

 

[Minion1186]

they are egr discharge ports... A cheap and simple way of creating some horsepower is to cut down the tubes to the hex base and reinstall them back into the manifold, its not going to give you 100 extra horsepower but it will wake up the motor a little bit.here's a pic of the finished product, I did this on my 307.

 

[hankthecrank]

OK, I guess my understanding of the EGR system is not too good. If cutting down these fittings is good, then wouldn't eliminating them be better? Thanks to everyone for responding by the way, excellent forum!

 

[DoubleV]

If cutting down these fittings is good, then wouldn't eliminating them be better?

Pretty much. I cut mine down, then just decided to eliminate em completely one day. Made no noticable difference with them removed compared to cut down, but it certainly seemed like it would be better and you don't have to worry about them coming loose. Now with my EGR removed, I have them plugged up with allen headed pipe plugs.

The real question of course is why in the hell did Oldsmobile put them there to begin with?

 

[RITTER]

Well, the EGR systems were designed to work at highway cruising conditions, for better fuel mileage. The system doesn't do anything at idle, acceleration or WOT