Outer Limits 4x4 Board

Hey guys, I'm trying to alter my sierra extractors (genie) which i bought new about a month before I decided to swap to a G16 mpfi. My basic plan is to cut the flange off the extractors and get another in the G16 bolt pattern cut and welded on then add a fitting for the oxy sensor. When I removed the factory manifold I discovered another hole in the back of the block which is bridged to the #4 (closest to firewall) exhaust port via the manifold. Where does this go and what does it do?? If I blank it off by just covering it with the new manifold will the engine run better, worse, no change or not at all?? Thanks in advance.

Bronson

The small hole in the back of the head is for the EGR valve, blocking it is no problem, most vitara 1.6 injection have problems with the EGR systems creating a low speed missfire, blocking it off is prob better than leaving it open.

Cheers matey, that's just what i wanted to hear!