Finally got around to yanking off the car's intake and started porting it out. The middle intake is easily the worst part of the whole system, as there is an easy 1/4 inch of potential porting on one side of each port. On the two long sides, there is probably only about 1/16 of an inch that can be removed. Tomorrow, I plan on finishing the port job and then wait 'til monday when I can pick up 3 fuel injector retaining clips for the ones I ruined while trying to figure out how to pull the damned rail off. Here's some questions that came to mind while working today:

1) If I increase the volume of each section of the V6 intake's "runners" that will increase airflow, but also decrease air velocity. How does that affect my engine's hp and torque curves? Will I be better off to just smooth out as much of the existing runner as possible, or increase volume and smooth?

2) I've heard much about siamesing the runners on a TPI motor. What would be expected if I siamesed two of the runners on each side on the V6 plenum? That would mean that 2+3, and 4+5 cylinders would have siamesing done. I'm expecting to get a slap over the head for this one, as it just doesn't make much sense to me, either.

3) How important are those bloody retaining clips for the fuel injectors? The thing won't be able to blow itself off the rail, as the rail is bolted into the lower plenum. I'd think that it's next to impossible, but I could be wrong there.

4) How important is it to replace the O-rings on the fuel injectors? The injectors on the car were replaced about a year and a half ago. The rings have no visible cracks, gaps, or flat spots, and are still pliable. Could I just give them a fresh coat of oil and throw them on?

5) Are there any mods possible on the V6 fuel pressure regulator?

6) Any tips on grinding away the metal on the plenums? I spent about 4 hours today using grinding stones, which only left a rough finish on the porting. I switched to a 60 grit flap wheel, which worked amazing, but that wore out very soon. I got a piece of 1/4 inch round rod and cut a slit in one end and am going to try using emery cloth in that slit. Any other tips to achieve a good, smooth port job?

 

1. Larger runners= high volume, low velocity good high rpm power, not as good low rpm power.

Reg runners,smoothed out= low volume, high velocity, good low rpm power, not as good high rpm power.

2. never heard of that one.

3. they're there for a reason.

4. very important, prevents fuel/air leaks, plus they're cheap to replace.

5. ?, maybe an adjustable fuel pressure regulator from a 4th gen application.

6. I'll leave that one for the experianced.

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85 Firebird. $150.00
2.8 Auto.
Blown Head Gasket.
turbo has arrived,