Messing with the Intake Manifold for gains?

[RedPhoenix]

I have to do the dreaded starter soon. I was wondering if there was anything i could do to the intake manifold to let it free up more power? Any sort of smoothening or honing i can do at home?

thanks

matt:werd:

 

[Zuffen]

The lower manifold has some nasty casting joins (as does the ports in the head) but the runner is so long you would hard pressed to port it all the way along.

I would think with a runner the length of the lower intake you would need to extrude hone them and this is no DIY job.

You could get brave and send it to a sand blaster and have them blast the internals and see if it had any effect.

 

[RedPhoenix]

ah, too bad, doesnt seem worth it then haha

 

[rivmasta]

extrude hone is pretty exe isnt it?

 

[Anaema]

yes, extrude hone would take care of the problem of the long runners.

 

[SCV8]

I took a few hours while waiting for my starter to be rebuilt to work on the ports; I limited my efforts to the divider down inside the ports.
The shape of this portion is rather blunt from the factory, and I was able to give it a sharper profile like that on a rocket's nose cone using a Dremel tool.
The ports can be protected by stuffing strips of oils soaked rags down behind the valves, and taping off the other ports. Remove the rags slowly, and carefully, then wipe out any residual shavings. I also used a shop-vac with a smaller sectioin of hose attached to help with the cleanup.
The results were pretty surprising, I had to raise the fuel pressure a bit to compensate, and it did add some real power, as well as better driveability.
Good luck if you decide to do this.

 

[RedPhoenix]

have a reference pic of what exactly you dremeled? i cant get a mental image in my head.

 

[SCV8]

http://www.lextreme.com/forums/attachment.php?attachmentid=5166&d=1169778273

That pic has a divider right down the middle of the port to separate the two secondary(?) ports that have their own valve.

This a technique that will give a great bang for your buck, or time invested.
You could tear the head off, and entirely apart to get some nice further gains, but this does alot for a relatively small amount of work, much of which is done already,with the starter replacement operation.
I only went down/back from the blunt edge 1/4" or so, just enough to get a fairly sharp thing going. Basically turned it from a rounded off, 1/8" turd-profile to this; http://www.military.cz/usa/air/in_service/aircraft/f16/pics/f16nose.jpg

Be careful to take equal amounts from each side, not just completing one side before starting the other side, but rather doing them both together, gradually, a few strokes at a time, removing debris with a short brush as you go.
I caught one of the rags and slung oil around once, but just cleaned it up, and started again.

 

[speeed_dmonx]

I like your work---that is one of the simplest and quickest ways to get more umph out of a v8..be it either injected or otherwise...I have done this to many sbc's with vortec heads and I have seen some very good gains with flow and power band...gasket matching and knife edging are what it is called..KISS PRINCIPLE applied and done well...my compliments to the chef...

 

[RedPhoenix]

thats awesome. good work.

do you have an adjustable FPR? or is the stock one adjustable?

 

[SCV8]

I managed to get the stock FPR to a higher pressure, but it is a one way adjustment; if you go too high, you can't go back. I was very careful when doing this. I did make an adjustable FPR, but haven't used it(yet).
Also, the port picture I posted is from another thread, the credit for that job goes to yet another hotrodder, but the smoothing effect done on the divider is much similar to what I'd done.