I did a quick search and could not find any specific information regarding porting the SPFI motors. I have a spare SPFI sitting in my garage and I was thinking about tweaking it with my Dremel. Looking at the intake, there appears to be a ridge that is there by design - for splitting off the flow to each cylinder I guess - so I don't think I want to mess with that. What about gasket-matching? How about the Throttle body-to-intake area?

 

I'm wondering if anyone has ever done any porting work to the SPFI's? I'm running out of things to do to this motor:

 

A/C Delete

Power Steering Delete

Mechanical Fan Delete

Accel Coil

Custom Intake

Timing Advanced to 24 BTDC

High Octane Fuel Only (pings otherwise)

Dual Row, Turbo Model Radiator

Y-Pipe to single cat to 2" Glass Pack, side exit exhaust

Custom Air/Oil Separator

 

The motor screams, and pulls to redline in every gear except 5th (which I think might be an aerodynamic issue ) but I want more.

 

Save the "Turbo" comments

Turbo;)

Turbo;)

Hmm...I never thought of that.

Didn't think you had.. Thought I would be a pal and suggest it.

 

Seriously.. you sound like you have pretty much hit a wall with your SPFI.. except for maybe some head work.

the bottle neck is the fuel injector. make a tb that has like 2 or 3 injecors shoting in from the side, instead in the middle, restrictint all that air. a good spfi rools!

Possibly work on the intake before the TB. It makes a nasty 90 degree turn at the TB, which might be a restriction. Ifyou could smooth out that turn, it might give you better breathing at high RPMs. Just a thought. I've had ideas of a ram air style set up using a hood scoop, but who knows if it would really work.

being an injected system it wouldnt mind smooth passages vs a carb head.

 

if you look down the intake port you will see some high spots that can be blended down. remove the valves and get them from there too, blend in around the valve guides. dont worry about the cracks between the valves, they may extend down to the valve guides themselves, but that is normal. use the snake atatchment for the dremel so the bulk of the tool itself doesnt get in the way.

i used the "roto-zip" style bit to machine away the bulk, and then the cone stones to smooth it out, and sanding drums to finish up.

 

my application was mpfi turbo, and so far our heads on carb block have seen WELL over 10,000 miles in the past monts since feb 04, and nwvwr had any problems

 

look around on this page and you will see the ported heads

http://www.warpthree.com/milesfox/87rx/87rx001.html

They do make performance cams. I bet you would notice some power from a set of cams.