What kinda gains would you see and how the hell do you do it? Take off the top of the intake and then.....?

 

Go to the boneyard first and get you an intake to play around with .Get use to using the grinder , or dremel , whatever you plan on using .I have been advised to do this by Karl and a few others and even read to do this in books . Ya need atleast 20 thousand rpms . I don't think you can really do anything with the upper plenum because there needs to be some turbulance for the air .But you can clean all the carbon out of it and crapola! I was discussing this with Karl earlier via-email .He told me its maily matching things up .I've also read in "HOW TO BUILD HORSEPOWER" that amateurs like us should stick to removing some of the small pieces of metal from passageways and smoothing rough edges .I will eventually port my lower intake and heads , but Im still in the research/learn mode .Reading books , learning from people with more knowledge than me like Karl and TomP .

 

IF it was me & this was important to do...
Go get a spare set of this stuff.
Check out the placement of the gaskets.
You do not care about the gaskets, except when the surfaces are mated.
You only want to remove material that disrupes smooth airflow.
Opening enlarging the passages, not enough 2.8 air flow generated for that extreme mission.
Unless you are constantly at 6,000RPM.
Make sure the surfaces mate well and the openings match the opposing surface (NOT JUST THE GASKET), when they are placed together. Mark the surface to be cut, with a magic marker. Remove, just that area, put together to check your work.
Go back to work.
IF you saw this/these parts in the yard, you would understand better, to see the small area to be removed.
It's not that much.

 

****, sorry guys. I meant polishing Sorry about that! But thanks, I might port it too.

 

congratulations Karl you just managed to confuse the hell outta me!

 

True polishing should be done to the exhaust side only. That helps with airflow and prevents carbon buildup. The intake side should be slightly rough to help with fuel atomization (like about 180 grit).

 

fuel atomization is not too much of an issue with a FI car
and you guys have you injectors right near the base of the intae as it is right? not sure so figure I would ask
but on a FI car the injectors are to fire a nice mist of fuel into the car so you can go ahead and polish things up quite a bit andthen downstream of the injectors I would still polish it up.
though if you have crappy injectors and they are just squirting and not misting it up then yeah having some turb will help

you should see the damn intakes mazda made for there N/A rx7
those friggers need to be ported bad b/c of how they put bumps in there and close thigns off like crazy
oh well

 

Hi Monkie,
I'm sorry to confuse yourself/perhaps others, also.
When I reassembled my engine (recently to cure all vacuum leaks and doing the 3.4 swap) I noticed somethings about the upper & Middle intake.
Even IF you try to gasket match the ports, when you connect the two halves, together, they will not line up correctly. To really make this "port match" for the upper & lower work, they must be removed from the car.
Then, just, "line up the bolt holes (as if they were to be tightened)" and then notice how far off the matching surfaces are.
It is a SLIGHT amount of "off", not very much (it was a decent mold made to cast these pieces).
To mark where you need to "remove", I use a magic marker. Then grind away the protruding material, check by quick slip fit assembly.
I hope this explains, better.
This is why the 3.4 intake is a one piece design. They eliminated the surface mating problem, by making the top piece for the air inlet system, a one piece design.

 

Could I just use a 3.4L intake on a 3.1L engine?

 

Monkie,
ANYTHING can be made to work with time, effort and money.
BUT when I rebuilt/did the 3.4 swap, I REALLY WANTED THAT ONE PIECE INTAKE.
I couldn't for two reasons.
Emissions (visual-would not be the same as the 2.8 3 piece set up-thus would fail, right away)
NO LINKAGE FROM MY 1985 set up would mate up correctly. NONE.
So I media blasted clean it and sold it.
You're blazing new trails by adapting that 3.4 intake set up to your current engine bay throttle linkage.

 

Well aint that a b!tch. So what you think I should do? If anything

 

Honest?
Go get a spare intake set from the yard, experiment, enjoy yourself.
Lots of them in the LA yards, most off the cars, too!
Intake is easy to cut into, as it is aluminum.