ddub

So I ported both my exhaust ports and started on the intake ports tonight. Here is a pic of one of the exhaust ports (removed diffuser, streetported RB template, and then I added the 2mm bevel that comes stock but is removed during porting on the top for better apex seal reliability).





Here is my first stab at intake porting, it's a combined secondary/aux port by removing the divider along with making it mildly larger, my 6port is becoming a 4! Haha




Let me know what you think, any comments, suggestions, what I did wrong, anything

sar

iTrader: (1)

I would think that making your 6 port into a 4 port would absolutely kill your low end torque

Aaron Cake

iTrader: (1)

Looks good....

You need to hit that exhaust port with a paper roll or other polishing device. Remove the burrs, and smooth everything out. It is very important to get the floor of the port as smooth as possible. Make sure that a "lip" of metal has not formed around the port where you did your grinding by running a razor blade over the port (pretend the razor is an apex seal).

As for your intake, it looks like you have a fetish for late closing. Use sandpaper (400 grit) and wet sand away the sharp edges around the port to protect your side seal. It looks like you moved them out quite a bit...is there still enough material to support the side seal? Hard to tell from that picture. Also, the port runners are very important. I usually increase their size by around 1MM all the way around. You then need to polish them SMOOTH, and make sure the transition between runner and port bowl is also smooth.

RotorMang13B

yea polish that sucker.... other than that not bad for a first time porting

ddub

Correct, it's just like removing the actuators and sleeves or wiring them open, low end will suffer. But by removing the divider and expanding the port all around slightly you will see greater gains in top end and peak power. As Kevin Landers says:

"This is not recommended for everyone, basically only those who want to totally strip their engine down and make it as simple as possible with no emissions concerns and limited city driving."


But we'll see how bad it really is, this is mainly why I have dubbed my car the unstreetable daily driver Well that and the fact that I'm putting in an aluminum flywheel and solid mounts all around. We shall see how it all turns out.

ddub

Yah the exhaust port is unfinished, that was just the rough port when I got done last night with the burrs. I will be going over it with some sandpaper drums later today. Thanks for the tip on the razor blade, didn't think about that.

Hehe, thanks. As for side seal clearance, I spoke to Kevin Landers about this as he is where I got the idea for this port, he said there shouldn't be any clearance issues with the side seals, but I could go ahead and make the edge of the port smooth and gradual into the iron just to be safe. As for the runners, this is what I've been hearing but once again I didn't get around it it last night. All of this porting was the rough job I did at about 10pm last night. I had some thoughts about the runners, though. A long time ago when I went to a shop to ask them about porting my intake manifolds on my Ford, I mentioned polishing to them and he explained that porting/polishing wasn't really used anymore. He said that polishing intake runners in manifolds wasn't a smart idea because the fuel wouldn't mix with the air properly, because fuel likes a somewhat rougher contour? I don't know if this is true or not, but when he was explaining it to me it made sense (mind you I was 16 and knew nothing about cars at the time, my memory of it might be hazy). But if this is true, I was wondering if it would apply to the runners going into the iron as well, and if smooth really is better.

ddub

Thanks

I was really scared and nervous since this was my first stab at porting, but hey gotta learn sometime right?

aarsudstrike

from what i remember when we had the heads ported on our stealth by moritz machine shop here in tulsa,ok they told us that the exhaust needs to b polished and the intakes have to b a little rougher to insure that as the air enters it is more turbulant and therefore mixes with the fuel better

ddub

Yah, that's what the guy at the shop said. That's why I was wondering how come everyone polishes the runners into the irons.

RotaryResurrection

iTrader: (8)

That's pretty much an open debate among builders of all sorts. Some want to go as smooth and polished as possible for airflow, some want to leave a rougher surface for atomization. There isn't a lot of hard data either way, but the fact that it takes hours of tedious work to completely polish a set of intake runners from start to finish (including the block) and you may gain very little, nothing at all, or possibly even hurt atomization (hence, the debate) doesnt make it seem worth fooling with, IMO. This is why I normaly do not "finish" ports back into the port runner or "port match" intake manifold surfaces.

Bottom line, once the air is moving through there, the only real big deal is the entrance and exit areas, their shape, size, and smoothness. I personally think a man can go with an internal streetport and a ported throttlebody and leave the rest alone. The time and money spent on anything else could probably never be justified by the rewards. I guess if you're bored, want to take on a project, then it's fine to do.

andrew lohaus

i agree that a mirror polish on the intake side is overkill, but youre saying any intake manifold proting/mathcing is needless, kevin??

ill admit theres next to nothing to be gained on the uper and middle intakes (im speaking of n/a's), but the lower can have quite a bit done to it. you can "egg-port" the secondary runners and significantly smooth out the 90deg bend into the side irons, and the center runners can be expanded up probobly 3/8th of an inch to match the top of the ports on the cener iron (i imagine the overlap was designed to create turbulance right in front of the primary injectors, or maybe they just had shitty castings, iduno).

ddub, have you considered completely grinding out the divider in your side plates and also on the LIM? at this point i dont see how it could hurt anything and it would increase runner volume even more.

ddub

Yes, I even talked to Kevin about that, and he said I could do it but the gains would probably be minimal for the amount of time it'd take. I did it on the manifold and that was bad enough, for the runners into the iron I'm going to knife edge the entrance for a smoother transition from the manifold.