My thoughts and pictures of porting my n/a 90 intake
#1
My thoughts and pictures of porting my n/a 90 intake
First of all, a couple people have pm/e-mailed me, asking me about places to port, and my thoughts. Well here they are. Over all the stock intake flows imop a 7.5-8 out of 10. Here's the notes i wrote down before i stated on my porting.
Throttle body, black plastic spacer & upper intake-
Small ridge before throttle plates should be removed. (Won't make much flow difference.)
Double throttle shaft should be removed, and all extra threads on butterflys should be ground down. (Not much flow difference.)
The two surfaces between the black spacer and upper intake should be port matched. (Will not make much flow difference.)
Intake plenum should be cleaned up (Remove all rought surfaces)
Where intake plenum and runners meet, should be ground down. Mildy restictive for bolth primary and secondary intake runners. (Will need extra long bit)
Port match upper manifold to gasket. (1/16" could be removed from secondary runners in upper manifold.) Little bit of restriction
Middle intake-
Port match upper intake/gasket to middle intake
Remove about 1/16" from secodarys.
Air sesor of some sort could be backed out to reduce turbulance in rear most runner. Very little restiction
1/4 bump in bottom of secondary runners. (Will increase air speed through section)
Clean up any rought edges, casting molds etc.
Good sized bumps where injectors sit in middle manifold. Probably most restiction in manifold in general.
On secondary sides, Intake gasket is 3/32" larger than secondary runners. Port match Middle to gasket/lower manifold. (Need lower manifold to verify.)
Should be good for 5-10hp imop.
These are just my rambling thoughts. I have no idea if you guys can understand them or not. But they make sense to me!
Let me know if you guys would like for me to post pictures of what i've done so far.
CJ
Throttle body, black plastic spacer & upper intake-
Small ridge before throttle plates should be removed. (Won't make much flow difference.)
Double throttle shaft should be removed, and all extra threads on butterflys should be ground down. (Not much flow difference.)
The two surfaces between the black spacer and upper intake should be port matched. (Will not make much flow difference.)
Intake plenum should be cleaned up (Remove all rought surfaces)
Where intake plenum and runners meet, should be ground down. Mildy restictive for bolth primary and secondary intake runners. (Will need extra long bit)
Port match upper manifold to gasket. (1/16" could be removed from secondary runners in upper manifold.) Little bit of restriction
Middle intake-
Port match upper intake/gasket to middle intake
Remove about 1/16" from secodarys.
Air sesor of some sort could be backed out to reduce turbulance in rear most runner. Very little restiction
1/4 bump in bottom of secondary runners. (Will increase air speed through section)
Clean up any rought edges, casting molds etc.
Good sized bumps where injectors sit in middle manifold. Probably most restiction in manifold in general.
On secondary sides, Intake gasket is 3/32" larger than secondary runners. Port match Middle to gasket/lower manifold. (Need lower manifold to verify.)
Should be good for 5-10hp imop.
These are just my rambling thoughts. I have no idea if you guys can understand them or not. But they make sense to me!
Let me know if you guys would like for me to post pictures of what i've done so far.
CJ
#3
mad scientist
One thing you overlooked. Look at where the lower intake bolts to the middle intake(right below the secondary injectors. The Intake runner on the secondary runners narrows down about 30%. The runners are not circular until just before the flange. You can stretch the circle out to a 90 degree square corner(rounded edges of course) towards the side of the flange where the mounting stud is. If you look close and feel inside the runner, you can see exactly what imtalking about. I had a bunch of pics, but I cant seem to find them. If I find them, I will post them.
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#10
This is probably the last one of the middle intake. Tomorow, i'll have some pictures of the throttle body, black spacer, and upper intake hopefully. I wish i had an extra lower intake to look at.
Let me know, if you guys want to see more tomorow, and by all means let me know what you guys think. By the way, i'm no professional....this is my first attempt at porting things.
CJ
Let me know, if you guys want to see more tomorow, and by all means let me know what you guys think. By the way, i'm no professional....this is my first attempt at porting things.
CJ
#12
college student
Join Date: Apr 2001
Location: Toledo, OH
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Looks pretty good to me.... probably better than my 1st attempt will be Was that with just a little dremel tool, an air tool, or the big makita grinding tool?
~Jesse
~Jesse
#14
mad scientist
25K rpm...thats nothing. I use a mini die grinder that spins 58K rpm
Heres is what I was talking about above. I cant find my pics, so I just colored one of yours red in the part that I gook out of mine. I did this to my manifold, and the gains were very impressive.
Heres is what I was talking about above. I cant find my pics, so I just colored one of yours red in the part that I gook out of mine. I did this to my manifold, and the gains were very impressive.
#16
Originally posted by pp13bnos
I see what your saying. But i think i want to get a lower manifold and gasket before i start grinding on something like that. I'd hate to go to far. CJ
I see what your saying. But i think i want to get a lower manifold and gasket before i start grinding on something like that. I'd hate to go to far. CJ
Just curious, but did you talk to Rob Golden about any of this? I'd be interested in knowing at what point he finds manifold porting necessary and what things he would do and where. Obviously you have one of Rob's nicely ported engines, so it's going to need more air than a stocker, but I'm skeptical of finding a lot of power in the manifold on any kind of stock or mildly ported setup. I would defer 100% to Robs judgement, but I can't recall him even mentioning this in all our discussions on porting. Are we talking big numbers, or something rather moderate considering all the work involved?
Later,
#18
I have'nt talked to Rob just yet. I was planning on bugging him this Friday. And hopefully he'll also have a extra 90 intake i can borrow.
To be honest, i don't think there is much more than 5-10hp. Maybe 15 on a porteded engine. But i'm no expert....so i'm just guessing. The reason why i did it was that i had an extra intake laying around. So i just decided i could'nt loose anything
About the 6 port sleeves. I'm the guy with it in my sig. They are basically peices of aluminum than fit into the corner of the 6 port sleeve. They're shaped so that the air/fuel mixture is curved into the engine, vs...doing a 90* turn.
CJ
To be honest, i don't think there is much more than 5-10hp. Maybe 15 on a porteded engine. But i'm no expert....so i'm just guessing. The reason why i did it was that i had an extra intake laying around. So i just decided i could'nt loose anything
About the 6 port sleeves. I'm the guy with it in my sig. They are basically peices of aluminum than fit into the corner of the 6 port sleeve. They're shaped so that the air/fuel mixture is curved into the engine, vs...doing a 90* turn.
CJ
#19
Originally posted by pp13bnos
I have'nt talked to Rob just yet. I was planning on bugging him this Friday. And hopefully he'll also have a extra 90 intake i can borrow.
To be honest, i don't think there is much more than 5-10hp. Maybe 15 on a porteded engine. But i'm no expert....so i'm just guessing. The reason why i did it was that i had an extra intake laying around. So i just decided i could'nt loose anything
CJ
I have'nt talked to Rob just yet. I was planning on bugging him this Friday. And hopefully he'll also have a extra 90 intake i can borrow.
To be honest, i don't think there is much more than 5-10hp. Maybe 15 on a porteded engine. But i'm no expert....so i'm just guessing. The reason why i did it was that i had an extra intake laying around. So i just decided i could'nt loose anything
CJ
Later,
#20
mad scientist
I saw this somewhere, I guess it was a different thread, but oh well. Someone, I think it was Blake, but I cant remember, stuffed a teflon rod into the 6 ports and took a grinder to it to make a smooth transition into into the intake ports. I have a few questions. What size teflon rod did you use? Where could I get a teflon rod like that, and how much would it cost. How noticable were the gains?
#21
Originally posted by mazdaspeed7
I saw this somewhere, I guess it was a different thread, but oh well. Someone, I think it was Blake, but I cant remember, stuffed a teflon rod into the 6 ports and took a grinder to it to make a smooth transition into into the intake ports. I have a few questions. What size teflon rod did you use? Where could I get a teflon rod like that, and how much would it cost. How noticable were the gains?
I saw this somewhere, I guess it was a different thread, but oh well. Someone, I think it was Blake, but I cant remember, stuffed a teflon rod into the 6 ports and took a grinder to it to make a smooth transition into into the intake ports. I have a few questions. What size teflon rod did you use? Where could I get a teflon rod like that, and how much would it cost. How noticable were the gains?
What I did (upon the suggestion and under the guidance of Rob Golden, in his shop) was remove the sleeves entirely and, during the course of a full rebuild, fill the ends of the 6-port runners with Teflon and reshape the ends to accomodate better flow. Without the sleeves the ports dead-end even worse than the sleeves. This can only be done during a rebuild and it looks something like this:
Judging power is a bit hard to do. The engine was given a large streetport (rally port) and was built for huge amounts of nitrous (large exhaust ports), so it's not easy to compare to "normal" or even other streetported engines. I will say, it took off like a rocket from 3K and up (without N2O). Much more powerful than my normal ride (an 89 GTUs with DP/PS; 147 rwhp).
Teflon is available from any local plastic distributor. You can get it in dowels, but you'll still have to turn it down to the right size (we just used a bench sanding disc). Careful, it gets hot really quickly when sanding. You'll also have to rough up the end of the runner pretty good. Finally, you might want to pin it in place with a roll pin from the side (right through the housing). I take no responsibility, however. Do this at your own risk!