Different intake port mod

Don W.

Don W.

Stab it and steer it
Done some searching, came up empty. Lot of folks have done that little "porting" job on the upper intake to better match the lower. This idea is different. I want to improve the performance of the stock SyTy intake, upper and lower. ( among other things no money for a fancy-dancy alum set.)

So, on the upper completely remove all the dividers except the middle one for strength. Resulting in one big open chamber. On the lower, flair the dividers (the middle one won't matter) so air will part smoothly down each port.

Reason? I have seen some posts over the years that indicate our manifold does not provide good, IE equal, air to all the ports leading to rich/lean conditions on individual cylinders. I think this might cure that.

Anyone done this? Thoughts? Opinions?

Side bar: Hopefully I'll have everything back from the machine shop next week and can finally start putting this motor together.

Thanks.
 
M

MikeRenz

not stock
Re: Different intake port mod

I won't hurt...but I don't think it will really help. You aren't changing the way the air flows through the manifold at all. By the time air reaches in ports, it's going the direction it wants to be going.

Also, I've had an upper intake that had all of the 'webbing' removed and it was still plenty strong. That cast aluminum is pretty thick...so there isn't a real need to leave the center one there.
 
Don W.

Don W.

Stab it and steer it
Re: Different intake port mod

Ya Mike, trying to mull all those things over in my head. I guess part of my theory is based on your comment "By the time air reaches in ports, it's going the direction it wants to be going." In the upper the air has to be divided soon after the TB and after it has made a severe direction change. But regardless, if each lower port has a full unobstructed "mass" of air to pull from it might breath easier. Fewer direction changes so-to-speak. Anyway just my :2cents: It sure would be interesting to put a motor on a dyno and quantify things like this.

Thanks
 
M

MikeRenz

not stock
Re: Different intake port mod

it's more of an issue at vacuum rather than under boost. But boosted air still generally follows the same path. Your main enemy is the back of the intake where the air first goes after entering the intake. it's extremely turbulent and misdirected from there. I've done some simple flow testing on the upper and it's pretty shocking just how poorly that upper directs air to the ports.

interested to see your results! hopefully it pans out well for you.
 
Don W.

Don W.

Stab it and steer it
Re: Different intake port mod

MikeRenz said:
it's more of an issue at vacuum rather than under boost. But boosted air still generally follows the same path. Your main enemy is the back of the intake where the air first goes after entering the intake. it's extremely turbulent and misdirected from there. I've done some simple flow testing on the upper and it's pretty shocking just how poorly that upper directs air to the ports.

interested to see your results! hopefully it pans out well for you.
Click to expand...

Well see, I'm trying to fix that...:rotf: Results will hard, more like impossible, to measure. Previously 1,3,& 5 would show a "correct" plug and 2,4,&6 would show a rich plug. If that gets better or goes away then that will be the one and only crude measure.

Doing a couple things different with this motor so I'm really looking forward to seeing it run.
 
M

MikeRenz

not stock
Re: Different intake port mod

are you running stock injectors? Are you running injectors that have been flowed? If so, you can get cute, or strategically place the better flowing injectors are the leaner ports. I did this when i built my v6, but never really got to do much testing on it since i'm a putz.
 
nallj92

nallj92

Active member
Re: Different intake port mod

from the performance standpoint the stock intake setup is kind of a lost cause for improving anything at all. If you like it for looks/originality great, but once you are getting more serious into the build 9-10sec etc, you would be better off going with a different intake setup anyway. JMO.

by cutting out the bottom and knife edging you are making the plenum size larger while shortening the runners. I don't think that would help the distribution of the air, like mike said.

some back to back flow testing would be very interesting with a head and modified upper/lower intake vs stock upper/lower.
 
It's just a six

It's just a six

Super Member
Re: Different intake port mod

Don,

I was trying to have RJ make a divider plate for our Sy/Tys that he has made for the Buick GN's Turbo T-Types.

Helps with improving equal airflow to all intake ports.

http://rjcracing.com/contact/

Example: http://rjcracing.com/product/power-plates70mm-tbplenums/

He was going to do the R&D work for free as long as we sent him some cylinder heads, intake manifold & TB.
It never happened because we could not get all the parts gathered up & sent to him.
 
STOUT74

STOUT74

Member
Re: Different intake port mod

Hey Don,

Here's a couple of pics of my upper plenum I've modded. No need to leave the middle web, the plenum is plenty thick enough. I rounded off the tops of the dividers on the lower to help with air flow.
 
Last edited:
Don W.

Don W.

Stab it and steer it
Re: Different intake port mod

STOUT74 said:
Hey Don,

Here's a couple of pics of my upper plenum I've modded. No need to leave the middle web, the plenum is plenty thick enough. I rounded off the tops of the dividers on the lower to help with air flow.
Click to expand...

Now that you posted this I recall your earlier post. I kinda knew that I couldn't be the first to do this.:lol: Anyway, have you run this setup and did you notice any difference?

Thanks.
 
STOUT74

STOUT74

Member
Re: Different intake port mod

The only way I have of seeing any difference is just reading the plugs, since I never had anyone bench test this.What I do know, pre-mod, rear 2 plugs were always a slightly different shade than the front four, if you were looking for it, there was a difference. Post-mod, all plugs are much closer in color now, really pretty hard to tell which hole they were in. So, I'm thinking it made some difference,:dunno:, I don't have any hard numbers on the flow difference.
 
Don W.

Don W.

Stab it and steer it
Re: Different intake port mod

STOUT74 said:
The only way I have of seeing any difference is just reading the plugs, since I never had anyone bench test this.What I do know, pre-mod, rear 2 plugs were always a slightly different shade than the front four, if you were looking for it, there was a difference. Post-mod, all plugs are much closer in color now, really pretty hard to tell which hole they were in. So, I'm thinking it made some difference,:dunno:, I don't have any hard numbers on the flow difference.
Click to expand...

Before teardown my motor showed rich on the pas side and normal on drivers side. :dunno:

I'm really tempted to do this. AND i really appreciate everyone's comments. I know we have an odd intake setup. Eyeball engineering can work and not work. Just thinking I'd like to do something.

Another really screwy thought was to split the upper in two, parallel to the gasket but above the dividers. Then porting the dividers just part way down and maybe welding a baffle or 2 of some kind to massage the airflow then weld it back together.:rotf:
 
M

MikeRenz

not stock
Re: Different intake port mod

It's just a six said:
Don,

I was trying to have RJ make a divider plate for our Sy/Tys that he has made for the Buick GN's Turbo T-Types.

Helps with improving equal airflow to all intake ports.

http://rjcracing.com/contact/

Example: http://rjcracing.com/product/power-plates70mm-tbplenums/

He was going to do the R&D work for free as long as we sent him some cylinder heads, intake manifold & TB.
It never happened because we could not get all the parts gathered up & sent to him.
Click to expand...

I'm still hoping he doesn't make it...or at least is slow enough that I beat him to it. I hope to de-shelf this project soon.
 
Don W.

Don W.

Stab it and steer it
Re: Different intake port mod

MikeRenz said:
I'm still hoping he doesn't make it...or at least is slow enough that I beat him to it. I hope to de-shelf this project soon.
Click to expand...

"De=shelf?" Good one. On some occasions I wish I could de-shelf my brain. It seems to go there on its own occasionally.
 
fivetodrive

fivetodrive

CRISPY
Re: Different intake port mod

Dang. I would have loaned him the parts to create it but someone closer would have to get the heads...
 
M

MikeRenz

not stock
Re: Different intake port mod

Rice Eater said:
Did this project ever get legs?
Click to expand...

I've put a good amount of time into it. I have done some pretty extensive testing of 9 variations of an intake plate. I've gotten it pretty close even airflow, but not as close as i'd like it to be just yet...thus i haven't gotten a prototype out there for someone to test.
 
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