Lower intake runners are bit bigger then head runners...How bad is this?

H

Highbredcloud

Active Member
Mar 4, 2003
1,075
1
36
Palos Hills, IL
#1
I have the systemax 1 intake wich goes with the stock upper intake...I also have a set of Powerheads, however, the runners on the lower intake are a bit bigger than the ones on the heads...The lower intake mates with the FEL-PRO 1250 gasket perfectly while the heads are a tad smaller...This intake was recommended to me by the owner of Powerheads, however, my concern is that I have a bigger opening going into a smaller head runners...so should I be expecting turbulance when the air enters the heads? I don't think velocity will be lost since the runners are the same width as the heads but it seems as though the air will be hitting the lower or upper edge of the head runners...any comments on this?

UPDATE as of 4/19/04: I measured the height of the runners on the Powerheads and they came out to be 2.0 inches...than I measured the runner's height on the lower Systemax one intake ant it came out to be 2 1/8 inches...I know that the heads fit a Fel-Pro 90361 gasket while the lower intake takes a Fel-Pro 1250...SO is 1/8 of an inch something to worry about? WILL this cause turbulant air once it enters the head? From my perspective the 1/8 of an inch "wall" will be on the upper side of the head runner right by the injector area on the intake...CAN someone PLEASE help me out...I need to know if I have to open up the heads...NOT sure if that is worth it...I NEED SOME HELP...thanks guys... :flag:
 

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#2
I wouldnt be worried about such a tiency wiency problem like that. The NA motor is sucking in as much CFM as it can at its specified rpm.A small problem like that shouldnt be a worry of yours, unless your spending SERIOUS $$$ on the motor, and plan on making 7XX HP. My ports arnt matched EXACTLY either, no worries. If your a stickler for having it fit properly, get yourself a dremel, or a file, and go to town, just keep the vacum on and cover your motor comletely. I hope this helps
 
#6
O.K guys here's what I found out...
Lower intake: Port Size: 1.97" height; 1.08" width...fits the FEL-PRO 1250 like a glove...

the POWERHEADS port sizes I don't have but it does fit the FEL-PRO 90361 gasket...Does anyone know how big that gasket is? I can't really measure the heads since I am away at school and they are 75 miles away from me...am looking on-line but no luck thus far...
 
#7
call the company, thats what i always do when i want some correct info.Just got off the phone with X2C and BAER,when u have a question that needs and answer,dont be afraid to go to the heart of the "problem".
 
#8
That's just it...I just called the company and I was the first one to tell him the systemax 1 intake had bigger runners than the heads...he did say that if it is by a little bit it shouldn't matter, however, the ideal thing would be to have a smaller intake going into larger heads...just as I thought...I just want to find out for sure how big of the difference is in the height of a fel-pro 1250 gasket and a fel-pro 90361 gasket...just to make sure that what I think is a little difference in hight actually is a little...and not alot in terms of cars performance...
 
#11
.200" is a lot, especially if it's all at the top or the bottom.

Are you sure that the systemax is not ported? I thought they were designed for a head with about 165cc intake runners.

If there isn't an easy solution, I think your best bet is to find another intake.

If you start to grind on the heads, you run the risk of undoing a lot of the things they did on their CNC machines. You would decrease the intake charge velocity by opening up the port, and that might hurt your torque with no guarantee of increased flow.

Since you say that you are using a stock upper intake, a tmoss ported lower might be a good choice for you. You will have the sleeper look also.
 
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