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Discussion Starter #1
I cam across this post on Mod Depot. It appears that this guys has bolted on a PI intake wihtout ANY other mods. No port matching, no spacer, no head porting. He claims 15-24 rwhp gains proven by a dyno. How could this be. How in the heck would the intake flow with the large interuption in air flow that would be caused by this. Any thoughts.

PI intake wihtout any modifications
 

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#1 The differences arent all that big. I've got a PI intake and put the old gaskets up against it... it's maybe 1/4" of an inch around a small section of the inner radius.

#2 The old intake really flows that poorly. The cross sectional area of the NPI intake is 70% of the size of the port in the heads at the gasket surface. The PI intake is about the same size as the head around the entire runner length.

Edit: sorry about my posting before, the page kept hanging up and I didn't think it was going through. All better.
 

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Discussion Starter #3
So then our options are to either epoxy new PI intake, port out the heads to match the PI intake, Buy an expensive conversion kit, or bolt it on the way it is. HMMMM Sounds to me like a lot of us will be bolting them on the way they are until a cheaper alternative comes out to adapt them to the NPI heads. Correct me if I'm wrong but the HP gain from the PI intake that was epoxied was around 20 so then a difference of 5 HP is definately worth not having the chance of the epoxy coming off.
 

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Sweet T
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I think the problems might start showing up when you start increasing airflow via forced induction or ported heads. It just seems to me like the difference in port shape, and the turbulence caused by it would just get worse the more air you tried to flow through it. In a mostly stock application, I wouldn't worry about it.
 

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Discussion Starter #5
Yeah I agree with that. It just doesn't make sense. Do you think a N2O application would be okay with that since the combustion of the gas doesn't occur until it reached the cylinders.
 

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Formerly Fdawg97LX
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good find man. i gotta add that to the list of mods

Frank
 

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I'd be worried about any sort of obstructions with a nitrous installation because that may increase your chances of puddeling the fuel. And, with a plastic intake, that would be the last thing I'd want to do. But, then again, turbulent flow does help particles stay suspended in the air...

Personally, I am looking to run the manifold kit as opposed to just putting the manifold on.

Pete
 

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Formerly Fdawg97LX
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what if the intake was port match like Jonny Langton and Kdanner did. would it be ok to use the n2o then. i plan to run n2o but i would like to do this cehap mod also.

Frank
 

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Discussion Starter #9
I am running a dry kit so I wouldn't think there'd be too much fuel puddling. My dad (who runs circle track race cars in the late model class) is under the impressiopn that the more turbulent the air the better the mixture and thus better combustion. It makes sense but I'm just not sure of all the negative effects vs the postive ones.

Frank.....As long as you port match the intake you'll be fine
 

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Man, If I had a stock-motored '96-'97 MN12 I would be doing this manifold swap RIGHT NOW.

that is the cheapest bang for the buck I have ever seen on our cars.

And that was untuned. I would bet you'd get plenty more power with the right A/F ratio up top and the right amount of timing.

I know www.karkraft.com used to sell the manifolds pretty cheap.

I sure as hell would not wait around.:ztoohot:

RichardM
 

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WOW, Im impressed. Thats my next mod in the listy after 98 GT heads an 01 PI cams :D ... YYYEEEEAAAHHHHHH. Nice find man....:thumbsup:
 

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West Virginia Chapter Director /, MA Drag Race Te
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LoppyJ22

You are correct in your assumption! The flow of nitrous on the dry kit would not matter and may acutally aid in the mixing with the incoming air going to the cylinder. I WOULDN'T try it on a wet system though. (even though it may work)

As far as your dads thoughts on the mixing, that is a true statement at least to some degree. He may remember when years ago the old racers trick to get better mixing was to use a screened intake gasket to help aid that.

Air flow on these newer style intakes since the fuel is delivered at the cylinder rather than the intake can be ported tighter and more slippery/polished a bit more cause you aren't mixing the air and fuel together at that point.

Velocity and overall filling of the cylinders is whats most important here and the tune so the fuel/air ratio is where it needs to be for ultimate power. The restriction will slow that somewhat I'm sure but the fact there is more area to induce the air should simply make it better.

Just my .02 cents
 

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My only concern.....and I don't know if it is valid or not....is there a possibility of a vacuum leak around the edge of the gasket with the port mis-match. I know he mentioned a possible small leak in his initial post. I would hate to go lean on a WOT run because I suddenly sucked some air past the gasket. Any opinions???
 

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i have a 95 t bird i take it these are for mustangs. so i would need the uper intake but fuel rails would work? another qustion is wat about the throttle cable will the fit? and how much is there and where can i get it?
 

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timb said:
My only concern.....and I don't know if it is valid or not....is there a possibility of a vacuum leak around the edge of the gasket with the port mis-match. I know he mentioned a possible small leak in his initial post. I would hate to go lean on a WOT run because I suddenly sucked some air past the gasket. Any opinions???
Tim, I'd expect the leak to manifest itself at idle... theres a big pressure difference across the gasket there, and it would raise the idle under those conditions. At WOT, the pressures will be closer to equal, so it shouldnt be as big an issue. I could be wrong, but that's my theory.
 

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Baddest N/A NPI in Canada
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jjjustin17, you need to update to 96 - 97 parts for a PI intake to work on your car.
 

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timb said:
My only concern.....and I don't know if it is valid or not....is there a possibility of a vacuum leak around the edge of the gasket with the port mis-match. I know he mentioned a possible small leak in his initial post. I would hate to go lean on a WOT run because I suddenly sucked some air past the gasket. Any opinions???
JL recommends a bit of RTV here and there where the seal is suspect.
 

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1MTNCAT said:
LoppyJ22

You are correct in your assumption! The flow of nitrous on the dry kit would not matter and may acutally aid in the mixing with the incoming air going to the cylinder. I WOULDN'T try it on a wet system though. (even though it may work)

Yeah, when I said nitrous may be a problem, I assumed a wet kit was being used. I don't think a dry kit would have any problem. Turbulent flow is good, but you need to induce that turbulence with as little loss of flow as possible. Personally, I think it would probably help a dry kit and probably hurt a wet one. I'm no expert, but that's just my guess since the mixing of nitrous and fuel occurs right where that gasket is.

Pete
 
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