Raised Top

Flex

Registered User
Hey bros,

I was looking at some raised tops for a new member during my recup and I had a thought. Has anyone ever tried to raise the low side of a top during the process so that they are both the same height? Even the MP top is taller on one side than the other. Was this just a lazy recast or is there some reason for one corner to be higher?
 
I believe it allows you to still use the stock i/c pipe, if it was straight across (even) then you wouldn't be able to get a good seal at the top and pipe connection. Just my guess at an answer.
 
Perhaps you are right dude. I thought about it an it could be a factor but the IC can move and I think that both tubes should be able to pivot enough to account for it.
 
I was also thinking..If someone cut-n-weld a whole new top, I'd buy it. It seems to me that the stock or raised ic top is like a wall. once the air leaves the supercharger it hits the top hat, then when there is nowhere else to go, it goes to the ic piping. if someone fabbed up a piece of piping that is a 90 degree angle, it would let the air smoothly leave the supercharger instead of hitting the wall of the top hat.

That's my theory and I'm sticking to it:D
 
I was also thinking..If someone cut-n-weld a whole new top, I'd buy it. It seems to me that the stock or raised ic top is like a wall. once the air leaves the supercharger it hits the top hat, then when there is nowhere else to go, it goes to the ic piping. if someone fabbed up a piece of piping that is a 90 degree angle, it would let the air smoothly leave the supercharger instead of hitting the wall of the top hat.

That's my theory and I'm sticking to it:D

Yeah, I would Imagine that working really well. Then you could run it the same size pipe as the IC pipe and it would flow way better then the stock hat. The only problem I see is hood clearance. But if you ran a cal hood it would work. I see it looking kinda like an 4.6 upper intake.

Shot I could make something out of steel. But not aluminum.
Has anyone else given this a thought?
 

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I don't know if the shape matters as much as its ability to exhaust the charge into the IC tubing. Keep in mind that it is exiting a triangular shaped opening and unlike an N/A engine (i.e. 4.6) it is being expelled under boost. As long as it is capable of flowing quickly, it shouldn't matter the initial shape.

I have already modded a raised top I purchased on the net by straightening out the bends at the front attaching bolts. This greatly opened up the diameter of the outlet. I think that if the top was also levelled, the flow improvement would be substanial.
 
>I think that if the top was also levelled, the flow improvement would be substanial.

The more you level the top, the more you increase the angle necessary to match the pipe to the IC - technically, improving flow at one point may mean hampering flow at the other...in reality, I'd think you would have to go a long ways before this became an issue, however.
 
I don't know if the shape matters as much as its ability to exhaust the charge into the IC tubing. Keep in mind that it is exiting a triangular shaped opening and unlike an N/A engine (i.e. 4.6) it is being expelled under boost. As long as it is capable of flowing quickly, it shouldn't matter the initial shape.QUOTE]

Here is an illustration of what I mean. Im not talking about the shape of the tube but the bends. The stock hat is like a wall. 12psi of air blows up hits the top then is forced right. With something like in my illustration (Custom). 12psi rush is out the blower and smoothly bends to the IC tube.
 

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I don't know if the shape matters as much as its ability to exhaust the charge into the IC tubing. Keep in mind that it is exiting a triangular shaped opening and unlike an N/A engine (i.e. 4.6) it is being expelled under boost. As long as it is capable of flowing quickly, it shouldn't matter the initial shape.QUOTE]

Here is an illustration of what I mean. Im not talking about the shape of the tube but the bends. The stock hat is like a wall. 12psi of air blows up hits the top then is forced right. With something like in my illustration (Custom). 12psi rush is out the blower and smoothly bends to the IC tube.

You mean like this

Ken
 

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Yours is obviously set up for an FMIC Ken. Did you ever compare that design to an ordinary raised top, such as the MP, for flow?
 
One thing to remember, the M90 does not pressurize the air inside the blower housing, it pushes air from the input to the output, with the pressure differential occurring at the output only when more air is being moved from one side to the other than the engine can consume.

Thus the air coming out of the blower isn't under pressure. The entire intake track from the back of the rotor lobes, to the back of the intake manifold valve sees essentially the same pressure when under boost.
 
Yours is obviously set up for an FMIC Ken. Did you ever compare that design to an ordinary raised top, such as the MP, for flow?

No I havent. The majority of the guys who have gone down the mod road is the top really has little to no worth HP wise untill one gets to a high HP level. This top is setup up for side mounted tube. If I had done this for myself I just would have fabricated a tube to go to the stock located IC. Tops are realivity easy to fabricate. Most out there have diffrent ideas on what is best


Ken
 
Dyno tests showed that a 3/4" raised top on a mildly modded SC showed no gains power wise. The only thing we saw was a small variance in blower outlet temperatures (we had a temp sensor on the top IC tube) by about 10 degrees or so which is nothing in the grand scheme of things. And that 10 degrees could have been anything. You don't see the temp change on the other side of the IC.

Fraser
 
so you're saying..I paid 180 bucks for a raised top, for nothing?? and guys buy 380 dollar MP tops for nothing as well?...
 
Unless your future goals is an MPX or an AR blower, I would say yup, that money could have been better spent elsewhere. Is it going to hurt having it, nope.

Fraser
 
so you're saying..I paid 180 bucks for a raised top, for nothing?? and guys buy 380 dollar MP tops for nothing as well?...


Thats what everyone is saying. Many mods that the money can be spent on that will show HP increases. One of the first things I did was build a 11/2" raised top and chromed it look nice but no change on the dyno

Ken
 
No HP gain! Wow, I really didn't see that. But I guess it make senses. Well I guess I kinda got put in my place.:p HEHE
 
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