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240Z Turbo

P90 Head Porting realizations

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I dont think the raised part of the chamber in between the valves is going to beneficial. What I would do in stead is to relieve the block and the head like you see on big block chevy engines on the exhaust side. Using a metal head gasket will enable you to open up the exhuast valve flow on the edge of the combustion chamber, then cutting a slight relief in the cylinder, and deck to mirror the relief in the head will improve the flow significantly, then with the other modifications to the port you should reach the numbers you are looking for.

The intake side of the head is easily improved with your porting, then use a stainless steel valve that is worked with the valve seat area close to the top of the valve head, remove excess valve area by countouring the valve to a smooth transition to the seat on the valve. That will improve the flow of the intake valve.

Now, the lift on the cam, you will want to watch the lift on the exhaust side as increased lift on a ported head tends to hinder flow, but with a good relief in the side of the combustion chamber it may improve. The trick here is to use the valve and the lift to promote an easy exit of the gases, with the relief in the head and the deck, you can use the valve as a base for the exit, then contour the port, to flow with the added opening in the combustion chamber and deck. Do you see what I am talking about?

anyway just some of my thoughts.

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I was told the ridge between the valves does, in fact, help performance. It is said to help direct charge and also hinder the ability to flow out the exhaust during valve overlap. The combustion chamber is critical to power for several reasons:

1) unshrouding of the valve to help increase flow

2) directing the charge towards the center of the bore

3) swirling of the charge to help promote a better burn

these can all be very significant in making power. I don't claim to understand the dynamics of this event as it relates to reshaping of a chamber. However, the important thing to realize is this has a significant affect on power. BTW, someone posted a pic of the Maxima N47 combustion chambers. Very interesting...heart shaped chamber...small cc....looks promising....me likes!

maximaN47cc.jpg

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Update:

The head is with the machinist who agreed to develope one intake/exhaust port on the chopped up head at a very good price. He will use epoxy instead of welding because it is just prototyping work. The price was good because he appreciated the head being chopped in all directions to take the guess work out of porting. He had many heads to show me at his shop and how modifying the chambers directly influences port flow and swirl. Interesting stuff to say the least. One of the mods he will be doing is to angle the spark plug towards the exhaust valve. I was shown a Busch series head and they only flowed in the 380+cfm range on the intake ports! :shock: I also checked out some top fuel heads...no wonder they flow so well! Heads with dual plug'd hemispherical chambers and much more. Anyway, he has a SuperFlow 600 with velocity probe and swirl meter. I should know something within 2 weeks time. Will keep you posted!

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I found this website a while back not sure if I posted it. It has some great info if you start digging. The company has an impressive track record with NHRA Bob Glidden mop the track with his engines :shock: . The one thing that impresses me is that everything is not a huge secret. Obviously they have trade secrects, but they explain all their concepts.

 

This one is good reading for ford, chev, hell any gear head.

 

http://www.theoldone.com/about/default.asp

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Guest nikko74z

All the fuss and no results?? This was just getting good. What do you need to keep this going. I want to know what full out flow for a p-90 is. Drop me a line and we will go from there.Later.

 

Nikko

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Guest JAMIE T

Guys, This stuff takes time. I know he said the guy would call him Thursday. But, that sounded optimistic at best. I have put over 40 real hours in a single cylinder head before. That was just porting time, not including flow bench testing. I'm sure James will post the results as soon as he gets them.

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i have a question couldn't you just replace the valve guides to better ones?I think msa has some better ones that wear better than the stock.Just a question cuz i was thinking of just using an old head i have here and porting the crap out of it and replacing the guides for better ones and trying it on a test motor.I think we have a guy here that can flow test it but i think he will charge an arm and a leg plus he's not an import guy v8's all the way for him so he'll prolly look at me funny :)I'm anxious to see what james comes up with.

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after spending many, many hours grinding away at my n42 head with a die grinder and now seeing this page I feel like i missed evolution or something.

 

The head slicing pics are a engineering delight.

I agree with the request for the n42 head pics , that will very handy for the auzzies here--p90 heads in oz are extremely rare.

 

A quick question..how does these flow figures affect a NA motor with a mild cam --ie 270 or 280 degree with 490 thou lift....Will it make a worthwhile gain???

 

keep up the good work.

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Guest eric-z
I think James has many peoples attention here. :wink:

 

hes got mine

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