has anybody thought about how bad our intake ports are? (charge mixing-wise)

[themadscientist]

Think about it. We have eight ports feeding four cylinders. That by itself is not much of a problem but what about the secondary butterflies and most importantly injector placement. The secondary butterflies are in theory a neat idea but anybody who has flipped those things open and looked down the port will likely come to the same conclusion I have, F-that silly crap. Now the four port euro head has, well four ports. Four oval ports that divide before the valves but more importantly a centered injector firing reasonably equally at both valves. Think about the eight port head, starting to realize what I have? yeah you have a wet port and a dry port. The injector is centered on one port and valve, the other port flows only air.I'm no engineer, don't claim to be but Madmomma didn't raise no dummy and you only need basic horse sense to start asking some straight questions.

1. how effectively is the charge getting mixed in the chamber?The charge is actually the sum of the collision of two columns of air, one saturated with fuel, the other bone dry and they are expected to fully homogenize in the chamber before it gets compressed and lit. To me that sounds completely impossible and very inefficient.

2. how much hotter is that dry valve than the wet one?The incoming charge has a cooling effect as it washes over the valve; how much I don't know. I do know that one valve is bathed in a super rich charge and the other again gets bubkis, air only. That dry valve has got to be hotter that the other. That could create a possible detonation source.

It makes me wonder if getting an even fuel flow might unlock some power, perhaps raise the boost threshold. You could perhaps modify the sub manifold to mount eight smaller injectors or mount four further back in a custom manifold and knife edge the splitter between the ports.

Discuss.

[zmannz]

I was thinking of an extra set of stock injectors on the manifold, one extra for each "dry" port.

[themadscientist]

There is not enough meat in the casting to cut reliefs for extra injectors to spray.

[float_6969]

I've considered all of these things in the past as well, and if you look at all of the latest design technologies, all of the variable port velocity mechanisms are now upstream from the injectors and use one port per cylinder.

The other thing that comes to mind is that the 4 port head used on the EDM CA's was created AFTER the 8 port head. I would have to say that Nissan must have realized something about the 8 port head that made it worth creating a whole new cast for the head...

[Ca_Silvia]

I've considered all of these things in the past as well, and if you look at all of the latest design technologies, all of the variable port velocity mechanisms are now upstream from the injectors and use one port per cylinder.

The other thing that comes to mind is that the 4 port head used on the EDM CA's was created AFTER the 8 port head. I would have to say that Nissan must have realized something about the 8 port head that made it worth creating a whole new cast for the head...

True but the 8 port head must have been Rand D for a few years prior to production. Also, what about all those crazy high hp CA we keep seeing. Are they 4 or 8 port intake vehicles? Common sense would lead me to believve they are 4 port for maximum peak air flow but that is just a guess.

[themadscientist]

The Norris car is four port as are all the high HP European cars but the Pady and other big power Japan cars are eight port.

[Ca_Silvia]

The Norris car is four port as are all the high HP European cars but the Pady and other big power Japan cars are eight port.

So its basically a wash then, kinda sounds like the intake flow doesn't really matter to make high hp.

[themadscientist]

it always matters. The Norris car retains the stock manifold which is definitely a restriction. The J-spec cars ditch the factory manifold which makes a big difference. Four port plus good manifold could mean 700hp.

[ca18detgabby]

Just spit balling, but wouldnt utilizing the charcoal canister make for more fuel being used by the "dry port" as it utilizes the over draft of fuel fumes as a fuel source instead of using the fuel itself.

not 100% on how the canisters work, but from what I understand thats what the idea behind them was. better MPG as you run on fumes instead of the fuel itself.

[r34 gtr]

Yes I have thought about it. You could cut out the material in there and make it a custom massive four port job, or you could just jump on a plane to England and stuff a four port head in your carry on. If you have family over there like me, its just a matter of remembering to pick one up from a breakers yard when you are visiting.

I plan on running meth injection, if I ran it through that other port by drilling and tapping a jet into the "dry" runner, then I would have the cooling effect on that valve too, and would have mixing of two fuels in the combustion chamber. It would also be very easy (and baller-status) to do.

[DALAZ_68]

what about converting the 8 port to a 4 port with a costume manifold and costum inj system and a standalone

[themadscientist]

Yes I have thought about it. You could cut out the material in there and make it a custom massive four port job, or you could just jump on a plane to England and stuff a four port head in your carry on. If you have family over there like me, its just a matter of remembering to pick one up from a breakers yard when you are visiting.

I have two four port heads

[meminto]

Out of curiosity, say you were able to prove that there is a benfit in increased horsepower or torque moving away from the 8 port head to the euro 4 port head or customised 8 port, however you want to do it...

If you could say, hypothetically that you found (examples only) 10-20 hp or 5-10 nm through the rev range, what would the cost v's performance gained ratio be?

Also when you say stock manifold being a restriction, do you mean an untouched manifold or a ported and flow tested stock manifold?

[mbmbmb23]

Get a greddy football intake and make a conversion plate to bolt it up to the CA middle intake (butterfly passage).....then relocate the injectors to the greddy manifold....delete the butterflies......jb weld the OEM injector holes. Plug in an SR top mount injectror fuel rail if the CA's doesnt work. Im pretty sure the greddy will work with top mount inj. You may have to hog out the butterfly passage....or.....weld the greddy to the 4 intake runners RIGHT before the butterfly passage.....like the custom CA manifolds weld on.

Heres the fake greddy "freddy" intake on ebay. Evidently the casting is rough....but guys cut em in half and port them. The price is right for a lil experimenting.

http://cgi.ebay.com/ebaymotors...ZWDVW


Modified by mbmbmb23 at 10:36 PM 7/11/2008

[DALAZ_68]

what about this one http://cgi.ebay.com/ebaymotors...l1318

Get a greddy football intake and make a conversion plate to bolt it up to the CA middle intake (butterfly passage).....then relocate the injectors to the greddy manifold....delete the butterflies......jb weld the OEM injector holes. Plug in an SR top mount injectror fuel rail if the CA's doesnt work. Im pretty sure the greddy will work with top mount inj. You may have to hog out the butterfly passage....or.....weld the greddy to the 4 intake runners RIGHT before the butterfly passage.....like the custom CA manifolds weld on.

Heres the fake greddy "freddy" intake on ebay. Evidently the casting is rough....but guys cut em in half and port them. The price is right for a lil experimenting.

http://cgi.ebay.com/ebaymotors...ZWDVW

Modified by mbmbmb23 at 10:36 PM 7/11/2008

[mbmbmb23]

It doesnt have injector bosses (ports)...otherwise its decemt...wonder if the velocity stacks are tuned to one another?

[float_6969]

I have a 4 port head as well and I'm hoping (one day) to do a side-by-side comparison.

[themadscientist]

Somebody is working on it.

[NUT-CSE]

I love the technical CA threads, its a shame my CA intelect is piss weak. Im just gonna keep taking in all this info that everyone has to offer.

[articzap]

You cannot spray the whole port before the butterflies, or you'll be pooling of fuel at the butterflies. So if you're going to leave the butterflies, theres a couple of things you can do. You can either add another injector computer controlled to come on when the secondaries open or you can close off the stock injector port or add one before the butterflies in the center as a "secondary" injector.

[r34 gtr]

TMS, those intake ports are drop dead sexy. Thats exactly what I had in mind.

I've always said, butterfly valves = weak sauce. I'm much happier without them.

[chausaster]

Yes I have thought about it. You could cut out the material in there and make it a custom massive four port job, or you could just jump on a plane to England and stuff a four port head in your carry on. If you have family over there like me, its just a matter of remembering to pick one up from a breakers yard when you are visiting.

I plan on running meth injection, if I ran it through that other port by drilling and tapping a jet into the "dry" runner, then I would have the cooling effect on that valve too, and would have mixing of two fuels in the combustion chamber. It would also be very easy (and baller-status) to do.

I honestly like this idea. I'm running megasquirt right now and adding a RPM based meth injection into the dry secondary butterfly port may yield an very easy wet port setup. If anyones got a spare 8-port intake manifold that they are willing to sell I'd totally like to try that idea.

edit: So looking into the system. I'm finding a few small problems. will fitting the meth jet near the beginning of the secondary butterfly port be too close? or does it spray kind of like an injector and have the time to cool and atomize? I'm not really familiar with meth injection.
Modified by chausaster at 3:02 PM 7/13/2008

[themadscientist]

I'm not really familiar with meth injection.

Modified by chausaster at 3:02 PM 7/13/2008

Just say no to drugs man

[chausaster]

Just say no to drugs man

Oh but I got so interested.... I can't stop now..... So going on after several hours of looking around and reading up. It seems that if 4 jets were ran near the beginning of split in each secondary butterfly ports you should still get a good mixture of methanol and air into the system to give sufficient cooling for the system and create a wet secondary butterfly port. I've found in the process of this a cheaper water\methanol injection kit that should suffice. http://www.enginerunup.com/ these guys have a cheap little kit that comes with most of the stuff needed to run the 4 port injection.

[DALAZ_68]

dare i ask...but what would happen if we remove the secondaries all together and fab a manifold directly to the head?

[lostmenoggin]

heres another...

http://cgi.ebay.com/Nissan-Sil...l1318

[themadscientist]

dare i ask...but what would happen if we remove the secondaries all together and fab a manifold directly to the head?

Just be sure to include the thermostat housing.

[chausaster]

heres another...

http://cgi.ebay.com/Nissan-Sil...l1318

This intake mani doesn't have any ports for fuel injectors. You may want to have some. Also If you live in the wonder winter weather land like I do 5 months outa the year. it may be good to have a spot where the fast idle stuff can sit.

[themadscientist]

all cars have a fast idle system

[float_6969]

LOL!