newbie question- does the port divider make a difference?

[cherrybomber]

was thinking of getting one for my 200 ci. is the performance gain really significant? what do you notice?

http://www.cliffordperformance.net/Merc ... _Code=F200

 

[fordconvert]

Is the rest of the car stock?

 

[CZLN6]

Howdy Cherry:

and Welcome to The Forum, Yes, it is that good.

About the port divider. No, that change alone is not significant. the down sides are that it is hard and time consuming to fit, it must be properly welded in place and if it comes loose it can make an irritating rattle. The reality is no one has ever done before and after testing on just adding a port divider. In almost all cases the divider has been added along with a header or/and a valve job/ performance cam. That make it impossible to say one way or another what's responsible for what. In some cases where the divider has come loose, people have simply removed it and didn't notice much of a performance degrade in street uses.

My belief is that if you're building a high performance engine and want the last enth of performance, your already doing head work, then it is worth it- but do it right. It will help to even cylinder exhaust flow. How much? I don't think anyone really knows.

YOu might want to use the search function on this forum. This topic has been cussed and discussed to death.

Again, welcome. I hope this is helpful

Adios, David

 

[cherrybomber]

thanks guys!

the engine itself is stock. i have some weird customer headers on that came with the car. i say weird because the bends are hmmm okay let me post a pic in a bit so you can decide for yourselves.

 

[MPGmustang]

IMO I don't think it would, maybe only if you decide to go super with a header... but if using the cast iron exhaust manifold, no, no on anything... I've been told by many that's it's really only a gimick that makes money.

my old stock engine got 72 hp, if by only adding "material" to cyls 3&4 I can gain an extra 10% hp, why not add more to the other cyl's and gain a total of 30%? manIt would be a 21hp increase because I added "material" to the exhaust... which restricts flow...

 

[rbohm]

8) as david indicated, it can add power, but how much, and is the effort worth the gains? those are the questions you need to ask.

1: how much?

well you have the cost of the part, and the amount of time needed to fit the part properly, and the cost of welding it in place. fitting the part is essentially labor only, but how much is your time worth to you?

2: is it worth the gain in power?

that depends, are you building a street engine, a street strip engine, or an all out race engine? if you are building an all out race engine, then yes the effort is worth the price. any advantage you can get in an all out race engine is generally worth the effort. for anything else though, i say no. the divider that is built into the exhaust manifold/header will be sufficient.

 

[cherrybomber]

thanks man.

that puts things into perspective. ill worry about the other stuff first then.

 

[CobraSix]

I ran my current set up both with and without a port divider, with no other interim changes. Manly because the port divider broke loose and was rattling, so I pulled it out.

to be perfectly honest, I didn't notice a difference, other than the engine being quieter. Now, if I was pulling a head off and rebuilding it, porting, etc...I'd probably stick it back in. Why? Why not? I don't think it hurts anything, and should only offer benefits, however minor. But as a stand along modification, not worth the effort or the exhaust gasket...

 

[mustang6]

I recently read a book on flathead engine performance and the issue of exhaust port dividers came up there too. While many people have talked about the port divider on our sixes "smoothing out" exhaust flow and equalizing port volumes, this book stated the main benefit (still related to exhaust flow) of a port divider is to prevent the exhaust pulse from one cylinder catching the overlap of the adjacent cylinder and causing a slight amount of reversion, thereby slightly contaminating the inbound fuel/air mixture of the next intake stroke. I haven't looked at the stroke cycles of the 3-4 cylinders in the small six, or the camshaft events, to determine how big of an issue this might be for us but I think it stands to reason that longer duration (more overlap) cams would be more affected by this reversion than shorter duration (stock) cams. This means that the port divider would have greater benefit to a small six with a large cam.

 

[Invectivus]

this book stated the main benefit (still related to exhaust flow) of a port divider is to prevent the exhaust pulse from one cylinder catching the overlap of the adjacent cylinder and causing a slight amount of reversion, thereby slightly contaminating the inbound fuel/air mixture of the next intake stroke.

I read somewhere that the Siamese ports were meant to lean out 3/4 which runs much richer than 1/6, for better balancing and tuning. I guess maybe to test that drop a narrow band on each tube of a header and measure before and after. IF that were true, adding it would make the middle pair run richer which wouldn't make power with timing set to prevent leaner 1/6 from detonating, but rather it would just lower mileage.

I would (and will) install one in my 2x2 as the better fuel balance wouldn't need leaning, and with a better breathing intake I could use a better breathing exhaust.

 

[turbo2256b]

Always seemed to run better with than without for me. One thing with a tube header was not to weld them in, but to add a couple allen head bolts in the header flange plate, that after installing the divider then putting the header on could be snugged up to hold the divider in place.