Extra Exhaust valves

[DDRaptor]

As so of who know my posts i'm always thinking outside the box, I'm still hoping to attend a technical school and become ASE certified as my career move. but I digress.

We all know our engines are 12 valves 2 IN 1 Ex
and carb head have auxillary valves which i have near seen an pictures of but my question since i have been looking at a 89 lx-i in nh that's $1g.

I'm wondering if it's possible to bore another hole in the head and use a small valve to aid the exhaust velocity. Obviously the first question will someone have to design a new camshaft, which would make sense but another question is.

Is it possible to connect this small valve to the exisisting exhaust valves so that a new lobe is not needed.

Thanks.
no flames just trying to think outside the box.

[DDRaptor]

found a nice site has some wrecked 2g and 3g

http://www.haprecycling.com/newarrivals/accordtbl.html

[cubert]

Possible? probably.



Worth the time and money? Probably not.

[2oodoor]

YOu are well outside the damaged parts box in the trunk, if you are not in the trunk. j/k
Carbed 3rd gen do not have that , the heads are pretty much the same as LXi. You are thinking of a CVCC head, PITA run fast run far away from those. You just need a little porting and polishing of exhaust chambers in the LXi head to accomplish plenty of flow.. and a good cam.

[DDRaptor]

Damn i know i read somewhere that carb heads have auxiallry valves i'm like huh i have never seen them.

So the benefits would be nil if an extra exhaust was added in??

[2ndGenGuy]

I often wondered about this myself. But yeah the 3g doesn't have the auxiliary valves. The US-model 2g does, and you could probably put that head on an A20 block for a little compression bump. I imagine if you pull the auxiliary chamber out, get a smaller exhaust valve, weld up the CVCC intake passages, bore through where the aux chamber was, into the combustion chamber and do a little bit of machining, you could get it done. The 2g ES2 head would be a good place to start. Theres tons of em, and nobody wants em.

But then you'd also have to design a custom cam. The cam lobe that runs the aux valve is set up for intake. So you'd have to set it up to open the valve on the exhaust stroke. I imagine you could maybe use the existing exhaust lobe somehow, and join the two rockers together. Then you could just grind off the aux valve intake lobe... Maybe?

[rjudgey]

It's not worth the trouble the exhaust port would still be the same size and that ultimately determines howmuch exhaust gas can get out, running a higher compression would increase exhaust gas efficiency coming out as higher compression decreases emissions. Your better off spending the money on larger custom valves and custom camshaft grinds, or better still a one off design of a 16 valve head that can fit an A20 block.

[MessyHonda]

might as well put in a b16 or b18 with custom mounts.

[carotman]

Anyway, on the A20A, the "other" exhaust valve is the spark plug.

[DDRaptor]

well the hard thing about this is how many cams are out there, not easy to pick one. colt cams, paeco, many shops that will grind you one. and i'm not good with engine builder's math to get the right combination without sacrificing idle too much.

[2ndGenGuy]

It's not worth the trouble the exhaust port would still be the same size and that ultimately determines howmuch exhaust gas can get out, running a higher compression would increase exhaust gas efficiency coming out as higher compression decreases emissions. Your better off spending the money on larger custom valves and custom camshaft grinds, or better still a one off design of a 16 valve head that can fit an A20 block.

The exhaust port would be the same size, but what about porting the crap out of that exhaust port, adding the second exhaust valve, and larger diameter headers! I imagine the exhaust port can be made quite a bit bigger than the exhaust valve and might be able to flow a bit more... Just a theory.

[cygnus x-1]

I think you could get the same benefit by reworking for bigger valves. Beyond that you may as well just go turbo.

C|

[A20A1]

Two valves with one lobe... I don't know if there is room to add a second rocker, or if a second rocker without a lobe directly behind it will work, because the force is offset.