18 replies to this topic

[nicklouse]

If it is just for the test why bother modifying it?

If you want to mod anything I would go back to a good single SU on a decent manifold.

[Dusky]

Well, I know myself and I'll probably fall in love with the twin' again ( excuse the pun). 

And as I have a few manifolds atm, I'd like trying to modify it :)

[gazza82]

Thought Minispares had Mr V's book?

[Spider]

Sorry, I think dusty you asked in another thread about reducing the size of the balance tube.

 

Yes, it can be done. Most of the HS2 Manifolds have plugs on the ends on the balance pipe. These are like freeze / welsh plugs, they are either 1.00" or 1.125" depending on the manifold (there  maybe other sizes that I haven't seen). These plugs are fairly readily available. Knock one out and that will give you better access to the balance pipe.

 

As they are only rough cast inside, see if you can get a drill bit in there to clean it up at some point, probably towards one end would be easiest and perhaps wisest, I wouldn't advocate trying to go for the middle.

 

Then fit an aluminumn plug in there, which of course can then be drilled (and bell mouthed) smaller. I'd suggest starting off at around 3/16" (5 mm?) but I wouldn't go any bigger than about 3/8" (10 mm). Some people have tried stuff like araldite, but that doesn't last. Maybe some of the metal putty stuff could also be tried, just what ever you do use, make sure that it won't break up or won't dislodge, I doubt your pistons and valves would like that too much.

 

Also, I'd suggest not making it at all smooth, unless you are only seeking high RPM Power and not at all concerned with the low end. The fitting of fins within can also pay dividends, but really to sort these, it would be best done on an engine dyno, it would take many hours.

 

One last thing I'll add is when modifying the manifold, don't consider it in isolation, look up it as an extension of the port.

Edited by Moke Spider, 01 March 2015 - 07:30 AM.