gamma exh port ?

Message

nberchem · #1 Post by **nberchem** » Thu May 28, 2009 1:35 am

I have some stock 400 cyls. The plan it to take the exh port up 1mm and widen it to 39mm.

My engine builder ans I were wondering if it was better to square off the port so the entire port is the same height, or leave the port lid rounded so it is highest in the middle and lower on the sides?

Thanks,
Nick

beek · #2 Post by **beek** » Fri May 29, 2009 2:36 pm

Keep same shape as stock.
leave the port lid rounded so it is highest in the middle and lower on the sides

nberchem · #3 Post by **nberchem** » Fri May 29, 2009 4:53 pm

Thanks beek.

That was the plan. I was told that Darcy uses squared ports, but they are hard on the rings.

Nick

gus · #4 Post by **gus** » Sat May 30, 2009 2:26 am

yea that would be a snag lookin for a place to happen

vma500 · #5 Post by **vma500** » Sat May 30, 2009 2:13 pm

yes , i agree with Beek

you cannot rise the RG500 ex-port the same way as RD500 ,
the RG pvs does not regulate ex-duration .....they only make the pipe-pulse longer @ lower rpms .

keep the port rounded at highest point

and if you tune it , just space up the barrels with thicker base- gaskets and compensate on the head-volume

not happy ? no problem .....it s al reversable

nberchem · #6 Post by **nberchem** » Wed Jun 03, 2009 6:57 pm

Thanks guys.

The thicker base gaskets are def. in the the plans.

Nick