Head volume increase

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
Steve.k
Guru
Guru
Posts: 1562
Joined: Sat May 28, 2016 10:41 am
Location:

Head volume increase

Post by Steve.k »

Well we opened up bowl area on intake runners of a3 heads from 231cc to 244 and port matched tunnel ram. Seen slight increase in flow but only by 5 cfm at best from .400 up. Going to see where that gets us last dyno run saw 434 peak at 6900.
Walter R. Malik
Guru
Guru
Posts: 6378
Joined: Tue Jul 24, 2012 11:15 am
Location: Roseville, Michigan (just north of Detroit)
Contact:

Re: Head volume increase

Post by Walter R. Malik »

Steve.k wrote: Mon Sep 17, 2018 1:15 pm Well we opened up bowl area on intake runners of a3 heads from 231cc to 244 and port matched tunnel ram. Seen slight increase in flow but only by 5 cfm at best from .400 up. Going to see where that gets us last dyno run saw 434 peak at 6900.
That should raise the RPM point of the peaks a bit; power may go up some because of a better port match.

Personally, in that case, I think the power will simply hang-on longer.
http://www.rmcompetition.com
Specialty engine building at its finest.
Frankshaft
Guru
Guru
Posts: 1037
Joined: Sun Jul 05, 2015 6:01 pm
Location:

Re: Head volume increase

Post by Frankshaft »

Walter R. Malik wrote: Mon Sep 17, 2018 3:07 pm
Steve.k wrote: Mon Sep 17, 2018 1:15 pm Well we opened up bowl area on intake runners of a3 heads from 231cc to 244 and port matched tunnel ram. Seen slight increase in flow but only by 5 cfm at best from .400 up. Going to see where that gets us last dyno run saw 434 peak at 6900.
That should raise the RPM point of the peaks a bit; power may go up some because of a better port match.

Personally, in that case, I think the power will simply hang-on longer.
It's possible it will quit earlier also. Port volume is more, because of bigger bowl, but if port cross section was small for combo and that was unchanged, it could peak sooner, may lose power. Or fill in some areas, but peak sooner, fall off harder if it's pulling on the port harder. Port match has to be WAAY off to gain power.
Steve.k
Guru
Guru
Posts: 1562
Joined: Sat May 28, 2016 10:41 am
Location:

Re: Head volume increase

Post by Steve.k »

Just picked heads up. Turns out hes 250 cc from 231. Csa is alot bigger he says although didn't do before and after measurement. We will dyno this way and see where we get. We will also try setting intake centerline to 110 instead of 107.7. Get a little more pull on heads if you will.
Mikej26
Member
Member
Posts: 103
Joined: Sat Jul 14, 2018 7:53 pm
Location:

Re: Head volume increase

Post by Mikej26 »

Sorry to resurrect this thread, but what were the results?
Steve.k
Guru
Guru
Posts: 1562
Joined: Sat May 28, 2016 10:41 am
Location:

Re: Head volume increase

Post by Steve.k »

No results yet. Engine just going together. Waiting on some parts :(
Post Reply