Cylinder Head Qs
#1
TECH Fanatic
Thread Starter
iTrader: (1)
Join Date: Jul 2004
Location: Summerville, SC
Posts: 1,155
Likes: 0
Received 0 Likes
on
0 Posts
Cylinder Head Qs
I know porting heads increase air flow, but where are the advantages in the powerband? Mostly upper rpms (greater than 4500)?
How about combustion chamber sizes and milling? Are there advantages across the board or lower rpm range?
Basically, I am tossing around the ideas on swapping heads on my lq9 (317). I have a TSP224r cam on a 112. I want to try to maximize naturally aspirated power between 2500 and 6200 to 6500 rpms.
How about combustion chamber sizes and milling? Are there advantages across the board or lower rpm range?
Basically, I am tossing around the ideas on swapping heads on my lq9 (317). I have a TSP224r cam on a 112. I want to try to maximize naturally aspirated power between 2500 and 6200 to 6500 rpms.
#2
FormerVendor
iTrader: (3)
Join Date: May 2002
Location: Reseda, CA
Posts: 1,853
Likes: 0
Received 0 Likes
on
0 Posts
Most guys see from 20-40rwhp and a torque increase of 30+ft/lbs across the rpm range. Generally the larger the cam the more more the cylinder head work helps. In the case of the truck intake manifolds, the upper rpm power is pinched off. Still the cylinder head work makes a felt seat of the pants difference.
Richard
Richard
#5
Not to hijack this thread, or anything... but how do ported 317 heads, from WCCH, compare with STOCK L92 heads. I saw the article in the November 2007 Hot Rod, and wondered if I could get close to the same results with ported 317 heads? The L92 look interesting, but using stock parts would be way less of explain to the SMOG police.
#6
Shorty Director
iTrader: (1)
Join Date: Nov 2001
Location: Valrico, Florida
Posts: 8,176
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Richard@WCCH
Most guys see from 20-40rwhp and a torque increase of 30+ft/lbs across the rpm range. Generally the larger the cam the more more the cylinder head work helps. In the case of the truck intake manifolds, the upper rpm power is pinched off. Still the cylinder head work makes a felt seat of the pants difference.
Richard
Richard
#7
FormerVendor
iTrader: (3)
Join Date: May 2002
Location: Reseda, CA
Posts: 1,853
Likes: 0
Received 0 Likes
on
0 Posts
Head and cam tow packages will see a greater gain in rwtq rather than rwhp. It's not uncommon to see close to 25ft/lbs from 1800rpms on up to 5000 with just head porting alone on a 6.0l engine. Add in a towing cam and rwtq will gain another 25ft/lbs. Since towing cams don't hold high rpm torque, rwhp numbers are less than a larger cam grind, however the rwhp numbers will still jump up some. The truck intakes flatten the power curve above 5000 so small cams in the 208º-212º range will make for nice towing type cams.
There's no glory in the small cams, but IMO towing cams are more pleasurable to drive daily due to the rapid torque response from the accelerator pedal. Small throttle inputs are met with crisp acceleration.
Richard
There's no glory in the small cams, but IMO towing cams are more pleasurable to drive daily due to the rapid torque response from the accelerator pedal. Small throttle inputs are met with crisp acceleration.
Richard
Trending Topics
#8
5 year bitches!
iTrader: (7)
Join Date: Oct 2003
Location: Pittsburgh!!!!!!!! Pa
Posts: 4,890
Likes: 0
Received 2 Likes
on
2 Posts
personally i wouldnt worry about ported headswith a stock truck intake. its kinda like kicking yourself in the nutts. you cna only take in so much air and if your intake is restrictive then everything else is just blah. i would find an intake that allows enough air in to take advantage of the ported heads
#10
Shorty Director
iTrader: (1)
Join Date: Nov 2001
Location: Valrico, Florida
Posts: 8,176
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Richard@WCCH
Head and cam tow packages will see a greater gain in rwtq rather than rwhp. It's not uncommon to see close to 25ft/lbs from 1800rpms on up to 5000 with just head porting alone on a 6.0l engine. Add in a towing cam and rwtq will gain another 25ft/lbs. Since towing cams don't hold high rpm torque, rwhp numbers are less than a larger cam grind, however the rwhp numbers will still jump up some. The truck intakes flatten the power curve above 5000 so small cams in the 208º-212º range will make for nice towing type cams.
There's no glory in the small cams, but IMO towing cams are more pleasurable to drive daily due to the rapid torque response from the accelerator pedal. Small throttle inputs are met with crisp acceleration.
Richard
There's no glory in the small cams, but IMO towing cams are more pleasurable to drive daily due to the rapid torque response from the accelerator pedal. Small throttle inputs are met with crisp acceleration.
Richard