What makes a bigger difference, cam gears or camshafts? I keep hearing cams, but I'm not sure which one they are talking about..Can you just get one or the other, or do you need to get both?

 

heres the breakdown:

cams work with your pistons. if you want the most from cams, you should
think about doing the bottom end also.

Cams do this: open and close the valves. based on this, the car "breathes"
and makes compression.

LCA: lobe center angle
Valve timing: the rates of the valves opening and closing hence
the V in Vtec Variable Valve Timing

The stock cams have typically in a Bseries Vtec engine 10.5mm of
lift, 230 duration intake and 9.5mm of lift with 220 exhaust duration.
This is the amount of degrees on the crankshaft that the valves are
actually open.

Consider this: JDM 98 Spec Civic Type R intake vs. US GSR

CTR:
intake valve opening: 18deg before top dead center
GSR:
10 degrees before top dead center
CTR:
exhaust valve closing: 10deg after top dead center
GSR:
7 deg after top dead center

CTR: 28 degrees of overlap at 0,0 cam settings
GSR: 17 degrees of overlap at 0,0 cam settings

the Type-R cams in this regard make more compression over the
stock counterparts and allow more valve duration which increases
horsepower and tq ALL OVER THE REV BAND.

Proper tuning on the cam gears can yeild a large bump in low and
mid range power with a slight upper end power increase above the
0,0 setting.

1999 GSR Tegra
Me before cams: 147/110 235/220 duration 10.6/9.5 lift
Me after cams: 159.8/121.4 and 118whp/tq at 5250rpm 243/235dur 11.5/10.5lift
Me after cam gear tuning: 163/125 and 122whp/tq at 5250rpm

I have everything stock but the cams, valvetrain and some MILD headwork.
I need to do my intake, exhaust, skunk manifold, TB, injectors, stand alone
fuel management, header and cat removal. Once I do that, it will be time
to get lightweight 16" rims, then build the bottom end for 9250 fuel cutoff
with higher compression: about 12:1 and then I can make the most of
the taller cam profiles like the Skunk2/2s and Jun/3s with the 260 durations
and over 12mm of lift. I want a daily driver with 20-25MPG and 225/160 to the
wheels. One day I will be an all motor Jedi.

 

Dollar for dollar cams make the biggest difference in performance(except NOS). Most everything else "enhances" performance.

 

tru that. the cams are what make air speed velocity in the
NA application. think of them as your turbo or SC...

 

damnnn, after the posts i've seen with MikeSarr, for such lil posts, i am deeply and very much impressed on your knowledge man

a tiny question though, what do you mean by 0,0 with the overlap. please explain.

 

dude, its all good. thanks for the thumbs up man its been
from alot of questions and dealing with good people, thats
all....reading and alot of site hopping.
anyways, to answer your question:

I drew up the numbers for the overlap on the cams
based on 0,0 meaning TDC on the cams with them
indexed on stock gears or set to 0,0 or a true 0,0
based on gasket compensation... i.e. true TDC timing
for a point of refrence. the overlap duration changes
based on a narrow or wide LCA approach which makes
the air speed velocity of the engine different at other
places of the rev band. 0,0 for instance in GSR
cams makes 17 degrees. 0,0 in CTR/ITR makes
28 and ITR/ITR makes 25. Overlap effects your
effective compression as well creating higher or
lower cylinder pressures depending on the cams
you select, your static CR and how your head flows...
I could go on a while.

I am still looking for someone to
articlulate for me the whole thing on Lobe
Center angles and how to make power tuning cams.
I know it from a fire down the hall reflected in the
celing of the cave instead of looking at the fire itself
(to coin a word picture by plato) and want the true
skinny or the rule of thumb experienced
engine builders and dynotuners know.

the GSR/ITR thing for boost was suggested to me by
John Wilson of http://www.lht-performance.net
when I called him inquiring about a Jackson Racing
Supie on my GSR. We talked for a while, I asked
him about the ITR intake valves being able to
go in the C1 and he was able to varify that.
Very kewl guy. Hes the guy you want to talk to.

The thing I laid out is based on the convo I had with
him in Jan. He says he makes another 20-25whp/tq
with this combo at 10-12psi boost levels and can
boost a bit harder because of the reduced heat in the
engine based on unburnt mixture being pushed out
the exhaust because the intake VTEC cams are usually
too fast for .7-8bar and up.

that is why he suggests going to a type-r exhaust cam
to help this process so the engine has more mechanical
efficiency under boost.

HKS does the same thing on thier turbo cams for
example. more duration and lift on the exhaust
side.

yea.. I have a few posts I came over from B series.net
a lil while ago great forum by the way and really liked
it here.