TRNorBRN6001
Needs a job
Posts: 2021
|
posted February 27, 2006 08:14 AM
Big Valve Head
Just curious if anyone has done a big valve head and kept the stock cams
in. As it would seem to flow around a similar amount as stock valves and hotter
cam. It would seem a cheaper alternative if you were going to replace your valves
any way and not have the added $800-$1200 expense of cams.
Not that I went this way, but would seem an interesting idea.
Maybe someone can blow us away with a little flow dynamic knowledge!
____________
TFA 200MPH CLUB MEMBER!
  
|
TRNorBRN6001
Needs a job
Posts: 2021
|
posted February 28, 2006 09:18 AM
Any comments would be OK.
____________
TFA 200MPH CLUB MEMBER!
|
Marcos Peguero
Zone Head
Posts: 568
|
posted March 01, 2006 10:33 AM
I realy dont think that this head would benefit with bigger valves. its like putting a bigger door in a hall but keeping the hall same size.
In a head that works better with a smaller hall (ports) anyway.
I havent seen anyone except the huge engines with cams.... and even muzzy does not recomend them.
|
VincentHill
Needs a life
Posts: 6520
|
posted March 01, 2006 11:03 AM
Gary, I do not see a "Lot of room for Larger Intakes (Maybe 1 MM to 1.5 mm on each valve and then the flow work to get the benefit in the port. Who says Cams cost $800 to $1200?
The last set of Cams I had made by Web Cam was about $400 to my Specs but this was an 8 valve engine!
____________
Made History @ Daytona and still one fast old man!!
|
TRNorBRN6001
Needs a job
Posts: 2021
|
posted March 01, 2006 02:43 PM
I was just think if someone was going to have thier head ported anyway and were also going to pick up new valves and already had the big cc's to suck the flow in. The valves and port work would cost around the same. I was also thinking just 1mm over on intake and exhaust. With a lower lift from the stock cams it would decrease the wear on the valve trane and the shorter duration might decrease overlap time, but still keep a similar amount of flow volume.
I went the conventional way on my bike, but was just curious if it might save the next person a couple of coins with similar HP and Tq results.
____________
TFA 200MPH CLUB MEMBER!
|
VincentHill
Needs a life
Posts: 6520
|
posted March 01, 2006 04:46 PM
Are you trying to make "ALL" of the HP?? Why not call Coby Adams and ask him?
____________
Made History @ Daytona and still one fast old man!!
|
y2kzx12r
Needs a job
CompetitionCNC.com
Posts: 3762
|
posted March 02, 2006 05:43 AM
From the numbers i,ve seen and crunched the valve size isnt a bottleneck. So its not going to yield a performance gain untill it becomes the bottleneck. I think this would be about 1600 cc or so and about 15,000 rpm.
____________
Y2KZX12R
CompetitionCNC.com
|
TRNorBRN6001
Needs a job
Posts: 2021
|
posted March 02, 2006 08:20 AM
I am trying to make as much reliable HP as possible and then just put
a touch of Nos on top. I am hoping for around 190-200 HP and a 70 shot.
Might just get this big boy to 205mph.
We had considered Coby for the head, but he is way too busy. So I just shot it off to
Carpenter for a little port and JC will put the stock size SS valves in and
a touch hotter cams along with HD valve springs.
But like I said I was just curious. Just curious again, where is the bottleneck
for the intake on a ZX-12?
____________
TFA 200MPH CLUB MEMBER!
|
Marcos Peguero
Zone Head
Posts: 568
|
posted March 02, 2006 10:05 AM
No botleneck in the port and valve department.
|
y2kzx12r
Needs a job
CompetitionCNC.com
Posts: 3762
|
posted March 03, 2006 05:55 AM
At 1375 cc the exhaust ports just start to become a bottleneck. Not a huge problem but there should be some power in opening them up to match the header.
In the chamber you can unshroud the intake valves and gain a few % flow. There isnt a velocity penalty by doing this either.
See the thread and pics on the 1375....
____________
Y2KZX12R
CompetitionCNC.com
|
TRNorBRN6001
Needs a job
Posts: 2021
|
posted March 03, 2006 06:04 AM
I have been following that thread very cool info. I also asked the person doing
my head to open the exhuast ports up a little since I was also running a touch
of nos. I'll also be running slightly higher lift and duration on the cams and
have a header that should be able to handle it better, compared to the stock one I
was running.
I do not know much at all about flow dynamic, intake velocity, charge stacking, ect.,
but find it very interesting.
____________
TFA 200MPH CLUB MEMBER!
|
Marcos Peguero
Zone Head
Posts: 568
|
posted March 04, 2006 04:32 AM
I would not g crazy with the exaust ones, I respect your opinion y2kzx12r but that I would not go that far at all.
That ramp in the exaust has a purpose.
|
y2kzx12r
Needs a job
CompetitionCNC.com
Posts: 3762
|
posted March 04, 2006 05:03 AM
very true marcos. i should have been clearer... dont touch the port floor. just the roof and sides to match the header.
____________
Y2KZX12R
CompetitionCNC.com
|
T-rex12r
Novice Class
Posts: 69
|
posted March 08, 2006 09:05 PM
I am running a big valve head with degreed stock cams, with the 1290 kit and sidewinder. Dynoed my bike a couple of days ago and got 203 on motor, and it was 12.2 a/f...still a little fat.
____________
MBD Racing
No Excuses!!!
Don't Give Them And
Don't Want to Hear Them!!
9.14@149 on Motor
"05 Tx Shootout Heavy Hitter Champ"
|
TRNorBRN6001
Needs a job
Posts: 2021
|
posted March 09, 2006 07:05 AM
Very Nice! If you do not mind me asking what is your compression ratio and torque?How did it feel after you slipped them big valves in? How much over on intake and exhaust?
I'm trying to get to HR to check out the first race of 2006. I might try my hand at the next ShootOut, HH class as I am 260lbs. Just need to extend to 64", Mod zipper on leathers,
and find out the rest of the rules. Maybe loose 10lbs. so them leathers don't bust a seem.
____________
TFA 200MPH CLUB MEMBER!
|
|
|
HOME
NEW TOPIC