good blower Cam?
06-07-2004, 05:25 PM
#2
TECH Regular
iTrader: (12)
Join Date: Mar 2003
Location: Hershey, PA
Posts: 453
Likes: 0
Received 0 Likes
on
0 Posts
generally everybody goes for more exhaust then intake,
i have 214/220 .559/.566 115 Chris @ ECS said that it was an excellent blower cam, and it's really stealthy, can't even tell the car has a cam in it
i have 214/220 .559/.566 115 Chris @ ECS said that it was an excellent blower cam, and it's really stealthy, can't even tell the car has a cam in it
Trending Topics
06-08-2004, 02:52 PM
#11
A quick way to describe it and I am sure some one else can do a better job than me, but what a blower needs is to help get rid of all the air you are pumping in ETC... The turbo uses the exhaust to turn the turbo so letting it all go through the exhaust is not needed as much as the turbo will at some point be almost sucking the air from the exhaust when it is spooling up ETC... So more exhaust duration is not necssary. I think I am not 100% sure on this cause I have not had a bunch of experience with turbos or even talked with them much it is just the way I visualize it so I hope that helps you a little. Some one who know Turbos well should really give you an answer that is more from experience.
06-08-2004, 03:01 PM
#12
LS1Tech Co-Founder
iTrader: (34)
From: http://www.holley.com/HiOctn/TechServ/SCTech.html
What a Supercharger Does
An internal combustion gasoline engine draws in air which is mixed with gasoline. This "fuel/air charge" is drawn into the cylinders as a result of the vacuum created when the piston travels down the cylinder. When the piston goes back up, this fuel/air charge is compressed to a fraction of its original volume. If an engine has a 9:1 compression ratio, the fuel/air charge will be compressed to 1/9th of its original volume. When the spark plug ignites this compressed fuel/air charge, the resulting combustion causes an expansion of the charge which forces the piston down.
As you pack more fuel and air into the cylinder, the combustion charge becomes more powerful and the engine produces more power and torque.
In an unblown engine, when the piston goes down on the intake stroke, atmospheric pressure tries to fill the void now present in the cylinder. If the cylinder filled completely with air, the engine would have a volumetric efficiency of 100%. Due to the restrictions in any engine created by the air cleaner, cylinder head and cam timing, all of the air that should get into the cylinder can't, so the typical engine's volumetric efficiency is less than 100%. By removing these restrictions, or at least reducing them by improving the cylinder heads and cam timing and using a larger carburetor, the volumetric efficiency of an unblown engine can be improved.
With a supercharger, the amount of air and fuel that can be packed into the cylinders greatly exceeds the 100% volumetric efficiency of a highly refined unblown engine. Since the air is now being forced into the engine, you can put a substantially denser fuel/air charge into the cylinders. On most street type blown applications running 6 to 7 pounds of boost, approximately 40 to 50% more fuel and air can be packed into the cylinders than in a comparable unblown engine.
The reason that larger displacement engines make more power and torque than smaller ones is that more fuel and air are available for combustion. As a result of supercharging, a small displacement supercharged engine can produce similar horsepower and torque to a naturally aspirated larger displacement engine.
What a Supercharger Does
An internal combustion gasoline engine draws in air which is mixed with gasoline. This "fuel/air charge" is drawn into the cylinders as a result of the vacuum created when the piston travels down the cylinder. When the piston goes back up, this fuel/air charge is compressed to a fraction of its original volume. If an engine has a 9:1 compression ratio, the fuel/air charge will be compressed to 1/9th of its original volume. When the spark plug ignites this compressed fuel/air charge, the resulting combustion causes an expansion of the charge which forces the piston down.
As you pack more fuel and air into the cylinder, the combustion charge becomes more powerful and the engine produces more power and torque.
In an unblown engine, when the piston goes down on the intake stroke, atmospheric pressure tries to fill the void now present in the cylinder. If the cylinder filled completely with air, the engine would have a volumetric efficiency of 100%. Due to the restrictions in any engine created by the air cleaner, cylinder head and cam timing, all of the air that should get into the cylinder can't, so the typical engine's volumetric efficiency is less than 100%. By removing these restrictions, or at least reducing them by improving the cylinder heads and cam timing and using a larger carburetor, the volumetric efficiency of an unblown engine can be improved.
With a supercharger, the amount of air and fuel that can be packed into the cylinders greatly exceeds the 100% volumetric efficiency of a highly refined unblown engine. Since the air is now being forced into the engine, you can put a substantially denser fuel/air charge into the cylinders. On most street type blown applications running 6 to 7 pounds of boost, approximately 40 to 50% more fuel and air can be packed into the cylinders than in a comparable unblown engine.
The reason that larger displacement engines make more power and torque than smaller ones is that more fuel and air are available for combustion. As a result of supercharging, a small displacement supercharged engine can produce similar horsepower and torque to a naturally aspirated larger displacement engine.
06-08-2004, 04:19 PM
#14
LS1Tech Co-Founder
iTrader: (34)
A traditional split works best for a blower since the issue is exhaust scavenging.
The other variable is overlap. We like to talk about 114+ LSA's alot but what we are really after is minimal overlap at .050. We don't want too much of the intake charge going out the exhaust. When you have a lot of overlap the intake valve AND the exhaust valve for a given cylinder are both open at the same time for a while.
There are several factors:
Lift
Duration
Overlap
Single vs dual pattern or split duration grinds
LSA
Also keep in mind that duration makes power but duration move your power peak up with nothing else changed, so a 224/230//114 will peak lower than a 230/236/114 cam. That increase in intake duration might shift the power peak up 200 rpms, or 600 rpms higher, it will really depend.
The other variable is overlap. We like to talk about 114+ LSA's alot but what we are really after is minimal overlap at .050. We don't want too much of the intake charge going out the exhaust. When you have a lot of overlap the intake valve AND the exhaust valve for a given cylinder are both open at the same time for a while.
There are several factors:
Lift
Duration
Overlap
Single vs dual pattern or split duration grinds
LSA
Also keep in mind that duration makes power but duration move your power peak up with nothing else changed, so a 224/230//114 will peak lower than a 230/236/114 cam. That increase in intake duration might shift the power peak up 200 rpms, or 600 rpms higher, it will really depend.
06-08-2004, 05:00 PM
#15
TECH Fanatic
iTrader: (6)
Join Date: Nov 2001
Location: Las Vegas
Posts: 1,101
Likes: 0
Received 0 Likes
on
0 Posts
A good stealth cam IMO would be a 218-222 560ish-570ish lift on a 115
the cam i chose is a custom comp. 224-230 567-591 on a 115+5. the intake is on an xe and the exhaust is on a xer.
the cam i chose is a custom comp. 224-230 567-591 on a 115+5. the intake is on an xe and the exhaust is on a xer.
06-08-2004, 05:24 PM
#16
10 Second Club
iTrader: (2)
Join Date: Sep 2002
Location: Orlando, Florida
Posts: 6,368
Likes: 0
Received 0 Likes
on
0 Posts
the z 06 cam is a cheap, blower cam. I'm getting one for 20 bucks and I guarantee I'll pick up 20 hp easy with it.
what colonel said a 220/224 at around .560-.580- lift on a 115 lsa is a really good blower cam. That will yield plenty of power to 6500. you don't and probably won't have to take it that high to be honest.
Area under the curve is what you want, forget bottom line numbers or dyno racing.
you can call comp cams and talk to brian brannen tell him your setup and he can do a similation on his engine analyzer dyno software.
what colonel said a 220/224 at around .560-.580- lift on a 115 lsa is a really good blower cam. That will yield plenty of power to 6500. you don't and probably won't have to take it that high to be honest.
Area under the curve is what you want, forget bottom line numbers or dyno racing.
you can call comp cams and talk to brian brannen tell him your setup and he can do a similation on his engine analyzer dyno software.
06-08-2004, 05:29 PM
#17
TECH Fanatic
Join Date: Sep 2003
Location: "Tr"Asheville
Posts: 1,937
Likes: 0
Received 0 Likes
on
0 Posts
So what would be an ideal turbo cam, a reverse split I'm assuming. My current cam that I have from being N/A is 230/236 .590/.578 114lsa +2 . This cam is up for sale btw, anyway I plan to run 20lb's of boost eventually, after I get all of the kinks worked out once I get everything setup. You guys have been talking a lot about SC cams how about a good turbo cam, don't mean to throw this post off topic away from the SC but I think there is some pretty good info here for all of us. Thanks.
-Sly
-Sly
06-08-2004, 06:44 PM
#18
TECH Addict
iTrader: (6)
Join Date: Dec 2001
Location: sojourning....looking for my city whose builder and maker is God.
Posts: 2,028
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by slyws6
So what would be an ideal turbo cam, a reverse split I'm assuming. My current cam that I have from being N/A is 230/236 .590/.578 114lsa +2 . This cam is up for sale btw, anyway I plan to run 20lb's of boost eventually, after I get all of the kinks worked out once I get everything setup. You guys have been talking a lot about SC cams how about a good turbo cam, don't mean to throw this post off topic away from the SC but I think there is some pretty good info here for all of us. Thanks.
-Sly
-Sly
230/224 duration, .573"/.568", 114lsa
232/226 duration, .575"/.570", 114lsa
234/228 duration, .598"/.588", 114lsa
06-09-2004, 10:28 AM
#19
LS1Tech Co-Founder
iTrader: (34)
I think an 2002+ Z06 cam would make a nice increase in power along with some LS6 or CC918 springs. It's got more intake and exhaust duration than a stock LS1 camshaft of any year.
For a turbo grind, Terry @ Cam Motion likes reverse splits, to keep the intake valve open as long as possible. But he also cautions that turbo cams tend not to be as big as supercharger cams. So a 230/236/115 +2 like mine does not necessarily translate into you getting a 236/230/115 +2. In fact, he said that going with intake duration over 230 might (emphasis on might), result in slower spoolup of a turbo setup. Again keeping in mind that duration makes power, you may find that a 230/224 is the biggest cam you may want to run.
Regarding some of the other blower grinds you guys are suggesting, those all sound cool but the duration splits may in fact be more limited than that and there may not be a configuration that comes in 220/224 but I would ask guys like Terry @ Cam Motion, or Brian Brannen @ Comp on that.
It's important to look at how much power you want to make by when.
My cam has worked out great, I might have been able to go with a bigger split ie 230/240 but my 230/236 works great... In a locked setup my 6900rwhp peak would be more like 6500-6600.
For a turbo grind, Terry @ Cam Motion likes reverse splits, to keep the intake valve open as long as possible. But he also cautions that turbo cams tend not to be as big as supercharger cams. So a 230/236/115 +2 like mine does not necessarily translate into you getting a 236/230/115 +2. In fact, he said that going with intake duration over 230 might (emphasis on might), result in slower spoolup of a turbo setup. Again keeping in mind that duration makes power, you may find that a 230/224 is the biggest cam you may want to run.
Regarding some of the other blower grinds you guys are suggesting, those all sound cool but the duration splits may in fact be more limited than that and there may not be a configuration that comes in 220/224 but I would ask guys like Terry @ Cam Motion, or Brian Brannen @ Comp on that.
It's important to look at how much power you want to make by when.
My cam has worked out great, I might have been able to go with a bigger split ie 230/240 but my 230/236 works great... In a locked setup my 6900rwhp peak would be more like 6500-6600.
06-15-2004, 02:52 PM
#20
Teching In
Join Date: Mar 2004
Location: California
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Pro Stock John
A traditional split works best for a blower since the issue is exhaust scavenging.
The other variable is overlap. We like to talk about 114+ LSA's alot but what we are really after is minimal overlap at .050. We don't want too much of the intake charge going out the exhaust. When you have a lot of overlap the intake valve AND the exhaust valve for a given cylinder are both open at the same time for a while.
There are several factors:
Lift
Duration
Overlap
Single vs dual pattern or split duration grinds
LSA
Also keep in mind that duration makes power but duration move your power peak up with nothing else changed, so a 224/230//114 will peak lower than a 230/236/114 cam. That increase in intake duration might shift the power peak up 200 rpms, or 600 rpms higher, it will really depend.
The other variable is overlap. We like to talk about 114+ LSA's alot but what we are really after is minimal overlap at .050. We don't want too much of the intake charge going out the exhaust. When you have a lot of overlap the intake valve AND the exhaust valve for a given cylinder are both open at the same time for a while.
There are several factors:
Lift
Duration
Overlap
Single vs dual pattern or split duration grinds
LSA
Also keep in mind that duration makes power but duration move your power peak up with nothing else changed, so a 224/230//114 will peak lower than a 230/236/114 cam. That increase in intake duration might shift the power peak up 200 rpms, or 600 rpms higher, it will really depend.
Does this sound right ? Shouldn't they be able to tune the car with the true dual exhaust. Could it be that the CAM is wrong for this application?