Need a cam recomendation for a 12:1 motor
05-23-2005, 05:43 AM
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Need a cam recomendation for a 12:1 motor The short block is done and ready to go in. I'm looking for a little advice, hopefully from someone with a similar set up, on a cam. My major concern is valve clearance issues.
Here are the specs on the short block (stock displacement): New standard bore block, steel crank, Manley H-Beam rods, Diamond Racing 12:1 pistons, Balanced rotating assy.
Heads: Ported LS1s, flow 302/227 @ .600. (will be touched up during rebuild, has stock vavles now, Manley Racemasters waiting)
Trans: 4L60E (Built), SY3500.
Computer: I do have LS1 Edit.
It is somewhat of a daily driver but does see alot of track time.
I will be using N2O at the track so I'm looking for a cam that will be suited for N/A and N2O applications.
Thanks
Here are the specs on the short block (stock displacement): New standard bore block, steel crank, Manley H-Beam rods, Diamond Racing 12:1 pistons, Balanced rotating assy.
Heads: Ported LS1s, flow 302/227 @ .600. (will be touched up during rebuild, has stock vavles now, Manley Racemasters waiting)
Trans: 4L60E (Built), SY3500.
Computer: I do have LS1 Edit.
It is somewhat of a daily driver but does see alot of track time.
I will be using N2O at the track so I'm looking for a cam that will be suited for N/A and N2O applications.
Thanks
Last edited by GHOSTRACER; 05-23-2005 at 05:28 PM.
05-23-2005, 06:17 AM
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Give Cam Motion a call. Tell them your setup and what your looking to accomplish. I know alot of people who have had great luck with them.
Originally Posted by GHOSTRACER
The short block is done and ready to go in. I'm looking for a little advice, hopefully from someone with a similar set up, on a cam. My major concern is valve clearance issues.
Here are the specs on the short block (346): New standard bore block, steel crank, Manly H-Beam rods, Diamond Racing 12:1 pistons, Balanced rotating assy.
Heads: Ported LS1s, flow 304 @ .600. (will be touched up during rebuild)
Trans: 4L60E (Built), SY3500.
Computer: I do have LS1 Edit.
It is somewhat of a daily driver but does see alot of track time.
I will be using N2O at the track so I'm looking for a cam that will be suited for N/A and N2O applications.
Thanks
Here are the specs on the short block (346): New standard bore block, steel crank, Manly H-Beam rods, Diamond Racing 12:1 pistons, Balanced rotating assy.
Heads: Ported LS1s, flow 304 @ .600. (will be touched up during rebuild)
Trans: 4L60E (Built), SY3500.
Computer: I do have LS1 Edit.
It is somewhat of a daily driver but does see alot of track time.
I will be using N2O at the track so I'm looking for a cam that will be suited for N/A and N2O applications.
Thanks
05-23-2005, 09:30 PM
#5
Originally Posted by PREDATOR-Z
I would say something like this 226/232, .593/.589 115lsa
I would say that would work.
There are going to be a number of cams that will work nicely, be good NA and better on the juice. I am assuming you have valve relives, so it would take a huge cam to get into P/V clearence problems.
I like the 231/237 cam on the 114LSA's.
Maybe a TR 230/236.
Basicially I would call someone like Thunder, Futural, Cam motion ect and someone will guide you in the right direction.
05-23-2005, 10:11 PM
#6
Nobody wants to mention Dynamic Compression Ratio (DCR) here?
DCR = the actual compression ratio of the motor from where the intake valve closes in the bore relative to where the piston is on it's upstroke.
There are good calculators for them on the net, problem is you need to plug in the actual intake valve closing point of the cam, not the intake closing point @ .050"
As JZ said here you don't have to worry about P to V due to the Diamond pistons in there.... They come with valve reliefs! Since this sounds like a race car and I would get away from the small duration wide LSA stuff like Preditor said, and go to more duration and a narrower LSA on a tame Hyd Roller profile. You need a good valvetrain matched to what you have because you should be able to twist some serious RPM on that bottom end.
Bret
DCR = the actual compression ratio of the motor from where the intake valve closes in the bore relative to where the piston is on it's upstroke.
There are good calculators for them on the net, problem is you need to plug in the actual intake valve closing point of the cam, not the intake closing point @ .050"
As JZ said here you don't have to worry about P to V due to the Diamond pistons in there.... They come with valve reliefs! Since this sounds like a race car and I would get away from the small duration wide LSA stuff like Preditor said, and go to more duration and a narrower LSA on a tame Hyd Roller profile. You need a good valvetrain matched to what you have because you should be able to twist some serious RPM on that bottom end.
Bret
05-24-2005, 02:08 AM
#7
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I would get away from the small duration wide LSA stuff like Preditor said, and go to more duration and a narrower LSA on a tame Hyd Roller profile. You need a good valvetrain matched to what you have because you should be able to twist some serious RPM on that bottom end.
Are you taking into consideratuion what he wants?
1- High SCR motors like reving higher with a built LS1 7000rpm would be an average medium.
2- He will be shooting N20 and since he has heads a 6 point difference traditional split will be good
3- Why 115, well because this would make this cam a -2 degrees of overlap and therefore ideal for "boost" situations which is what N2O does by increasing cylinder pressures after ignition.
4- Why a 226 on intake, for trq down low (with a little more intake lift)
Anyways, this is MY idea of a high CR/N2O street/strip motor.
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05-24-2005, 02:23 AM
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I had the same situation until I contacted Ed Curtis (EDC).
12:1 Cr, forged guts with 200-300 shot of nuts to boot. Same stall range, and stuff, except the heads I chose were AFR 225's.
231/243 (traditional 12*) .6307/.6222 114* LSA 111* ICL
Not sure how that meets everyone else requirements but it is similar to what Cammotion came up with. And Ed has been one of the best guys to deal with for stuff like this.
Charlie
12:1 Cr, forged guts with 200-300 shot of nuts to boot. Same stall range, and stuff, except the heads I chose were AFR 225's.
231/243 (traditional 12*) .6307/.6222 114* LSA 111* ICL
Not sure how that meets everyone else requirements but it is similar to what Cammotion came up with. And Ed has been one of the best guys to deal with for stuff like this.
Charlie
05-24-2005, 06:02 AM
#10
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Originally Posted by CAT3
I had the same situation until I contacted Ed Curtis (EDC).
12:1 Cr, forged guts with 200-300 shot of nuts to boot. Same stall range, and stuff, except the heads I chose were AFR 225's.
231/243 (traditional 12*) .6307/.6222 114* LSA 111* ICL
Not sure how that meets everyone else requirements but it is similar to what Cammotion came up with. And Ed has been one of the best guys to deal with for stuff like this.
Charlie
12:1 Cr, forged guts with 200-300 shot of nuts to boot. Same stall range, and stuff, except the heads I chose were AFR 225's.
231/243 (traditional 12*) .6307/.6222 114* LSA 111* ICL
Not sure how that meets everyone else requirements but it is similar to what Cammotion came up with. And Ed has been one of the best guys to deal with for stuff like this.
Charlie
05-24-2005, 09:10 AM
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Originally Posted by PREDATOR-Z
Yes, but try to taylor to his needs not a max effort motor.
However... When people post their personal experience with a "certain" profile, it allows the poster to think a little bit harder about all the possible choices available. By presenting results when using a big cam or small cam or anything in between, it will keep the brain cells stimulated and really does help when deciding on which direction to go.
Besides... when a person has specific goals and requirements, this is where a custom design shines over just recommending he use an "XXX" cam or the latest "Porno Star" profile. Everyone has their own individual goals and requirements and as such, opinions on what to use, will always vary and be a matter of personal preference.
Until he sets these goals, we're all just guessing right?
Ed
05-24-2005, 10:05 AM
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Originally Posted by EDC
Absolutely...
However... When people post their personal experience with a "certain" profile, it allows the poster to think a little bit harder about all the possible choices available. By presenting results when using a big cam or small cam or anything in between, it will keep the brain cells stimulated and really does help when deciding on which direction to go.
Besides... when a person has specific goals and requirements, this is where a custom design shines over just recommending he use an "XXX" cam or the latest "Porno Star" profile. Everyone has their own individual goals and requirements and as such, opinions on what to use, will always vary and be a matter of personal preference.
Until he sets these goals, we're all just guessing right?
Ed
However... When people post their personal experience with a "certain" profile, it allows the poster to think a little bit harder about all the possible choices available. By presenting results when using a big cam or small cam or anything in between, it will keep the brain cells stimulated and really does help when deciding on which direction to go.
Besides... when a person has specific goals and requirements, this is where a custom design shines over just recommending he use an "XXX" cam or the latest "Porno Star" profile. Everyone has their own individual goals and requirements and as such, opinions on what to use, will always vary and be a matter of personal preference.
Until he sets these goals, we're all just guessing right?
Ed
Right now, I've got a Lunati (230/237, .544/.540, 112 lobe sep). This cam works well on N2O but seems to fall flat at high RPMs. N/A, it is pretty lazy down low.
05-24-2005, 10:28 AM
#13
For a motor that runs a 12-1 compression ratio I would keep the Cam at a 112 with a 110ICL.That way it will be less prone to Detination.The Nitrous will work well with that.Since the Head's are kindof lacking with the stock Valves I would do a duration of around 228/232 with .580 lift.Of course I'm expecting that a good set of headers-catback is going on the car. I've found big split's move the power range up on the rpm band and husrt's the midrange drivability.
05-24-2005, 12:52 PM
#14
Originally Posted by PREDATOR-Z
Sorry but would you kindly justify what you said?
Are you taking into consideratuion what he wants?
1- High SCR motors like reving higher with a built LS1 7000rpm would be an average medium.
2- He will be shooting N20 and since he has heads a 6 point difference traditional split will be good
3- Why 115, well because this would make this cam a -2 degrees of overlap and therefore ideal for "boost" situations which is what N2O does by increasing cylinder pressures after ignition.
4- Why a 226 on intake, for trq down low (with a little more intake lift)
Anyways, this is MY idea of a high CR/N2O street/strip motor.
Are you taking into consideratuion what he wants?
1- High SCR motors like reving higher with a built LS1 7000rpm would be an average medium.
2- He will be shooting N20 and since he has heads a 6 point difference traditional split will be good
3- Why 115, well because this would make this cam a -2 degrees of overlap and therefore ideal for "boost" situations which is what N2O does by increasing cylinder pressures after ignition.
4- Why a 226 on intake, for trq down low (with a little more intake lift)
Anyways, this is MY idea of a high CR/N2O street/strip motor.
"DCR = the actual compression ratio of the motor from where the intake valve closes in the bore relative to where the piston is on it's upstroke."
The piston doesn't compress as much volume as we think it does since the intake valve doesn't seal off the combustion chamber until it is closed. That plays a big role in this.
As for your points....
1) RPM, yeah a built bottom end should be able to do 7,000rpm + and with 12:1 you can do that and it can still be driveable. You can still have something drivable if you have vacuum and low speed TQ, the compression is good for both of those things.
2) Additional exhaust duration might be usefull here, all depends on how much N2O you throw at it. Then agian looking at what the heads actually move for airflow might be a good idea to determine the actual intake and exhaust durations and lobes rather than making it a arbitrary 6 degs because "its a N2O" cam. PLUS WE NEED TO KNOW HOW MUCH N2O IS BEING PUT TO THIS MOTOR.
3) At least you get that the LSA has an effect on the overlap, but -2 degs is not optimal for overlap on N2O.
Explain EDC's cam for CAT3 to me then....
231/243 (traditional 12*) .6307/.6222 114* LSA 111* ICL
Looks like +9* of overlap at .050 to me.
I've had a cam in a motor on Mike Morans dyno that really liked N2O and it had +38* of overlap at .050 in it.... shoulda run like crap from your rule. Odd thing is that it REALLY liked N2O. Liked it enough to break the block in half. A Chevy Block not a Ford one, that's too easy.
4) So intake duration has nothing to do with the intake valve opening and closing specs for the RPM range and compression ratio that he is running?
Bad thing on this board is that you have to disprove someone to make your point.... this time it happened to be you, sorry about that.
Originally Posted by GHOSTRACER
Right now, I've got a Lunati (230/237, .544/.540, 112 lobe sep). This cam works well on N2O but seems to fall flat at high RPMs. N/A, it is pretty lazy down low.
Originally Posted by Slowhawk
For a motor that runs a 12-1 compression ratio I would keep the Cam at a 112 with a 110ICL.That way it will be less prone to Detination.The Nitrous will work well with that.Since the Head's are kindof lacking with the stock Valves I would do a duration of around 228/232 with .580 lift.Of course I'm expecting that a good set of headers-catback is going on the car. I've found big split's move the power range up on the rpm band and husrt's the midrange drivability.
The RPM range should really determine the duration size range... 228 might be a bit to small for this motor.
The big split cams or cams with a lot of exhaust duration can hurt midrange tq due to the exhaust valve events, but we do have N2O here, no clue how much yet though.
Bret
05-24-2005, 02:02 PM
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Wow, a 12:1 motor in Indiana running 91/93 u/l octane? You have definitely entered the danger zone in terms of potential for detonation.
With heads that flow that good you really don't need a huge cam. You could do ~230/590/114 and deminish clearances concerns.
With heads that flow that good you really don't need a huge cam. You could do ~230/590/114 and deminish clearances concerns.
Originally Posted by GHOSTRACER
The short block is done and ready to go in. I'm looking for a little advice, hopefully from someone with a similar set up, on a cam. My major concern is valve clearance issues.
Here are the specs on the short block (stock displacement): New standard bore block, steel crank, Manley H-Beam rods, Diamond Racing 12:1 pistons, Balanced rotating assy.
Heads: Ported LS1s, flow 302/227 @ .600. (will be touched up during rebuild, has stock vavles now, Manley Racemasters waiting)
Trans: 4L60E (Built), SY3500.
Computer: I do have LS1 Edit.
It is somewhat of a daily driver but does see alot of track time.
I will be using N2O at the track so I'm looking for a cam that will be suited for N/A and N2O applications.
Thanks
Here are the specs on the short block (stock displacement): New standard bore block, steel crank, Manley H-Beam rods, Diamond Racing 12:1 pistons, Balanced rotating assy.
Heads: Ported LS1s, flow 302/227 @ .600. (will be touched up during rebuild, has stock vavles now, Manley Racemasters waiting)
Trans: 4L60E (Built), SY3500.
Computer: I do have LS1 Edit.
It is somewhat of a daily driver but does see alot of track time.
I will be using N2O at the track so I'm looking for a cam that will be suited for N/A and N2O applications.
Thanks
05-24-2005, 04:37 PM
#16
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SStroker
I just gave my exemple of what I would do, not that this is the cam of all cams.
EDC is well known on this board for his, how should I put it, "innovative style" in designing his cams. He has his style and so do others.
Please do not try to nurse me on N2O, as I've had my share of thrills and mistakes.
I, personally would run such a big cam like EDC's for a street/strip car, wouldn't you agree, that it would be a least borderline radical?
Show me one thing wrong with the cam I quoted (BTW it is not an off shelf cam).
Now you'll tell me that you can't because specs at .050 do not mean squat. And you're right, but if so, it also means you know squat about that cam too.
So how can you make any judgement.??
I think I made my point, your opinion is duely noted,
Thanks.
I just gave my exemple of what I would do, not that this is the cam of all cams.
EDC is well known on this board for his, how should I put it, "innovative style" in designing his cams. He has his style and so do others.
Please do not try to nurse me on N2O, as I've had my share of thrills and mistakes.
I, personally would run such a big cam like EDC's for a street/strip car, wouldn't you agree, that it would be a least borderline radical?
Show me one thing wrong with the cam I quoted (BTW it is not an off shelf cam).
Now you'll tell me that you can't because specs at .050 do not mean squat. And you're right, but if so, it also means you know squat about that cam too.
So how can you make any judgement.??
I think I made my point, your opinion is duely noted,
Thanks.
05-24-2005, 07:01 PM
#17
heres what Ed spec'd for my motor with 12.02 SCR; 238/236 112+0, DCR ended up being 8.49.
im running diamond dome pistons with 2cc valve reliefs, 5.7 heads milled .020, .045 cometic, and a .035 quench.
valve reliefs measure .165 and .109 intake and exhaust respectively off the top of my head.
im running diamond dome pistons with 2cc valve reliefs, 5.7 heads milled .020, .045 cometic, and a .035 quench.
valve reliefs measure .165 and .109 intake and exhaust respectively off the top of my head.
05-24-2005, 07:38 PM
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I e-mailed Cam Motion and this was their recomendation: X2244-2341-13+3, 231/239, 591/612, lobe center 113, centerline 110. This seems a little radical for my application. Am I wrong?
I was thinking more along these lines: CompCams, XER273HR, 224/230, .581/.588, 114 lobe sep.
Opinions??
I was thinking more along these lines: CompCams, XER273HR, 224/230, .581/.588, 114 lobe sep.
Opinions??
05-24-2005, 08:37 PM
#19
Predator.... I'll need a little bit more info on this setup but I'll explain why I'm right here in a bit.
Ghostracer...
How much N2O?
How much Gear
What's your raceweight
What's the full flow chart on the heads? 302 seems high to me on stock valves but so be it.
Bret
Ghostracer...
How much N2O?
How much Gear
What's your raceweight
What's the full flow chart on the heads? 302 seems high to me on stock valves but so be it.
Bret
05-24-2005, 09:27 PM
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Originally Posted by SStrokerAce
Predator.... I'll need a little bit more info on this setup but I'll explain why I'm right here in a bit.
Ghostracer...
How much N2O?
How much Gear
What's your raceweight
What's the full flow chart on the heads? 302 seems high to me on stock valves but so be it.
Bret
Ghostracer...
How much N2O?
How much Gear
What's your raceweight
What's the full flow chart on the heads? 302 seems high to me on stock valves but so be it.
Bret
N2O - up to a 200 shot (wet)
Gear - 3.42
Raceweight - 3700 with driver
Flow #'s - .100 - 65 / 55
.200 - 145 / 111
.300 - 207 / 155
.400 - 259 / 189
.500 - 289 / 217
.600 - 302 / 225
Thanks again
Doug