Cams
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boke_as_hell
- Posts: 17
- Joined: Thu Feb 17, 2005 9:04 am
- Car: 92 240sx hatch
Cams
I know this is a repost in a way. I seached the archives for cams to use on the KA-T, but didn't find a definite answer. So ... I'm gonna ask what are you guys using in your KA-T?
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boke_as_hell
- Posts: 17
- Joined: Thu Feb 17, 2005 9:04 am
- Car: 92 240sx hatch
Re: (IWannaS15)
that's awesome...some idiot that's ricing one out, threw 2 not not 1 but 2 rod threw the block, but the head was untouched other than the intake cam snapping...so i have 2 S13 exhaust cams. Thanx for the info.
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hannibal
- Posts: 9680
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- Location: Washington DC
Glad I could help with my limited knowledge 2 exhaust cams are good for the top end, but hurt spool up/low end slightly. I'm planning on trying S13 int and exh (240/248). Ive also heard of guys using the S14 232 intake cam with the 248 exh cam.
I have a question...What is the goal in selecting cams for a turbo motor? Are you going for high lift and long duration while avoiding too much overlap?? I guess I'm asking how the motor is effected by changing intake and exhaust cams.
I understand top end improves (while low end suffers) when going from 232/248 to 240/248 to 248/248. But why doesnt anyone use a 240/232 setup??
I have a question...What is the goal in selecting cams for a turbo motor? Are you going for high lift and long duration while avoiding too much overlap?? I guess I'm asking how the motor is effected by changing intake and exhaust cams.
I understand top end improves (while low end suffers) when going from 232/248 to 240/248 to 248/248. But why doesnt anyone use a 240/232 setup??
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nonchalant rage
- Posts: 101
- Joined: Tue Apr 06, 2004 6:50 pm
- Car: s12
Re: Cams (boke_as_hell)
boost designs also has 2 different sets of KA cams.i believe crower is working on putting out as many as 5 camsets for the KA, ,
Here's some information I got in this thread zerothread?id=103095
This is a direct copy and paste of SimpleEnigmas post; hopefully it will help you out a bit.
1.) Consider your application....race cams on a fairly stock daily driver = rough idle, questions from the cops, and doesnt always mean big gains.
2.) Lift......the depth the valve drops into the cylinder....generally the more lift, the greater the volume of air the valve can get through it before it shuts. Huge lift is not always the best way to go.
3.) duration and overlap....duration is the amount of "time" (degrees of rotation) that a cams lobe holds the valve open (i.e 274 duration means that for 274 degrees of that cams 360 degree movement for one complete rotation, the valve is open.) The longer the valve stays open, the more air can enter the cylinder.....again, consider your application....big duration usually mean large overlaps between the intake and exhaust cams. Overlap is the amount of rotation in the intake and exhaust cams where the I/E valves are both open simultaneously. This generally takes place when the piston is pushing exhaust gas out of the cylinder. The overlap is used to make intake air help push exhaust gas out and at the same time aid the intake air in entering the engine more efficiently (think along the lines of a vacuum, as the exhaust gas exits, the incoming fresh air is pulled into the engine by the vaccum created by the exiting exhaust gas). This makes engine have to work less to draw air into the cylinder. This helps reduce parasitic power loss (the less work an engine has to put in to running itself the more efficient it is) and improves hp gains......once again, everything in moderation....huge overlap is not always the answer....
Your application is the number one item to consider when choosing a cam setup. NA and Turbo setups dont like the same cam grinds. Huge overlap in a set of turbo cams actually helps to defeat the function of the turbo by allowing some of the compressed air to completely bypass the cylinder and exit into the exhaust header, wasting the air. Cams with little or no overlap arent good in NA setups because the overlap aids the piston in expelling exhaust gas and improving engine efficiency.
So can someone expand on that maybe?
This is a direct copy and paste of SimpleEnigmas post; hopefully it will help you out a bit.
1.) Consider your application....race cams on a fairly stock daily driver = rough idle, questions from the cops, and doesnt always mean big gains.
2.) Lift......the depth the valve drops into the cylinder....generally the more lift, the greater the volume of air the valve can get through it before it shuts. Huge lift is not always the best way to go.
3.) duration and overlap....duration is the amount of "time" (degrees of rotation) that a cams lobe holds the valve open (i.e 274 duration means that for 274 degrees of that cams 360 degree movement for one complete rotation, the valve is open.) The longer the valve stays open, the more air can enter the cylinder.....again, consider your application....big duration usually mean large overlaps between the intake and exhaust cams. Overlap is the amount of rotation in the intake and exhaust cams where the I/E valves are both open simultaneously. This generally takes place when the piston is pushing exhaust gas out of the cylinder. The overlap is used to make intake air help push exhaust gas out and at the same time aid the intake air in entering the engine more efficiently (think along the lines of a vacuum, as the exhaust gas exits, the incoming fresh air is pulled into the engine by the vaccum created by the exiting exhaust gas). This makes engine have to work less to draw air into the cylinder. This helps reduce parasitic power loss (the less work an engine has to put in to running itself the more efficient it is) and improves hp gains......once again, everything in moderation....huge overlap is not always the answer....
Your application is the number one item to consider when choosing a cam setup. NA and Turbo setups dont like the same cam grinds. Huge overlap in a set of turbo cams actually helps to defeat the function of the turbo by allowing some of the compressed air to completely bypass the cylinder and exit into the exhaust header, wasting the air. Cams with little or no overlap arent good in NA setups because the overlap aids the piston in expelling exhaust gas and improving engine efficiency.
So can someone expand on that maybe?
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nonchalant rage
- Posts: 101
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- Car: s12
Re: (Veriest1)
it should also be noted that duration should be measured at .050" lift, if its any less the company is probably just trying to make the numbers seem big.
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hannibal
- Posts: 9680
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Re: (nonchalant rage)
Veriest, thats good info you posted.
I should have searched
I should have searched
Re: (IWannaS15)
Eh, I just happened to remember where the thread was and didn't figure you would search for info concerning NA cams.IWannaS15 wrote:Veriest, thats good info you posted.
I should have searched
Re: (Veriest1)
That's why the PDM turbo cams are short duration large lift... Good for turbo.
STOCK 91 Cams - Intake - 207 degrees duration @.050”, .350 lift; Exhaust 215 duration @.050”, .367 lift.
C.702.S Stage II Cams - Intake 221 duration @.050” .379 lift; Exhaust 231 duration @ .050" lift, .390 lift
C.702.T STAGE II DOHC Turbo Cams – Intake 221 duration @.050”, .380 lift Exhaust 221 duration @.050” .380 lift
STOCK 91 Cams - Intake - 207 degrees duration @.050”, .350 lift; Exhaust 215 duration @.050”, .367 lift.
C.702.S Stage II Cams - Intake 221 duration @.050” .379 lift; Exhaust 231 duration @ .050" lift, .390 lift
C.702.T STAGE II DOHC Turbo Cams – Intake 221 duration @.050”, .380 lift Exhaust 221 duration @.050” .380 lift
Re: (Red-KAT)
I did a search and cant find info...
Whats the Stock DOHC spec's?
Whats the Stock DOHC spec's?
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IvanAtSPRacing
- Posts: 479
- Joined: Tue Apr 20, 2004 3:56 pm
- Car: I make cars fast
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Crower does have cams. I have two and 1/2 sets in stock.
Stage II Turbo camsIntake and exhaust are the same spec211° @ .050" with .397" lift
I have been waiting on them to finish the valve springs and Ti retainers so I can get them into the R&D S13 head to do the Crower V Stock cam dyno testing. They finally got the spring seats done and shipped them out to me. I believe I will see them tomorrow.
I hope to have the car on the dyno within the next couple weeks.
Modified by IvanAtSPRacing at 10:02 PM 3/3/2005
Modified by IvanAtSPRacing at 10:55 PM 3/4/2005
Stage II Turbo camsIntake and exhaust are the same spec211° @ .050" with .397" lift
I have been waiting on them to finish the valve springs and Ti retainers so I can get them into the R&D S13 head to do the Crower V Stock cam dyno testing. They finally got the spring seats done and shipped them out to me. I believe I will see them tomorrow.
I hope to have the car on the dyno within the next couple weeks.
Modified by IvanAtSPRacing at 10:02 PM 3/3/2005
Modified by IvanAtSPRacing at 10:55 PM 3/4/2005
Re: (NateDogg)
I’m secure with my masculinity and all… But if I were driving around with “Flower” cams people would suspect some serious wrist flicking action out of me…
Anyways... I would like to see some Dyno #'s from you Ivan... In a normal 10psi type of car... But some Dyno beast would be fine too.
Anyways... I would like to see some Dyno #'s from you Ivan... In a normal 10psi type of car... But some Dyno beast would be fine too.
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Ubernoober
- Posts: 539
- Joined: Mon Mar 08, 2004 6:51 pm
Just as a bit of clarification to Veriest1's excellent post....
the "degrees" of cam duration are calculated in CRANK degrees. Which on a four stroke is 720 degrees of rotation for a single engine cycle. So a 270 degree cam holds the valve open for 270 degrees of crank rotation. You will find this makes much more sense when you try to calculate overlap, lobe ceterline and lobe separation angles. A LOT easier.
the "degrees" of cam duration are calculated in CRANK degrees. Which on a four stroke is 720 degrees of rotation for a single engine cycle. So a 270 degree cam holds the valve open for 270 degrees of crank rotation. You will find this makes much more sense when you try to calculate overlap, lobe ceterline and lobe separation angles. A LOT easier.
As a side note, a member on freshalloy i believe has had a turbo ka for like 4 or 5 years and experimented with pretty much every cam combo. He found 248 intake/232 exhaust to work very well for all around use and a balance of top end and midrange. I also know that rick (533 whp s14) tried dual 248s and didn't gain anything...maybe too much overlap? the 248/232 setup is what I want to do, and you only need one s13 exhaust cam then too.