Forced Ind. Cam
09-17-2005 | 05:03 PM
#41
Here is my reaction....
1) 224/224//114 at a minimum or don't bother doing a cam.
2) Focus on duration more than lobe separation
3) If you plan to keep the revs below 6500, that will dictate a different cam from say an engine going to 7000. What is your plan?
4) Do you have stock heads and intake?
1) 224/224//114 at a minimum or don't bother doing a cam.
2) Focus on duration more than lobe separation
3) If you plan to keep the revs below 6500, that will dictate a different cam from say an engine going to 7000. What is your plan?
4) Do you have stock heads and intake?
09-17-2005 | 08:41 PM
#42
Originally Posted by sycotic_reject
...i've never heard of a choppy turbo'd motor, all of them always are idlieing very smooth, they usually have about 115 lsa's in them 
09-18-2005 | 05:35 PM
#43
John,
It's not always about duration. It's about how much air you can get in and out of the motor. So a low duration high lift could work as well. Look at the TR and MTI stealth cams.
Another thing is a 224 on a 114 has -4* overlap @ .050. You could use a 224 on a 112 and still have 0* overlap at .050. A 228 cam on a 114 has 0* overlap at .050.
One other thing to think about is the fact that a 224* cam is going to peak at a different RPM with a different intake manifold and forced induction.
It's not always about duration. It's about how much air you can get in and out of the motor. So a low duration high lift could work as well. Look at the TR and MTI stealth cams.
Another thing is a 224 on a 114 has -4* overlap @ .050. You could use a 224 on a 112 and still have 0* overlap at .050. A 228 cam on a 114 has 0* overlap at .050.
One other thing to think about is the fact that a 224* cam is going to peak at a different RPM with a different intake manifold and forced induction.
09-18-2005 | 05:47 PM
#44
This thread is all about generalizations.
My only generalization about cams is that a 224/224 cam is an okay general duration to keep in mind... for say a 6-8psi setup shifted below 6500 rpms.
Mind you, turbo vs sc, lt1 vs ls1... small cubes vs big cubes... we can't really generalize much at all.
My first cam was 230/236//115 worked nice. I went to a 236/246//114 to pick up the area under the curve. Zero overlap is not always possible of course if you go with a big cam. 2000 hp race cars have a lot of overlap but they are as you say "keeping the valves open longer" so they are pumping a lot of air in and out. If we go with your generalization than all race cars would be running zero or minimal overlap... not the case. Lots of 236/246-250 duration stuff out there for some racing classes like in the NMRA.
My only generalization about cams is that a 224/224 cam is an okay general duration to keep in mind... for say a 6-8psi setup shifted below 6500 rpms.
Mind you, turbo vs sc, lt1 vs ls1... small cubes vs big cubes... we can't really generalize much at all.
My first cam was 230/236//115 worked nice. I went to a 236/246//114 to pick up the area under the curve. Zero overlap is not always possible of course if you go with a big cam. 2000 hp race cars have a lot of overlap but they are as you say "keeping the valves open longer" so they are pumping a lot of air in and out. If we go with your generalization than all race cars would be running zero or minimal overlap... not the case. Lots of 236/246-250 duration stuff out there for some racing classes like in the NMRA.
09-18-2005 | 08:04 PM
#45
LIL SS and Pro Stock John-
you guys seem to be fairly knowledgeable on the turbo cam subject so maybe you can help me out and let me know what you think of the custom girnd ive come up with. heres the link to my thread. Thanks, Allen
https://ls1tech.com/forums/forced-induction/381580-help-me-choose-cam.html
you guys seem to be fairly knowledgeable on the turbo cam subject so maybe you can help me out and let me know what you think of the custom girnd ive come up with. heres the link to my thread. Thanks, Allen
https://ls1tech.com/forums/forced-induction/381580-help-me-choose-cam.html
09-19-2005 | 01:24 PM
#46
John,
I understand the generalisation. What I was trying to point out however, is more based on what the general population want on this site. Most people here are not throwing extreame cams at their daily drivers.
If they have heads on a car that flow to .600, why up the duration farther than it needs. The more duration, you could have slower spool (unless overlap is reduced), harder time smoging, moves the power band higher in the RPM's ect. You can pack the same amount of air in to the cyl's with a small duration high lift as you can a high duration small lift.
The point behind it was you can still get some lope out of a car and get good performance from the cam. A 224 on a 112lsa will give some lope and does not have a ton of overlap. It should work fine in a turbo application. Would a 114lsa work better since there is even less overlap from .006 to .050? Don't honestly know as it other things can now change like shift point.
Like you stated, generalizations can only go so far. With out truly knowing peoples needs/wants from their car and all the equipment they are planing on using, it's hard to say what will really work as there are many different roads to the same house
I understand the generalisation. What I was trying to point out however, is more based on what the general population want on this site. Most people here are not throwing extreame cams at their daily drivers.
If they have heads on a car that flow to .600, why up the duration farther than it needs. The more duration, you could have slower spool (unless overlap is reduced), harder time smoging, moves the power band higher in the RPM's ect. You can pack the same amount of air in to the cyl's with a small duration high lift as you can a high duration small lift.
The point behind it was you can still get some lope out of a car and get good performance from the cam. A 224 on a 112lsa will give some lope and does not have a ton of overlap. It should work fine in a turbo application. Would a 114lsa work better since there is even less overlap from .006 to .050? Don't honestly know as it other things can now change like shift point.
Like you stated, generalizations can only go so far. With out truly knowing peoples needs/wants from their car and all the equipment they are planing on using, it's hard to say what will really work as there are many different roads to the same house
