reverse-pattern camshafts
07-27-2009, 01:42 PM
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I've got a 230/224 .575/.563 111LSA. I needed something to make plenty of low-end torque, but still not run out of breath up high. Although I've sacrificed a few ponies up top (5-ish?), I've gained lots of torque around 3500.
07-27-2009, 04:01 PM
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https://ls1tech.com/forums/generatio...side-coin.html
I know it is a looong thread but it explains a lot of where and when to use reverse splits with some dyno graphs and results
I know it is a looong thread but it explains a lot of where and when to use reverse splits with some dyno graphs and results
07-27-2009, 05:31 PM
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https://ls1tech.com/forums/generatio...side-coin.html
I know it is a looong thread but it explains a lot of where and when to use reverse splits with some dyno graphs and results
I know it is a looong thread but it explains a lot of where and when to use reverse splits with some dyno graphs and results
Thanks for the link predator
07-27-2009, 06:38 PM
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they get bashed alot but seem to put down very nice numbers and torque curve, i was talking to a fellow on youtube who had a custom nitrous cam for his 408, it was something like 282/276 680/660 on a 120 lobe seperation, i was intreged to say the least! gained 300 hp on a 300 shot so it must of worked lol.
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07-28-2009, 08:32 AM
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I'm by NO MEANS a "camshaft guy". Yeah, I know what the numbers mean (anyone can look that up), but I don't know how or why a "230 degree intake lobe" means more power than a "224". It lets in more air - I got that. But, there's so much more that I DON'T know.
That being said, here's the reasoning I used when I chose this cam. I asked myself the following questions:
At what RPMs do I spend the most time?
I'm road racing, so it's a little different range than most. But, you can do the same. I reviewed some data from a race. I found that I was always above 3500RPM, all the way to my 6200 redline. If I fell below 3500, I'd shift to a lower gear and get the RPMs back up.
At what RPM do I wish to make good power?
I looked at certain points on track - specifically, what RPM am I at when entering the 2 long straightaways. For one, I am at about 4000rpm. For the other, I'm at 3500. So I needed power pretty quickly. However, I also don't need 500rwhp, as I just don't have the traction. I needed some power, but I needed it to build quickly and smoothly from those RPMs. For a street guy who wants a good "redlight cam", I'd see what RPM and hp range you can handle without breaking tires loose. Start there, and choose a cam that builds tq/hp from that RPM.
Do I need high RPM hp more than mid-range tq?
For me, this answer was "probably not". Why? Well, by the time I'm at the end of a straight, I need to be past a guy. If I'm just catching him at the end, I'm going to be off-line trying to pass, and probably screw both of us up going into a turn. But, if I can pass early or halfway down the straight, I can be back on-line before braking for the next turn. But, I can't have the cam completely drop off. I need more of what I call "maintenance" up top. Not lose hp, but keep what I got.
After I answered those questions, I went dyno graph searching. A dyno graph is not a definite answer or the last word. But, it's the best thing I have at my disposal. I gathered multiple dyno graphs of people with different cams, but with a similar car to mine (bolt-ons, intake, exhaust, stock heads, etc.).
Then, I looked to narrow the field. I discarded the ones that obviously made huge top-end but no middle. Once I got to about 3-4 "finalist" dyno graphs, I did math. I measured each cam at 50rpm increments, starting at 3500. Basically, I did:
TR 230/224
RPM - tq - hp
3500 - 350 - 230
4000 - 370 - 280
4500 - 385 - 330
5000 - 385 - 370
5500 - 375 - 395
6000 - 355 - 410
6500 - 330 - 405
Then, you add all the tq and hp numbers to get a "total area under the curve". For the TR 230/224, that's 2550tq and 2420hp. I then did the same for the other "finalists". This was the best way that I could think of to answer those questions people always bring up like, "Well, Cam A makes 10 more tq from 4000-5000, but Cam B makes 7 more from 4500-6000. Which is better?"
The TR 230/224 was the best that I could find. It made the most power under the curve, by a tiny amount. The deal-maker was that it had a mice little bump in tq between 3500 and 4000. That means, if I can get traction, I'll get a nice little jump coming out of Turn 5 and onto the back straight. This will set me up to pass the guy in front before Turn 8.
Anyway, I hope someone finds this helpful. Kind of an "uneducated man's guide to finding a cam."
That being said, here's the reasoning I used when I chose this cam. I asked myself the following questions:
At what RPMs do I spend the most time?
I'm road racing, so it's a little different range than most. But, you can do the same. I reviewed some data from a race. I found that I was always above 3500RPM, all the way to my 6200 redline. If I fell below 3500, I'd shift to a lower gear and get the RPMs back up.
At what RPM do I wish to make good power?
I looked at certain points on track - specifically, what RPM am I at when entering the 2 long straightaways. For one, I am at about 4000rpm. For the other, I'm at 3500. So I needed power pretty quickly. However, I also don't need 500rwhp, as I just don't have the traction. I needed some power, but I needed it to build quickly and smoothly from those RPMs. For a street guy who wants a good "redlight cam", I'd see what RPM and hp range you can handle without breaking tires loose. Start there, and choose a cam that builds tq/hp from that RPM.
Do I need high RPM hp more than mid-range tq?
For me, this answer was "probably not". Why? Well, by the time I'm at the end of a straight, I need to be past a guy. If I'm just catching him at the end, I'm going to be off-line trying to pass, and probably screw both of us up going into a turn. But, if I can pass early or halfway down the straight, I can be back on-line before braking for the next turn. But, I can't have the cam completely drop off. I need more of what I call "maintenance" up top. Not lose hp, but keep what I got.
After I answered those questions, I went dyno graph searching. A dyno graph is not a definite answer or the last word. But, it's the best thing I have at my disposal. I gathered multiple dyno graphs of people with different cams, but with a similar car to mine (bolt-ons, intake, exhaust, stock heads, etc.).
Then, I looked to narrow the field. I discarded the ones that obviously made huge top-end but no middle. Once I got to about 3-4 "finalist" dyno graphs, I did math. I measured each cam at 50rpm increments, starting at 3500. Basically, I did:
TR 230/224
RPM - tq - hp
3500 - 350 - 230
4000 - 370 - 280
4500 - 385 - 330
5000 - 385 - 370
5500 - 375 - 395
6000 - 355 - 410
6500 - 330 - 405
Then, you add all the tq and hp numbers to get a "total area under the curve". For the TR 230/224, that's 2550tq and 2420hp. I then did the same for the other "finalists". This was the best way that I could think of to answer those questions people always bring up like, "Well, Cam A makes 10 more tq from 4000-5000, but Cam B makes 7 more from 4500-6000. Which is better?"
The TR 230/224 was the best that I could find. It made the most power under the curve, by a tiny amount. The deal-maker was that it had a mice little bump in tq between 3500 and 4000. That means, if I can get traction, I'll get a nice little jump coming out of Turn 5 and onto the back straight. This will set me up to pass the guy in front before Turn 8.
Anyway, I hope someone finds this helpful. Kind of an "uneducated man's guide to finding a cam."
07-28-2009, 09:16 AM
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I'm by NO MEANS a "camshaft guy". Yeah, I know what the numbers mean (anyone can look that up), but I don't know how or why a "230 degree intake lobe" means more power than a "224". It lets in more air - I got that. But, there's so much more that I DON'T know.
That being said, here's the reasoning I used when I chose this cam. I asked myself the following questions:
At what RPMs do I spend the most time?
I'm road racing, so it's a little different range than most. But, you can do the same. I reviewed some data from a race. I found that I was always above 3500RPM, all the way to my 6200 redline. If I fell below 3500, I'd shift to a lower gear and get the RPMs back up.
At what RPM do I wish to make good power?
I looked at certain points on track - specifically, what RPM am I at when entering the 2 long straightaways. For one, I am at about 4000rpm. For the other, I'm at 3500. So I needed power pretty quickly. However, I also don't need 500rwhp, as I just don't have the traction. I needed some power, but I needed it to build quickly and smoothly from those RPMs. For a street guy who wants a good "redlight cam", I'd see what RPM and hp range you can handle without breaking tires loose. Start there, and choose a cam that builds tq/hp from that RPM.
Do I need high RPM hp more than mid-range tq?
For me, this answer was "probably not". Why? Well, by the time I'm at the end of a straight, I need to be past a guy. If I'm just catching him at the end, I'm going to be off-line trying to pass, and probably screw both of us up going into a turn. But, if I can pass early or halfway down the straight, I can be back on-line before braking for the next turn. But, I can't have the cam completely drop off. I need more of what I call "maintenance" up top. Not lose hp, but keep what I got.
After I answered those questions, I went dyno graph searching. A dyno graph is not a definite answer or the last word. But, it's the best thing I have at my disposal. I gathered multiple dyno graphs of people with different cams, but with a similar car to mine (bolt-ons, intake, exhaust, stock heads, etc.).
Then, I looked to narrow the field. I discarded the ones that obviously made huge top-end but no middle. Once I got to about 3-4 "finalist" dyno graphs, I did math. I measured each cam at 50rpm increments, starting at 3500. Basically, I did:
TR 230/224
RPM - tq - hp
3500 - 350 - 230
4000 - 370 - 280
4500 - 385 - 330
5000 - 385 - 370
5500 - 375 - 395
6000 - 355 - 410
6500 - 330 - 405
Then, you add all the tq and hp numbers to get a "total area under the curve". For the TR 230/224, that's 2550tq and 2420hp. I then did the same for the other "finalists". This was the best way that I could think of to answer those questions people always bring up like, "Well, Cam A makes 10 more tq from 4000-5000, but Cam B makes 7 more from 4500-6000. Which is better?"
The TR 230/224 was the best that I could find. It made the most power under the curve, by a tiny amount. The deal-maker was that it had a mice little bump in tq between 3500 and 4000. That means, if I can get traction, I'll get a nice little jump coming out of Turn 5 and onto the back straight. This will set me up to pass the guy in front before Turn 8.
Anyway, I hope someone finds this helpful. Kind of an "uneducated man's guide to finding a cam."
That being said, here's the reasoning I used when I chose this cam. I asked myself the following questions:
At what RPMs do I spend the most time?
I'm road racing, so it's a little different range than most. But, you can do the same. I reviewed some data from a race. I found that I was always above 3500RPM, all the way to my 6200 redline. If I fell below 3500, I'd shift to a lower gear and get the RPMs back up.
At what RPM do I wish to make good power?
I looked at certain points on track - specifically, what RPM am I at when entering the 2 long straightaways. For one, I am at about 4000rpm. For the other, I'm at 3500. So I needed power pretty quickly. However, I also don't need 500rwhp, as I just don't have the traction. I needed some power, but I needed it to build quickly and smoothly from those RPMs. For a street guy who wants a good "redlight cam", I'd see what RPM and hp range you can handle without breaking tires loose. Start there, and choose a cam that builds tq/hp from that RPM.
Do I need high RPM hp more than mid-range tq?
For me, this answer was "probably not". Why? Well, by the time I'm at the end of a straight, I need to be past a guy. If I'm just catching him at the end, I'm going to be off-line trying to pass, and probably screw both of us up going into a turn. But, if I can pass early or halfway down the straight, I can be back on-line before braking for the next turn. But, I can't have the cam completely drop off. I need more of what I call "maintenance" up top. Not lose hp, but keep what I got.
After I answered those questions, I went dyno graph searching. A dyno graph is not a definite answer or the last word. But, it's the best thing I have at my disposal. I gathered multiple dyno graphs of people with different cams, but with a similar car to mine (bolt-ons, intake, exhaust, stock heads, etc.).
Then, I looked to narrow the field. I discarded the ones that obviously made huge top-end but no middle. Once I got to about 3-4 "finalist" dyno graphs, I did math. I measured each cam at 50rpm increments, starting at 3500. Basically, I did:
TR 230/224
RPM - tq - hp
3500 - 350 - 230
4000 - 370 - 280
4500 - 385 - 330
5000 - 385 - 370
5500 - 375 - 395
6000 - 355 - 410
6500 - 330 - 405
Then, you add all the tq and hp numbers to get a "total area under the curve". For the TR 230/224, that's 2550tq and 2420hp. I then did the same for the other "finalists". This was the best way that I could think of to answer those questions people always bring up like, "Well, Cam A makes 10 more tq from 4000-5000, but Cam B makes 7 more from 4500-6000. Which is better?"
The TR 230/224 was the best that I could find. It made the most power under the curve, by a tiny amount. The deal-maker was that it had a mice little bump in tq between 3500 and 4000. That means, if I can get traction, I'll get a nice little jump coming out of Turn 5 and onto the back straight. This will set me up to pass the guy in front before Turn 8.
Anyway, I hope someone finds this helpful. Kind of an "uneducated man's guide to finding a cam."
I am not an expert,leave the designing of bumpsticks to Predator-Z.However I do have a fair amount of knowledge on cam basics.One reason why camshafts with a lot of duration dont work well at low RPM's is because at a certain point,the exhaust valve is open while the piston is still coming down on the power stroke.At low RPM's this can cause un-burned air/fuel to go out the exhaust valve and reduce VE.In addition, during valve overlap...at the end of the exhaust stroke the intake valve opens while the piston is still coming up in the cylinder.Finally,low rpm torque can also be reduced by too much intake duration.A camshaft with too much duration can sap low end by having an intake valve open too far into the compression stroke.This can reduce the overall cylinder compression(not CR)at low rpms.That is why it is necessary not to the select the right cam for your engine.Engines built for top end and peaky HP/TQ curves benefit from a loapy cam.On the other hand,your DD LS1 might fall flat on its face with that same camshaft at low rpms.There are a number of ways of adjusting your camshaft such as advancing the camshaft for low-end,or retarding for top-end also.
Last edited by lovescamaros28; 07-28-2009 at 09:56 AM.
