Need blower CAM grind recommendations
06-24-2019, 11:17 AM
#61
I agree. He will lose boost but will make more power. It's a give an take. Having 0 degrees of overlap means no loss of boost but you sacrifice power.
The OP was aware of this and wanted options.
He received them, asked questions and settled on the biggest camshaft knowing what to expect.
14 degrees of overlap will drive quite well in a 427 with cathedral heads with a good tune.
This is not a worry.
The OP was aware of this and wanted options.
He received them, asked questions and settled on the biggest camshaft knowing what to expect.
14 degrees of overlap will drive quite well in a 427 with cathedral heads with a good tune.
This is not a worry.
06-24-2019, 11:18 AM
#62
TECH Apprentice
Thread Starter
06-24-2019, 11:20 AM
#63
It's not technically correct. You make more power with more overlap. Period. The boost levels go down. But your HP per lbs of boost goes up.
It's why a cam takes 2-3lbs off a blower combo and heads another 2-3lbs. But yet the HP goes up... 60HP and 40HP, respectively and typically.
So you add 100HP and lose 5lbs of boost. Sounds good to me. Then you pulley down to get the boost back and you end up adding quite a lot of power overall (if the blower has RPM for it). I'd rather not lift the heads. And an F1 blower moves enough air you don't need a lot of boost to make a lot of power on a 427.
It's why a cam takes 2-3lbs off a blower combo and heads another 2-3lbs. But yet the HP goes up... 60HP and 40HP, respectively and typically.
So you add 100HP and lose 5lbs of boost. Sounds good to me. Then you pulley down to get the boost back and you end up adding quite a lot of power overall (if the blower has RPM for it). I'd rather not lift the heads. And an F1 blower moves enough air you don't need a lot of boost to make a lot of power on a 427.
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AndyTA (06-24-2019)
06-24-2019, 11:20 AM
#64
TECH Apprentice
Thread Starter
I guess I was looking at some other factors. You can make a car sound like whatever you want with tuning.....I can make a stock cam lope. The other point is that you'll have to run a smaller pulley to achieve the same amount of boost of a cam with lesser overlap, making it more prone to belt slip. Sure, you can make 800whp at a given boost with this cam. What happens if you could have made 900whp at the same boost with a cam that had less overlap? Either way, was just confirming the setup when I glanced through the thread. It's your build, enjoy it!
This will be a street duty daily driven car. I'm not running DR's unless I happen to take it to the strip.
Planting 800whp on the streets is no easy task - there comes a point (as you know) where more power is simply useless when the tires can't take any more.
06-24-2019, 11:22 AM
#65
This is where this camshaft will shine, in the top end.
Even with losing some boost the power will be certainly be there, This will rev all the way out.
Just wait and see.
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AndyTA (06-24-2019)
06-24-2019, 11:23 AM
#66
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IDK if it is rocket surgery. Whatever makes more power NA also makes more power boosted. What if the earths atmospheric pressure was to double (equal to 14psi boost) .... would you pick heads and cam differently for NA? likely not.
06-24-2019, 11:23 AM
#67
It's not technically correct. You make more power with more overlap. Period. The boost levels go down. But your HP per lbs of boost goes up.
It's why a cam takes 2-3lbs off a blower combo and heads another 2-3lbs. But yet the HP goes up... 60HP and 40HP, respectively and typically.
So you add 100HP and lose 5lbs of boost. Sounds good to me. Then you pulley down to get the boost back and you end up adding quite a lot of power overall (if the blower has RPM for it).
It's why a cam takes 2-3lbs off a blower combo and heads another 2-3lbs. But yet the HP goes up... 60HP and 40HP, respectively and typically.
So you add 100HP and lose 5lbs of boost. Sounds good to me. Then you pulley down to get the boost back and you end up adding quite a lot of power overall (if the blower has RPM for it).
06-24-2019, 11:28 AM
#69
You didn't even read what I said. You gain efficiency with overlap (it's still an airpump). You can make back up the boost by pulleying down (if you can--which I said) or you simply make more power at a lower boost level (also what I said). The blower is going to do what the blower is going to do. They are rated for CFM... you can't push a D1SC to 1200rwhp. So, you size the blower to the engine and application. You then size the cam and heads to the RPM range and intended usage. This isn't just pick **** and ignore the trade-offs.
Point remains--you can always add boost. But at some point you get diminishing returns. Blower efficiency. Intake charge. Belt slip. All those come into play. But you can create a more efficient airpump to make better use of the CFM being generated by the blower. Ultimately, I wouldn't give two ***** about the boost level. I care about getting to the power level without the blower turning into a hot air dryer.
Point remains--you can always add boost. But at some point you get diminishing returns. Blower efficiency. Intake charge. Belt slip. All those come into play. But you can create a more efficient airpump to make better use of the CFM being generated by the blower. Ultimately, I wouldn't give two ***** about the boost level. I care about getting to the power level without the blower turning into a hot air dryer.
06-24-2019, 11:33 AM
#70
You didn't even read what I said. You gain efficiency with overlap (it's still an airpump). You can make back up the boost by pulleying down (if you can--which I said) or you simply make more power at a lower boost level (also what I said). The blower is going to do what the blower is going to do. They are rated for CFM... you can't push a D1SC to 1200rwhp. So, you size the blower to the engine and application. You then size the cam and heads to the RPM range and intended usage. This isn't just pick **** and ignore the trade-offs.
Point remains--you can always add boost. But at some point you get diminishing returns. Blower efficiency. Intake charge. Belt slip. All those come into play. But you can create a more efficient airpump to make better use of the CFM being generated by the blower. Ultimately, I wouldn't give two ***** about the boost level. I care about getting to the power level without the blower turning into a hot air dryer.
Point remains--you can always add boost. But at some point you get diminishing returns. Blower efficiency. Intake charge. Belt slip. All those come into play. But you can create a more efficient airpump to make better use of the CFM being generated by the blower. Ultimately, I wouldn't give two ***** about the boost level. I care about getting to the power level without the blower turning into a hot air dryer.
06-24-2019, 11:42 AM
#72
It is a fact that you will make more power with a bigger camshaft regardless if you are boosted or not.
It is also a fact that overlap will bleed off some boost.
As I stated earlier 14 degrees of overlap in a 427 is perfectly fine.
Overlap makes an engine more efficient in the higher rpm's also.
Remember ddn, the OP wanted this and it will work.
What do you think of the 6 degree overlap camshaft for this build then?
It is also a fact that overlap will bleed off some boost.
As I stated earlier 14 degrees of overlap in a 427 is perfectly fine.
Overlap makes an engine more efficient in the higher rpm's also.
Remember ddn, the OP wanted this and it will work.
What do you think of the 6 degree overlap camshaft for this build then?
06-24-2019, 11:42 AM
#73
More duration or just more overlap? More duration.....completely believable. You're taking larger gulps of air. Same duration and just more overlap, no. I'm talking strictly overlap comparisons here. if you want to compare 2 completely different cams thats not apples to apples.
06-24-2019, 11:46 AM
#74
More duration or just more overlap? More duration.....completely believable. You're taking larger gulps of air. Same duration and just more overlap, no. I'm talking strictly overlap comparisons here. if you want to compare 2 completely different cams thats not apples to apples.
I would like to read your opinion and advice
06-24-2019, 12:01 PM
#75
06-24-2019, 12:10 PM
#76
TECH Apprentice
Thread Starter
Honestly, it is very apparent to me from this thread that there is very little to gain from going back and forth. I wasn't going to post up initially at all but wanted to confirm I read the thread correctly. I should have left it at that and not replied. I've done enough boosted setups and researched input from people like Martin Smallwood and Comp and others that I am comfortable with my chosen ideas of spec'd a cam for boost. Not sure how many others in here have built boosted setups before and spec'd cams, but they obviously have their own ideas. To each their own and YMMV. I'll stick to the boosted section
I'm happy with my choices/selections at the end of the day. Lets be honest, this is a debate that will never end.
06-24-2019, 12:10 PM
#77
Honestly, it is very apparent to me from this thread that there is very little to gain from going back and forth. I wasn't going to post up initially at all but wanted to confirm I read the thread correctly. I should have left it at that and not replied. I've done enough boosted setups and researched input from people like Martin Smallwood and Comp and others that I am comfortable with my chosen ideas of spec'd a cam for boost. Not sure how many others in here have built boosted setups before and spec'd cams, but they obviously have their own ideas. To each their own and YMMV. I'll stick to the boosted section
Thanks for letting us know that we are a bunch of ignorant dumb asses.
Why don't you list a camshaft specification for the OP's combination in this thread and let us see.
I sure want to.
06-24-2019, 12:38 PM
#78
06-24-2019, 12:43 PM
#79
Please list an appropriate camshaft specification for the OP please.
Explain why you chose the specs.
Maybe I could learn a thing or two.