What determines spring pressure/rate you want?
02-13-2008, 10:27 AM
#1
What determines spring pressure/rate you want? Seems like a not talked about enough aspect of the combination so lets hear it.
What determines how you set your springs up... which ultimately determines if your reaching your max power.. yea or nay
is it the lobe?
What determines how you set your springs up... which ultimately determines if your reaching your max power.. yea or nay
is it the lobe?
02-13-2008, 12:11 PM
#3
It seems that this is not looked at enough on here. All the discusion when it comes to springs is about lift and matching lift. Either you want a spring good to .600 or .650 but no one talks about install height and opening and closing and pressures. There should be a big red sticky or something. A lot of people take a cam from one vendor and buyu some heads off the shelf from another and then dont properly match it up. I know this was the issue now with my last project. Had to be there was no other explanation. I had a custom ground cam and off the shelf heads with springs. The powerband was not where it should have been. It peaked to early.
02-13-2008, 12:18 PM
#4
but no one talks about install height and opening and closing and pressures.
A lot of people take a cam from one vendor and buyu some heads off the shelf from another and then dont properly match it up. I know this was the issue now with my last project. Had to be there was no other explanation. I had a custom ground cam and off the shelf heads with springs. The powerband was not where it should have been. It peaked to early.
A lot of people take a cam from one vendor and buyu some heads off the shelf from another and then dont properly match it up. I know this was the issue now with my last project. Had to be there was no other explanation. I had a custom ground cam and off the shelf heads with springs. The powerband was not where it should have been. It peaked to early.
Got Patriot's 225/229 580/590 114+4 cam...
02-13-2008, 03:54 PM
#5
I always shoot for a minimum of 135 on the seat. My current setup is 138 on the seat and 350 open. This is with a PSI 1511 beehive spring. I usually have a spreadsheet setup with all the required measurements, including the calculated ones, so I can track the setup of both heads. When I have done spring stiffness checks, I found all of the springs I have checked to date to be consistent and right on the money for force vs. advertised height. Too light on the seat can result in valve bounce.
The flip side is too much force and you can kill a set of stock lifters as well.
The flip side is too much force and you can kill a set of stock lifters as well.
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02-13-2008, 06:03 PM
#8
True, which is one reason I was specific to mention I had a beehive setup as there is less mass. Bottom line, the spring is the only energy source available to keep the valve train dynamics in check. Its one of the reasons a dyno is such a valuable tool in my opinion, a lot of focus is on the absolute number when if fact shape of the curve especially in the higher RPM's can provide good information on how stable the valve train is.
02-15-2008, 03:03 PM
#10
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Here's the short answer. It all depends on your goals
For the average mild street car spring recommendations come from past experience and customer feedback. Usually with information like NA or forced induction, lift, lobe type, RPM, valve weights, (nothing specific just Ti, stock steel, etc), lifters, dimensional limitations of the cylinder heads, we can point you in the right direction and get you the performance you want.
If your looking for every last HP and stable dynamics at 10,000+ RPM it will take weeks of dynamics and durability testing between the spintron, dyno, and track. With a large amount of testing you can develope different trend lines and zero in on the right spring package.
Not everybody can do this because of time and money, but there are still methods of testing that can be done to optimize your own set up. Trying different install heights on the dyno or even trying a few different sets of springs. This will still take a considerable amount of time for the average person and most don't feel that it's worth it for that extra 5 hp they might get.
A large amount of engines out there are over sprung. But too much spring is better than not enough I guess
For the average mild street car spring recommendations come from past experience and customer feedback. Usually with information like NA or forced induction, lift, lobe type, RPM, valve weights, (nothing specific just Ti, stock steel, etc), lifters, dimensional limitations of the cylinder heads, we can point you in the right direction and get you the performance you want.
If your looking for every last HP and stable dynamics at 10,000+ RPM it will take weeks of dynamics and durability testing between the spintron, dyno, and track. With a large amount of testing you can develope different trend lines and zero in on the right spring package.
Not everybody can do this because of time and money, but there are still methods of testing that can be done to optimize your own set up. Trying different install heights on the dyno or even trying a few different sets of springs. This will still take a considerable amount of time for the average person and most don't feel that it's worth it for that extra 5 hp they might get.
A large amount of engines out there are over sprung. But too much spring is better than not enough I guess
Last edited by Yeahdoug; 02-15-2008 at 03:09 PM.
02-15-2008, 03:12 PM
#11
I'll tell you what you really need someone that knows what they're doing. I was listening to Erik look through the PAC catalog trying to figure out what spring will work with the lifter choice we made... Sounded like a language I've never heard of before.. LOL.. latin would have been easier I think...
02-15-2008, 03:26 PM
#12
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I'll tell you what you really need someone that knows what they're doing. I was listening to Erik look through the PAC catalog trying to figure out what spring will work with the lifter choice we made... Sounded like a language I've never heard of before.. LOL.. latin would have been easier I think...