Box Stock

10.8 Springs

MO Predator Racer

MO Predator Racer

Member
At local track you can run 10.8 springs…I have a set of red HD 10.8 springs. They don’t check spring pressure but they just look at them and usually look for a green stripe but they don’t state you just use dyno cams green stripe valve springs…would red be legal? I don’t know how to get ahold of tech man so I can’t ask him. It is in a predator class.
 
In that particular case a 10.8 is a 10.8… your altering a box stock anyhow I shouldn’t matter. If you had a way to check them for pressure put the better one on your exhaust side the heat on that valve with a stock restrictive exhaust will tax that one sooner that the intake side will.
 
Can you even buy springs that come on a predator from Harbor Freight? I guess if you change them you have to go with aftermarket 10.8.
 
OVALTECH1 said:
There are stock appearing springs out there that have more psi than those factory springs but not quite 10.8 pound that work really well also.
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I saw Dover had some trick springs but we can run 10.8s so I am gonna run some…I mean we don’t don’t turn the rpm but it is nice to have foot spring pressure and have it be consistent. So basically if I run these red 10.8 springs I will be fine?
 
Yes you will be fine. A lot of those 10.8 springs you have to work to get them in spec on a stock class clone. This is an alter parts class so I can’t see how they would be checked out of spec. Unless they are teching the springs ?
 
MO Predator Racer said:
I saw Dover had some trick springs but we can run 10.8s so I am gonna run some…I mean we don’t don’t turn the rpm but it is nice to have foot spring pressure and have it be consistent. So basically if I run these red 10.8 springs I will be fine?
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You will be fine if the spring is a true 10.8. If the track checks it with the clone spring tester and it passes good to go. However there are many advertised 10.8 springs that are more than 10.8 and that will get you tossed with the tester. I purchased 10 sets and I had to work 4 of the sets to get them legal. Not an easy task so be careful asking for legal springs from your supplier if you don’t have the tester to see if ya got ripped off. You could get a set of springs that aren’t as good as the ones you already have. NOW, here is another wrench in the works. I took a set of springs out of a winning engine after I dynoed it. Put a set of legal 10.8 in and re dynoed. Lost h.p. The springs I took out weren’t shot but not good 10.8. If there is an rpm rule like we have, 5500 on the stand, the engine will win races all the time at 4800/4950. You won’t float springs at that rpm unless absolutely worn out. I haven’t seen any that are absolutely worn out. Food for thoughtful
 
MO Predator Racer said:
At local track you can run 10.8 springs…I have a set of red HD 10.8 springs. They don’t check spring pressure but they just look at them and usually look for a green stripe but they don’t state you just use dyno cams green stripe valve springs…would red be legal? I don’t know how to get ahold of tech man so I can’t ask him. It is in a predator class.
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To test them get one of those spring smasher tools
 
Of they don't check spring pressure you will be fine. Every single dyno red hd spring I have tested on my intercomp spring tester has tested over 10.8 and they say that they will need worked to achieve proper pressure. The paint will come off though, some brake cleaner and a rag and the red wipes right off.
 
you can tell the reds from the greens by the number of windings . the red has almost one less turn. the spring is obvious to me without the paint
 
boomer216 said:
Of they don't check spring pressure you will be fine. Every single dyno red hd spring I have tested on my intercomp spring tester has tested over 10.8 and they say that they will need worked to achieve proper pressure. The paint will come off though, some brake cleaner and a rag and the red wipes right off.
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When you say they need to be worked what so you mean? I run box stock. I put some new 10.8 springs in I got from BMI. Our track will never check them.
Can't tell any difference. I have been Racing in the 4600 to 4700 rpm range gear range. I am going up a couple of teeth on the rear. I hear 4800 to 4900 for box stock. Just want to get to that rpm and look at lap times.
 
bullerman said:
When you say they need to be worked what so you mean? I run box stock. I put some new 10.8 springs in I got from BMI. Our track will never check them.
Can't tell any difference. I have been Racing in the 4600 to 4700 rpm range gear range. I am going up a couple of teeth on the rear. I hear 4800 to 4900 for box stock. Just want to get to that rpm and look at lap times.
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If you're only running 4600-4700 rpm (which is good) you weren't floating the valves with the stock springs. By putting stiffer springs in it you have actually lessened your horsepower, and you didnt have much to be wasting by making the engine harder to rotate.
 
Yes I know with what I run i don't want stronger springs. I never detected floating the valves. Been thinking about putting the old springs back in. I checked both springs on my gram scale. I know this isn't how you do it and u know it isn't accurate but I could compare the strength of one to the other. I use a small drill press. I set my gram scales on the press. I take a old flathead lifter and chuck it up. I set the stop on the press to where it stops the lifter at .815 and read the scale. The stock springs were a hair weaker. I took pictures of the readings but deleted them. Dang was just wondering how you work the springs to make them weaker.
 
bullerman said:
Yes I know with what I run i don't want stronger springs. I never detected floating the valves. Been thinking about putting the old springs back in. I checked both springs on my gram scale. I know this isn't how you do it and u know it isn't accurate but I could compare the strength of one to the other. I use a small drill press. I set my gram scales on the press. I take a old flathead lifter and chuck it up. I set the stop on the press to where it stops the lifter at .815 and read the scale. The stock springs were a hair weaker. I took pictures of the readings but deleted them. Dang was just wondering how you work the springs to make them weaker.
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You don't make them weaker.
You make them take a set to be shorter. This makes them under the 10.8#@.815 rule.
The springs may have less open load, so they will pass the 18#@.650 rule.

Search coil spring design.

https://www.acxesspring.com/coil-spring-design-basics.html

This should get you started.
 
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bullerman said:
When you say they need to be worked what so you mean? I run box stock. I put some new 10.8 springs in I got from BMI. Our track will never check them.
Can't tell any difference. I have been Racing in the 4600 to 4700 rpm range gear range. I am going up a couple of teeth on the rear. I hear 4800 to 4900 for box stock. Just want to get to that rpm and look at lap times.
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When I check them at the required heights, they are always 11.6-12.0@.850 and 18.8-19.2@.650 usually around a pound more than legal limit so I have to sand on the ends of them to get them to meet spec.
 
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