Box Stock Predator

[Collin]

Whats max RPM that you can run on a box stock predator?

 

[XXX#40]

Go to the track you plan on running and ask the tech man to check your rpms, set them to what he says using his tach, because that's the only one that really matters

 

[Collin]

Do you know what rpm they start floating the valves at?

 

[racing promotor]

They vary but no need to try to max them out, they race best at 4900 max

 

["J'-remy]

the valves will start to float around 4500 when start to go down hill. they are problems in the predator motors someone told me they are 7lb springs and junk at that.

 

[DynoDon]

Springs are anywhere from 18 lbs to 16 lbs using the clone checker. They average 17 plus but I have seen them at 18. You aren’t going to float the valves on a stocker with an rpm rule

 

["J'-remy]

 

["J'-remy]

these dips are the valves floating ^^^^^^^
well before 4500. the weakest springs i have ever encountered on all 3 of my motors about as hard to push as a ball point pen . 17 to 18lbs really? not in any motor purchased in the last few years

 

[Collin]

Then it goes back up with HP past that point

 

[cking]

Springs are anywhere from 18 lbs to 16 lbs using the clone checker. They average 17 plus but I have seen them at 18. You aren’t going to float the valves on a stocker with an rpm rule

I dont think they come stock with 18lb springs?

 

["J'-remy]

no it surges like the governor. It's not a good thing for an engine to do. you will hear it when people are at the track reving their kart on a stand whaaaaaaaaaaaaa-gah the gah, when the engine stops climbing, is when the valve floats and the donk is when the piston hits the valve that's open at the wrong time

 

["J'-remy]

I dont think they come stock with 18lb springs?

if it did you would get more power by replacing them with 10.8

 

[DynoDon]

My bad. I should have explained better. When using the 10.8 and the 18 lb clone checker that is what I get. There was a controversy here in pa over replacing the springs with the 10/8 - 18 lb springs. I did testing on the springs that came in on 10 new engines and all were really close on the 18 lb check. So when I say 18 i
I mean by clone rules. We made the rules around the 18 lb test

 

[DynoDon]

Max wire diameter on spring wire is .071” with a maximum tension of 10.8 lbs. at a height of .850”, and a maximum tension of 18 lbs at .650”

 

[22Scadoo]

At my local track we are allowed to remove the governor and also run the 10.8 springs. I have been running with the stock springs. How much of an improvement would I pick up by swapping the stock ones for the 10.8s?

 

[racing promotor]

At my local track we are allowed to remove the governor and also run the 10.8 springs. I have been running with the stock springs. How much of an improvement would I pick up by swapping the stock ones for the 10.8s?

with nothing else being done, I'm being told stick with the stock springs, stiffer will only hurt it's performance.

 

[Komet99]

How does a person limit the RPM if it is to high per the tech inspector?

 

[bullerman]

with nothing else being done, I'm being told stick with the stock springs, stiffer will only hurt it's performance.

So on the track racing at 4800 to 4900 the stock springs should be good Racing Promoter.

 

[racing promotor]

So on the track racing at 4800 to 4900 the stock springs should be good Racing Promoter.

Yes you want a weaker spring.

 

[bullerman]

I wonder if I have mine adjusted on the stand to turn 5400 rpm and I have the gearing to where I am 4900 at the end of the straightaway will it float the valves on the track? Just wondering.