flat piston problems

tundrabeagle3

tundrabeagle3

Member
#1
#1
I tried a stock height flat top piston in my predator today and it feels more sluggish than before mostly on the bottom end. I have a 90 jet, header, modified stock air box and the head sanded down .40. I tried 91 and it helped but its still not as good as before . Do I need to rejet?
 
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tundrabeagle3

tundrabeagle3

Member
#5
#5
Ok I got it fixed and it is pretty beastly now it surprised me. I had a gx140 e tube that I had tried before the piston and it ran too rich. I tried it with the flat top piston and it fixed my problem and I can now notice the increase in power. Thanks for the replies
 
tundrabeagle3

tundrabeagle3

Member
#6
#6
I am curious as to what my compression ratio is now my head is sanded down .40 also. In the manual it says the stock compression ratio is 9:1 which sounds higher than the older predators? Although it doesn't idle hard like the older predator I had with a 14 cc head
 
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Prowler08

Prowler08

New Member
#7
#7
Correct me if I am wrong... But if you had a dished piston before, and went to a flat top piston... In a Predator you would be .020 farther in the hole... So compression might not be that noticeable... If at all...
 
DBMonster85

DBMonster85

New Member
#12
#12
I bought that piston as well. I'm glad I figured that out because I already bought the 20 over rod and the hemi piston would have been shorter then my dish. then I noticed the 5750 flat top. good toknow I might have to jet up but I'm already running race fuel and a 24mm flatslide and I think I'm a little rich now so I hope it is ok. we will see!!! good info thanks.
 
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