Jester Posted June 22, 2012 Report Share Posted June 22, 2012 Curious if anyone knows how much boost a stock KA piston will handle. I really want to push some pressure through this engine that I want to build. Just not sure how badly I want to spend $500 on forged pistons. Thanks guys Jester Quote Link to comment
flatcat19 Posted June 22, 2012 Report Share Posted June 22, 2012 Open ended question. KA that you will be building. Knowing what pistons are going in will be the variable in your equation. Quote Link to comment
ggzilla Posted June 22, 2012 Report Share Posted June 22, 2012 We already know that information -- he's asking specifically about stock KA pistons. All Datsuns can handle 5psi. A totally stock KA can handel 10 psi boost Quote Link to comment
flatcat19 Posted June 22, 2012 Report Share Posted June 22, 2012 Derp. I read what I wanted to. Quote Link to comment
Jester Posted June 22, 2012 Author Report Share Posted June 22, 2012 10 would be cool. Although I would really like to go more. Quote Link to comment
HRH Posted June 22, 2012 Report Share Posted June 22, 2012 I'd stick to 7 or 8 for safety's sake. Stock pistons are strong enough, but one wrong calculation and a little too lean, boom! 1 Quote Link to comment
Eomund Posted June 22, 2012 Report Share Posted June 22, 2012 I've seen stock KA's boosted to 15 and they were decently reliable, but it's a hell of a risk. I agree with the 7-8 number. It's well within it's capabilities and will get you a fair amound of horse power. Quote Link to comment
Jester Posted June 22, 2012 Author Report Share Posted June 22, 2012 Yaaaaaaaaaa, I guess that would be enough to have some fun anyway. Thanks guys, I appreciate the help. Quote Link to comment
Laecaon Posted June 22, 2012 Report Share Posted June 22, 2012 also, this isn't a ka he is building. Static CR is like 4.99:1... So pretty low. Quote Link to comment
ggzilla Posted June 22, 2012 Report Share Posted June 22, 2012 Yes that's a little low. I like to run 5.5 in my hotrods. But anyways a stock KA piston can handle (reliably) 10 pounds boost - regardless of the engine it is in. If the engine runs lean and pre-detonates, that is not the piston's fault. Quote Link to comment
Jester Posted June 22, 2012 Author Report Share Posted June 22, 2012 Doing some Google searching this morning has lead me to the understanding that the stock compression for the KA ranged from 8.5:1 - 9.5:1. I think if I set mine up with a little over 8:1 static, and feed it about 8-10# of boost, she will be OK with stock pistons. Thoughts????? This is for the engine in my wagon build thread. Quote Link to comment
BEEBANI Posted June 22, 2012 Report Share Posted June 22, 2012 Jes, if you haven't already, hop on over to http://www.ka-t.org/ those guys love talking boosted single cam ka's Quote Link to comment
sssr20det510 Posted June 22, 2012 Report Share Posted June 22, 2012 The problem with boosting a KA isnt the pistons its the engine management. Stock engine management increases the timing. you would need to take timing out for boost and also need to increase fuel pressure for every pound of boost. Most turbo KA's blow up because the timing advances too much and they lean out and detonate Quote Link to comment
flatcat19 Posted June 22, 2012 Report Share Posted June 22, 2012 ^ That right there is golden!!! Quote Link to comment
jesusno2 Posted June 23, 2012 Report Share Posted June 23, 2012 does nobody consider a boost creep either??? just cause your set at 10psi doesnt always mean it will stay their Quote Link to comment
fo0manchu Posted June 25, 2012 Report Share Posted June 25, 2012 yes like other people said, its all about the tune. Also, what sized turbo are you running? 10lbs on a t28 vs t4 will yield very different results. or you can use water/meth injection and run 14lbs safely all day. Just as long as you don't run out of h20/meth. Keep pre-detonation down and you'll be good. Quote Link to comment
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