Question for the KA crowd

[Jester]

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

[flatcat19]

Open ended question.

 

KA that you will be building.

Knowing what pistons are going in will be the variable in your equation.

[ggzilla]

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

[flatcat19]

Derp.

I read what I wanted to.

 

 

[Jester]

10 would be cool. Although I would really like to go more.

[HRH]

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!

[Eomund]

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.

[Jester]

Yaaaaaaaaaa, I guess that would be enough to have some fun anyway.

Thanks guys, I appreciate the help.

[Laecaon]

also, this isn't a ka he is building. Static CR is like 4.99:1... So pretty low.

[ggzilla]

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.

[Jester]

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.

[BEEBANI]

Jes, if you haven't already, hop on over to http://www.ka-t.org/ those guys love talking boosted single cam ka's

[sssr20det510]

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

[flatcat19]

^

That right there is golden!!!

[jesusno2]

does nobody consider a boost creep either??? just cause your set at 10psi doesnt always mean it will stay their

[fo0manchu]

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.