sohc pistons in de, another way
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duckman240sx
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sohc pistons in de, another way
ok well i heard that u have to mill down the pistons in order for sum clearance and stuff like that but if u just cut sum valve reliefs in the pistons and then u still gone that extra c.r. an di also have another question if there isnt ne great headers out there why hasnt sumone else tryed to custom make sum for the n/a ka
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deviousKA
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i dont believe that the sohc pistons need to be machined to fit into the dohc. The factory 9.1:1(higher than reg. kaE) pistons that came in early 89 240sx may have to machined (yeild 11.6:1 in de).
Some people say you need to machine the tops of the sohc pistons to fit others say different. From what i have picked up from posts that i trust is that no modification is necessary for either. But your idea of cutting valve reliefs is much better than milling down the top of the piston. Demcj should know the answer.
As far as n/a ka headers, a 4-1 design would be the best for top end hp. Im sure some have made their own (race teams most likely make their own). Only affordable 4-1 design header for ka24e i have seen is pacesetter.
Some people say you need to machine the tops of the sohc pistons to fit others say different. From what i have picked up from posts that i trust is that no modification is necessary for either. But your idea of cutting valve reliefs is much better than milling down the top of the piston. Demcj should know the answer.
As far as n/a ka headers, a 4-1 design would be the best for top end hp. Im sure some have made their own (race teams most likely make their own). Only affordable 4-1 design header for ka24e i have seen is pacesetter.
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duckman240sx
- Posts: 82
- Joined: Wed Nov 12, 2003 9:00 pm
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duckman240sx
- Posts: 82
- Joined: Wed Nov 12, 2003 9:00 pm
well i was searching around and finally come back to the realnissnan site, i was wondering about there custom pistons if they can custom them to ur personal spec then why not just order high c.r. pistons from them and then u can go even higher then 11.6 maybe like 12.3, since thats what i heard was the highest u should go with having to bump up to race gas but myabe its different for the 240s, i heard that bout civcs , $630 doesnt seem to bad for custom pistons im sure they come with rings to and there forged im sure there a good investment, just my thought
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deviousKA
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you will need really high octane to properly run 12.3. CR/octane is not a direct ratio for all engines. Hondas can run higher compression ratio with lower octane than ka nissans, it is due to the combustion chamber/head design iirc. I would say 11.6:1 would be the highest you could go on pump gas, and even then you should be adding octane boost of some sort. You can always retard your timing but that decreases overall performance.
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TrunkMonkey
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hey guys usually the difference between the sohc and dohc is valve configuration in the piston that is why there are two different pistons in the arias catalog for Ka24e and KA24de. not trying to post commercially but they are available and 11.5:1 is on the shelf at dynoflo i've made the call because i researched trying to build a all motor and naturally aspirated ka motor. if i'm not mistaken i think the price came to $460 shipped for either one. regarding pump gas and race fuel that will depend on elevation and air density many varibles come in to play i wouldn't go anywhere over 10:1 at sea level with 91 octane but that is my personal preference