Head games-Nissan vs Honda

Non-technical 240sx stuff in here.
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niceguy
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Head games-Nissan vs Honda

Post by niceguy »

I'm just curious, omitting the VTECH technology, what makes Honda engines/heads less prone to detonation than your average KA or SR head (ignoring QRs)?

Is there something specific in the design or layout of the chambers?

That's all....

Jeremy
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the.planetary.gear
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Post by the.planetary.gear »

sorry bud but that just isn't true. ive seen hondas break a crankshaft in three places because of eratic detonation. and it was all because of timing. vtech is great. however its important to know that ANYTHING with variable valve timing has a "vtech" strategy. its very cool but very difficult to tune around. a nissan head on the otherhand (while being rather prehistoric) is nearly impossible to mess up. ive set my timing (no joke) a full 180 degrees out (popping out the intake and whatnot) and it didn't hurt a thing. set it right and ran like a champ. but detonation does happen i suppose (nothing is innocent). the most common reason (on a turbocar) is the combustion happening to early due to compression problems over boosting or bad timing. if you're puttering along and you dip the throttle you will throw some timing at the car so that the acceleration is smooth and efficient. now you have a turbocar and you've fiddled with your afc and when you dip the throttle you throw 40degrees at the engine. DETONATION blam slam crack blech. can happen to anyone man. honda and nissan and anything else is prone to it if things aren't done properly.
niceguy
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Post by niceguy »

I can't believe I misspelled VTEC, oh well....

Re Honda heads being 'superior', I was just referring to what seems like most Hondas/Acuras running rediculous CRs from the factory and running FI on top of that.

Of course I'm not a Honda guy so I'm basically going by what the tuner mags used to always mention (haven't bought a mag in a few years now), that Honda heads were more detonation resistant, thus allowing more CR vs a stock Nissan 4cyl head.

However, I've also never believed everything the mags said so I was just curious as to whether this was true or not, and if so, why....
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TinyT
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Post by TinyT »

in response to what you were saying about FI and high compression, the only thing that allows you to do that without detonation is a very high octane level

you want lots of boost and no detonation--diesel FTW
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flip240
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Post by flip240 »

between nissan and honda heads, there's nothing really that much different since both (at least DOHC) use pent-roof chambered heads. the biggest difference is the angle of the intake-exhaust sides, but i don't think it affects the results you're seeing that much
- Phil - Concord Gray S14 - 339 rwhp, 340 ft-tq @ 12psi
Daily driven turbocharged KA24 for 10 years and counting. 2004-2014
My setup: KA24DE-T
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