ka24de various questions - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Raysurc · 04-16-2005, 08:13 PM

i have a couple of questions regarding the engine, or engines in general[some things i dont know yet] with that said, im planning on having some maintainence done to the engine in my '93 coupe 240sx. by 'maintainence', i want an engine rebuild, through upgraded parts. but im debating wether to go ka-t or n/a. ka-ts are badasses, but having a n/a car with "more than average horsepower" constitues a "damn, now THATS badass" in my book.

1. i understand that if going force fed, the compression should be lower. my question is why is this so with motors?

2. with pistons, what happens with the cars performance when they are concave or convex at the top?

3. im assuming that a n/a cars hp wont be as high as a force-inducted car, but if got engine rebuild with n/a in mind, how much horsepower is achieved through engine, and how much is potentially achievable through the car as a whole?

all in all, im leaning towards a naturally aspirated engine. if you can give me answers or constructive feedback, it would be most appreciated.

aznpoopy · 04-16-2005, 09:45 PM

there's alot of info you can get by searching; not just on zilvia but on the net in general.

1. lower compression with FI = less chance of detonation. iirc you can potentially get more power with a higher compression engine and FI, but you need much more sensitive tuning to make sure it doesnt implode.

2. honestly i don't know. i know the shape of the piston can help control turbulence in the engine or help control combustion. i'm sure the answer is out there on google.

3. that kind of depends on just how 'hardcore' you are willing to go with the rebuild. one thing i do know is if you are building up a n/a ka24de, the upper limit on n/a power is quite low. iirc, around 215hp (?) for much, much more money invested in then a turbocharged ka-t with the same amount of horsepower.

Ritz S14 · 04-16-2005, 09:48 PM

2. Dome pistons that concave up are ususally for N/A cars, because the upwards dome decreases volume.
Dome pistons that convave downward allows more volume, so with turbo.. you get more powA.

*crioten* · 04-17-2005, 07:56 AM

if you decide to go na on a ka, go with a sohc rather than the dohc... the sohc's respond better to na tuning

04-16-2005, 08:13 PM	#1
Raysurc Leaky Injector Join Date: Jan 2005 Location: San Diego Mira Mesa Age: 38 Posts: 72 Trader Rating: (0) Feedback Score: 0 reviews	ka24de various questions i have a couple of questions regarding the engine, or engines in general[some things i dont know yet] with that said, im planning on having some maintainence done to the engine in my '93 coupe 240sx. by 'maintainence', i want an engine rebuild, through upgraded parts. but im debating wether to go ka-t or n/a. ka-ts are badasses, but having a n/a car with "more than average horsepower" constitues a "damn, now THATS badass" in my book. 1. i understand that if going force fed, the compression should be lower. my question is why is this so with motors? 2. with pistons, what happens with the cars performance when they are concave or convex at the top? 3. im assuming that a n/a cars hp wont be as high as a force-inducted car, but if got engine rebuild with n/a in mind, how much horsepower is achieved through engine, and how much is potentially achievable through the car as a whole? all in all, im leaning towards a naturally aspirated engine. if you can give me answers or constructive feedback, it would be most appreciated.

04-16-2005, 09:45 PM	#2
aznpoopy Post Whore! Join Date: Mar 2003 Location: New Jersey Age: 44 Posts: 5,013 Trader Rating: (1) Feedback Score: 1 reviews	there's alot of info you can get by searching; not just on zilvia but on the net in general. 1. lower compression with FI = less chance of detonation. iirc you can potentially get more power with a higher compression engine and FI, but you need much more sensitive tuning to make sure it doesnt implode. 2. honestly i don't know. i know the shape of the piston can help control turbulence in the engine or help control combustion. i'm sure the answer is out there on google. 3. that kind of depends on just how 'hardcore' you are willing to go with the rebuild. one thing i do know is if you are building up a n/a ka24de, the upper limit on n/a power is quite low. iirc, around 215hp (?) for much, much more money invested in then a turbocharged ka-t with the same amount of horsepower.

04-16-2005, 09:48 PM	#3
Ritz S14 Post Whore! Join Date: Jul 2004 Location: C A L I F O R N I A Age: 43 Posts: 3,586 Trader Rating: (0) Feedback Score: 0 reviews	2. Dome pistons that concave up are ususally for N/A cars, because the upwards dome decreases volume. Dome pistons that convave downward allows more volume, so with turbo.. you get more powA.