limitations of the KA

Post by **raging panda** » Wed Apr 23, 2003 8:36 am

So everyone says that its really hard to get significant power out of the KA naturally aspirated. I want to know why. Is it because of its larger stroke over bore? Is it because there is less of an aftermarket to support increasing the power? It's just that I see little Honda engines starting with less power and ending up making somewhere in the neighborhood of 200hp sometimes and I wonder why I can't do that with my wonderful piece of Nissan technology. Someone enlighten me.

Post by **Rownan** » Wed Apr 23, 2003 8:36 am

Yes it is partly due to the long stroke of the KA and the unwillingness of it to rev high. Honda engines make so much power because they make it at 8000 rpms. But they sacrifice torque, which is where the KA shines. They make nice amounts of horsepower in NA form but even when modded they have less torque then we do from the factory.. It is a trade off, and in a naturally aspirated 4 cylinder engine, it is difficult to have both.

There are things you can do to make that kind of power in a KA without turbo, but it requires work(IE more than just bolt-ons!)

Timhttp://www.projectaspec.com

Post by **I am Technoman** » Wed Apr 23, 2003 8:36 am

I’m convinced the KA can’t get over 200RWHP because of the intake plenum and sock throttle body. In order for the motor to make that much power it needs inhale way more air than the intake system and runners can handle. It also needs to rev higher. With a good set of throttle bodies (48 mill) and “tuned high lift cams” I could see a KA making over 200RWHP. This mod would cost as much as a turbo application. But only net you maybe 220 RWHP.

Post by **Rownan** » Wed Apr 23, 2003 8:36 am

Yeah my dream is to make a custom intake manifold for my NA KA... It would be such an interesting project, but at the moment, my research is coming to the conclusion that it make not be worth my while...

Post by **96_S14_SE** » Wed Apr 23, 2003 8:36 am

Why not? I plan to make my own hopefully soonish using the stock runners lobed off about 6-8" from the head. Hone the insde of them, and am toying with the idea of adding velocity stacks welded to them and the SM plenum. The plenum will possibly be 4" od 3.5" id aluminum, but Im not 100% on that.

With out the velocity stacks it could be made dirt cheap, even with buying a used upper runner portion / aluminum stock (I got a quote of 36$ for the 4" od peice Ill need) / new used tb (was going for a vh45 one but dont think I will anymore, even though I can get one now)....

With out the stacks I could fab one up for the sub 100 range easy, by going this route. I havent been able to find raw stacks retail though so who knows...

It may or may not turn out to be optimal on the first go (probably wont) but once you get the idea started, modding it shouldnt be too hard. Time consuming, yeah but that goes with any prototype part

One day Ill fab one out though and if it flops... Oh well, as it wont be the first time a coustom project failed, nor will it be all that expensive of a failure.

Post by **Aries** » Wed Apr 23, 2003 8:36 am

Rownan wrote:Yeah my dream is to make a custom intake manifold for my NA KA... It would be such an interesting project, but at the moment, my research is coming to the conclusion that it make not be worth my while...

Not worth your time when it has already been done.I'll post dyno numbers in a little while.

Post by **raging panda** » Wed Apr 23, 2003 8:36 am

Why was it that it wasn't worth the time? Wouldn't the shorter intake runners make quite a difference at least somehow in throttle response or something, even if it didn't make tons of power? I know that you know better than I do but I'm really kind of shocked by that. I was thinking about making one of those rectangle looking plenums with straight runners and a bigger throttle body and a Z32 maf. I think that would make a big difference in the air intake.

Post by **SSS** » Wed Apr 23, 2003 8:36 am

You can't go too short with the runners, otherwise you lose out with torque in the low to mid range.

Post by **Rownan** » Wed Apr 23, 2003 8:36 am

raging panda wrote:Why was it that it wasn't worth the time? Wouldn't the shorter intake runners make quite a difference at least somehow in throttle response or something, even if it didn't make tons of power? I know that you know better than I do but I'm really kind of shocked by that. I was thinking about making one of those rectangle looking plenums with straight runners and a bigger throttle body and a Z32 maf. I think that would make a big difference in the air intake.

I simply say "not worth the time" because I probably would have a hell of a time fabricating something like that. I do not doubt the performance gain at all.

limitations of the KA

limitations of the KA

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums