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View Full Version : Higher Revving KA?


sykikchimp
07-15-2002, 11:49 AM
I know we've talked about using the z22 crank to possibly de-stroke the KA, and make a higher revving engine.  But would it be possible to lengthen the Rod by moving the piston connecting point (not sure of actual term) further up the piston to keep the same stroke but reduce the rotational speed of the piston?

Fresh 240SX
07-15-2002, 11:55 AM
Like a stroker ? you lost me....

sykikchimp
07-15-2002, 12:13 PM
no..  The KA is already stroked.  I'm thinking that if you could lengthen the Rods without changing the crank you could keep the 2.4 liter displacement and still make it rev higher.  Higher rev's = more HP.  (with appropriate cams and modification to the Head of course.)  I'm wondering if there is a way to increase revability of the motor WITHOUT destroking it.

Fresh 240SX
07-15-2002, 06:25 PM
ohhhhhhhhhh gottcha....

well anything is possible with $ right?

im sure you could change the connection point if you had some place machine you the set up, but it would either work or bomb huge..... and like you said alot of head work would need to be done to make it all run together.....

makes you think tho... i never really considered something like that... but the potential is there

drift freaq
07-15-2002, 08:34 PM
well I can attest to the fact that lightening my flywheel on my KA made it rev up smoother and faster than a stocker. It also made it spin up to 6.5-7K almost effortlessly . The results a very snappy response for a bone stock engine with exhaust and intake. When I do my turbo setup this thing is going to haul ass. But yes It already is one of the faster KA's I have driven and seen. Yes I am going to dyno it before I
Turbo it and yes I may run it down the strip to see its 1/4 miles times.

sykikchimp
07-15-2002, 09:33 PM
come to find out there is a Nissan Motorsports kit that does exactly what I was thinking about.  They move the wrist pin closer to the piston compression surface the same distance they lengthen the rod.  Not sure of price.  fairly interesting concept though.  combine that with a touch more compression, seems you would have a fairly nice gain in overall performance.  Maybe I'll find out one day.

SaintlyCharBoy
07-15-2002, 11:08 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ July 15 2002,11:33)</td></tr><tr><td id="QUOTE">come to find out there is a Nissan Motorsports kit that does exactly what I was thinking about. They move the wrist pin closer to the piston compression surface the same distance they lengthen the rod.</td></tr></table><span id='postcolor'>
where can one find info on this Nissan Motorsports kit of which you speak?

AceInHole
07-15-2002, 11:19 PM
moving the pin anywhere on the piston will not affect max piston speed. &nbsp;The piston is still travelling the same distance in the same amount of time.

Using a longer rod does increase TDC and BDC slightly, and the piston will be accelerating a tad slower initially. &nbsp;The affect would be more torque IIRC.

misnomer
07-16-2002, 04:03 AM
Lengthening the rod will not increase displacement TDC and BDC will be the same positions relative to each other, just farther towards the valves. This does give you higher compression, however. Pretty much as Ace said it, a longer piston with that setup will give you a bit more torque from the higher compression, but no more displacement.

sykikchimp
07-16-2002, 08:06 AM
It wouldn't increase compression at all if you move the wrist pin. &nbsp;It should lower the angle of the rod, &nbsp;which should cause the engine to spin easier b/c it doesn't have to apply as much force to get the piston moving. &nbsp;You gain some leverage on the piston. &nbsp;Not sure how this relates to torque, but should allow the engine to make power at higher RPM's. &nbsp;I don't think you could lengthen the rod without moving the wrist pin b/c you would hit the head on the edge of the piston cylinder. &nbsp;Isn't the compression usually adjusted with the Piston Surface, not piston hieght>??