I need information!!
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blue_hauder
- Posts: 63
- Joined: Sat Dec 14, 2002 10:26 am
- Car: 2007 G35 Coupe 6MT Black on Black, 2000 Dodge Ram Cummins, 1999 Toyota Solara SE V6 5 speed, 1999 Ha
i think someone's been playing with cartest too much-
my $.02- if you want to make a stroker KA, you'd better be stuffing it into a pickup truck, or *maybe* autocrossing it with a 4.6:1 rear (and even then, preferably in a 510 instead of an S-chassis), because it's simply not going to make the kind of power you want for any other kind of use.
our engines go bang at about 7500 for two reasons; the lack of a fully counterweighted crank, and the rod:stroke ratio, which as stock is just on the "bad" side of "well-balanced".
the one guy i've read about doing a destroke (yes, less) in a KA *still* had to do a bunch of clearancing inside the block to fit a _smaller_ fully counterweighted crank. i hate to think what you'd have to do to stuff a bigger FCW crank in there- or the tiny rods you'd have to run unless you found some way to increase deck height.
given a fixed deck height; when you increase stroke, you decrease your redline. that's simply the way it is, and even with a bigger non-counterweighted crank that you could _maybe_ grind in there, giving yourself less RPM to work with is not the way to make NA horsepower.
unless you're using chemical or mechanical means of getting more oxygen into the combustion chamber, less RPM means less overall flow. as someone else said, you can't fight physics... and even with the maximum 1mm overbore, you'll need a lot of stroke (over 2mm) to gain more than just an extra .1liter- how that translates into "40% more torque" i am unclear on.
finally, your tuning plan simply doesn't make sense. you're talking about setting up your cylinder head and throttle body for high-rpm flow, while using camshafts and a bottom end configuration that are only suitable for low-rpm use. that motor probably won't run well anywhere in the RPM range, because even at low rpm, you're not going to have a lot of flow through those hogged-out intake ports and that huge throttle body (nevermind the fact that except for boring out for the huge throttle body, you're completely ignoring the less-than-optimal intake manifold which happens to be in between the two).
do you *have* a 240sx? if so, have you *looked* at the motor? i also like where you're planning on going with rotating mass reduction- that's the next thing on my list after i get suspension and a differential, and my plan for that area is pretty close to yours
, but i think you need to seriously re-evaluate your engine build ideas before you put all the money you're not making doing data entry into your car.
but by all means- prove me wrong, build a 11sec all-motor KA so i know i can do it too. right now i don't think it's likely, even with a plan that makes more sense than yours.
sorry for the burn, but you're kinda asking for it.
my $.02- if you want to make a stroker KA, you'd better be stuffing it into a pickup truck, or *maybe* autocrossing it with a 4.6:1 rear (and even then, preferably in a 510 instead of an S-chassis), because it's simply not going to make the kind of power you want for any other kind of use.
our engines go bang at about 7500 for two reasons; the lack of a fully counterweighted crank, and the rod:stroke ratio, which as stock is just on the "bad" side of "well-balanced".
the one guy i've read about doing a destroke (yes, less) in a KA *still* had to do a bunch of clearancing inside the block to fit a _smaller_ fully counterweighted crank. i hate to think what you'd have to do to stuff a bigger FCW crank in there- or the tiny rods you'd have to run unless you found some way to increase deck height.
given a fixed deck height; when you increase stroke, you decrease your redline. that's simply the way it is, and even with a bigger non-counterweighted crank that you could _maybe_ grind in there, giving yourself less RPM to work with is not the way to make NA horsepower.
unless you're using chemical or mechanical means of getting more oxygen into the combustion chamber, less RPM means less overall flow. as someone else said, you can't fight physics... and even with the maximum 1mm overbore, you'll need a lot of stroke (over 2mm) to gain more than just an extra .1liter- how that translates into "40% more torque" i am unclear on.
finally, your tuning plan simply doesn't make sense. you're talking about setting up your cylinder head and throttle body for high-rpm flow, while using camshafts and a bottom end configuration that are only suitable for low-rpm use. that motor probably won't run well anywhere in the RPM range, because even at low rpm, you're not going to have a lot of flow through those hogged-out intake ports and that huge throttle body (nevermind the fact that except for boring out for the huge throttle body, you're completely ignoring the less-than-optimal intake manifold which happens to be in between the two).
do you *have* a 240sx? if so, have you *looked* at the motor? i also like where you're planning on going with rotating mass reduction- that's the next thing on my list after i get suspension and a differential, and my plan for that area is pretty close to yours
, but i think you need to seriously re-evaluate your engine build ideas before you put all the money you're not making doing data entry into your car.but by all means- prove me wrong, build a 11sec all-motor KA so i know i can do it too. right now i don't think it's likely, even with a plan that makes more sense than yours.
sorry for the burn, but you're kinda asking for it.
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C-Kwik
- Moderator
- Posts: 8070
- Joined: Thu Aug 01, 2002 9:28 pm
- Car: 2013 Chevy Volt, 1991 Honda CRX DX
Magicsurfman - Powerful NA KA's have been built for NASPORT GT3 cars. It certainly is possible. But keep in mind that these motors are far from streetable and reliability a racing season of races(if that) is pushed way to the back of the engine builder's mind. I've heard they rev to some 8000 RPM idle at about 3000 RPM. It will have serious blow-by due to high piston to wall clearances. The motor is cammed to hell and will have no low or midrange power. All its power wil be made in a short range up in the top part of the rev band and have been tuned to work with the headers to increase volumetric efficiency. You may also want to take into account these high compression motors run on race fuel. They are not anything close to the daily driver's we use. If you'ld like an idea of what it would cost you to build one, call Nissan Motorsports USA or Specialty Engineering up in Canada. JWT also might have some insight here as well.
I wish you the best of luck, but I'd rather you be realistic and save your money for some realistic mods rather than burn your wallet over some silly wager.
I wish you the best of luck, but I'd rather you be realistic and save your money for some realistic mods rather than burn your wallet over some silly wager.