If you have a stock intake manifold, READ THIS:

[corn322]

continuing from my previous post, about the runners...I see in the pics the runners seem to come to the head at downard angle... is this for less restrictive airflow into the head?pics:

would that make a huge difference in airflow?

I also had an idea on my drive home from school:could you rifle the inside of the intake runners, so that the air would be spinning in like a vortex as it enters the head? although upon futher thought this could cause problems in the head, like when it splits to go to the 2 different valves. or the centrifugal forces would cause the gasoline to fly out and deposite on the walls of the intake.

[InsanityInc]

rifling the runners would probably just cause turbulence and slow the air down. Also, I have to assume that your thinking on why the runners are curved is correct, since if the air has to deflect off the head as in the second picture, it's going to lose velocity.

[NateDogg]

You are trying to discount the hard facts. You saywords and I bring numbers. Unfortunately, words do not make your car go faster, numbers do.

Tuning is always a series of compromises. You're not going to have a magical manifold that will increase power from 2000rpm all the way to 7000rpm. It just won't happen, unless its tied to a positive displacement blower.

What I am suggesting is using physics to your advantage. I'm sure that everyone knows the KA needs every bit it can get.

[corn322]

I, for one, think he is on to something. I'll buy one. Although, $300 - $400 is a bit pricy. If the price range could be dropped to $250 - $350, that would be nice.

from looking at the graphs in demcj's link to freshalloy, if this intake helps the ka like it helped that dudes sr, I think this will help making a 200hp ka a lot easier.

[klattr1]

$300-$400 isnt really pricey at all for an aftermarket intake manifold. it has about much time and development into it as a turbo manifold. have you seen any of the aftermarket int. man. for the sr's?they get up to $500 easy except for the $300 Top-Speed copy.id pay between $300 and $400 for sure if it was solid quality but they have to figure out about Idle Air Control Valve and coolant passages. thats why im thinking about using the universal plenum and using the plate and velocity stacks and welding up my own.I wonder what the displacement size of the plenum is?We need something bigger than the displacement of our motor!

[jmauld]

For $300-$400, I'm in.

Well, as long as there is significant gain shown on a dyno of a NA KA.

[klattr1]

well, there would be a bigger gain with a turbo added to it. its just so hard to make alot of power NA without spending as much as a turbo would cost.

[jmauld]

This is in the NA section, so let's assume that they were intending it to be made for a NA engine....

[TrunkMonkey]

This is in the NA section, so let's assume that they were intending it to be made for a NA engine....

but that's just it, you're not going to see any huge gains with this manifold if you're n/a. unless you already have a serious engine build up to take advantage of the short runners the most it will do is smooth out the powerband...but don't expect it to look anything like the b18's graph or the theoretical KA chart that was posted earlier.

-demetrius

[InsanityInc]

You are trying to discount the hard facts. You saywords and I bring numbers. Unfortunately, words do not make your car go faster, numbers do.

No, actually I'm not. Also, the only fact you've even brought up is that an 11" long 1.5" diameter runner will have a multiple reversion wave effect that will cause a torque boost at 7000 rpms. Woo. You failed to consider everything else that goes along with having a runner that size. There's a reason why much shorter runners are used.Quote »Tuning is always a series of compromises. You're not going to have a magical manifold that will increase power from 2000rpm all the way to 7000rpm. It just won't happen, unless its tied to a positive displacement blower.[/quote]Yes, actually you could. It wouldn't be the best idea, but I'm sure if you made the runners ridiculously short you could move the peak torque to 7000 rpms. Your peak torque is the point at which your cylinders get the maximum amount of air and fuel into them across your entire rpm range. That's all it is. Using a reversion wave to create a higher peak torque number has compromises, in that your torque at other rpms is going to suffer, because there's more to consider than just reversion waves. Runner length in and of itself makes a huge difference in how high the engine can achieve an adequate fill.

Take the posted SR graph for example. It doesn't seem like it's been tuned to make use of a reversion wave, while the stock manifold obviously was. The stock manifold has a better peak, but worse overall, while the aftermarket manifold is exactly the opposite.

[InsanityInc]

but that's just it, you're not going to see any huge gains with this manifold if you're n/a. unless you already have a serious engine build up to take advantage of the short runners the most it will do is smooth out the powerband...but don't expect it to look anything like the b18's graph or the theoretical KA chart that was posted earlier.

-demetrius

Your peak torque is achieved at the point that the cylinders have the maximum amount of fuel and air in them that they ever get over the entire RPM range. By moving to shorter runners, you allow that maximum fill (or very close to it) to be achieved at much higher rpms. Since horsepower is a function of torque based on rpms, simply moving the same torque number to a higher rpm makes you gain power. In many cases (such as the SR graph) even moving a lower torque number to a higher rpm will make you gain power. As you'll notice from the theoretical graph I posted, I just took the same torque numbers, and moved them up higher.

Also, please explain what massive difference exists between the KA24DE and the b18b. Go on.

Not to mention, from the looks of the SR graph, the curve *would* look different than my theoretical graph, probably BETTER than my theoretical graph, as the SR maintains peak torque all the way up to redline.

[TrunkMonkey]

Your peak torque is achieved at the point that the cylinders have the maximum amount of fuel and air in them that they ever get over the entire RPM range. By moving to shorter runners, you allow that maximum fill (or very close to it) to be achieved at much higher rpms. Since horsepower is a function of torque based on rpms, simply moving the same torque number to a higher rpm makes you gain power. In many cases (such as the SR graph) even moving a lower torque number to a higher rpm will make you gain power. As you'll notice from the theoretical graph I posted, I just took the same torque numbers, and moved them up higher.

the flaw with this whole thing is that unless you physically change the amount of air compressed in the combustion chamber (i.e. cams, boost, higher compression ratio) you're not going to make as much power as you think. without supporting mods, just an intake manifold upgrade isn't going to solve the KA's breathing problem. it's stroke is just too big.

Also, please explain what massive difference exists between the KA24DE and the b18b. Go on.

i don't remember ever saying massive, but anyways...the difference is stroke. you do realize that the KA's bore is just as big as the B18's stroke right? the B18's pathetic 1.8L is much easier to fill with air at 7k rpms than the KA's 2.4. if there was an economical way to destroke the KA, you'd see a similar powerband to the b18. to top it off, it's impossible to compare cam specs between two completely different engines.

Not to mention, from the looks of the SR graph, the curve *would* look different than my theoretical graph, probably BETTER than my theoretical graph, as the SR maintains peak torque all the way up to redline.

the SR is boosted. the less restrictions you have between the turbocharger and the combustion chamber, the more air you're going to cram in. this is not the case when you're n/a.

my point is, i've never seen anyone upgrade thier intake manifold without some types of supporting mods to take advantage of it.

it's a lot like raising your compression ratio. by itself, it's absolute weaksauce. you'll only see about 4-5% gains for every point raised (something like 7-8hp at the flywheel for the KA). but once you start applying other mods, that 4-5% starts to grow.

-demetrius

[InsanityInc]

Quote »the flaw with this whole thing is that unless you physically change the amount of air compressed in the combustion chamber (i.e. cams, boost, higher compression ratio) you're not going to make as much power as you think. without supporting mods, just an intake manifold upgrade isn't going to solve the KA's breathing problem. it's stroke is just too big.[/quote]We're not raising the amount of air getting into the combustion chamber, that's not the point. We're making it possible for the cylinder to fill to it's maximum at higher rpms. If a cylinder burns X amount of fuel/air at 5000 rpms, it makes the same amount of torque by burning X amount of fuel/air at 7000 rpms, but since your rpms are higher, your horsepower goes up.

Quote »i don't remember ever saying massive, but anyways...the difference is stroke. you do realize that the KA's bore is just as big as the B18's stroke right? the B18's pathetic 1.8L is much easier to fill with air at 7k rpms than the KA's 2.4. if there was an economical way to destroke the KA, you'd see a similar powerband to the b18. to top it off, it's impossible to compare cam specs between two completely different engines.[/quote]A .6L difference spread across 4 cylinders isn't very much. Also, it isn't much easier, it's barely easier at all. You fail to consider that a 2.4L engine, while having more volume to fill, also has more escaping exhaust, and a larger cylinder volume which creates a lower pressure zone (compared to the smaller cylinder) inside the cylinder, which draws air in faster, exactly proportionally to the increased size. See, you've just said the engines are quote "Completley Different". I beg to differ. The breathing characteristics of the engines are almost exactly the same.

Quote »the SR is boosted. the less restrictions you have between the turbocharger and the combustion chamber, the more air you're going to cram in. this is not the case when you're n/a.[/quote]Not true. 14 psi is 14 psi. It's a question of wether or not you have few enough restrictions to be able to pressurize the cylinder to 14psi before the valve closes. Turbo engines still have a maximum fill. If your intake system is so ****ty that you never achieve maximum boost inside the cylinder, then yes, changing the intake system will change the amount of air getting into the cylinder. However, if you're boosting 14psi, and your engine gets 14psi at low rpms, but not at high rpms, that means your intake tract is too restrictive. By replacing the manifold, you achieve 14psi at higher rpms, you don't magically get more into the cylinder with the same boost.

Same deal with N/A. You're not trying to get more air in. You're just trying to get the same amount of air in at higher rpms.

[deviousKA]

Are there any pictures of these manifolds you speak of InsanityInc? Maybe i missed them skimming through. Where is the injector placement/angle? Inside diameter of intake runners? Any details besides short runner? Efficiency of overall design is most important, seems to be a lot of discussion on runner length etc... which are just the basic factors.

Oh and btw, you cannot really compare say a b18 to a ka24de in flow characteristics as simply as you make it seem. Overall displacement of the engine really has very little to do with it. You must consider factors such as stroke, rod/stroke ratio, etc... These have a major factor in how the cylinder is designed to fill. The honda engines run much lower rod stroke ratios, and shorter strokes. Their piston acceleration to and away from tdc/bdc as well as the dwell time at those two points is completely different. The cams and cylinder head flow characteristics are set up to work most efficently with their own setup.

A b18 probably flows equal amount of air as ka (if not more). Not statically .6l less.

[InsanityInc]

Are there any pictures of these manifolds you speak of InsanityInc? Maybe i missed them skimming through. Where is the injector placement/angle? Inside diameter of intake runners? Any details besides short runner? Efficiency of overall design is most important, seems to be a lot of discussion on runner length etc... which are just the basic factors.

Actually, the only person who mentioned runner length was NateDogg, and I just pointed out that tuning for a reversion wave isn't the only consideration when making a manifold.

Quote »Oh and btw, you cannot really compare say a b18 to a ka24de in flow characteristics as simply as you make it seem. Overall displacement of the engine really has very little to do with it. You must consider factors such as stroke, rod/stroke ratio, etc... These have a major factor in how the cylinder is designed to fill. The honda engines run much lower rod stroke ratios, and shorter strokes. Their piston acceleration to and away from tdc/bdc as well as the dwell time at those two points is completely different. The cams and cylinder head flow characteristics are set up to work most efficently with their own setup. [/quote]Stroke actually has nothing to do with it directly. Displacement is displacement as far as filling is concerned. Your rod to stroke ratio, however, does affect it somewhat. THe B18B has an 89mm stroke. The KA has a 96mm stroke the B18B has a rod length of 137mm, the KA's is 165. Giving them respective rod:stroke ratios of 1.54 and 1.71, which is actually another point of how the KA should flow better than the B18B, since the rod:stroke on the KA is closer to the ideal 1.75.

Quote »A b18 probably flows equal amount of air as ka (if not more). Not statically .6l less. [/quote]

I doubt it. The KA is designed to have high-velocity air entering the cylinders at low rpms (secondary butterfly valves and long runners), and thusly at low rpms it increases the effective displacement beyond 2.4L. Also, if the B18B flowed 2.4L of air, it would be a miracle engine, considering it would produce the torque of a 2.4L motor in a 1.8L package without a turbo. If you're reffering to operational flow rather than peak flow, then I'm sure there are points in the high-rpm ranges that the B18B does flow more air than the KA, largely due to the intake manifold.

My point is that in all respects, the B18B should flow WORSE than the KA at high rpms (has milder cams, worse rod:stroke, etc), but it actually flows better at high rpms, and the problematic factor with the KA is the intake manifold. My intent wasn't to say that the KA is going to look like the B18B with the different intake manifold, my intent was to display that the KA manifold is a serious hindering factor in the high-rpm breathing of the engine.

[deviousKA]

rod/stroke and stroke length are definate factors. They determine piston acceleration and average speed directly at any rpm. Even tho the r/s ratio is lower on the honda, due to the lower stroke it will have lower average piston speed at any rpm compared to ka. The ka manifold is designed to resonate or come into "powerband" with the harmonics to suit its rpm range. That is why the runners are long.

My point is that in all respects, the B18B should flow WORSE than the KA at high rpms (has milder cams, worse rod:stroke, etc), but it actually flows better at high rpms, and the problematic factor with the KA is the intake manifold. My intent wasn't to say that the KA is going to look like the B18B with the different intake manifold, my intent was to display that the KA manifold is a serious hindering factor in the high-rpm breathing of the engine.

I agree, but it isnt entirely because of the manifold. operational flow is all that matters for the sake of that honda argument. The b18 flows much different. Anyways im not arguing about that one anymore. I agree stock intake manifold is major hinder to top end performance, have you seen mine?

[BomexS13]

post pics please

[InsanityInc]

rod/stroke and stroke length are definate factors. They determine piston acceleration and average speed directly at any rpm. Even tho the r/s ratio is lower on the honda, due to the lower stroke it will have lower average piston speed at any rpm compared to ka. The ka manifold is designed to resonate or come into "powerband" with the harmonics to suit its rpm range. That is why the runners are long.

The rod/stroke affects breathing somewhat, but stroke in and of itself does not. What stroke does affect is the operational range of the engine, due to piston speed.

Quote »I agree, but it isnt entirely because of the manifold. operational flow is all that matters for the sake of that honda argument. The b18 flows much different. Anyways im not arguing about that one anymore. I agree stock intake manifold is major hinder to top end performance, have you seen mine? [/quote]

No, I have not.

Quote »post pics please[/quote]It doesn't exist yet.

[Open4Cycle]

One good advantage of port injection is to have dry intake runners thus enabling us to utlize the ram effect of long runners. I think the most over looked part of changing to a short runner intake here is the cam. Yes it has been stated that the cam has an effect but the numbers you posted were lift and duration which really has nothing to do with it. Lobe centerlines and overlap play the key role in tuning with intake.My 2 cents

[InsanityInc]

I also wasn't posting those figures and telling people to design a manifold. I posted those figures to show that for all intents and purposes (besides the intake manifold), the KA should have a better top end.

[RedHatchback]

Hell,if anybody made an aftermarket intake manifold that looked like the first 4 pics,I would definetly buy one! Count me in for the manifold!!!!! Can it be made to adapt a Q45 throttle body with no EGR? If so I'm am for sure,without a doubt in!!!

[InsanityInc]

I'm fairly sure it's going to have an EGR fitting. Also, it might come set up for the Q45 throttle body normally, or just have an adapter plate.

[SSS]

Those of you who have modified the E intake manifold (i'm looking at you DeviousKA ), what length did you decide on for the runners?

[S14Swap240sx]

count me in once we get some serious pictures and if the price stays between 300-400

[w1ngzer0]

rod/stroke and stroke length are definate factors. They determine piston acceleration and average speed directly at any rpm. Even tho the r/s ratio is lower on the honda, due to the lower stroke it will have lower average piston speed at any rpm compared to ka. The ka manifold is designed to resonate or come into "powerband" with the harmonics to suit its rpm range. That is why the runners are long.

I agree, but it isnt entirely because of the manifold. operational flow is all that matters for the sake of that honda argument. The b18 flows much different. Anyways im not arguing about that one anymore. I agree stock intake manifold is major hinder to top end performance, have you seen mine?

Going N/A and only buying a intake manifold from this guy

[Guam_Guy]

I'll tell you guys what, if you are willing to pay some company 300-400 bucks for a manifold you can build yourself your nuts! Here is a manifold I am making right now. Very easy to do if you have the resources.

[Guam_Guy]

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Modified by Guam_Guy at 2:55 AM 10/4/2004

[Guam_Guy]

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[izmobile]

cam overlap might be a cause for honda to outflow nissan.

[vvaffle]

Count me in as a possible buyer.