'93 240sx lacks higher RPM power

[Bigvinnie]

No, it won't. The 60mm TB already has a CFM rating FAR above the power anyone has attained on an NA KA.

Then I guess you might as well rule out the ITB KA guy's that use the 43mm ITB's off of the 1200 and 1300 hyabusa engines. High end performance as well as a strong and powerful curve all the way through the power band.

[DjPantsSpecR]

The only thing i really want to add to this discussion was about the intake tube length, and i know exactly what you are talkin about Insanity, we were discussing this when developing an intake for the U of M's FSAE race car. Absolutely, in theory this is entirely correct.

However, in making my own intake i noticed a few things. This was even using 248/248 cams which exploits power far too high, making peak power at a point that this motor wont even rev to. The intake piping must be only 2.75 inches in diameter, but i had cut it to be about eight inches long. All i could notice is that it still was making power up higher, in places that were very useless before (granted this is probably around the 6500 area, and i'll certainly agree that power had already fallen on its face). Its very easy to tell that this intake length was far too short for the intake manifold, this is a huge mismatch here.

I take the stock rubber tube that attaches directly to the TB and attach my intake pipe to that for a grand total of about 15 or 16 inches. I can honestly say that the power band shift is very noticable. Instead of wasting power by not being able to actually rev high enough to see it, moving that power band down a little more "increases" power. in that i mean a grand total of more power was seen because its been shifted down to where its actually uselful, very hard to explain but very easy to feel on the butt dyno.

I'm not gonna sit here and pretend that i haven't just entered my second year of mechanical engineering, i'm certainly not the real deal yet, so just by using trial and error you can only conclude that while intake manifold runner length is a serious, serious factor in where power is produced, intake tube length also has to be a contributing factor. Its like stacking tolerances, if thats understandable at all.

how many cars do you see that run the intake all the way over the hot *** radiator and over to a box on the same side as the exhaust manifold? seems kinda counter-intuitive, especially when its so easy to put the intake where the battery currently is. My only obvious answer to that is, a short intake has to suck for low end torque production, and clearly the KA was all about making torque (long runners, long intake, 2.4 liters, gigantic stroke, etc)

again, this is only a little reasoning and a lot of trial and error, so i can only suggest you try for yourselves before you discredit this.... also i think nissan engineers were thinking the exact same thing

[Nismo_Freak]

Of course variation in manifold vacuum can be measured there, you're sucking air through it. However, air doesn't resonate through the intake pipe, or else vacuum measured there would have an obvious rhythmic fluctuation. Air never travels back through the intake pipe. The only effect it would have on helmholtz resonance would be the part of the equation put in for plenum size, since it basically becomes a plenum extension when you're at WOT. Therefore having a larger diameter pipe would help the same as having a bigger plenum, and hurt the same way as well.

Blah blah blah... I'm not arguing with you, and playing your stupid games.

One day you'll have to deal with people that know more than you and it will be an ugly day.

Not that I don't have years of a chemical engineering degree behind me or anything.

[InsanityInc]

The CORR offroad ka24de use "Web Cams" special grind, and custom buckets. You cant get much lift out of the cam before the lobes start walking off the side of the bucket/shim.

Any idea what that grind is specifically?

[InsanityInc]

Then I guess you might as well rule out the ITB KA guy's that use the 43mm ITB's off of the 1200 and 1300 hyabusa engines. High end performance as well as a strong and powerful curve all the way through the power band.

The one dyno there is of ITBs didn't net very impressive results. Also, the increased throttle body area isn't the reason for the gains that are there.

Quote »Not that I don't have years of a chemical engineering degree behind me or anything.[/quote]Ok, so next time a question comes up about chemistry, I'll be happy to defer to you.

Not to mention that a degree doesn't make you right. A degree should make you more capable of arguing your side of something due to your knowledge.

[deviousKA]

Any idea what that grind is specifically?

Not specifically no, but they are over .500" lift and 300 degree duration. If your interested you might want to give Dave Rebello a call. He does not overlook the CORR engines but helps with some middle man part sourcing.

B.C. Gerolamy/B.C. Heads also would be a shop to contact if your interested in information. This shop manufactures a few odds and ends for these engines (intake manifold that i know of), they may also do some of the headwork or have knowledge of the custom valvetrain.

Be prepared to fork over a large chunk for these custom buckets/cams and machining necessary to use them in the ka24de head.

[Bigvinnie]

Not specifically no, but they are over .500" lift and 300 degree duration. If your interested you might want to give Dave Rebello a call. He does not overlook the CORR engines but helps with some middle man part sourcing.

B.C. Gerolamy/B.C. Heads also would be a shop to contact if your interested in information. This shop manufactures a few odds and ends for these engines (intake manifold that i know of), they may also do some of the headwork or have knowledge of the custom valvetrain.

Be prepared to fork over a large chunk for these custom buckets/cams and machining necessary to use them in the ka24de head.

Yep Rebello racing cost a crap load of money. But then again they have pioneered the KA since it's birth, and they also school any performance shop when it comes to boosted and blown L28's, very impressive company if you ask me. They will be doing the bottom end on my high compression KA, I will put the engine together myself though, cant afford there $4700 price tag.....

[InsanityInc]

Not specifically no, but they are over .500" lift and 300 degree duration. If your interested you might want to give Dave Rebello a call. He does not overlook the CORR engines but helps with some middle man part sourcing.

B.C. Gerolamy/B.C. Heads also would be a shop to contact if your interested in information. This shop manufactures a few odds and ends for these engines (intake manifold that i know of), they may also do some of the headwork or have knowledge of the custom valvetrain.

Be prepared to fork over a large chunk for these custom buckets/cams and machining necessary to use them in the ka24de head.

Well, I don't want to use those cams specifically. A KA needs a lot more work than cams to run to 8600rpms even semi reliably. I just want to see what the grind is like so I can get an idea of what a milder one needs to look like.

[deviousKA]

You will be looking at more than $4700 in parts alone for a race bottom end, unless you opt to use the oem (or modified oem) crankshaft. Starting with a truck core is the way to go if you would ever like to go dry sump or have access to off the shelf billet steel flywheels.

No matter what route is taken with the cams, the bucket/shim arrangement is key. If you plan to stay low (relative) lift, you can work with custom shims (pure custom, modified bmw/volvo/toyota etc.) to get some room for a regrind, reduced base circle.

Swapping to enlarged/one piece buckets is the only way to get decent amount of lift for the 2.4+ displacement. Your limited to roughly ~.450 lift with the stock shim size, and thats pushing it.

[Nismo_Freak]

Ok, so next time a question comes up about chemistry, I'll be happy to defer to you.

If you know anything about college or this degree you'd understand that high level physics and chemistry are involved. It just so happens that thermodynamics, wave properties, fluid dynamics, and the other basic concepts that affect flow properties are an integral component to the curricula.

But of course you know it all so why bother even putting in my knowledge.

[InsanityInc]

If you know anything about college or this degree you'd understand that high level physics and chemistry are involved. It just so happens that thermodynamics, wave properties, fluid dynamics, and the other basic concepts that affect flow properties are an integral component to the curricula.

But of course you know it all so why bother even putting in my knowledge.

Hey guess what, high level physics were involved for my degree too (for some reason I still don't understand), so join the ****ing club. Make an argument instead of waving around your degree.

[Nismo_Freak]

Hey guess what, high level physics were involved for my degree too (for some reason I still don't understand), so join the ****ing club. Make an argument instead of waving around your degree.

LOL, I've made plenty of arguements and yet you do nothing but argue about crap you obviously don't understand to the least degree. Believe me, you got more than just me laughing at you chief.

[InsanityInc]

LOL, I've made plenty of arguements and yet you do nothing but argue about crap you obviously don't understand to the least degree. Believe me, you got more than just me laughing at you chief.

Oh, right, like how your torque number is all that matters for acceleration, even though an engine produces two power strokes for every crankshaft revolution, so even if the wheels are going 50mph and your engine is going 7000 as opposed to 3000, you get 14,000 applications of torque per minute as opposed to 6000. But that's just crazy talk.

Or how your intake air pulses down the runner, out the manifold, through the intake pipe, somehow doesn't shoot out the filter, then magically heads back towards your ports again. Oh, but I'm sorry, it obviously reverts through the pipe because YOU CAN MEASURE THE VACUUM THERE. Silly me.

I've yet to see you make any kind of convicing argument about... anything, as a matter of fact.

[Bigvinnie]

Or how your intake air pulses down the runner, out the manifold, through the intake pipe, somehow doesn't shoot out the filter, then magically heads back towards your ports again. Oh, but I'm sorry, it obviously reverts through the pipe because YOU CAN MEASURE THE VACUUM THERE. Silly me.

UHHHH I think he was refering to scavaging, where exhaust pulses force a charge through the intake system.

As stated by the V-Max outlaw website:positive wave pushes exhaust back into the cylinder and in some cases, if there is enough valve overlap it will travel up the intake track and cause triple loading of the intake charge (air is drawn through, pushed back and drawn through again.)

[InsanityInc]

UHHHH I think he was refering to scavaging, where exhaust pulses force a charge through the intake system.

As stated by the V-Max outlaw website:positive wave pushes exhaust back into the cylinder and in some cases, if there is enough valve overlap it will travel up the intake track and cause triple loading of the intake charge (air is drawn through, pushed back and drawn through again.)

Yes, I do know what exhaust scavenging is, and nobody was talking about that in this thread. We're talking about helmholtz resonance in the intake manifold.

[deviousKA]

Hey Vinnie, I missed that post you made about the front cover/timing configuration.

There are a few ways to go about doing this, depending on what your starting with. Your looking at less fabrication and and overall cleaner setup by starting with either a frontier, or an altima ka24de head. These lack the upper cover mounted distributor and have a slimmer design in that dept (closer fit to sohc style cover). A small amount of fabrication is still necessary, on mine i modify the covers by building up the edge with multiple beads of weld and get it re-decked, then drill&tap. It all gets cleaned up afterwords of course.

As far as the actual timing chain components your going to need a few custom items as well. The lower single chain you will need to get a custom length, mercedes master and half links come in handy if your modifying an existing chain, if you go with performance oriented chain (Renold, Iwis, rollmaster (iwis), tsubakimoto) you should get master and/or half links from same manufacture. The size is 06 british standard. My personal favorite is tsubakimoto, which is only available direct from japan in 20ft or longer rolls. IWIS is german and only available direct from manufacture in rolls as well, although there are a few retailers in austrailia that you could contact and see if they will sell in unbound length (rollmaster, rolmac).

You will need a custom fit lower gear for the ka tooth count on the l/z crank snout diameter. I get batches of these made up from time to time, dont have any extras at the moment though. Im not going to divulge the information on how i do this publicly, if you want to know you can email me [email protected] .

With a few slight adjustments of the original Z style timing guides everything goes together quite nicely. Original style hydraulic tensioners can be used, but on mine i use adjustable Malvern-Racing tensioners which are no longer made. Kameari may make adjustable Z style tensioners but you would have to contact them to find out as they arent listed in their catalog.

I dont make up full bolt on assemblies to sell, but i do complete longblocks on request. Might arrange some various hybrid kits in the future once i get some of this casting/mold work done, but will all be tailored to NA/race use.

[Nismo_Freak]

Oh, right, like how your torque number is all that matters for acceleration, even though an engine produces two power strokes for every crankshaft revolution, so even if the wheels are going 50mph and your engine is going 7000 as opposed to 3000, you get 14,000 applications of torque per minute as opposed to 6000. But that's just crazy talk.

Or how your intake air pulses down the runner, out the manifold, through the intake pipe, somehow doesn't shoot out the filter, then magically heads back towards your ports again. Oh, but I'm sorry, it obviously reverts through the pipe because YOU CAN MEASURE THE VACUUM THERE. Silly me.

I've yet to see you make any kind of convicing argument about... anything, as a matter of fact.

Hahha, you just keep thinking that buddy. You have a hard time even remotely understanding what I say that much is obvious.

[Bigvinnie]

Hey Vinnie, I missed that post you made about the front cover/timing configuration.

There are a few ways to go about doing this, depending on what your starting with. Your looking at less fabrication and and overall cleaner setup by starting with either a frontier, or an altima ka24de head. These lack the upper cover mounted distributor and have a slimmer design in that dept (closer fit to sohc style cover). A small amount of fabrication is still necessary, on mine i modify the covers by building up the edge with multiple beads of weld and get it re-decked, then drill&tap. It all gets cleaned up afterwords of course.

As far as the actual timing chain components your going to need a few custom items as well. The lower single chain you will need to get a custom length, mercedes master and half links come in handy if your modifying an existing chain, if you go with performance oriented chain (Renold, Iwis, rollmaster (iwis), tsubakimoto) you should get master and/or half links from same manufacture. The size is 06 british standard. My personal favorite is tsubakimoto, which is only available direct from japan in 20ft or longer rolls. IWIS is german and only available direct from manufacture in rolls as well, although there are a few retailers in austrailia that you could contact and see if they will sell in unbound length (rollmaster, rolmac).

You will need a custom fit lower gear for the ka tooth count on the l/z crank snout diameter. I get batches of these made up from time to time, dont have any extras at the moment though. Im not going to divulge the information on how i do this publicly, if you want to know you can email me [email protected] .

With a few slight adjustments of the original Z style timing guides everything goes together quite nicely. Original style hydraulic tensioners can be used, but on mine i use adjustable Malvern-Racing tensioners which are no longer made. Kameari may make adjustable Z style tensioners but you would have to contact them to find out as they arent listed in their catalog.

I dont make up full bolt on assemblies to sell, but i do complete longblocks on request. Might arrange some various hybrid kits in the future once i get some of this casting/mold work done, but will all be tailored to NA/race use.

That is great you answered alot of questions that I was having problems with. On another note, you told me in another thread that the Z series isn't siamesed, every time I read over the chiltons, I swear it says "similar to L series" using the same internals. I'm not understanding the NON siamese from siamesed engines. I thought a siamesed engine had the same internals and different block. Can you clear this issue up. Thanx Vinnie.

[deviousKA]

The Z series is very similar to the L series, internals basically indentical. The L series are not a siamesed design because all of these run a small bore (under 87mm). Some of the diesel versions of the L may be siamesed but that is of little concern.

Starting with the z22 (87mm bore) nissan siamesed the cylinders. This simply means that they are joined in between.

Visual aid:

This cannot be seen externally because the engines are closed deck design, imagine if the deck was removed or if the block was cut in half when looking at that picture. Picture is way out of scale but should give you an idea. Note that there are small diagonal coolant passages that run in between the bores on the siamesed blocks.

That picture you posted is accurate except for one blatant thing, none of the L or Z series have removable cylinder liners.

edit: BTW, KA is siamesed design.

[vvaffle]

Sorry to interupt what seems like a very good discusion between vinnie and devious but I am completely lost whenever you guys talk about anything regarding the valves (I'm also lost when you talk about some other things, but mostly valves and the head). So I was wondering if there is any place where I could educate myself. I mean, how did you guys learn all this stuff?

[DjPantsSpecR]

I'll try to field that one... cuz they are badasses.

no, actually i imagine, especially devious i know a lot less about vinnie, but i can only imagine they've learned what they know by taking a lot of motors apart, building a lot of crazy one-off ideas, EXPERIENCE. Everyone makes mistakes, thats where you learn the most.

Or a lot of college courses can give you a bunch of useless knowledge like i'm currently getting... There is no way you can pick up the knowledge these cats have in any quick amount of time, but there are always some good books to be read.

this is gonna sounds retarded, but when i was younger i read alot of the Honda builder's handbooks. The only reason these are useful is because they take your hand and walk you throw all the basic engine stuff and you'll learn everything basic you need to know. Then they'll start talking about Honda's eventually, thats when its time to put down the book...

You used to be able to learn a lot from Sport Compact Car too...

Maybe they if they could they could throw you some suggested reading, or maybe even some websites. My three favotire books are Tune to Win and Engineer to Win, but Maximum Boost is also a good, but dated read.

Now go take your motor apart

[deviousKA]

I just run away when all the difficult questions come up, haha jk.

It depends on where you need to start. First of all you need to tackle the basics that apply to any valvetrain and what all of the components do/how they work together. Once youve got the basic concept of camshafts/cam lobes/basic cam timing down you then apply it to whatever configuration or platform you work with.

With ka24's, the sohc and the dohc are a world apart in their design. The sohc can actually be seen as more complex in a way because they have rocker arms that transfer the camshafts operation over to the valves. On a dohc, the valves are basically operated directly by the camshafts. Both accomplish the same feat when all is said and done, and most of the rules apply to both.

http://auto.howstuffworks.com/camshaft.htm

If that is extremely basic and I offended you , not my intention. Up a couple posts i was talking about buckets and shims, that is something that is best understood when you can actually look at the parts in question. On the howstuffworks link i gave that first animation is similar to how a dohc ka24de operates, except that there is 2 cams and 16 valves (instead of one cam and 8 valves). The little cylindrical parts that are under the cam lobes and above the valves are the "buckets", the "shims" sit on top of the buckets under the cam lobe and are there for adjustments.

Like DjPantsSpecR said, start taking stuff apart! Experience is key. You dont need years and years of experience or anything like that just keep at it. Im only 20 and started building nissan/datsun/toyota engines as a kid in my dads shop.