Kevin,

Its not really a matter of tracking down someone who's done it. They would be extremely popular if they did. We are THE biggest Nissan/Infiniti source on the web. Not tooting our horn or saying we know everything, just referencing our knowledge base. I would think that one of our 50,000+ members would have heard of a 200WHP NA KA. I don't search for any info myself, because I thinks it's pointless. As I referenced in almost all of my posts, why bother?

WD

WDRacing wrote:Kevin,

Its not really a matter of tracking down someone who's done it. They would be extremely popular if they did. We are THE biggest Nissan/Infiniti source on the web. Not tooting our horn or saying we know everything, just referencing our knowledge base. I would think that one of our 50,000+ members would have heard of a 200WHP NA KA. I don't search for any info myself, because I thinks it's pointless. As I referenced in almost all of my posts, why bother?

WD

I don't think that any of the 50,000 members realized that the KA engines were running crank scrapers stock from the factory and have done so for well over a decade. Those louvers in the pans -- they are a form of scraper.

So, I would temper the collective wisdom proportionately. Of course there might be people that knew that but just chose to keep quiet. That does seem likely.

I will ask the gentleman who did the dyno cell testing on the Dodge 2.4 NA setup on our site. My guess from the percentages is that it was in excess of 200. He might not want to say, of course, as that engine went straight from the dyno into a race car. BTW, the Dodge has a stroke of 101mm versus the KA24's 96mm but it also has a fully counterweighted crank.

Kevin -

After you blew off building my parts for over 3 weeks, then went on vacation in the middle of that time, with no regard for MY schedule?

No phone call, no email, no contact. How hard is it to pick up the phone and say, "Hey Greg, this is taking longer than I thought."

I spent half the cost of your scraper and windage tray in storage fees for backing up the machine shop, which I told you VERY clearly.

After I had to track you down to find out where my order was, and then NO offer was made to compensate me for my inconvenience, I wasn't ABOUT to waste further time trying to convince you that the fitment was off.

Customers don't like to hear, "I'm sorry". They want to hear, "I'm sorry, let me make it up to you."

Especially when that customer is building one of the most visible 240sx's ever built. Especially when that customer RUNS a performance parts business, deals with customers on a daily basis, and takes good care of the irate ones (even when they have no good reason to be irate).

BTW, the louvers in the KA pan might serve to reduce windage, but by no means are they close enough to the crank to be construed as a "scraper" by any means.

As far as "talking to someone who's been in the game longer", there's no real need. Even the guys campaigning 240sx's in Auto-X and SCCA will support what's being said here.

IF there was a 200+ hp n/a DOHC KA, it hasn't been made public and it's not being campaigned in any races.

This bickering is getting way old.The point of the matter is that we currently have no evidence of a 200whp ka, but that is generally considered the NA goal. Done.Whether its worth it to go through all the R&D to create a possibly feasible, streetable KA engine at that hp level is up to the owner of said engine, so saying its pointless to attempt it when you can just go turbo is not a valid statement in this forum IMO. This is the NA KA forum, if people want huge hp levels by going turbo, they can visit the turbo forum. Some people for some reason or another enjoy moderate power levels and choose to stay NA. So unless we've got important theoretical knowledge in this thread, I propose this be locked and/or deleted. We've got plenty other 200whp threads anyway, I'm sure.

AZhitman wrote:Kevin -

After you blew off building my parts for over 3 weeks, then went on vacation in the middle of that time, with no regard for MY schedule?

I didn't blow off building your parts -- you just have to realize there were a lot of people with orders that were ahead of you. I build all the parts myself -- it takes a lot of time. You placed your order on May 17th -- it was shipped express to you on Saturday, June 10th.

I also think my wife explained to you that the "vacation" was her graduation gift. It was also my first time off in about two years as well.

I have about 2 solid months of work in front of me now.

AZhitman wrote:No phone call, no email, no contact. How hard is it to pick up the phone and say, "Hey Greg, this is taking longer than I thought."

That's a valid criticism. I should point out, however, that I typically spend 5 hours a day writing emails -- that is time I cannot spend making scrapers. That doesn't include phone calls.

AZhitman wrote:I spent half the cost of your scraper and windage tray in storage fees for backing up the machine shop, which I told you VERY clearly.

Yes, I even remember where I was standing -- very memorable. I had the impression you expected me to fly back from Detroit right that moment. Sorry.

I have talked to a lot of fabricators who got out of the business for reasons like your phone call. Not worth it.

AZhitman wrote:After I had to track you down to find out where my order was, and then NO offer was made to compensate me for my inconvenience, I wasn't ABOUT to waste further time trying to convince you that the fitment was off. Customers don't like to hear, "I'm sorry". They want to hear, "I'm sorry, let me make it up to you."

Especially when that customer is building one of the most visible 240sx's ever built. Especially when that customer RUNS a performance parts business, deals with customers on a daily basis, and takes good care of the irate ones (even when they have no good reason to be irate)."

Well, Greg, try building all the parts you sell from scratch. I assure you it is a lot more work.

Actually I deal with many distributors and your attitude runs counter to virtually all of them.

We didn't charge you for the express shipment. Hope that helped.

AZhitman wrote:BTW, the louvers in the KA pan might serve to reduce windage, but by no means are they close enough to the crank to be construed as a "scraper" by any means.

You simply do not know what you are talking about. Sorry. You might know a lot about many things but windage is not one of them.

AZhitman wrote:As far as "talking to someone who's been in the game longer", there's no real need. Even the guys campaigning 240sx's in Auto-X and SCCA will support what's being said here.

IF there was a 200+ hp n/a DOHC KA, it hasn't been made public and it's not being campaigned in any races.

Just because something has not been made public does not mean it does not exist or did not exist. And it certainly doesn't mean it COULD not possibly exist. There are specialized courses in modal logic but this is covered in most college level introductory critical thinking courses.

Well, that's all I needed to hear (then) and now.

When I have a catback that takes nearly a month to make and deliver, I make amends.

I don't tell people that my dog died, my wife has cancer, I haven't had a vacation in eight years, my neighbor stole my tools, etc...

Business owner to business owner, I'd recommend a disclaimer on the website - I tell my customers not to expect a deliver for EIGHT business days. If it comes before that, they're ecstatic. If it takes longer, I dig into my wallet.

I hope all goes well with I-J, I certainly mean no ill will with this. In fact, if there's a 200+ hp KA out there, I hope your product is attached.

Ajax wrote:This bickering is getting way old.The point of the matter is that we currently have no evidence of a 200whp ka, but that is generally considered the NA goal. Done.Whether its worth it to go through all the R&D to create a possibly feasible, streetable KA engine at that hp level is up to the owner of said engine, so saying its pointless to attempt it when you can just go turbo is not a valid statement in this forum IMO. This is the NA KA forum, if people want huge hp levels by going turbo, they can visit the turbo forum. Some people for some reason or another enjoy moderate power levels and choose to stay NA. So unless we've got important theoretical knowledge in this thread, I propose this be locked and/or deleted. We've got plenty other 200whp threads anyway, I'm sure.

It is pretty old, I agree. In the early 1970s Renault offered a bolt in kit for the NA 1600 807 engine. Brought it up to 100 hp per liter. One hundred hp per liter NA is not such a big deal but apparently here 10 years is considered a wide enough spread for research purposes.

Talked about that very topic with one of my theoretical linguistics professors. He was a founder of the field of psycholinguistics back in the 1950s. We talked about how most grad students only go back 10 years in their research. He said it was funny to him at times because many of the papers he reviewed were written by authors totally oblivious to his own research on the same topic. I just thought it was sad.

Pseudointellectual academic babble has no place on a car forum.

No one's arguing hp/litre, that's a given.

All we're saying is, since the KA24DE was introduced in 1991, there have been no known instances of it exceeding 200 hp.

So, given an engine introduced 16 years ago, with internal modifications likely not being common for the first several years of its existence, it's PERFECTLY acceptable to look at the last 10 years (more than HALF of its life) as a valid determinant of what has been (and what has NOT been) done with that engine.

AZhitman wrote:
Pseudointellectual academic babble has no place on a car forum.

That's rich. You go talk to some grad students and professors with 40 years teaching under their belt and check it out, okay?

But you may just be referring to this forum rather than car forums in general?

AZhitman wrote:No one's arguing hp/litre, that's a given.

All we're saying is, since the KA24DE was introduced in 1991, there have been no known instances of it exceeding 200 hp.

I think if you reread the thread there are people who claim to know of it being done but they were shouted down and threatened.

AZhitman wrote:So, given an engine introduced 16 years ago, with internal modifications likely not being common for the first several years of its existence, it's PERFECTLY acceptable to look at the last 10 years (more than HALF of its life) as a valid determinant of what has been (and what has NOT been) done with that engine.

You're forgetting the aforestated rigor of the "looking," to wit: "I don't search for any info myself, because I thinks it's pointless. As I referenced in almost all of my posts, why bother?"

Don't ever get into an argument with a good philosophy student; you'd quickly be road-kill. Seen it happen many times -- brutal.

Well, very few philosophers know d!ck about building high-horsepower KA's.

I'm a past grad student, and one thing I've learned is that it makes NO matter how much one "wishes" unicorns did exist.

Philosophy students annoy me - Too much bellybutton-gazing and pseudointellectual pablum-spouting for my liking.

They can win all the arguments they want, at the end of the day, no one's paying them for their "enlightenment".

You go play in the theoretical realm, me and reality are getting along just fine.

"Shouted down? Threatened?" Pfft. If I was in the business of "silencing" folks, we'd have simply deleted their posts. Think about it.

Anyone who's aware of that elusive 200+ hp n/a KA24DE, don't be scared: Pop on in with a dyno sheet and I'll eat my crank scraper.

All the arguments I've witnessed with philosophers ended in shouting matches... Anyway. If anyone has credible, documented proof of a 200 whp NA KA engine, please post it now.

No one? Wow. That was an incredible silence.Please get over yourselves and get back to figuring out HOW we can get closer to that elusive 200whp mark. Sorry, I'm letting too many things get me more angry than I should be.

AZhitman wrote:Well, very few philosophers know d!ck about building high-horsepower KA's.

They really don't have to in order to analyze the arguments here.

AZhitman wrote:I'm a past grad student, and one thing I've learned is that it makes NO matter how much one "wishes" unicorns did exist.

The second half of the course was about symbolic logic -- stay awake next time.

AZhitman wrote:Philosophy students annoy me - Too much bellybutton-gazing and pseudointellectual pablum-spouting for my liking.

You missed the recent part where one recognized that you don't know what you're talking about?

AZhitman wrote:They can win all the arguments they want, at the end of the day, no one's paying them for their "enlightenment".

You did.

AZhitman wrote:You go play in the theoretical realm, me and reality are getting along just fine.

Bet you didn't know about Wittgenstein's engineering patent. Check it out.

I rather think you'd be parlaying auf Deutsch save for Turing as well.

Sleep tight.

AZhitman wrote:"Shouted down? Threatened?" Pfft. If I was in the business of "silencing" folks, we'd have simply deleted their posts. Think about it.

Anyone who's aware of that elusive 200+ hp n/a KA24DE, don't be scared: Pop on in with a dyno sheet and I'll eat my crank scraper.

Live footage at 11:00!

Ajax wrote:All the arguments I've witnessed with philosophers ended in shouting matches... Anyway. If anyone has credible, documented proof of a 200 whp NA KA engine, please post it now.

No one? Wow. That was an incredible silence.Please get over yourselves and get back to figuring out HOW we can get closer to that elusive 200whp mark.

Many philosophers actually read -- I know, that's really irritating. You should reread what I wrote about the Dodge 2.4 having a fully counterweighted crank.

Ajax wrote: Sorry, I'm letting too many things get me more angry than I should be.

The information you seek is out there -- go on, ask Kas Kastner. He might know something.

http://www.kaskastner.com/kasbio.html

When I reference going turbo instead of boost its actually very viable. I was explaining why we haven't had a 200WHp NA KA yet, because the simple addition of boost is far to easy to ignore.

I'm not saying go turbo or go home. I never silence creatvity. I'm all for discussing various methods of increasing VE.

BUT I WILL NOT SIT BACK A WATCH PEOPLE JACK UP A GOOD THREAD BY SAYING IT'S BEEN DONE. IT HASN'T...PERIOD, IN FACT, EVERY POST AFTER THIS THAT SAYS IT HAS WITHOUT DOCUMENTED PROOF WILL SIMPLY BE DELETED.

Ok, now that we have that covered. If there are any further idea's or suggestions, please feel free to discuss them, it's still an open forum.

What should we use as a target RPM? Once we figure that out, we can work on the rest.

Oh yeah, no more babble about crap unrelated to this thread and topic. I'll edit it and you won't like what I put...don't like it...leave. There is no room for people with no sense of humor in life. If we take offense to everything, then we have no room for growth.

I bet Kevin has Flowers all over his bed and dreams of fairies and flying. Greg dreams about me...lol and I am absolutely perfect in every way

even his cat is perfect

Dude, save the horsecrap for someone who will pay you for it.

If it was worth something, you'd get a paycheck for it.

Kastner hasn't built a KA24DE in his life to my knowledge, so why do you keep harping on him? His accomplishments, while notable, are IRRELEVANT to this discussion.

I have spent time talking with several folks close to him (Brabham, Knight and Millen spring immediately to mind), so it's not like you're "enlightened" and we're "in the dark".

Maybe I am retarded, I couldn't understand any of the nonsense you posted.

It probably earns you TONS of points with the pimply-faced Debate Club chicks and the shriveled old guys who spent more time pondering irrelevant crap than they did enjoying life.

I'll be sleeping just fine - You keep chasing rainbows and unicorns, and I'll be boiling the hides off my 400-hp KA-T.

yeah a turbo on a stock old *** motor compared to the reliability of a freshly built Na ka hmmm , whats gonna last , whats gonna be consistent , whats just gonna break down and need a rebuild anyways - i dont know if everyone thinks turbos were just invented or what , BUt there are alternatives , and i think a fresh well build Na ka would rock. and all the turbo luvas can go polish thier blow off valves

stocker240 wrote:yeah a turbo on a stock old *** motor compared to the reliability of a freshly built Na ka hmmm , whats gonna last , whats gonna be consistent , whats just gonna break down and need a rebuild anyways - i dont know if everyone thinks turbos were just invented or what , BUt there are alternatives , and i think a fresh well build Na ka would rock. and all the turbo luvas can go polish thier blow off valves

I'm sorry, but that was one of the most uninformed incorrect statements I've ever read.

If you mean to say that a rebuilt NA KA in stock form will be reliable, then yes you are correct. But if you mean a built KA thats used for as much power as possible, then no, you are not.

You also need to rethink your entire thought process about turbo's. If by consitant you mean the same amount og boost and more power then NA will be able to make EVER...then yes.

This is a thread about how to build a high WHP NA KA, not a FI vs NA thread. NA will always be slower, that is simple fact.

WD

WDRacing wrote:-snip-

What should we use as a target RPM? Once we figure that out, we can work on the rest.

Why don't you try 7500 rpms? If you looked at my site that is what the Dodge 2.4 was dynoed at max.

That engine was dynoed in an OEM level dyno cell -- it was run at 7500 rpm steady -- and many other rpm points -- to allow the oil and coolant temperatures to stabilize, which is of interest in a road racing engine that you expect to last. The Mopar sponsored teams have taken a boosted 2.4 in excess of 10,000 rpms and 1400 (? -- think that's right) hp for drag racing. Remember that the Dodge is running a stroke that's 5mm longer than the KA and getting away with this.

This is what you should be doing -- looking at other current examples of 2.4 NA engines and analyzing their characteristics. It is a lot of work. The answers don't fall from the sky.

That's what I do -- analyze hundreds of different engines and build products for them based on that analysis.

WDRacing wrote:-snip-

There, I saved you some editing.

AZhitman wrote:Dude, save the horsecrap for someone who will pay you for it.

If it was worth something, you'd get a paycheck for it.

It must be -- I have designed, personally built and sold umpteen thousands of windage control devices for hundreds of different engines. That's more successful products for more different engines from more different marques than any company in history. That's me and my wife, and in about four years time.

Horsecrap? No, a lot of hard work.

AZhitman wrote:Kastner hasn't built a KA24DE in his life to my knowledge, so why do you keep harping on him? His accomplishments, while notable, are IRRELEVANT to this discussion.

I have spent time talking with several folks close to him (Brabham, Knight and Millen spring immediately to mind), so it's not like you're "enlightened" and we're "in the dark".

Kastner was in charge of over 225 experts at Nissan Motorsports that were active during the developmental time of the KA. Seems like doing him the courtesy of a query would not be too great a waste of your time. He might not know who to direct you to but I feel he would be very straight forward about that.

AZhitman wrote:Maybe I am retarded, I couldn't understand any of the nonsense you posted.

It probably earns you TONS of points with the pimply-faced Debate Club chicks and the shriveled old guys who spent more time pondering irrelevant crap than they did enjoying life.

I'll be sleeping just fine - You keep chasing rainbows and unicorns, and I'll be boiling the hides off my 400-hp KA-T.

Yeah, yawn, like I just wrote, you only have about 1000 hp to go to match what is current state of the art for at least one example of a dedicated drag racing turbo-charged 2.4.

Shift_Kouki wrote:Could anyone tell me how to figure out (with math / simulations) how to figure out the ratio of lengths for headers, overall exhaust length, intake tube, plenum, and intake mani. (I think i may have goofed there... Is the intake plenum the same thing as the intake manifold??)

Scientific Design of Exhaust & Intake Systems (Engineering and Performance) by Philip H. Smith, John C. Morrison

I have the second edition but a third has been published. Very worthwhile reading and the math is not too severe.

Edit: Just thought of something -- if you really get into this, perhaps to make a career, you might want to look at the first and second editions and see what information might have been left out in the later editions.

Sorry to mention Renault engines again but the factory service manuals are a good example of this happening. I have manuals from the 1960s that show many variations of engines and equipment that were left out of subsequent editions. It is a bit disconcerting because the manuals still purport to cover the same years and engines. It is also something you're not going to find out about by Googling -- not yet, at least.

Another good source of hard empirical knowledge are the over 8000 declassified NACA papers (predecessor to NASA) that are online. They cover many of the modifications that were tried back during what was a zenith of piston driven engine development. A lot of people paid with their lives to generate some of that data -- what really works and what doesn't.

Good luck.

Edit: Just checked and there are 14,469 papers available. Automotive enthusiasts might be familiar with NACA ducts.

Modified by Kevin Johnson at 11:57 PM 3/22/2007
Modified by Kevin Johnson at 12:20 AM 3/23/2007

Kevin Johnson wrote:
Hi Vinnie,

The crank in that photo is fully counterweighted -- the engine was lent to me by SCCA member Paul Neal.

I know Kevin I was being an A$$hole. The second time that I looked at that picture to make a correction I knew that it came from the main page of your web site, plus the 2 weights at the ends of the cranks are narrow. The first time it actually did fool me, but having heart problems causes my vision to go funny sometimes. The bullnose on that L20b crank fooled me at first, (only 4 of the 8 weights are bullnosed). When I saw it the second time I realized my own humility and that it came from your web site....OOOOH Well.

Greg, and Kevin!!!!!! stop bickering it isn't professional.... When every one see's this the only reputation's you are hurting are your own. I tell people good things about Gregs product's and Kevin's product's and this isn't helping out either of you!!!!!!

Bigvinnie wrote:I know Kevin I was being an A$$hole. The second time that I looked at that picture to make a correction I knew that it came from the main page of your web site, plus the 2 weights at the ends of the cranks are narrow. The first time it actually did fool me, but having heart problems causes my vision to go funny sometimes. The bullnose on that L20b crank fooled me at first, (only 4 of the 8 weights are bullnosed). When I saw it the second time I realized my own humility and that it came from your web site....OOOOH Well.

Honestly, I did not have a problem with you posting the pic or speculating about the number of counterweights. It is often very difficult to tell from pictures what design a crank is. Sorry it came across that way.

Bigvinnie wrote:Greg, and Kevin!!!!!! stop bickering it isn't professional.... When every one see's this the only reputation's you are hurting are your own. I tell people good things about Gregs product's and Kevin's product's and this isn't helping out either of you!!!!!!

Yes, I know it is not professional. It is a quirk of my personality which I openly admit. It is one of the reasons I chose not to be a professor or teacher -- I did not want to inadvertently hurt young students.

Kevin Johnson wrote:Yes, I know it is not professional. It is a quirk of my personality which I openly admit. It is one of the reasons I chose not to be a professor or teacher -- I did not want to inadvertently hurt young students.

Ditto.

If this were an "in person" conversation, we'd probably get along fine.

so its over now I can post a ka based question that may be ignorant but hey I'm a newb..

ka24e cam timing... any gains to be had in that area? I have no real experience in this area so any advice would be good...I know de guys have had luck

Wait? The bickering is over? We can post questions again?

Thank God... I was about to make a post like Bigvinnie's and make a new thread that might stay on topic more.

@ Kevin -- Thanks, I guess I was searching through the wrong key words in scholar google the other day.

* NOW * Back to my current pipe dream topic of maxing out NA HP in the KA.

If going all out... lets use 7K as our RPM limit. Lets also bore out 2mm to 91mm and stroke 4mm out to 100mm. That gives us a respectable displacement of 2.6L. At the same time, compression should be upped to 11:1 if on pump gas. More if we run better fuel.

I am pretty sure the KA needs a re-worked intake system to breathe properly at those speeds. -- So ports, manifold / runners, and head.

A long duration, high lift cam (and some tweaking of ignition timing) would also be called for as well as an suitable exhaust system... For me this would be Headers, a down pipe, a resonator... and calling it a day.

Anyone have any ways to improve such a motor??

but all that comes back to the whole why spend so much when an efficient turbo kit can produce more then said setup....

dont get me wrong I'd love to see some 200+ N/A dohc motors running around. LOVE to have one too, but the cost vs rewards dont add up enough. Local guy may be on here, orion, made 328 whp at 12 psi of boost. I cant quote how much he has spent but its not as much as a "streetable" n/a setup at 200whp, not to mention he doesnt have a narrow powerband, which re brings the point of why spend so much... anyone have a dyno of a kade with int/exh/header/testpipe/cams/cam gears/pulley/flywheel/ TUNED ecu? I would like to see it please!

sheesh now I'm debating ,FTL!

Shift_Kouki: In theory, everything you say SHOULD make more power, and I think you're on the right track.

However, I (and several others) have had a DOHC head on a flow bench, and it's pretty damn efficient as designed. There's some cleanup to be done, and gasket-matching / port-matching to be done, but all in all, not enuogh to magically find a lot of "lost power".

I've often wondered about Extrude-Honing the KA head, especially in my application. (NOTE: I'm not a numbers-chaser, because 400 whp is already absurd for an S-chassis car that's driven on a regular basis.)

I think Crower's new KA cams, coupled with some light cleanup of the ports and EH treatment of the runners would be a great start.

Some phenolic gaskets to isolate the intake runners from heatsoak might be worthwhile as well - In fact <if one is good, three is better>, this application should be carried throughout - The manifold-to-head gasket, the intermediate gasket between halves, and the TB gasket...

Might be better off ditching the OEM manifold completely, as runner length is NOT optimized for HP. A log-type design (like the Xcessive)with internal velocity stack-shaped ports might be more appropriate.

Rather than all the "physical" head work, I'm thinking the critical thing for this motor (which KJ touched on) is RPM's.

How to get the DOHC up over 7K rpms? If an SR can be built to see 9K, and a VH can withstand 8K (stock), certainly the same principles should be applicable to the KA valvetrain.

Higher compression means higher temps, and less efficiency, so keep that in mind - Somewhere along the line you'll bump into that "diminishing returns" wall. Certainly a candidate for race gas, but not very convenient or practical for a streeter.

Mine's bored 2mm, with stock stroke, all forged internals, and .5 less compression pistons... I'd love to have seen what it would do off-boost.

The one thing that intrigues me is that it produces peak power FAR below that elusive high redline.... Which means we *just might* be trying to "polish a turd".

Using a low RPM isn't going to get you 200WHP. I'm also quite familiar with Team Mopar's 2.4, I used to follow Sean Carlson's team a few years back.

It's good to use a similar CC engine as an example, but they are still very different engines.

The KA24DE has been taken to 8000rpm with just spring changes. So it's not all that difficult to extend the power band. With the crank lightened and the rotating assembly balanced and the enitre valvetrain redone with as light as affordable parts, 8.5 to 9k should be well within reach. This will be the main source behind the power increase.

So lets use 8.5 as a rpm goal. Anything less and I seriously doubt you'll reach the goal. And if you can reach the goal without using that rpm, then you'll eclipse the goal by breaching the 7k mark. Make sense?

At this point, we have to decide if we're building a drieveable motor, not daily but still useable, or a dyno queen. I hate dyno queens with a passion.

SO lets build somthing we can drive to the car meets once a week to show off. I'll add on to this later, I have to take care of a few things.

WD

Going from information from Nismo -- lose the girdle. Swap in some truck main caps. That by itself will give you back 5% in internal parasitic power loss. I think the girdle is a NVH item and unneeded at these power levels.

Run at least 5" of vacuum in the sump; you can go up to 15" without too many problems. Five inches is the border for low tension rings to work effectively. Piston ring friction is the largest source of internal friction. You might be able to go to just two rings (I am presuming the engine uses three presently -- don't recall offhand).

Higher vacuum reduces pumping losses but consumes more power. The gains from deleting the girdle will diminish when/if you pull more vacuum but you will also be improving the quality of your oil supply.*

These two mods in themselves might get borderline cases over the hump.

*One common issue in high speed valve train stability is air entrainment in the oil. I am presuming the KA24 is running hydraulic lifters. You might want to contact DCR (Darrell Cox Racing) for product development. They have some techniques for improving this in the Mopar 2.4 that may well transfer over to the KA.