making KA rev to 8k rpms.... how hard?

[cyrus240sx]

how hard would it be to make a ka24de rev to 8k rpms? could you do it with cams, springs, and retainers, or would you need more stuff done?

and if thats too hard... whats the highest I could go without braking the bank on tons of headwork?

[InsanityInc]

Worry about getting it to breathe that high before you get it revving that high.

[Florida240sx]

Why does exeryone want their KA to rev?Use the redline you have. Power is dropping off.If you have a dyno and it's still making power at 7k let me know. But yea upgrade valvetrain.And you'll be safer.Don't know how much abuse it can take though.

[cyrus240sx]

well the reason i wanted a higher redline is im getting ready to go turbo and i want something for big power, so i was going to get the PK GT35 from http://www.phatka-t.com. now according to their dyno on the s13.... it doesnt hit full boost until around 4200 rpm. i would be getting a cam that would make use of the turbo in the high rpms and if i could rev farther than 7k, it would make me alot faster.... i think

[Florida240sx]

Get car made for torque and get turbo for high rpm....

[Nismo_Freak]

well the reason i wanted a higher redline is im getting ready to go turbo and i want something for big power, so i was going to get the PK GT35 from http://www.phatka-t.com. now according to their dyno on the s13.... it doesnt hit full boost until around 4200 rpm. i would be getting a cam that would make use of the turbo in the high rpms and if i could rev farther than 7k, it would make me alot faster.... i think

You will be moving pretty good by 3500 RPM.

You will find that full boost is a luxury you don't get to use everyday in most situations as the car accelerates rapidly.

Cams will facilitate more lag as well.

The KA will need more bottom end work to rev to 8k constantly. Even with built internals you are still inviting rod failure due to the high stress due to the astronomical piston acceleration (from the stroke)

7200 is easily do-able IMO... built motor I'd look at 7700 tops to keep things together for the long haul.

[Nismo_Freak]

Power is dropping off.

That doesn't mean the car isn't still accelerating.

My bone stock 140 HP NX jumped about 2 car lengths on my friends modified S14 simply due to the fact that I was operating a 7800 RPM redline so I held out 2nd gear longer.

RPM is the large reason the GTR is so widely used, if it didn't have it's high revving powerplant it would have been more closely matched by the Supra.

[PandaS14]

8k is doable. I wouldn't do it without aftermarket rods, pistons and accompanying hardware tho. The head with a few minor mods (valvesprings and retainers) will be able to hold 8k rpms for days in a row. The bottom end is the problem. So with aftermarket rods and bolts, the bottom end shouldn't stretch any. However, I would get the lightest rods and pistons you could tho. Since the stroke is so long, making piston speeds very very fast, you want the lightest components possible, to reduce stress on the rotating assembly. This will be crucial to making the bottom end hold together. A full dynamically balanced rotating assembly is key too. Any bad harmonics, and kaboom. This is very difficult tho, because the ka crank being half counter weighted does not lend itself to a good balance/harmonics.

I say 8k is doable because the dohc race motors for the baja trucks see up to 11k pretty regularly, and stay together.

don't get me wrong, I'm saying 8k once in a while. Not like bouncing off rev limiter drifting.

[cyrus240sx]

thanx for the input... i just sit around wondering about different things i could do to my car.... most of em i probably wont do... or wont have the money to do for a long while ( like make it look like a jdm s14a and paint it white lol)

[thekage]

8k is doable. The bottom end is the problem.

Hes right.. its the bottom end. I remember a huge discussion on this before. It was brought up that the huge problem is the piston speed and the crank itself. You are looking at massive amounts of money... I remember Devious was pretty adamint that it was pretty useless..

[PandaS14]

yes, the stock ka crank is damn near useless.

[HashiriyaS14]

Hell, what would it cost to build up an engine like that? What do the Rebello-built GT3 KA24E's sell for, something like $30,000, right?

To hell with that. I can get a 265hp 7500rpm Tomei Derive Phase 3 crate engine w/ITB's for $16k.

While the crate engine itself isn't available from TODA, you could build this entirely from the parts they sell individually:

The only other option that I can see is a used SCCA GT3 KA24E, which will run you about $8000 w/spares, but it'll have some hard hours on it. I think they make about 250hp@8000+rpm, but I don't know how long they can do that for.....

[Veriest1]

Around 30,000 for a whole used GT3 car..

GT3 SOHC are going for about 6500 used. That's without the carbs and such though.

If you do all the work yourself it's a lot less and the engine is fresh.

What's the lifespan on the TODA engine you posted?

[HashiriyaS14]

What's the lifespan on the TODA engine you posted?

I don't really know, hell, I don't even know the hp or redline. TODA doesn't give out too much info on their racing engines.

The Tomei crate engines are designed with street applications in mind though, well, you know, as streetable as a 265hp NA 4cyl can be....

Veriest: You're right, I remember seeing the listings now, it was about $30k for a whole car, wasn't it?

I don't really know how long those GT3 KA's run for....if you can get the whole thing done for significantly less than $6500 yourself...might actually be a viable engine for some people. Crazy people...with money.

[240marcuSX]

ever try stuffing bowling balls into marble sacks??

[Thee 240sx Owner]

I remember a guy in cali had an NA built SOHC that made 298hp and 263lbs of torque at 7k rpm.. but that was a fully internally balanced motor and external oil pump and everything else was fully built with ITB's

[HashiriyaS14]

I remember a guy in cali had an NA built SOHC that made 298hp and 263lbs of torque at 7k rpm.. but that was a fully internally balanced motor and external oil pump and everything else was fully built with ITB's

Now THAT I want some pictures & detailed specs of. 298hp@only 7k rpm is a bit insane though.....

Can you get any more info on this engine?

[Thee 240sx Owner]

ya let me try and find the link.. this was a while back

[Nismo_Freak]

Contrary to popular belief, you can't get a Tomei engine.

You pretty much have to be racing you 240SX, and have alot of support and coverage to run one of the engines.

The process involves several interviews with Tomei in person.

[KADreams]

I personally believe that to safely and reliably rev to 8000-8500 RPMs on a consistant basis in a KA you need no less than titanium rods. I think a set from Pauter runs around $2500. Piston speeds are absolutely insane at these RPMs. The KA valvetrain is very solid and with upgraded springs/retainers could handle 9000RPMs all day long. You will also need to modify your oil pump to provide more pressure and flow. The stock pump won't cut it at these speeds and the motor will eat bearings like candy.

[drifter_for_life06]

I don't really know, hell, I don't even know the hp or redline. TODA doesn't give out too much info on their racing engines.

That's because you have to have a racing license to even begin to buy their motors. Call and ask to fin out for yourself

[HashiriyaS14]

That's because you have to have a racing license to even begin to buy their motors. Call and ask to fin out for yourself

You have to have an awful lot more than that, I believe. I don't think TODA "sells" their racing engines at all. Insomuch as I am aware, they are only "leased" to teams competing in FIA-sanctioned events, with TODA approval.

This means that, effectively, the teams have the engine, they can use it, and they can blow it up, but in the end, all parts go back to TODA, and the engine is always serviced by TODA, I suppose to keep anyone else from being allowed to tinker with their technology.

EDIT: About TOMEI, I know that (as dumb as this will sound) Paul Walker had a "GENESIS" RB26 in his R34 (his real one, the one SCC blew up). I didn't know that it was that hard to get one, I figured it just required writing a check.

[InsanityInc]

That doesn't mean the car isn't still accelerating.

My bone stock 140 HP NX jumped about 2 car lengths on my friends modified S14 simply due to the fact that I was operating a 7800 RPM redline so I held out 2nd gear longer.

RPM is the large reason the GTR is so widely used, if it didn't have it's high revving powerplant it would have been more closely matched by the Supra.

Uh. No. God this is so wrong I don't even know where to start. If you jump 2 car lengths because he SHIFTS, then he either has an automatic or palsy. Even if for some wonky reason you did get two car lengths because he shifted, he would gain them back as soon as you shifted, so it would be irrelevant. Power is power, regardless of where it is in the powerband. And in actuality, the lower, the better since you'll get a much better powerband. The only way that RPM itself can help you is in very specific tests (0-60, a car that doesn't have to shift into third or even second will edge out one that does) but even in those cases, the difference is maybe a tenth of a second or two, not 2 carlengths. Please. Feel free to run your KA out to 7000, you're just slowing yourself down. By your logic, your NX would gain on a viper.

[HolyShiznit]

Hehe, all this talk about making the KA rev is pathetic. Look at Ivan's power band with the cams and the GT35, who wants to rev MORE? He already has an awesome power band nice and flat, it's about AREA UNDER THE CURVE not revving it out. 2 years on my KA-T, and with my latest built motor I have no desire to rev it out, it's plenty enough for me, especially when I get the crower cams in.

And if revving it out means NOTHING if you fall out of your power curve, you want to shift INTO your torque band, so you essentially keep the turbo on "boil" and inside your powerband. By that logic a Honda should ALWAYS beat a 240, and yet......

[Veriest1]

....

Just because a motor is capable of high RPMs doesn't mean it doesn't make power down low.

Once the KA is made to breath better up high and has cams yadda yadda it will have power there too and the increase in RPMs will be benificial.

The best example of what Alan is talking about is in autocrossing where the cars don't normally need third gear. Every now and then though there is straight long enough to hang third gear for a few seconds. The driver is now faced with the decision of holding the car in second or shifting to third then downshifting again. What's faster? Depends on how much time you lose during the upshift vs how long you can hold third. Chances are you're going to be better off just holding second for a bit just below redline. Now what if you had another 1000 rpms to work with... all of the sudden you have one less decision to make on course. This is a good thing and now you're faster than the guy who decided to shift and the guy who decided to hold second. At least through that section of the course.

For drag racing what if you have to shift into fourth and your opponent doesn't but otherwise the two of you are about equal? Assuming you both make a good run you lose. Stop light to stop light this could even be the shift into third.

[InsanityInc]

....

Just because a motor is capable of high RPMs doesn't mean it doesn't make power down low.

Once the KA is made to breath better up high and has cams yadda yadda it will have power there too and the increase in RPMs will be benificial.

The best example of what Alan is talking about is in autocrossing where the cars don't normally need third gear. Every now and then though there is straight long enough to hang third gear for a few seconds. The driver is now faced with the decision of holding the car in second or shifting to third then downshifting again. What's faster? Depends on how much time you lose during the upshift vs how long you can hold third. Chances are you're going to be better off just holding second for a bit just below redline. Now what if you had another 1000 rpms to work with... all of the sudden you have one less decision to make on course. This is a good thing and now you're faster than the guy who decided to shift and the guy who decided to hold second. At least through that section of the course.

For drag racing what if you have to shift into fourth and your opponent doesn't but otherwise the two of you are about equal? Assuming you both make a good run you lose. Stop light to stop light this could even be the shift into third.

You're completely disregarding that cars that have different revability are also geared very differently to compliment the operating abilities of the engine. Sure, those situations COULD happen, but that doesn't make having a higher redline just for the sake of having it a good idea.

[Veriest1]

I guess that's just the way you disregarded my examples with this statement.

Quote »The only way that RPM itself can help you is in very specific tests (0-60, a car that doesn't have to shift into third or even second will edge out one that does) [/quote]Even so, increasing RPMs on a KA and providing it the capability to breath at those RPMs will help whether the gear ratio is changed or not.

Gear ratios and how they vary from car to car isn't something I'm very familiar with. I do know many people lower their final drive for faster acceration. Mustangs and M3's come to mind. For example the M3 came in many trims in '95 and one was the CSL which, among other things, included a lower gear ratio that was adopted in the '96+ models however they didn't change the rev limit of the engine for the CSL's to compensate. So there are some courses where the non CSL gear ratios will have a bit of an advantage over the lower CSL ratio and the same problem of to shift or not to shift comes into play.

[InsanityInc]

I guess that's just the way you disregarded my examples with this statement.

Even so, increasing RPMs on a KA and providing it the capability to breath at those RPMs will help whether the gear ratio is changed or not.

Gear ratios and how they vary from car to car isn't something I'm very familiar with. I do know many people lower their final drive for faster acceration. Mustangs and M3's come to mind. For example the M3 came in many trims in '95 and one was the CSL which, among other things, included a lower gear ratio that was adopted in the '96+ models however they didn't change the rev limit of the engine for the CSL's to compensate. So there are some courses where the non CSL gear ratios will have a bit of an advantage over the lower CSL ratio and the same problem of to shift or not to shift comes into play.

And the times when it will come into play are almost completely irrelevant when taking the car as a whole. And it's certainly not 2 car lengths, that was just a ridiculous statement.

As for changing gearing based on the engine, take the viper for example. It redlines at 5k. A viper has a top speed around 200mph. That obviously requires very wide gearing. Specifically, a 3.07 final drive. While the redline is lower than say an NX or 240, a viper can do 0-60 in first gear.

[Nismo_Freak]

Uh. No. God this is so wrong I don't even know where to start. If you jump 2 car lengths because he SHIFTS, then he either has an automatic or palsy. Even if for some wonky reason you did get two car lengths because he shifted, he would gain them back as soon as you shifted, so it would be irrelevant. Power is power, regardless of where it is in the powerband. And in actuality, the lower, the better since you'll get a much better powerband. The only way that RPM itself can help you is in very specific tests (0-60, a car that doesn't have to shift into third or even second will edge out one that does) but even in those cases, the difference is maybe a tenth of a second or two, not 2 carlengths. Please. Feel free to run your KA out to 7000, you're just slowing yourself down. By your logic, your NX would gain on a viper.

LOL, you are completely fooled by your own ignorance.

I am in 2nd gear, he is in 3rd.

If we produce the same amount of power, my car will ALWAYS out accelerate his at this point. A Viper produces 3.5 times the torque than my NX, and it's gearing is wider but the final output in terms of power is still greater.

Multiplication of force via gearing, quite possibly the sole reasoning why shifting after the torque begins to drop off is not the fastest way down a straight line.

Physics > your logic.

[InsanityInc]

LOL, you are completely fooled by your own ignorance.

I am in 2nd gear, he is in 3rd.

If we produce the same amount of power, my car will ALWAYS out accelerate his at this point.

No. You are soooo wrong. Your car ends up going slower at higher gears because of increased air resistance, which doesn't factor in when you're going the same speed. If you are making 300hp and you're in second gear and I'm making 300hp and I'm in third gear, and we're both going the same speed, in a car the same weight and aerodynamically the same, we have the same acceleration. Torque itself means absolutely nothing for acceleration. The fact that you're trying to dispute this proves you haven't got a ****ing clue what you're talking about.

So you're wrong in the theoretical realm, and I'll tell you why you're wrong in reality as well. If you rev your KA out to 7000, and I shift at 6400, then gain the same amount of speed lower in the RPM range, I will be accelerating faster than you. End of story. This is because engines do not have a perfectly linear powerband. The only way you'll show a faster time on paper is if that shift happened very soon before the end of the E.T. before the superior acceleration makes up the time differential from the shift, and/or before you yourself shift to make up that time difference.

Quote »Multiplication of force via gearing, quite possibly the sole reasoning why shifting after the torque begins to drop off is not the fastest way down a straight line.[/quote]First, when did I say shifting after torque drops off? You decide your shift points based on a number of factors, one of which is when your power drops off, and another is where you will end up in your powerband after you shift from that point.

Quote »Physics > your logic. [/quote]No, you're actually being owned by logic and physics right now.