i currently have a stock valvetrain, except for the s13 248/248 cams. I will be getting a Enthalpy tuned ECU soon and he said i would be able to set my RPM limit as high as i want. Ive heard that the KA can hit 7200rpm safely. Is that too much for a stock valvetrain? i want to get the ECU so my setup will be tuned, then get upgraded valves, valve springs and retainers. what should i set the RPM limit at? i know KAs cant rev that high, but i want to stay in gear a bit longer because im tired of shifting at 55 mph in 2nd gear. i cant even hit 60mph without shifting to 3rd!

Personally I wouldn't take my motor up that high, besides I don't think your going to be making any power up there that would be worth it (I know it sucks because that shift in there kills my 0-60 times as this is an annoyance to me too). I don't know for sure what the KA can handle as far as Rev's but with the long stroke to the KA I would say revving the piss out of it isn't a good Idea at least until you upgrade the springs and everything else up there (maybe ya would even want some bottom end work to deal with the stress of the high rev's for insurance sake), the cams are gonna dictate where and when your making power throughout the power band not how high you can rev and like I said Personally I shift at 5.5k just because I too am not making power up there either just something that needs "correction" about the KA if your having that much of a problem not having a high revving engine sorry to say your gonna have to get cams if you want power that high in the RPM band. Just my .02Peace,Pat

turbo98_240sx wrote:I shift at 5.5k

Damn son, it's not a Powerstroke haha.

depends alot on the setup where the powerband falls off too much

my jwt ecu rev limit is 7200rpms, when racing i usually shift between 7000-7200rpms on a stock valve train

I shift just above 6800 maybe 7k but the clutch is in by then.Depends where the other car is on how hard I push.

7200 rpms it is then!

sunnys14 wrote:7200 rpms it is then!

But why? if the power starts dropping at 4.6K why do you need to rev to 7.2?Your shifting point should be so that when you hit the next gear the rpms drop to just below maximum power, which is guess what? 4.0-4.5

You people don't understand engine dynamics, Better valvetrain will not make more power, it will only allow the motor to rev higher without disintegrating and without supporting mods to have more top end flow, there is no point in getting better valvetrain in the first place.

And if you do, you will trade off low end torque that we all love so much, key word is trade off, not loose a bit low end to have huge gain top end, doesn’t work that way, its one or the other.

You want a high revving engine, buy a Honda.

who said power my drops off at 4.5k? my turbo, 248/248 cams, flywheel and cranky pulley helps me VERY much at higher RPMS. i would just like to rev a bit higher because i have s13 cams so i can maximize my power band and stay in gear a bit longer. i am posting to see what the stock valvetrain would be able to rev. i know KA isnt a high revving motor thats why im not asking to rev to 8k. i will be redoing my valvetrain after i reflash my ECU.

The lighter flywheel and crank pulley allows your motor to rev quicker not flow more top end, it doesn't increase horsepower or change the power band in anyway (exception for the under driving accessories) it makes your car faster by allowing you to reach maximum efficiency faster.

The cams do allow more flow, but engine volumetric efficacy remain virtually unchanged, you will need to redo the entire intake system, short runner intake, remove secondary butterfly and a crazy head port, then you will be able to utilize the 7k redline, but in the process you will loose low end torque, so the car will be less street able more highway friendly, if that's what you want I say go for it, you'll probably pull on 911's on the freeway, when those suckers were built for the autobahn

PS. your post count as off 8/21/05 is 187...hmm...

Checkered-Member wrote:The cams do allow more flow, but engine volumetric efficacy remain virtually unchanged, you will need to redo the entire intake system, short runner intake, remove secondary butterfly and a crazy head port, then you will be able to utilize the 7k redline, but in the process you will loose low end torque, so the car will be less street able more highway friendly, if that's what you want I say go for it, you'll probably pull on 911's on the freeway, when those suckers were built for the autobahn

LOL... totally incorrect in all regards.

You can't increase flow and not change engine VE.

Acceleration is about applying the most amount of WHEEL torque (read: WHEEL not ENGINE) over time.

Low end torque is a misconception, you have a small displacement 4-cylinder engine. The only reason it stands a chance against a larger motor that produces REAL low end grunt (like a 454) is that it comes factory with a 4.08 rear end gear. It's also the same reason why Honda's can put out 180wtq. yet wax your all-knowing *** because they slapped a 4.70+ final drive in.

7000rpm is what s13s have stock. i have an s14 with s13 cams. shouldnt that mean technically i should have one too?

why does post count have to do with anything?

I had my stock valve springs shimmed to 74lbs. Stock is 65lbs. When I over reved to over 10grand I didn't even float a valve with crower cams. So I'd say stock is fine just have your machine shop shim the vavle springs to make them stiffer.

sunnys14 wrote:why does post count have to do with anything?

Nothing.With his post count, he should know S14 dont have secondary butterflies. Of course crank pulleys and flywheels dont make power, they just rob less of it...

I'd go with JWT's redline of 7200rpm. You should be able to hit 60mph in 2nd by 7200rpm. Also, if you use a J30 VLSD, I think the lower ratio will let you hit 60 in 2nd.

sunnys14 wrote:why does post count have to do with anything?

The police code for murder is 187…

Nismo_Freak wrote: It's also the same reason why Honda's can put out 180wtq. yet wax your all-knowing *** because they slapped a 4.70+ final drive in.

4.40 in all b-series except the JDM hype arr

shimming may be ok with stock, longer duration cams but doesn't it increase the chance of coil bind?

sunny, what turbo are you using and do you have a dyno? i'm curious to see where power peaks too

DRIFTEADOR wrote:4.40 in all b-series except the JDM hype arr

shimming may be ok with stock, longer duration cams but doesn't it increase the chance of coil bind?

sunny, what turbo are you using and do you have a dyno? i'm curious to see where power peaks too

I still want a turbo D16Z6 in a 92-95 hatch.

I think it'd be fun.

sunnys14 wrote:why does post count have to do with anything?

People that have huge post counts have a big pen15, or was it a big ego, I can't remember.

No you were right the first time Alan, big pen15 was the answer

Checkered-Member wrote:But why? if the power starts dropping at 4.6K why do you need to rev to 7.2?Your shifting point should be so that when you hit the next gear the rpms drop to just below maximum power, which is guess what? 4.0-4.5

Actually, the way to choose your shift point is to compare the HP at the RPM you shift from with the RPM you shift to(or you can compare torque at the wheels at given wheelspeeds, but looking at HP is usually easier on paper). The goal is to put as much torque to the ground as possible at all times.

Quote »You people don't understand engine dynamics, Better valvetrain will not make more power, it will only allow the motor to rev higher without disintegrating and without supporting mods to have more top end flow, there is no point in getting better valvetrain in the first place.[/quote]Depends on what you mean by better. Better design? Better(higher flowing) cams? Bigger valves? From a design standpoint, the shim on bucket design the KA employs is the lightest type currently used. It is directly actuated and has the least amount of mass so spring rates can remain lower for a given amount of lift, ramp-up and engine speed. Essentially, the lightest spring that will prevent valve float is best as it provides the least amount of friction. However, the question posed in this thread is merely asking if the OEM valvetrain can handle more revs. The answer actually depends on a lot of factors, but if you are using stock S13 camns, I think it will be fine up to a 7200 RPM redline. A cam that opens a valve faster does require higher spring rates. There is likely some excess amount of spring rate in the valve then is actually required for stock cams, so I would not worry unless you are getting into a very aggressive cam.

Quote »And if you do, you will trade off low end torque that we all love so much, key word is trade off, not loose a bit low end to have huge gain top end, doesn’t work that way, its one or the other.[/quote]Who is we all? While I am all for having a flexible motor, if it comes down to it and my main goal is high performance, then I will trade off low-end torque in a heartbeat. Who here races their KA at 2000 RPM?

Nismo_Freak wrote:
I still want a turbo D16Z6 in a 92-95 hatch.

I think it'd be fun.

Several of my friends are too broke to build up a car, but decided they wanted to anyways, so they all have turbo D16s in 89-91 civics. I used to make fun of them until I went for a ride in one of the cars and heard the total amount invested

Back on topic, perhaps ask rick about this. He uses stock cams (s14 no less IIRC) with the springs and retainers from ka24de.com and revs to 8k.

C-Kwik wrote:Who is we all? While I am all for having a flexible motor, if it comes down to it and my main goal is high performance, then I will trade off low-end torque in a heartbeat. Who here races their KA at 2000 RPM?

Here's my point of view when increasing power in my car, street-ability comes first, everything else is second. Why? Because me and 95% of people on this forum use their car as daily driver.

Why would I build an engine that will be used to its full potential only 99% of the time. Yet so many of us sacrifice or at least hurt street-ability to only gain a second in the quarter because we think it makes our pen15 bigger...

but you dont daily drive WOT (and if you do, i hate you ) so why do you need more low end? if you want to accelerate faster you simply press the pedal further down. racing is where you want all the power you can get and, aside from take off, 100% of racing is spent on high rpms.

edit: btw, is that a home depot motorsports lip kit?

DRIFTEADOR wrote:but you dont daily drive WOT (and if you do, i hate you ) so why do you need more low end? if you want to accelerate faster you simply press the pedal further down. racing is where you want all the power you can get and, aside from take off, 100% of racing is spent on high rpms.

I want good acceleration at partial throttle, I don't want to mash the throttle like Honda owners, my friends civic never drops below 2k, he has to get 4K rpms to get the same acceleration I get at 2.5. I don't want to abuse the motor by having to get it to 3-4K every time I accelerate.

Quite, efficient, reliable, good gas mileage, doesn’t burn up tires.

DRIFTEADOR wrote:edit: btw, is that a home depot motorsports lip kit?

LOL....it is...how did you know?...I'm a ricer and wanted to try something different, well anyway, real sides and rear I already order from ImportFan it's their GDB kit.

And the front will always be that way, car is lowered -2.25" and if I had a real front end it wont be drivable, again street-ability comes first.

hehe, i've seen too many on hondas to not notice when i see one. well, that and i dont know of a kit that extends 3" straight down all around

heres one with dyi brake ducts

Checker, you came in here and made a bunch of uneducated statements about total BS. People read these forums alot, try to keep your opinions to a minimum in the technical forums. If you want to toos opinions around in gen chat feel free, but keep the rest to yourself.

Thanks

WDRacing wrote:Checker, you came in here and made a bunch of uneducated statements about total BS. People read these forums alot, try to keep your opinions to a minimum in the technical forums. If you want to toos opinions around in gen chat feel free, but keep the rest to yourself.

Thanks

<3

C-Kwik wrote:
Depends on what you mean by better. Better design? Better(higher flowing) cams? Bigger valves? From a design standpoint, the shim on bucket design the KA employs is the lightest type currently used. It is directly actuated and has the least amount of mass so spring rates can remain lower for a given amount of lift, ramp-up and engine speed. Essentially, the lightest spring that will prevent valve float is best as it provides the least amount of friction. However, the question posed in this thread is merely asking if the OEM valvetrain can handle more revs. The answer actually depends on a lot of factors, but if you are using stock S13 camns, I think it will be fine up to a 7200 RPM redline. A cam that opens a valve faster does require higher spring rates. There is likely some excess amount of spring rate in the valve then is actually required for stock cams, so I would not worry unless you are getting into a very aggressive cam.

Hey look at me bumpin an old thread!

Good info C, would like to add a bit to this. If you increase your cams duration (without increasing lift) you are actually working your valve springs LESS since now there isnt such a steep deceleration ramp as there is on a lower duration cam with the same lift. ie your valve springs arent trying to close close the valves as fast as before so you get a bit more RPM headroom on the same weight valve springs

And actually shimless buckets are even lighter than shimmed buckets, these are buckets that are indivdually sized in thousandths so it gets a bit more expensive when setting lash to buy the right sized bucket instead of the right size shim, but in the case of my STI that comes stock with shimless buckets compared to my 02 WRX wagon, it saves about 25% per bucket. Alot of us WRX guys swap out the shimmed buckets for STI shimless buckets when we do rebuilds. You guys should find out if there is a commonly avaialbe shimless bucket out there when you guys rebuild your heads, anything to help these KAs rev!

One other point about running bigger duration cams that no one really ever mentions is it will lower your dynamic compression ration a bit as well, which helps out when trying to put boost on top of a stock compression KA!

I take my stock engine to 6800rpm usually once a day... Its seen 7000rpm+ on mis-shift(not sure how far my engine made it, but I hit third on accident while trying to hit 5th when racing a vette).LoL GZ manifold just makes your engine BEG to be taken to 7k...
Modified by nissanfanatic at 8:08 PM 1/1/2006