Who winds thier Ka-t the highest

[sumfoo1]

I'm working on a ka project and was wondering what Valves/valve springs cams intake manifold, rods/pistons etc. Are you using.

I'm just wondering if there are any 8500-9000 rpm Ka-t out there and how they did it .

[s13rb25det]

the ka does not like to rev at all. mostly because of the timing chain and half balanced crank. turbo magazine is doing an article about making a ka make like 750hp and rev to 10k and they are doing all sorts of stuff to it.

[Skeeg]

big valves... .7 over exhaust and .5 over intake. v3 cams, fully machined and polished head. fully built block, whole engine blue printed and balanced.....

that and u might be able to rev to 8grand, possibly 9k but i wouldn't risk it. course, you will pay more for the engine itself then you did for your car most likely!! lol

[TheOne]

if you really wanna rev that high, prolly gonna have to buy 1 of'em ams fully counterweighted cranks, along with building the top end.

as the stock crank will prolly crack in half after 8k rpm, not only that but it'll stop makin power after maybe 6k rpm.

[480sx]

Like these guys have said, a Ka doesnt like revs. Doesnt need to rev. The engine was built for incredible low to mid range Tq for a 4 cyl, and thats its strength. Rev to 7k, or 7.5 or so, shift, and let the low end do what its designed to do. You dont need to rev to make power, especially on this motor. This is no honda .

Like these guys said, if your stuck on revs+ka you need to get a FCW crank. However, there are 100's of better ways to spend your money.. Gotta remember your Power to Dollar ratio.

So far, the one guy(that i know of) who has the BC stroker kit + the FCW crank running a fully built setup isnt really very impressive at all. The TQ curve that makes a KA so much fun is gone, replaced by a weak sauce honda like dyno sheet. Hes still in the process of tuning it, and i wonder if his tuner knows what hes doing but thats neither here nor there.

[cornercarverzx5]

^ for sure, the ka has such awesome low and midrange because it has a long stroke and high rod angularity, that's why it responds well to boost and why the sr can rev so high since it's stroke is a lot shorter. it would cost way too much to get the efficient high revving power you are looking at, your money can be spent much better on other options

[24DSXY1]

I think Ivan's ams 9 second ka revs to 8500.

[nelson8708]

get some custom aluminum rods to go along with the AMS crank. The head is good for some high revving since it is cam over bucket design (like the ca and rb). Its the stroke that prevents it from making power in the top end.

[sumfoo1]

I didn't know about the crank. that and the small ports must be the main problem... I wasn't really planning on winding it that high... i was just wondering what was possible.

People keep blaming the stroke but honestly guys i think thats bull... i've reved a 392 ci small block ford to 8000 rpm before and didn't have any issues once the oiling problem was fixed (98mm crank aaaaannndddd being a v motor it had 2 cylinders between the mains )

But yeah any motor i get will be worth more than the car cause the car i'm buying is for 900 bucks with a "bottom end knock" or more than likely a spun rod bearing.

I was just trying to get an idea of what i should do while the motor is all the way apart... i haven't even purchased the turbo kit part yet but while i'm rebuilding the motor i figured i would try to built it the best i can...

So on the $/hp scale is building the head really worth it @ all? The final goal for this car is either a gt30 or gt35 @ 20-25 lbs of boost. I'm planning on going stand alone with big injectors and a huuuuge fuel pump because i want it to be able to be a flex fueled vehicle so i can stop, get the car drunk and crank up the boost.

[WDRacing]

The biggest thing to consider when increasing the usable rpm band is will it actually be used. By that I mean, is the car going to be raced alot? Because shifting the power band up that high requires a cam profile and turbo that will support the in/out flow for those rpms. This will diminish the daily driving range.

The key to fast is creating the largest usable torque curve for any particular application. When you can create a power curve that spans from 3k to 7500, I fail to see the need to rev to 9k.

Things to be considered for increasing the rpms for the KA on boost are cams, valve train, rods and intake manifold. The crank will be fine IMO, but using a good forged rod is important. So isn't having the assembly balanced.

The KA will rev, it just needs some work to get there. It's not a hard concept to grasp, just improve the motors ability to move air. Then increase it's weak points so you can increase the rpms accordingly.

WD

[sumfoo1]

Thanks WD the goal right now is to make a car that is about 400 whp capable on moderate boost. But thats not the final goal for the car and i just don't want to have to build the bottom end of the motor again if i didn't blow it up.

[cornercarverzx5]

there is a formula for any given engine to fins it's rpm range

for safe level it's: 22000 / stroke

for max level it's: 27600 / stroke

so for the ka:

safe-5820.8max-7302.5

so to find how high you want to go use this, but remeber you have to match the cam profile to to the engine rpm or else you will hit the "cam redline" where you no longer flow air efficiently

[sumfoo1]

^ so they made the stock motor rev to a "nonconservative" level that seems odd usually you can push the stock crank at least 500rpm farther without fret. I also am aware that cam turbo and intake need to be matched to the desired rev limit.I mean no since in revving a t25 to 9000 rpm because it would choke the motor.

It was more of a hypothetical question.. i just want to make sure i'm not building boost and dropping out of it on every shift.