# Ka24e/z24i na build for the track. Suggestions/options wanted!



## kronic_chronicles (Oct 23, 2008)

I'm wanting some help and/or suggestions for bulding a naturally aspirated ka-e or z24i. Its for asphalt racing, 4 cyl class. Reason for not using the dual cam is because the max displacement for a 16 valve motor is 2236cc with stock valve size. I have two complete ka-de motors and one z24 block. I will have a single cam head shortly. The chassis will be a kouki z31, with a ka engine in it. Reasoning for the z31 is that it has been beat to hell, and I already have it in my possession. The car deserves more than being junked, and its not worth restoring and would too expensive to get it to pass inspection.

The class is mostly made up of foxbody mustangs. There is one Honda that is doing well, but the Saabs are dominating. I know that the ka-e has a stock hp of ~140. The mustangs have ~90hp. I strongly believe the ka or z motor will easily do better than the mustang 2.3, and hopefully the saab 99 also.

One main question I've had for a while, can anyone tell me if the intake manifold from a z24i will bolt onto a ka head? I can check this out at the junk yard if no one knows for sure. The class will allow fuel injection, but a majority of the cars are carb'd. Rules for fuel injection include stock intake manifold, a restrictor (size determined by officials), all air (including idle) must enter through restrictor, no funneling air.

I'm not planning on dumping $10k into this engine, so its not going all out. I have to stay under 2451cc. I have read that the max rev on a ka motor is ~7k. Our mustangs are built for 8k, but i don't believe the ka will need to be that high to compete. The block will work whichever way I go, ka or z24.

The main reason I am considering carb is because they will get suspicious if the car is dominating too much. The independent rear suspension may get me in trouble already, so I am wanting ideas to restrict myself and compare my car to my family's cars during practices before competing. I feel the fuel injected has more options to tune electronically and may be too effective. I have high hopes in Nissan and their technology, so its stuck in my head that it will beat ford, honda, and sabb lol. I could think too highly of Nissan, but I doubt it.

Gear rations is another thing I would like advise on. We are running on two 3/8 mile high bank tracks, with one of them being resurfaced this year. I have three FS5W71C transmissions, two from s13's, and one from a z31, along with two T5s from the z31 (yes i know the T5 wont bolt on, i would make an adapter). I would prefer to run my z32 lsd, but I may end up going with the z31 open diff or a j30 lsd. We have to run 13 inch rims with max width of 7 inches, so I cannot adjust gear ratio with tire/rim size. Our two cars are currently running in 4th gear, but are also using 4 speeds and a ford 9".

Suspension shouldnt be too much of an issue. With the z31, I have separate springs and shocks in the rear, and the mustang racing springs we have will work under the rear of the z31. The caster/camber adjustments may take some creative work to still abide by the rules, but I believe we can figure it out.

I am doing research, using google and the search button, so no flaming please =). I would like suggestions though, and am open minded so throw any crazy ideas out there lol. Thanks in advance for all ideas, opinions, and suggestions.


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## rogoman (Dec 16, 2004)

Go with fuel injection. It's so much easier to tune with fuel management accessories that are available. Carbs are a real pain to deal with plus parts are hard to get.


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## kronic_chronicles (Oct 23, 2008)

I would rather go fuel injected and run a socketted ecu or retune my megasquirt from my turbo z, but I'm afraid that if I do too well from the start the class will kick me out. thats why i'm leaning towards carb for the time being, until more people swap over to fuel injected. my family is staying with carb for next season. I'd like to win, but i cant win by alot or the officials will get suspicious. 

three years ago they threw out a guy who had rwd and independent rear suspension because he was walking all over everyone. the fwd cars have basically the same setup for rear suspension as i would, but being rwd i dont think i could get away with it if i dominate the class every weekend.

my current idea is single cam head with z24/dual cam block. dual cam bottom end internals. modified z24 manifold with holly 2 barrel carb. z32 brakes. 71c transmission with z32 or j30 lsd. still not sure what cam to use, would like suggestions on duration and lift for 3/8 mile. running in 3rd or 4th gear at ~5-6k is what im planning. basically running open headers, intake and exhaust port matched.


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## rogoman (Dec 16, 2004)

IMO, a cam with around 270 degrees of duration and around a 0.400" lift would give you more mid to high end power while still maintaining good mid range torque.


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## 91nismod21 (Feb 19, 2011)

go to OandJperformance.com.they have alot of stuff for ka-es and ka-des.i just bought a cam from them for my 91 d21 ka-e.its got 260 duration and 445 lift.this would be good for you for some good kick off the corner.....that is if you find a ka-e motor


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