Powerplant Discussion/Options.

[Riggle]

First off, I just want to say this is about THE best forum for actual race talk regarding the S chassis I have ever seen. Incredible amount of knowledge and actual constructive discussions going on, I have read through the entire 25 pages of old threads and thoroughly enjoyed just about every one of them. I am a bit more of a 'lurker' than a 'poster' and the race banter is top notch quality.

I value the input of the mature race oriented crowd here and finally have a predicament that is in need of some supplementary advice.

I have only been into racing my S13 for the last 2 race seasons so I am still sort of green, but have managed to snag the points championship at my local sports car club (G) and come in top 5 (PAX - ST modifier) in quite a few lapping/track days (amongst throngs of S2k, Evo, STI, C5, ect).

I am definitely hooked and love everything about it, but I feel I am at the point of moving up progressively in the power dept. The car is currently in ST trim with NO power mods, we are talking stock down to paper filter. It has been purely suspension/tires and getting to know my car and driving habits with seat time being my biggest priority. Having a slow car is paying dividends as I can outdrive quite a few of my fellow club members in their own vehicles when I co-drive with them. Now I am not THAT good of a driver as the ST class civics/ZX2's DESTROY me when I go to SCCA events and I most definitely get humbled when I play out there (Milwaukee Region ST class).

Now here is the predicament I am faced with. I have a 1990 240SX hatch with the SOHC KA and it is bar-none the cleanest I have ever seen. Never has seen snow and has only seen rain on a handful of occasions. I want to generate a bit more power but have a REALLY hard time sticking money into the SOHC engine when I feel as though its not the best power plant option. My goal is only 300-350 hp, but I am looking to make that as economical and reliable as possible. I don't really care about my SCCA classing or anything as I go out and drive just to do it. I have no aspirations of winning SCCA nats or any sort of NASA events.

So considering I want to hold onto the car due to the cleanliness of the chassis here are my options.

-Turbocharge the KA24E.
-Swap in a KA24DE and do the same.
-Swap in SR20DET via front clip.
-Dare I say...swap in LS1 (buy in is $$)

I also want to make it clear that I don't NEED the 300-350hp, its just where I want to end up. I would be EXTREMELY happy with a stock SR and put-put around at stock power levels and be happy as a clam. The whole 100hp I have now has been fine for the last 2 years. The end goal of 300-350hp is my end game. Also the only reason the LS is on that list is the fact that I co-drove an LS1 powered FC RX7 on some A6's and was awestruck.

I REALLY just want to avoid the "If I could go back, I would have done it WAY differently" scenario as the collective experience of this board has probably had WAY more of these than you all care to admit.

I am also not looking for the global approval of random internet strangers via a message board, just curious what some of you more seasoned veterans would do given my situation. For me the race season is over (not the case in warmer regions I know) and now is the time to build for next season if something of this magnitude is going to be taken on. I suppose I should also note that I am a BMW/MINI tech and would be performing all of the work myself with a top notch shop at my disposal (no shade tree chit here).

Sorry about the long winded post and I hope this is in the right section.

Thoughts?

[cdlong]

I don't really care about my SCCA classing or anything as I go out and drive just to do it. I have no aspirations of winning SCCA nats or any sort of NASA events.

I'd rethink this part. I autoX my car and up until now I've just been doing whatever the hell I wanted to the car and just ran in the class I thought most appropriate. Now that I've decided to stick to the rules of a certain class, I'm much happier with the direction and limits on the car. It sounds like you can get the job done, and you might want to be competitive in the future.

I'm not familiar with the road race classing, but I assume any of these big power adders will bump you up a class. You'll probably want some room to grow anyway, I'd just check for things that are downright illegal or bump you into a wildly different class. I'll use autoX classes because that's what I know, the first 3 would all bump you into Street Modified, i think there's a min weight/displacement factor, but those are basically equivilant. the LS would bump you into Modified, which is generally for tube frame and open wheel cars. It would still be fun, but don't expect to ever get a trophy or keep up with your competition. Just so we have all the information, can someone provide what class each would bump to?

That being said, I vote SR. It's a light weight, proven system, more affordable than an LSx, and you can slowly invest in more power (rather than start right at your peak goal).

[hai1206vn]

Another vote for an SR swap. You can add more power & mod as you wish toward the 300-350hp range, without internal upgrade, so that saves a lot of trouble. Do that and go play Street Mod, have fun. Since it doesn't matter if you don't win, just build the car so you can enjoy. The SR also works well with track abuse.

That said, I'll turbo my KA. It's perfectly fine right now so why swap out? My car will just stay street/autocross so low boost & medium revs won't break it.

[Matt93SE]

If you don't care about classing, then the first question is budget. power costs money- how much do you want to spend?

All of the ways above are capable of 300hp. some are going to be more reliable than others. A KA-E at 300hp is going to be just about to the limits on a reasonbale budget build. a KA-DE will have much more potential, but will cost more since you need a donor engine/car.
An SR is definitely capable of it with baubles and bolt ons, but the entry fee is more.
the LSx is even more money, but you're looking at a dead-nuts reliable 400+ hp without breaking a sweat.


As has also been mentioned, if you ever plan to TRY to get into club racing, you'll be wishing you'd kept to some sort of ruleset. I built my car the way I wanted, then tried to go club racing. It's still got a stock 130k mile KA in it, but I'm stuck in Super Touring because of some minor things like alu flywheel and big brakes. That puts me up against former- and current- World Challenge cars when I run on the national level. Those are $100k builds with badass engines and sequential trannies and Moton shocks and etc...

vs. me with JDM coilovers and a stock engine and homemade Wilwood brake kit.

If I had it to do over agian, I would *probably* pull off the simple mods and run the car in Improved Touring for a while. instead up stuck in $$$balls-out Super Touring$$$.

So if you ever plan to race this car competitively, it's definitely something you need to keep in mind.

there's my been-there-done-that $0.02

[Tower240sx]

I love my SR but for the same price as a front clip you can assemble a much more capable KA24DE and a turbo kit and not have to guess what's lurking inside.

LS's are tempting but require a large commitment on several fronts...like the rest of the car immediately becomes inadequate,

Best of luck,

This is the fun part, keep us posted

[logr]

v8 can run in XP which is a very tough class. Actually they are all tough. Stay with a Nissan engine and you can run SM, much easier class. That's a joke.

I fit the "mature" part quite well, actually, many younger people don't think so.

SR or turbo a KA, either way will give you all most people want. I like SR for the ease and simplicity but a turbo KA does the job too.

Once you go this way, there is no going back. Compare SM to ST where you run and decide if you are ready.

I could never go back but I like power very much.

[Black R]

Don't look at me!

I did 2jzgte and it was a toss up vs the lsx.
I'm thinking this was a good idea gone bad or vice versa. Idk yet. Ask me next year.

But I do have my sm civic still...

[Def]

I prefer an SR, but any engine will get you to your goals.

[WorkInProgressK]

Running A KA-turbo will be the cheapest for your goals, since you need the same injectors, maf, tune, turbo upgrades anyway on an SR. Better do it with a cheaper and more available engine.

[PoorMans180SX]

I vote SR. You can gradually upgrade, and don't need engine management till you're up near 250whp.

KADE's are decent engines and all, but not that plentiful in the midwest, and need forged pistons to reach your goals.

If you're looking for a little more work-->reward ratio, VQ30's from Maxima's are pretty cheap, light, and have big potential. AND there will be soon be an adapter to mate them to the KA trans.

[Tower240sx]

either a KA or SR should get a Nistune board as soon as you start mods soo....yeah

[WorkInProgressK]

either a KA or SR should get a Nistune board as soon as you start mods soo....yeah

as soon as you change turbo's

[stewiefied]

I've been almost where you are, but with a blown kade. I would also vote to look into some rule sets just for the future. You may not care about it now but i bet you will later on and having that one part that bumps you into a much higher class really sucks.

One option would be to just do bolt ons for the ka-e and run ITA/ST. But that is all money down the drain later on if you do try to reach the 300-350 mark.

My opinion would be to swap in a ka-de and add a s15 t28. There are plenty of donor engines in Chicago for cheap(got mine for 450 with trans). Later on you can build up the motor and turn up the boost and your at your power goals. You Sounds like you have the facilities to do the work.

[No Rotr]

I went the SR route and have never been really happy with it. I have the standard bolt on stuff and a T28 turbo so it made around 250 whp. Silly little parts that break are a pain to get when you're in a jam (i.e. coil or any det specific part). They like to run warm and they make no torque. You have to deal with the JDM aftermarket stuff when you mod it which I hate with a passion, but aftermarket stuff is there. Now mine blew up but I think that may have had a lot to do with a lack of a real tune. So I am going the turbo KA route next year...I think. Its about the same weight, actually makes some torque, and can get simple parts from regular auto parts stores. So my vote is ka24de plus turbo. Done right it should last you at those power levels

[Def]

I'm sure the KA can take 350 rwhp in stock form, but approaching that and track usage? I don't know how happy 9.5:1 CR is with that much heat and boost.

With how cheap you can pick up an SR motorset if you look around, I don't see how a KA is really that much cheaper once you get to the ~300 rwhp range where I might start thinking of new pistons at a minimum and freshening up the engine while you're in there just due to the stock CR. At that point, you're up to the cost of an SR easily.

I think the powerband of an SR, especially with a bigger turbo and cams is much better than a KA, but that's just me.