1990 240sx with a fresh SOHC KA. we do Lemons races and soon ChampCar races with it. The car handles really well, but we are lacking in the power department. Looking at either putting a turbo on our current motor (5-10psi) or a complete swap. This is budget racing so I don't have unlimited funds, but this is also not a daily driver so I'm not worried about AC, Power steering, etc etc.

looking for moderate power levels (200 and up) with reliability of getting thrashed on for 8hrs a day. We are all pretty good wrenches, this is just our first foray into the import world.

Lets hear some opinions!

Turbos are usually not as reliable as NA engines, there's just more stuff to go wrong.
BUT, keeping it moderate (I'd say 7psi and under) really improves your chances.
What would you be thinking of swapping over to?

Having slapped a turbo on the ka24e on my first hatchback and running a built ka24de turbo on my s14 currently, i will speak to a couple of points as they apply:

Power: you wont have trouble hitting your 200hp mark on the stock bottom end. I ran 8psi untuned on mine from about 210k miles of the engine's life until about 245k. It was loads of fun and had a great powerband. Back then KA engines were dime a dozen and I had a spare in my garage so I turned up the boost to see what she would toleratel. I made it to about 10-12 psi. The cheap manual boost controller i was using was spiking badly. Which brings me to point 2.

Reliability: I was in NASA SE and ran HPDE events while I was stationed on the east coast. I am familiar with the lemons series and what you'll be asking from the car. The short of this is you CAN make the car reliable enough to tolerate a turbo in a race series BUT at the cost of weight and money. Not sure if this would break the budget here. Youre going to be adding a lot of weight to the nose of the car too. Ic piping intercooler and oil cooler. Ill get on later and speak more to this. There are budget options for the injectors and parts.

Have you looked at a ca18det? As far as reliable budget 200hp goes... i'd go that route. Where's Ryan at when you need him...

Im currently on lunch break doing some digging... i THOUGHT you could make a hybrid high compression KA by bolting the DE head on the E block (DE head has 18cc less volume per combustion chamber so you'd be around 11.7:1 depending on the CR in your E, with an arguably better flowing head) but it's not a hugely popular (or possible?) route since you still wont make 200hp off of it most likely.

I would not recommend the CA haha. They aren't really common enough for knowledge and parts to be around.
The longest I've seen one last without issue was about 2 hours at National Corvette Museum Motorsports Park.

The CA is a VERY popular engine in other parts of the world, especially Australia, so don't worry about parts availability. Reliability isn't an issue with a CA anymore than a KA or an SR. The only reason my first rebuilt CA failed was from a bad oil filter. That thing saw 8k RPM multiple times a day, basically 7 days a week, for probably 5 years... That being said, you're on a budget, and you already have a KA. And getting 200hp with a small amount of boost isn't very difficult and probably the cheapest option... If you're set on NA and want reliability, you either need to spend lots of money on internals to increase compression and peak RPM, or put a more rev-tolerant or a larger displacement engine in.

Since we're on the subject, an NA KA that makes 200whp is pretty hard to do, at least on pump gas;
https://www.nicoclub.com/archives/natur ... 240sx.html

Now, if race gas or E85 is an option, things get easier...

float_6969 wrote: ↑

Wed Jan 08, 2020 11:02 am

The CA is a VERY popular engine in other parts of the world, especially Australia, so don't worry about parts availability.

I meant if you need a part that day or overnight (as often happens in racing, or the days before a race)... its less likely to happen with a CA than it is with a KA or SR.

Ryan - did you ever race yours at a legit track?

A CA is basically a Pulsar engine, so I never had trouble getting parts locally, but that's an old enough car now, they don't stock parts like they used to. I've still not had any trouble getting things quickly through online retailers. I mostly use FRSport. But, that being said, yes, KA and SR parts are easier to get locally for sure.

Yeah, there's a track here in Topeka, Heartland Park. Not competitively though. Just a track day once. Engine did fine. My crappy brakes at the time did NOT, lol! I've done autocross mostly. It's been a few years since I've done anything though. I was hoping to pick it back up this year, but an old lady smashed my S14 and I'm still fighting insurance. If things keep progressing at this rate, I won't have it fixed it time to anything this year before I get busy with work.

To echo what you're saying about parts availability, I've had mixed experiences with parts on my KA locally. Coolant temp sensors and TPS along with generic felpro gaskets are generally available. I had to wait a couple of days for a rear main seal kit though. And yes I cross shop between advance/autozone/oreileys. All of these engines are aging. Im having to buy my oil filters ahead of time because they dont stock the HP2008 K&N filters I use anymore. Valvecover gaskets are a mixed bag. Not in stock and (luckily for me) most of the stores around here seem to have an error in their inventory and will order S14 gasket sets regardless of the year of KA24DE...

They certainly don't have alternators, distributors, and coolant pumps around here. I can snag a thermostat and gasket same day though.

Mileage varies.

Basically the same situation for the CA. I can get them to bring stuff in in a couple of days at most, but not much setting on the shelf anymore.

Thanks for all the replies! Budget is probably 2k. The current motor is freshly rebuilt, .050 over, with new Pistons, rings, etc. I'm not looking to raise the compression as running more than 91(prefer 87 as fuel is expensive over 15hrs of racing).

Only interested in doing a swap if it is going to get me some displacement. obvious easy answer is a LS swap, but they don't do that well in road racing applications without a lot of money. They tend to overheat. Would also mean a tranny swap = $$$

Looking at the VH45de. Fits, excellent hp in stock form, lightweight, reliable.

Also have a 289 and Ford top loader for free, but not really sold on that being a good option.

Thoughts?

Didnt take the lower octane into account; with a turbo on the stock bottom end even at 8 psi you're going to want to run higher octane than 87 and a range colder plug in order to not flirt with detonation which the oem cast pistons are rather susceptible to (moreso the DE than the E motor that youre running but still...) or retard your base timing on the stock ecu which is going to gutpunch your response out of boost.

Whats your fuel delivery situation? Are you running stock pump and fuel tank or a fuel cell and something else? Regardless of turbo or swap thats a weakpoint on your car that will need to be addressed.

What pistons are you running and did you gap the rings to stock spec?

Is one of your guys a welder or are you going to have to pay someone for fab work? That's going to make or break your LS budget there but it sounds like you've already sort of ruled it out.

The LS fits because of the engine profile. Id be interested to see if the 289 fits without sawzalling a huge hole in the hood. Ive never seen it done on this chassis.

The VH is nice but.... the adapter plate in order to put a transmission on it is over $400 alone (assuming you are gonna want a manual) and then you're going to be asking a lot from your KA transmission. Is an automatic transmission ok? I know someone who has swapped a VH, I'll ask if he can add his $.02 as I'm not well versed on the swap.

Yea, if you're trying to stick with pump gas, boost is out. What about an NA VG30 from a z32? They make over 200hp bone stock and you won't have to worry about an adapter plate to fit a manual transmission.

float_6969 wrote: ↑

Thu Jan 09, 2020 5:50 am

Yea, if you're trying to stick with pump gas, boost is out. What about an NA VG30 from a z32? They make over 200hp bone stock and you won't have to worry about an adapter plate to fit a manual transmission.

I thought about that too ryan, as you can get an entire engine, transmission, harness, and ecu for around 2 grand but they are quite heavy. Sad that the cd009 transmission is made out of gold or a vq swap would be more feasible.

I was waiting to see what capabilities they have to fabricate mounts, piping, etc...

Lemons and chump car series can be hugely fun but the budget aspect really puts a stranglehold on performance upgrades. Which i think is what makes it so competitive and driver oriented.

Hey, OP, have you considered E85? That would increase your octane to over 100 and really open up options for what you can do power wise. An E85 powered, high compression NA KA would make for a decent race engine for your budget and should be able to hit your power goals and still be pretty reliable.

NukeKS14 wrote: ↑

Thu Jan 09, 2020 7:43 am

float_6969 wrote: ↑

Thu Jan 09, 2020 5:50 am

Yea, if you're trying to stick with pump gas, boost is out. What about an NA VG30 from a z32? They make over 200hp bone stock and you won't have to worry about an adapter plate to fit a manual transmission.

I thought about that too ryan, as you can get an entire engine, transmission, harness, and ecu for around 2 grand but they are quite heavy. Sad that the cd009 transmission is made out of gold or a vq swap would be more feasible.

I was waiting to see what capabilities they have to fabricate mounts, piping, etc...

Lemons and chump car series can be hugely fun but the budget aspect really puts a stranglehold on performance upgrades. Which i think is what makes it so competitive and driver oriented.

We are capable of making most anything that can be done with a welder and regular shop tools. No cnc machines or anything special like that.

float_6969 wrote: ↑

Thu Jan 09, 2020 8:06 am

Hey, OP, have you considered E85? That would increase your octane to over 100 and really open up options for what you can do power wise. An E85 powered, high compression NA KA would make for a decent race engine for your budget and should be able to hit your power goals and still be pretty reliable.

We would have to pull out and completely tear down our just built motor to add in high compression Pistons, change valve seats to put up with e85, and rework the heads to flow better. That's a lot of time and money for a small net gain. Then trying to source e85 all the time at the different tracks.

We generally go through 80-90 gallons in a weekend. s*** gets expensive real fast

NukeKS14 wrote: ↑

Thu Jan 09, 2020 3:05 am

Didnt take the lower octane into account; with a turbo on the stock bottom end even at 8 psi you're going to want to run higher octane than 87 and a range colder plug in order to not flirt with detonation which the oem cast pistons are rather susceptible to (moreso the DE than the E motor that youre running but still...) or retard your base timing on the stock ecu which is going to gutpunch your response out of boost.

Whats your fuel delivery situation? Are you running stock pump and fuel tank or a fuel cell and something else? Regardless of turbo or swap thats a weakpoint on your car that will need to be addressed.

What pistons are you running and did you gap the rings to stock spec?

Is one of your guys a welder or are you going to have to pay someone for fab work? That's going to make or break your LS budget there but it sounds like you've already sort of ruled it out.

The LS fits because of the engine profile. Id be interested to see if the 289 fits without sawzalling a huge hole in the hood. Ive never seen it done on this chassis.

The VH is nice but.... the adapter plate in order to put a transmission on it is over $400 alone (assuming you are gonna want a manual) and then you're going to be asking a lot from your KA transmission. Is an automatic transmission ok? I know someone who has swapped a VH, I'll ask if he can add his $.02 as I'm not well versed on the swap.

Stock fuel delivery system. Flow matched injectors. Our team mechanic built the motor so I'm not 100% on ring gaps, what the new Pistons are, etc. I know the Pistons are .050 over as we had a crack in the cylinder wall and had to bore and sleeve.

I'd be willing to run 91 octane but anymore than that and it's going to be expensive to race.

Firephil wrote: ↑

Thu Jan 09, 2020 4:32 pm

Stock fuel delivery system. Flow matched injectors. Our team mechanic built the motor so I'm not 100% on ring gaps, what the new Pistons are, etc. I know the Pistons are .050 over as we had a crack in the cylinder wall and had to bore and sleeve.

I'd be willing to run 91 octane but anymore than that and it's going to be expensive to race

Gotcha. If youre running the stock gap on rings and cast aluminum pistons 8 psi is about as far as I would tempt fate. Assuming that you're running the 9.1:1 over the earlier 8.6:1 compression ratio. Lower cr would give you more margain of course but I am guessing you pushed compression ratio gor power and response. The overbore is going to affect it too. Even still you may be on borrowed time here. If you're able to fab your own IC piping, down pipe, and wastegate dump, you're on the hook for flanges couplers clamps gaskets, an ebay .57 trim t3 t4 for budget, sohc manifold, wastegate, blow off valve, oil feed and return lines, the stock injectors arent going to handle 8 psi so you'll need an upgrade there, range colder spark plug, oil cooler, and an adjustable fpr wouldnt hurt. It's been a while, ill look into what you can do.about your MAF but I dont think.itll flow that much cfm either.

You'll want to dial base timing back a couple of degrees if you're trying to use the stock map here.

What weight of oil are you using? Id go to 10w40 minimum and you can nab an oil pump off of an L28et for a cheap upgrade to flow when you do the oil cooler.

You have any plans for tuning?

I sent a PM your way but I have a used Walboro 255 I pulled from my tank. You can have it for free. Youll want to get a 20 amp relay and rewire it too. Lots of guides out there I can find one if you need. Rewire the ignition coil while you're at it.

MsD blaster coil wouldn't hurt things either if you find one on the cheap.

Stock injectors for your motor are high impedance 260cc. You could upgrade to top feed injectors from the aforementioned ca18det (370cc) and a resistor pack from a DSM for budget.

Stock clutch is going to start to slip at 200-225hp too so plan on that too.

Firephil wrote: ↑

Thu Jan 09, 2020 4:23 pm

float_6969 wrote: ↑

Thu Jan 09, 2020 8:06 am

Hey, OP, have you considered E85? That would increase your octane to over 100 and really open up options for what you can do power wise. An E85 powered, high compression NA KA would make for a decent race engine for your budget and should be able to hit your power goals and still be pretty reliable.

We would have to pull out and completely tear down our just built motor to add in high compression Pistons, change valve seats to put up with e85, and rework the heads to flow better. That's a lot of time and money for a small net gain. Then trying to source e85 all the time at the different tracks.

We generally go through 80-90 gallons in a weekend. s*** gets expensive real fast

Sorry, I wasn't thinking E85 for just a high compression build. It would work for boost too. There's no need to change pistons or valve seats for E85. It would also allow for optimal ignition timing and more power. You would need fuel system upgrades and tuning, but you'll need that for boost regardless.

They really didn't make squeezing HP out of these engines easy did they?

Talking with my team and I think we are going to rebuild the spare 24e we have and build it to take a minimal amount of boost. It needs an overhaul anyways. We can run the motor we have now and be competitive in B class.

Cheap, reliable, powerful. Pick 2

The stock motor is stout and tolerates a lot of abuse. There is a big difference between kicking around town doing periodic WOT pulls on the highway and the kind of stress you'll be seeing on a track though.

Looks like the stock KA24E maf flows to 250-275hpish and tops out around there so you're good in that regard.

What kind of engine management are you planning to use here?