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Am I missing something concerning the KA24DE-T and SR20DET?

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I've wanted to do either a V6 or straight 4 swap for a while now, to put the engine fully behind the crossmember, and save a little weight. I also like the idea of having tons of room to work on it and plenty of room for a large electric fan (probably a taurus one). I've been considering both the SR20DET and KA24DE-T.. and the results I have found from them have been interesting.

 

I've read claims that the KA24 shares the same valvetrain / head design as the RB26DETT, although I didn't see any real source or information to back this up. However, what I have seen is dyno sheets with KA24DE-T's making the same HP or more, with tons more torque than the SR20DET. Yet.. the SR20DET is 2x the cost, there must be something I'm missing.

 

Any input? I'd love to see constructive discussion on both of them.

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I would just do some research on both engines to see what the benefits would be of each. If you already have a KA, the costs of building that engine up will be cheaper of course. From what i remember the KA needs stronger rods to get high horsepower numbers out of it, better pistons also with a turbo.  

 

But the KA is capable of producing high horsepower numbers. Someone on here put a KA in a Z, check his thread if you haven't read it.

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Meh its sorta you're choice. Both are very similar, and can make the same amount of power. Sr20's can make 350+ on stock internals and be reliable while for a KA that's pushing it. Then again it all depends on your tune. Oil pan on a KA is a pain since it's one piece while the SR is 2 piece. 

 

Another bit of info, the SR is much lighter than the KA which was my deciding factor. 

 

As for the price, well you need to look for deals. for me it was easier to buy a car with the SR running and then part the car out. At this point I have paid $300 for my SR, and it still has an aftermarket intake and exhaust that I'm reusing. I also have a KA in my 240sx that I will probably try and do a minimal turbo setup on. but that won't happen for a while. My best advice for you is do more reading, and factor in how available both motors are to you. 

 

Since I had to start from scratch, it was fairly easy to pick one, but if I just had a KA laying around then I'd use that. I also do a lot of reading on Zilvia, nicoclub, and 240sxforums

Edited by BluDestiny

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Yes, you are(OP) missing a lot.

 

What do you want?

What can you do?

What do you know?

Do you really believe everything you see on the internet?

 

The KA is 20% bigger with a long stroke. Yes, it can give you more torque after you do all that it takes to make that, rods, pistons, injectors, manifold, turbo, etc.

 

The SR is a bolt in(sort of) solution with 275ish hp in stock form with stock reliability and drivability.

The stock SR with a bigger turbo is ready for a lot more.

It's easy.

It revs to the sky and loves it.

 

Leave it stock for a great driving experience.

It will give you great mileage(30+), can go way too fast for a 40 year old car and runs like a stock modern car with tire burning power. A stock SR will give you more power than most people could ever use in a Z. It is plenty for autox, track days and many, many tickets.

 

The KA, SR and L all weigh pretty much the same once installed with all the stuff needed.

 

I really like my SR 240Z. It weighs 2300# and has 51% on the rear tires with me in it. It does everything I want but there are many ways to skin a cat.

 

"Good judgement comes from experience and much experience comes from bad judgement." Got that from an old farmer. It's very true.

Edited by logr

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Yes, you are(OP) missing a lot.

 

What do you want?

What can you do?

What do you know?

Do you really believe everything you see on the internet?

 

The KA is 20% bigger with a long stroke. Yes, it can give you more torque after you do all that it takes to make that, rods, pistons, injectors, manifold, turbo, etc.

 

The SR is a bolt in(sort of) solution with 275ish hp in stock form with stock reliability and drivability.

The stock SR with a bigger turbo is ready for a lot more.

It's easy.

It revs to the sky and loves it.

 

Leave it stock for a great driving experience.

It will give you great mileage(30+), can go way too fast for a 40 year old car and runs like a stock modern car with tire burning power. A stock SR will give you more power than most people could ever use in a Z. It is plenty for autox, track days and many, many tickets.

 

The KA, SR and L all weigh pretty much the same once installed with all the stuff needed.

 

I really like my SR 240Z. It weighs 2300# and has 51% on the rear tires with me in it. It does everything I want but there are many ways to skin a cat.

 

"Good judgement comes from experience and much experience comes from bad judgement." Got that from an old farmer. It's very true.

 

 

Not to argue, but the SR is no more of a bolt in swap than a KA24. 

 

I think the biggest concern for me is budget, I see stock SR20's go for no less than 1,500 online, usually more. Then you have to add in the same components as you would any other motor. Bigger injectors, turbo, etc.

 

It seems to be that a KA24 with a reasonable turbo (HX35/HY35) can make 300 HP on stock components with ease. 

 

I'd honestly perfer an SR20, just because I like their exhaust sound more. But budget constraints are in place.

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Also the SR has things like oil squirters for the pistons and 8.5:1 compression from the factory(obviously you can change that when you build a KA). A stock bottom end can hold 400hp+  if it is tuned right. Tuning is key with either platform. SR Also has a larger aftermarket support vrs the KA. 

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I've wanted to do either a V6 or straight 4 swap for a while now, to put the engine fully behind the crossmember, and save a little weight. I also like the idea of having tons of room to work on it and plenty of room for a large electric fan (probably a taurus one). I've been considering both the SR20DET and KA24DE-T.. and the results I have found from them have been interesting.

 

I've read claims that the KA24 shares the same valvetrain / head design as the RB26DETT, although I didn't see any real source or information to back this up. However, what I have seen is dyno sheets with KA24DE-T's making the same HP or more, with tons more torque than the SR20DET. Yet.. the SR20DET is 2x the cost, there must be something I'm missing.

 

Any input? I'd love to see constructive discussion on both of them.

 

A KA is not a low compression engine. Tuning is critical in making a KA-T that doesn't eat it's self and vomit parts all over the road. Also, your pricing is not looking at what it takes to make a KA-T correctly. You need a quality turbo ($800 to $1200 starting), a manifold ($500 to $1200), injectors ($250 to $500), computer ($500 to $1600), exhaust ($200 to $800), IC setup ($250 to $900), and more random little things unless you are a good fabricator. Then with all that bolted up you will then need to pay for a dyno tune, dial in the details, and still just have the basics to run the system. If you don't care about blowing the engine up, you can push it a bit, but you will probably need a water/meth injection kit. If you want to make it as reliable as an SR, you will need another couple thousand in internals and labor to drop the compression and beef up the internals.

 

The reason the SR costs more is because it already comes with all the requirements of a turbo engine. If you want to DIY a turbo engine, you really need to understand that it is extremely easy to have $5000 into the engine just to get it stable... and there are still no guarantees that it won't randomly pop a weak part. An SR will run all day long with around 300HP on stock everything (assuming a T28), but will start to cost the same in upgrades as you push the envelope (after all replacing turbo, injectors, computer, etc will cost the same for the SR as a KA).

 

The key is what you plan to do with the car. Are you shooting for 400HP+ or just looking to double the power of the L24? If you are going for 500HP it doesn't matter which you choose because you will be basically rebuilding both engines to support that power. I would suggest looking at the website I started tossing together about things to think about when doing an SR swap, it's not complete, but it has a lot of information:

 

http://www.sr240z.net

 

Not to argue, but the SR is no more of a bolt in swap than a KA24. 

 

I think the biggest concern for me is budget, I see stock SR20's go for no less than 1,500 online, usually more. Then you have to add in the same components as you would any other motor. Bigger injectors, turbo, etc.

 

It seems to be that a KA24 with a reasonable turbo (HX35/HY35) can make 300 HP on stock components with ease. 

 

I'd honestly perfer an SR20, just because I like their exhaust sound more. But budget constraints are in place.

 

The SR is a turbo engine, so it is much more "bolt on" than a KA-T. Neither bolts into the car directly, but when it comes to upgrades, the SR already has low comp pistons, oil squirters, etc. The KA was never designed to be boosted, so it is extremely tune dependent or requires rebuilding it to handle the power. To get 300HP from an SR is generally under $500, to get 300HP from a KA will be $2000+, but once you build it you will have a larger displacement turbo engine to work with.

 

Typically people see a KA-T running 400 HP and say "OMG LOOK AT THE TORQUE!" but then never see the engine again... and this is because it destroyed it's self the next week due to detonation or melt down. In case you haven't noticed, most people run E85 on KA-T builds that have a low budget to help offset detonation risk. It is very possible to run a turbo on any kind of engine, but if the engine wasn't designed for it, your experience becomes critical in keeping it running. If people tried to do the idiotic things they do with SRs to a KA-T you would never see them on the road.

Edited by CasperIV
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The way I see it, is that the KA has bottom end issues. The stock crank sucks and will be it's biggest limitation unless you bite the bullet for a pricey aftermarket one.

 

The SR has valvetrain issues. I know people rave about how well the rev, but that has nothing to do with what I'm talking about. The SR head just has some serious drawbacks that people rarely look at objectively.

 

And by contrast, both engines are very strong in the other's weakness. The SR has a pretty stout bottom end, but obviously it was factory force induced, so it makes sense. The KA has an insanely good head that not only flows well, but also has a head that will rev to the moon, and be quite stable too, if you're bottom end allows it...

 

 Personally, it seems to me like a lot more SR's blow up left and right than KA's, but that could be simply how many of them are out there. Even here though, it seems like many of the people that have had SR's in their cars for a long time have been through a couple of longblocks... Maybe asking for too much power? Possibly. I think the problem in that regard is the same with ANY motor. People can't be happy with 300hp when they know they're just a couple PSI away from a lot more power. Instead of building the motor for more power to begin with, they cross their fingers and hope it all holds together.

 

Oh, and I think subtle_driver's thread on here is a great example of a successful KA-T build. He did it all for insanely cheap, and probably much less than it could have been done with a SR. He WAS running E85, but personally I think that's just plain wise for ANYONE running 20+psi of boost, regardless of platform. To blame his success on the fuel he chose would be like saying a farmer cheats by using a tractor. E85 was simply a tool he used to get him to his goals.

 

And if you wanted my personal choice between the two.... Neither... If I wanted a turbo 4 cylinder I'd want a better platform to start with. But that's me.

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Most of the SR's that blow up are from poor tuning or poor craftsman. I have not seen many properly built KA's stand the test when. The SR's poor valve train issues are solved with a VE head. SR is a built proof engine and will outlast any KA built to the same specs. The SR was a factory designed turbo engine and the KA is not. Sure you can probably make a KA have the same power and maybe gain a little more TQ out of the displacement, but it will not take an ass whippin like the SR will, at least not for an extended period of time. 

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The SR was a factory designed turbo engine and the KA is not. 

 

That basic distinction is exactly why I wouldn't put stock in your, or many other's opinion on the SR vs KA comparison.

 

The L block was never intended as a turbo block when they made the first castings. Why don't people like 1 Fast Z care about sourcing a "turbo motor" when building 700+ whp engines?

 

So a SR has heavy duty piston crowns, woopie! As soon as you throw out the "build to same specs" you COMPLETELY throw out the "SR is designed for boost" argument, because the only things that can't be changed easily aren't any special between turbo versus non-turbo engines, and that includes SR's. People like to tout things like "but OIL SQUIRTERS!! OMG!!", but have no ability to see through the internet BS.

 

Any I'd bet that MOST engines of ANY type blow up due to poor tuning or craftsmanship. Most L engines that blow are around the 350-450whp mark, because that's where the detonation becomes extremely hard to control.

 

Oh, and I love it when people throw around the term "bullet proof", as though that means anything. Compared to what? Every engine has it's limits, even the SR. The Honda K series has proven to take 500-600hp on stock internals, and that's NOT a "factory turbo motor"... would you call THAT bullet proof?

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That basic distinction is exactly why I wouldn't put stock in your, or many other's opinion on the SR vs KA comparison.

 

The L block was never intended as a turbo block when they made the first castings. Why don't people like 1 Fast Z care about sourcing a "turbo motor" when building 700+ whp engines?

 

So a SR has heavy duty piston crowns, woopie! As soon as you throw out the "build to same specs" you COMPLETELY throw out the "SR is designed for boost" argument, because the only things that can't be changed easily aren't any special between turbo versus non-turbo engines, and that includes SR's. People like to tout things like "but OIL SQUIRTERS!! OMG!!", but have no ability to see through the internet BS.

 

Any I'd bet that MOST engines of ANY type blow up due to poor tuning or craftsmanship. Most L engines that blow are around the 350-450whp mark, because that's where the detonation becomes extremely hard to control.

 

Oh, and I love it when people throw around the term "bullet proof", as though that means anything. Compared to what? Every engine has it's limits, even the SR. The Honda K series has proven to take 500-600hp on stock internals, and that's NOT a "factory turbo motor"... would you call THAT bullet proof?

 

Sure you can build almost any engine to last and out perform the next, but then money and common sense hit. 

 

I am sure there are several motors out there that can "take" 5-600hp stock. But its reliability that is the key. I have personally seen SR's take mid 400's for years on a stock bottom end, but I have yet to see a KA do the same. You say oil squirters and crowned pistons don't matter, but I don't think that's the case. Turbo motors are built to be turbo motors. 

 

We can go round and round on this but ultimately it comes down to opinion and a persons leg humping factor. You can prove an engine one way or another all day long and a person would still believe it either way. 

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New to the forum and after 4 yrs owning a KA I'm still learning. Great read guys, sounds like you all know what you are talking about. I own a 240SX with the KA, I wanted to boost and to keep the stock motor instead of going SR. yes everything has its limits and what's great for the goose might kill the gander.

Love the information you guys put out and it pushes me more to keep researching and keep researching. I have picked up most of the parts for my build and I'm not looking to push more than 500HP. The bottom end will have forged internals and the head will be ported, other than that keeping fingers crossed on great machune work to ensure relaibility for daily driving.

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