RB25DET 240sx Swap

[NVmySX]

@Mr.K

If you’re looking at SR power, you might want to just look at turbo-ing your KA. Its obviously not got the same JAYDEEEMM bling factor, but its going to give you the same amount of power, more or less. Also, you’re really going to want to try and see if you can do some of the work yourself, since its going to save you a ton of money. There are plenty of resources on the intarwebz on swaps for these cars, so learning how to do it shouldn’t be an issue. If you don’t have the space, then you’re obviously not able to do that. I still think considering a V8 would be of interest. Cheap motor, cheap parts.

Im just weighing out my options at the moment, gathering up info on each swap (SR and/or RB25) so that in the future, IF I DECIDE to go either route, ill be prepared … Ya bout turbo-ing the KA, ive read some articles & forums about that & from what I heard its good for saving money AND like you said, you pretty much get the same amount of power “more or less” lol … But heres the thing, my KA is pure stock n still going strong at 280,000 km LOL … Im just waiting until i cant get any more “purrs” out of her then ill start weighing my options in real time (bolt on turbo? SR? RB25?) …

Now heres the thing, is it worth to rebuild my KA n bolt on a turbo or jus do a swap for an SR n put some extra mods to the SR for more power? (im not including RB25 cuz it has its own criteria lol)

[Zman86]

@NVmySX

eh Zman86 another question, what would a basic swap be without the little extras here & there for the swap … For example, just installing the engine into the 240sx with the front clip, motor mounts & any basic parts (No extras) … Is there such a thing or do i actually do need all those parts u listed (besides the engine, mounts, clip, etc)

You dont need some of those things, they were just what I would install to make a goodcar to drive daily. The last car I looked at, the guy had kept the stock rad, and said he had nothing but problems with the car overheating, so I would definatly reccomend upgrading the rad to an aluminum unit. I also forgot to mention you cant retain a mechanical fan either way you go, so you will ave to upgrade to an electric setup. The Greddy manifold is also not nescessary, you can retain the stock intake with the over the valvecover setup, and they make cheap intercooler kits for that setup as well. Theres also the wiring that needs to be taken care of. I think if you do it yourself you have to swap in the skyline instrument cluster whick takes some work. Wirings something I prefer to have done right once, and would rather pay to have it done, but if you have the skills and the patience, then I’d do it yourself.

So, if you have a donor car, I guess to do a bare minimum swap would require

Skyline front clip- Around $3000
Mckinney full swap kit- $1260
Quality aluminum rad- $500 (you could find cheaper, but consider this an investment)
Ebay intercooler kit- $300-$400 for the factory intake setup style
I’d also at least change the sparkplugs in the engine.
Forgot to mention replacing the clutch above too, much easier to do with everything out of the car than to pull the tranny back out.

I’m sure I’m missing a couple things…

On the KA engines, we pulled one apart at work to check out the insides and replace some stuff before going back into the car. With 230 000km on it, the factory hone marks were still visible on the cylinder walls and all the bearings had little to no wear on them. Cams also had minimal wear. rebuild parts were quite cheap, and I imagine you could rebuild a KA for probably a grand, maybe less if it dosent need much and you dont go too crazy.

[NVmySX]

@Zman86

Ya, works a large factor. I was planning a good year for my swap, but I now may be buying a car thats allready done. As much as I hate to do that, it makes more financial sense. As for an SR swap. My buddy has an Sr swapped 240 and he is at about 10 grand. I’d say just about the same amount of mechanical skill is required, however its almost as expensive as doing an RB swap. SR’s do have some advantages and disadvantages though. I’ve not really read up on SR swaps, this is just what I can think of off the top of my head with the knowledge I have.

Advantages

Aluminum block and head- much lighter, better for handling and balance than the iron block RB engines

Cheaper initial costs- SR engines can usually be found for cheaper than RB’s

Good aftermarket support

Smaller size to work with, you dont have two extra cylinders and the extra length to deal with

I believe you can retain the stock driveshaft with an SR swap, helps out with the $ factor

Disadvantages

Aluminum block and head- aluminum is a pain in the ass to work with. should you ever need machine work done to the block, goodluck finding a shop to do and be prepared to shell out the $. You really have to watch torque specs and observe proper assembly procedures, but you should be doing that anyways. Aluminum blocks (in general) are also not as stout as iron blocks, and everything is more prone to warpage. I think RB engines have an aluminum head, so theres a disdvantage the of an Iron block and an aluminum head having different heat expansion rates due to the different properties of the metals. Always use the best headgasket you can buy with Aluminum head/iron block engines.

Performance parts are still expensive

less displacement = less torque- I’ve read alot about how much better the RB cars take off due to the extra torque they produce, plus you got two more cylinders. An RB engine should also be smoother revving.

SR swaps are everywhere, though still very cool, you dont have the coolness factor of opening your hood to reveal an RB

Once again, I dont have much hands on experience with either engine, I’m just going with my basic engine knowledge, so anyone feel free to call bs on me, I wont mind.

no dude its alright its not bs lol, im jus gathering any info that any1 can share with me, im open to anythin

[NVmySX]

@Zman86

You dont need some of those things, they were just what I would install to make a goodcar to drive daily. The last car I looked at, the guy had kept the stock rad, and said he had nothing but problems with the car overheating, so I would definatly reccomend upgrading the rad to an aluminum unit. I also forgot to mention you cant retain a mechanical fan either way you go, so you will ave to upgrade to an electric setup. The Greddy manifold is also not nescessary, you can retain the stock intake with the over the valvecover setup, and they make cheap intercooler kits for that setup as well. Theres also the wiring that needs to be taken care of. I think if you do it yourself you have to swap in the skyline instrument cluster whick takes some work. Wirings something I prefer to have done right once, and would rather pay to have it done, but if you have the skills and the patience, then I’d do it yourself.

So, if you have a donor car, I guess to do a bare minimum swap would require

Skyline front clip- Around $3000
Mckinney full swap kit- $1260
Quality aluminum rad- $500 (you could find cheaper, but consider this an investment)
Ebay intercooler kit- $300-$400 for the factory intake setup style
I’d also at least change the sparkplugs in the engine.
Forgot to mention replacing the clutch above too, much easier to do with everything out of the car than to pull the tranny back out.

I’m sure I’m missing a couple things…

On the KA engines, we pulled one apart at work to check out the insides and replace some stuff before going back into the car. With 230 000km on it, the factory hone marks were still visible on the cylinder walls and all the bearings had little to no wear on them. Cams also had minimal wear. rebuild parts were quite cheap, and I imagine you could rebuild a KA for probably a grand, maybe less if it dosent need much and you dont go too crazy.

I see … so basically all the money that id put into having an RB25, i cud just rebuild my KA, bolt on a turbo & probly still have some cash left over with most likely the same amount of power (hp yes, torque no lol) … Fuck i hate dilemmas LOL … Decisions decisions eh … lifes all about choices lol …

How bout this, for an ok RB25 swap, id choose these:

Skyline clip - $3000
McKinney Full Swap Kit - $1260
Greddy Intake Manifold - $780
Koyo Rad - $500-$700
New Intercooler Kit (Greddy) - ?
Wiring Harness Mod - ?
Performance Clutch (ACT maybe) - ?

Would that be an ok swap as a “START” for having a RB25 then l8tr along the line, install parts individually?
I dont need a donor car lol, id just do it on my car

[Zman86]

To run the greddy manifold, the IC kit will be more expensive, and if you want to run a Greddy IC, huge money. Plus you need a Q45 Throttle body and an adapter. Main things are rad/rad fans/clutch. I’d also be running high quality fluids in everything, and dont forgot RB’s need premium fuel. And HP is just a by-product of torque. You can have all the HP in the world, if you have no torque, your car will be a slug off the line. For example, look at a Honda S2000, basically useless below 4000-5000rpm until you get the revs up.

[NVmySX]

@Zman86

To run the greddy manifold, the IC kit will be more expensive, and if you want to run a Greddy IC, huge money. Plus you need a Q45 Throttle body and an adapter. Main things are rad/rad fans/clutch. I’d also be running high quality fluids in everything, and dont forgot RB’s need premium fuel. And HP is just a by-product of torque. You can have all the HP in the world, if you have no torque, your car will be a slug off the line. For example, look at a Honda S2000, basically useless below 4000-5000rpm until you get the revs up.

I just took a look on eBay for the Greddy Intake Manifold Plenum & Greddy Intercooler Kit (LS-Spec for Skyline GT-S ECR33 RB25DET Model) … Both items for a lil over $1200 lol … How much is the Q45 Throttle body & the adapter? Would i require the Greddy Fuel Rail Line with the Intake Manifold Plenum?

As for the fuel & oil, im very well aware of what id need to run this sucker good lol

[Mr.K]

@NVmySX

Im just weighing out my options at the moment, gathering up info on each swap (SR and/or RB25) so that in the future, IF I DECIDE to go either route, ill be prepared … Ya bout turbo-ing the KA, ive read some articles & forums about that & from what I heard its good for saving money AND like you said, you pretty much get the same amount of power “more or less” lol … But heres the thing, my KA is pure stock n still going strong at 280,000 km LOL … Im just waiting until i cant get any more “purrs” out of her then ill start weighing my options in real time (bolt on turbo? SR? RB25?) …

Now heres the thing, is it worth to rebuild my KA n bolt on a turbo or jus do a swap for an SR n put some extra mods to the SR for more power? (im not including RB25 cuz it has its own criteria lol)

Well…with anything, there is always a risk. You could throw a turbo onto your KA and it could blow instantly, or it could go for 10 years without a problem. You could swap an SR in and it could blow after a few miles, or it again, could last nearly forever. Your “safest” bet would be to tear your KA apart and check the condition of the internals. If they look fine, throw it back together, or if budget allows, start replacing stuff. At least you know at this point that you’re investing in stuff thats going to last, whereas an SR/RB could be completely torn to bits from some guy overseas doing a little Tokyo drift right into a wall, only after beating the crap out of the engine for months.

Unless you have a lot of money to blow (doesn’t sound like it) you should factor in future repair and maintenance costs and make sure whatever option you choose is affordable not only now but down the road. Thats why I suggested the KA and/or a V8, because they’re North American engines and parts can be found in any wreckers in your local area. The V8s I suggest would be out of Silverados which wreckers have tons of.

Someone mentioned some torque thing…torque is directly related to horsepower, and vice-versa. The equation goes sort of like this: HP = (torque x RPM) / 5252. Thats why high-revving engines always have more HP than torque, and a lot of the low rev engines have higher torque values, since most of their power is made under 5252 rpm. I’m not a technical expert, so I’ll stop there before I say anything too stupid.

[NVmySX]

@Mr.K

Well…with anything, there is always a risk. You could throw a turbo onto your KA and it could blow instantly, or it could go for 10 years without a problem. You could swap an SR in and it could blow after a few miles, or it again, could last nearly forever. Your “safest” bet would be to tear your KA apart and check the condition of the internals. If they look fine, throw it back together, or if budget allows, start replacing stuff. At least you know at this point that you’re investing in stuff thats going to last, whereas an SR/RB could be completely torn to bits from some guy overseas doing a little Tokyo drift right into a wall, only after beating the crap out of the engine for months.

Unless you have a lot of money to blow (doesn’t sound like it) you should factor in future repair and maintenance costs and make sure whatever option you choose is affordable not only now but down the road. Thats why I suggested the KA and/or a V8, because they’re North American engines and parts can be found in any wreckers in your local area. The V8s I suggest would be out of Silverados which wreckers have tons of.

Someone mentioned some torque thing…torque is directly related to horsepower, and vice-versa. The equation goes sort of like this: HP = (torque x RPM) / 5252. Thats why high-revving engines always have more HP than torque, and a lot of the low rev engines have higher torque values, since most of their power is made under 5252 rpm. I’m not a technical expert, so I’ll stop there before I say anything too stupid.

Ya ur right about the SR’s/RB’s & some guys pullin off “tokyo drifts” lol … its one of those “press your luck” situations whenever you go for a SR/RB (unless u change the internals then ur fine lol) … But at least from this thread since the beginning, ive learned quite a bit n have my options laid on the table pretty good … its good to know ahead of time & do some hmwk … thanks! … I guess for now, ill jus ride out my KA with its 280,000 kms lol (still going good surprisingly; well not really, the car was never “beaten” if u kno what i mean) my uncle 1st bought it then my brother so i kno the history of the car which is good lol …

I wudnt wanna go for the V8 LOL im not that much of a sucker for POWER lol … I guess in the end its up to me to make the right choice, well more like a preferred choice, as long as i accept whats coming or what can be with wat i choose right … anythin else u wanna add?

[Zman86]

Thanks for putting up the HP equation, I forgot about it. Unless you went with an all aluminum V8 swap, I imagine the car would be very front heavy, a small aluminum V8 may be in the same weight category as an RB25, probably bit more. I’ve driven a newer silverado with a 6.0L and the truck hauled ass, I couldnt imagine that engine in a small coupe. Chevy also has a 4.8 (or 4.7, cant remember) and you cant forget Chevy 5.7’s and 5.0’s, chrysler has a 4.7, Ford has 5.0L and 4.6’s. You could easily build a 5.0 that puts out 250hp for cheap, or better yet, put in a GT40 engine out of a 97 Ford Explorer, one of the better engines that have come out of the Ford factory. Options are endless, it all comes down to how much money you want to spend and how much work you want to do, and also what type of driving are you planning on doing. And most JDM engine dealers offer some type of warranty, but you usually have to provide documentation that it was installed by a liscensed mechanic at a shop.

Edit- Just read your last post, Good luck with whatever you decide to do man!

[Mr.K]

@Zman86

Thanks for putting up the HP equation, I forgot about it. Unless you went with an all aluminum V8 swap, I imagine the car would be very front heavy, a small aluminum V8 may be in the same weight category as an RB25, probably bit more. I’ve driven a newer silverado with a 6.0L and the truck hauled ass, I couldnt imagine that engine in a small coupe. Chevy also has a 4.8 (or 4.7, cant remember) and you cant forget Chevy 5.7’s and 5.0’s, chrysler has a 4.7, Ford has 5.0L and 4.6’s. You could easily build a 5.0 that puts out 250hp for cheap, or better yet, put in a GT40 engine out of a 97 Ford Explorer, one of the better engines that have come out of the Ford factory. Options are endless, it all comes down to how much money you want to spend and how much work you want to do, and also what type of driving are you planning on doing. And most JDM engine dealers offer some type of warranty, but you usually have to provide documentation that it was installed by a liscensed mechanic at a shop.

Edit- Just read your last post, Good luck with whatever you decide to do man!

An all aluminum V8 (LS1, LS2, LS3, etc) has been weighed in as being less than the stock KA. The Iron block/Aluminum head V8s (LT1, Vortec 5300/6000) are a bit more, but I would imagine that they’re around RB25 weight, if not a little less. The Liter count on V8s like those look big, but physically the engines aren’t very big and don’t weigh much, which is the advantage. Stock any of the listed engines put down ~300HP or more, and can be had for $2500 for the LS1 and $1600ish for the LT1, and even less for the Vortecs.

Given you know the engine’s history, I’d say your best bet is to keep it and upgrade as you see fit. Price check a rebuild kit and a turbo setup. Try and get a quality rebuild kit (forged stuff), not much point in replacing stock parts with shit parts =p.

[Sky14]

if your serious and not jsut wondering.
pm me and ill give you all the info you need. i put a 25 in my kouki

[NVmySX]

So im guessing with all the work & parts & money required for doing an RB25 swap into a 240, i think from the money aspect of the swap, you could easily gain more hp & torque on a KA by rebuilding it & bolting on a good turbo … Let’s say the budget would be the same as for a good daily driver car with an RB like Zman86 mentioned as you’d do the KA rebuild with a bolt on turbo, would the outcome be better for the KA? RB?

[Fobwall]

@Zman86

SR swaps are everywhere, though still very cool, you dont have the coolness factor of opening your hood to reveal an RB

I had a feeling that this is the main reason why people want RB’s. It’s just for the sake of being different. Fucking ricers. 240 owners definitely seem to be the next breed of ricers.

[oneeightseven]

If you are interested in getting rid of your ka for a different engine, get some info on an sr20 swap. It’s pretty common now and aftermarket parts are easily accessable. Redtop or Blacktop should be able to push out some good horsepower and torque while still keeping the car and engine a reliable daily driver. Talk with Varun. I’ve only heard great things about him and his engines along with his service. Pm him to set up a meet and work out your options.

[NVmySX]

@oneeightseven

If you are interested in getting rid of your ka for a different engine, get some info on an sr20 swap. It’s pretty common now and aftermarket parts are easily accessable. Redtop or Blacktop should be able to push out some good horsepower and torque while still keeping the car and engine a reliable daily driver. Talk with Varun. I’ve only heard great things about him and his engines along with his service. Pm him to set up a meet and work out your options.

Well in the beginning, my 1st choice was an SR20 … Its cheap (compared to an RB25 or RB26), reliable & accessible & easily can be upgraded to have a good amount of power … Also its good for some1 who doesnt have a high budget … Like the reason why i posted this thread is because i wanted to see what ppls opinions were about the RB25 & how much were the costs for everything (engine, swap, parts, etc) … So at least now i have a better vantage point on what i can purchase or whats out there that will suit me & my needs …

About Varun, he pm’d me a few days ago & gave me his number & told me to call him up & let him know what my plans & goals are with the car … But thanks again

[NVmySX]

@oneeightseven

If you are interested in getting rid of your ka for a different engine, get some info on an sr20 swap. It’s pretty common now and aftermarket parts are easily accessable. Redtop or Blacktop should be able to push out some good horsepower and torque while still keeping the car and engine a reliable daily driver. Talk with Varun. I’ve only heard great things about him and his engines along with his service. Pm him to set up a meet and work out your options.

Now for an SR20 swap, what would i be looking at when it comes to the price of the swap & parts … I believe the engine is, for a Redtop, about $1800 ? Please correct me if im wrong any1 lol … Any clips required? Wiring harness mods? Intercooler upgrades? Intake manifold? Rad? Clutch? Exhaust (id pick the A’pexi GT Spec Downpipe with the GT Spec Exhaust ) … Spark plugs (higher cc’s), AEM fuel rail? anythin more … ?

[oneeightseven]

It all depends on your goals and what you want out of the engine. Some engines can be found for cheaper, some more expensive. Depends who you get it from, shipping or picked up, slightly modded or fully stock, etc. SR20 are usually a pretty straight forward swap. As for intercooler upgrades, rad, clutch, exhaust and what not, that is up to you. Of course its recomended that some of these items be swapped for better performing ones, but its totally up to you. An SR20 would require less work and less modification then compared to swapping an RB or LS. Also it would cost less money and be a bit more reliable as a daily driver. I’m no expert at these things, so like i stated earlier, talk with Varun (slipperysilvia). He’s your man for these kinds of things. Try setting up an in person meet to discuss your goals, budget, and anything else you may have questions about.

[Zman86]

@Fobwall

I had a feeling that this is the main reason why people want RB’s. It’s just for the sake of being different. Fucking ricers. 240 owners definitely seem to be the next breed of ricers.

I dont really think an RB swap is rice. Not only is it for the sake of being different, RB’s are almost bulletproof if well taken care of in stock form, and you have much more torque on tap. Weight distribution becomes a problem though.

I’d say have fun with the KA till it goes, and in the meantime save your money and plan out your swap ahead of time, collecting all the parts you need and such. Makes life alot easier. With an SR swap, you can also retain your stock mechanical fan and rad, saving more money. For the most fun with a tighter budget, I’d say go SR, my friends car is an absolute blast and is pretty damn fast too, and all he has really done is an aftermarket exhaust manifold and a 3" Megan Exhaust. I’d say try to get a ride in a few cars with each swap you are considering, and see which one would suit your needs best.

[NVmySX]

@Zman86

I dont really think an RB swap is rice. Not only is it for the sake of being different, RB’s are almost bulletproof if well taken care of in stock form, and you have much more torque on tap. Weight distribution becomes a problem though.

I’d say have fun with the KA till it goes, and in the meantime save your money and plan out your swap ahead of time, collecting all the parts you need and such. Makes life alot easier. With an SR swap, you can also retain your stock mechanical fan and rad, saving more money. For the most fun with a tighter budget, I’d say go SR, my friends car is an absolute blast and is pretty damn fast too, and all he has really done is an aftermarket exhaust manifold and a 3" Megan Exhaust. I’d say try to get a ride in a few cars with each swap you are considering, and see which one would suit your needs best.

Even b4 considering any swaps, I was planning to jus ride out my KA then rebuild it, get some good aftermarket headers, cold air ext., new exhaust & exhaust manifold and thats it … that wud be one lil project … if not that then id consider the SR swap (which ive been thinking about for most of the time then a RB25 swap (the SR would def be better for my budget & id still get a good kick out of too) …

So ur buddy has an SR & has the aftermarket exhaust manifold & 3" Megan exhaust done to it and thats it? how fast is his car?

[system]

well ive owned both a sr with basic mods (intake, full 3inch turbo back exhaust, front mount bov ect) as well as a ka-t (t25, 370cc, 3" turbo back, intake front mount ect) and my buddy has just bought a rb25det with (3" turbo back, intake, front mount, ect)
in my opinon the rb25 is the best engine as it has a huge amount of more torque then both the other engines, the ka-t does have quite a bit of torque but the rb25 just trumps it. The engine is in almost stock form but has as much power as I would ever need, the fact that its in stock form i would think is better for reliability. It is a nice swap and if i had the money i would do this over a built ka-t or sr as the power goal for me would be around 280-300whp.

in my opinion RB25DET > KA24DET > SR20DEt

Also apparently you can use the stock engine mounts with a little work and get the driveshaft lengthened for about $200 but dont quote me on this.
Also for the rb25 set up you dont need after market engine management if you want around 300hp but for ka-t and Most Srs with that much power you would probably need an emanage and wideband.

Lastly the sounds of a tubo I6 engine owns a 4banger