Honda k24 240z

[jessejames]

A lot has happened since the last update.  We milled down part of the transmission and clutch cover to make it work. The oil pressure was turned down on the dry sump pump and we switched to a thinner oil. 

 

The car was tuned on shell 93 first and made 325whp at 10psi.

 

The car was then tuned on pump gas with octane booster and made 387whp at 12 psi.

 

An e85 tune might be down the road. 

 

My tuner is keeping the tune very conservative. When I build the motor, he believes we can hit  430whp on pump gas. 

 

For comparison purposes I have included a dyno graph of a stock 2019 Audi A5. It's a 2.0 turbo that supposed to have 248bhp. You can see from the dyno chart it's putting down about 212whp.

 

[jbusam]

Could you have notched the hood latch to move the engine back and up a little more?

[jessejames]

7 minutes ago, jbusam said:

Could you have notched the hood latch to move the engine back and up a little more?

Not with the cd09 transmission. If I used a smaller transmission like the s2000 or bmw zf, its possible.

[jbusam]

ah I see. so the bellhousing was limiting rearward travel. S2000 wouldn't be worth it since they don't handle the power well. Zf would be worth trying though. for someone else.  thanks for the response. I love the idea of the kswap in a datsun. all the good straight six options are so ridiculous in price. out of curiosity, did you consider the ford 2.3 ecoboost?

[jessejames]

I only considered the k24 and k20. The aftermarket support and cheap prices of the engines, and their power potential was the deciding factors. 

[jessejames]

We did an e85 tune, same boost level of 14psi but with more timing. We end up with 450whp.

[300zxNoMore]

So I've got two 1973 240 Z's sitting in the back yard where I'm staying. One looks like it is in pretty good shape but I'm told the motor is blown. The other was supposedly purchased as a donor car. I haven't looked at it yet but let's just say I have my doubts it is going to be worth swapping.. 

 

I was on OfferUp today and was browsing things people post for free and a inline motor listed as "RSX motor free". The little voice in my head said "that looks like it might just fit" so I jumped on the googlizer typed in "will a K20" and Google's search suggestions all but confirmed it. 

 

I've never done a motor swap on a car but I'm no stranger to making things work for a purpose they were not originally intended for. I have plenty of experience working on vehicles of all sizes ranging from go carts to diesel rigs. I have no problem making custom mounts or doing some light machining like jessiejames has described in this thread.. 

 

So as some of you have already guessed, I have questions..

First: on a scale of 1-F*#&ed (assuming the free motor is mostly complete and doesn't need to be bored out by a drilling rig) what level of difficulty should I expect if I were to attempt this swap?

 

Second: If I were to decide to buy the car I would want a boost friendly engine setup. Is there a better option then a free K20A3?

 

Third: How much cheddar should I expect to be forking out when it's all said and done? I'd likely do all the work myself and I have no problem salvaging what I can at the scrap yard, "lowest cost possible" would be the idea if I do this.

 

Thank you all in advance for your answers. 

[golfandcars]

On 6/22/2023 at 4:13 AM, 300zxNoMore said:

So I've got two 1973 240 Z's sitting in the back yard where I'm staying. One looks like it is in pretty good shape but I'm told the motor is blown. The other was supposedly purchased as a donor car. I haven't looked at it yet but let's just say I have my doubts it is going to be worth swapping.. 

 

I was on OfferUp today and was browsing things people post for free and a inline motor listed as "RSX motor free". The little voice in my head said "that looks like it might just fit" so I jumped on the googlizer typed in "will a K20" and Google's search suggestions all but confirmed it. 

 

I've never done a motor swap on a car but I'm no stranger to making things work for a purpose they were not originally intended for. I have plenty of experience working on vehicles of all sizes ranging from go carts to diesel rigs. I have no problem making custom mounts or doing some light machining like jessiejames has described in this thread.. 

 

So as some of you have already guessed, I have questions..

First: on a scale of 1-F*#&ed (assuming the free motor is mostly complete and doesn't need to be bored out by a drilling rig) what level of difficulty should I expect if I were to attempt this swap?

 

Second: If I were to decide to buy the car I would want a boost friendly engine setup. Is there a better option then a free K20A3?

 

Third: How much cheddar should I expect to be forking out when it's all said and done? I'd likely do all the work myself and I have no problem salvaging what I can at the scrap yard, "lowest cost possible" would be the idea if I do this.

 

Thank you all in advance for your answers. 

Not to hijack this thread but i can answer a couple of your questions regarding the K series engines as i was a Honda guy before i dove into old Z's. The K20A3 is the worst K series offering, you wont make anywhere near the power OP has made even with boost. I would say 300 hp is probably about the max for that motor. It does not have "real" VTEC, it only has variable valve timing on the intake cam. The valves are smaller in the head and the pistons have a weird shape as well as being lower compression. All that being said, its still a good engine, especially for free 99 lol. If you can do your own fab work swapping it in a Z will probably cost you a few grand still but would be a fun setup and quicker than an L series engine. The great thing about doing it using this engine is once its done your setup for a K series and you can find better K series options in the wild for very reasonable, so down the road if you wanted to upgrade, its just a simple engine swap. Hopefully this helps.

[A to Z]

Personal observations......"only 300 hp" is a lot in a z car.  There is no cheap way to build a Z car correctly, and swaps are never as easy as they make it look online.

[Iiro]

On 5/15/2023 at 6:38 AM, jessejames said:

We did an e85 tune, same boost level of 14psi but with more timing. We end up with 450whp.

 

Excellent news and your project has been a great inspiration to mine.

I'm having 260Z with K24, BMW originated 6-speed manual, 370Z rear diff, bigger brakes, etc. It's a budget build, but hopefully reaching similar power levels and a fun car to drive.

 

Currently building my own intake and exhaust manifolds.... and learning to weld aluminium in the process

[manimal]

On 5/8/2023 at 10:17 AM, jbusam said:

Could you have notched the hood latch to move the engine back and up a little more?

With the S2000 trans you can and you can get the shifter to pop out in almost the OEM position. It still requires a curved shift lever like the Z to get the shifter in a better position.

On 6/22/2023 at 2:13 AM, 300zxNoMore said:

So as some of you have already guessed, I have questions..

First: on a scale of 1-F*#&ed (assuming the free motor is mostly complete and doesn't need to be bored out by a drilling rig) what level of difficulty should I expect if I were to attempt this swap?

 

Second: If I were to decide to buy the car I would want a boost friendly engine setup. Is there a better option then a free K20A3?

 

Third: How much cheddar should I expect to be forking out when it's all said and done? I'd likely do all the work myself and I have no problem salvaging what I can at the scrap yard, "lowest cost possible" would be the idea if I do this.

 

Thank you all in advance for your answers. 

Late to the party, but a free engine is great for mockup. You could get the car to a running state on the free engine, then swap in a JDM import engine with the USDM engine accessories pulled from the free engine. As for cost, $10k+ to do it right. Some may have done it for a bit less, many don't remember to add up all the little incidentals. If your goal is more roadkill style and you can wait for deals, you can probably do it for $5-6k not including turbo stuff.

/end hijack

OP, nice to see it running after all the common non-standard engine swap headaches! 

[jessejames]

Hey guys, sorry I haven't been on the forums much lately. Too busy enjoying the car. So far I have to say I love the setup. Honda parts are so much cheaper than JDM Nissan parts (having come from an SR20DET).  I moved to Toronto from Vancouver and local tuners are telling me I should be able to make 450WHP on their local pump gas and even more on E85. I'm hesitant as the K24A2 is mostly stock.  

 

I believe this swap can be done on the cheap. The big issue is going to be moving the steering arm around the engine to fit the K series. The rest is pretty straight forward. I'm happy to answer any questions. 

 

 

[jhm]

Super cool…glad you’re finally getting to enjoy it!  I’ve been following your build and the car looks impressive.  👍👍

[jessejames]

Had the Z tuned again on 94 Octane. Still had 14psi. The wastegate spring was too soft so boost started to drop in the rev range.

 

TLDR: 446 WHP and 389 ft/lbs