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1990 prelude K20 z3 swap

57K views 218 replies 30 participants last post by  euphorictree88@gmail.com 
#1 ·
Hey, I'm restoring a 90 prelude and have come across a k20z3 swap. It has been done but not much was documented about it. Does anyone have any thoughts? ideas?
 
#2 ·
Generally speaking K series wont fit without a massive hole in the hood or appalling ground clearance. If you do a search under my name I did a CAD drawing of what it would look like.

It could maybe be done with subframe trimming and increasing tilt. Similar to what I did in my H22 swap thread #2.

P.S. Someone send me a K series and I will find a way.
 
#3 ·
Anything is possible with time and money :)

Custom.... I can do it... :) However it will take some work. BA has a lot of room front to back... compared to other chassis's. Yes K series taller motor so Hood clearance or lack of would be your biggest concern being that the BA hood comes down quite a bit to a point to the front.
 
#4 · (Edited)
No mounts for it, but even if mounts were to be made for it, the biggest issue is that terrible ground clearance.

The K20 is taller than an H22 and most people in the community dont want to give up ground clearance which is why the H22 has not taken off as big as was hoped.

Its really not that much harder to do the swap kit, but you will require to cut the hood and you will still not be able to lower the lude at all because the 3rd gen is the most unique chassis of all Honda's exluding the NSX.

You are better off with H22 or B16/18/20b swap like we have discussed in past.

Since we do not have spare hoods floating around and a custom one would cost around $800-$1100 to make its an added cost just to do this swap.

Being unique costs money that 99% of most 3rd genners are not willing to pay.

Here are some pics:








Here are MustardCats CAD drawings to put things in perspective:












And what you are not seeing in these picures are the fact that the engine is sitting on the ground and now wheels on the ground.

And I am sure you have seen these floating around:













And lets add the many threads discussing this swap again:

1. http://www.preludepower.com/forums/showthread.php?t=352287&highlight=k20+swap

2. http://www.preludepower.com/forums/showthread.php?t=203612&highlight=k20+swap

3. http://www.preludepower.com/forums/showthread.php?t=361721&highlight=k20+swap

4. http://www.preludepower.com/forums/showthread.php?t=359225&highlight=k20+swap

5. http://www.preludepower.com/forums/showthread.php?t=352287&highlight=k20+swap

6. http://www.preludepower.com/forums/showthread.php?t=343608&highlight=k20+swap

7. http://www.preludepower.com/forums/showthread.php?t=345950&highlight=k20+swap

8. http://www.preludepower.com/forums/showthread.php?t=344386&highlight=k20+swap

9. http://www.preludepower.com/forums/showthread.php?t=336435&highlight=k20+swap

10. http://www.preludepower.com/forums/showthread.php?t=305497&highlight=k20+swap

etc..... I think you get the picture here.

Now dont get me wrong, the swap can be done just fine, its keeping the swap in the engine bay that is your cost as well as the ground clearance.
If you dont mind getting rain in your engine while idling at a stop light, then go for it.
But with most things this is really just a one off kit type of thing.

The B series kit has not taken off at all because most new kids picking up these old chassis have no idea what a real cost of custom parts are because they are all so used too civic/integra prices.
Not the case here.
 
#8 ·
If you use a better ratio FD and even bigger wheels/tyres you can get more ground clearance without losing much else. Aesthetics may play a part but for those going in this far, a lip and skirt solution sorts that relatively easy (and can get you some nice aero at the same time).
It would obviously harm the CofG and handling a tad but most could live with that (or not even notice).

If you have the mindset and ability/access to those that do, then this swap is perfectly viable. For those wanting to just swap parts in... forget it.
 
#9 ·
Uniqueness Definetly... different

I am an H guy though... about a decade ago... when K's were new... guy before me had a bolt on K20, hondata etc... It made like 180 whp and like 135 trq. My bolt on JDM H22 made 185 whp and 155 trq... Mustang dyno... Guy spent probably double on the swap then I did... from then on haven't been much of a K guy...

Doing a K20 to H22... its a no brainer on price... hp, torque... H. K24 has more potential.
 
#15 ·
The k20z3 is only 2 inches taller than the b21a. They are the same width and depth. The axle hole on the k20z3 is the same height from bottom of trans as the b21a as well. This means that tue additional hieght can be dealt.with by hood protrusion rather than decreased oil pan clearance.
 
#16 ·
the h22 is bad enough with clearance, and slamming your lude in not optional unless you go to the fabrication extent as musturdcat did, or you live in area with zero pot holes.
with the money you would put into kswap you could have a high comp h22 running e85, with plenty of cash left over for bolt-ons...hell you can damn near have a reliable h22 turbo if done correctly.
 
#17 ·
I think the money end of it depends on how much you get the motor for and what kind of deal you can broker on the fabrication.

The swap is easy as you convert the z3 motor to the 05-06 rsx harness, and run the 05-06 rsx pcm. Realistically the only issue then become the mounting, which isn that hard; as long as your good with a hole in the hood.

The ground clearance, wont be that bad, as the b21a oil pan sits the same as the k20z3 depth wise. I would love to see this swap take place and would love to check it out in person.


Mustard cat did an h22 swap correct?
 
#36 · (Edited)
Hi, I have been reading the posts and a lot of it is bang on. I bought a full k20 z3 swap for pennies on the dollar, out of a 08 si. got everything and came across a good fab shop, was able to find a compatible ecu to bi-pass the key security, a wiring harness to go back top the obd 1 or 0 as well as some mounts, I still need some of them to be custom fab however saves some time and just waiting to see the size of hole will be in the hood to custom fab a scoop. I'm low on funds until the new year until I can sell the b21a swap I pulled out of the car to get the ball rolling again. I would love to show another lude enthusiast when I get the ball rolling
 
#18 ·
Its too costly bro.

Thats the whole point to this swap.
It is just way too costly to lose more of the ground clearance and the hole in the hood is rediculous for us 3rd genners when we do not hoods to replace so easily or if at all.

Once you go with this swap there is no interchanging of anything and the whole point to any swap is to keep as much as close to OE as possible.

As you can see for the pictures I posted, the guy in Malaysia is almost stock height and he still has a hole in the hood.

Just for a 6 speed tranny?

The H swap is still the best bang power to dollar ratio and you dont have to give up much, and still get some low for better handling and style.

Ask yourself why you do not see real 3rd genners trying to do this swap?
Its not because for lack of trying, its because its too much to sacrifice as well as cost.

The H swap is even more popular than the B16/18/20b swap even after I made the swap kit, hardly anyone wants to purchase the kit.

And only one person has done this K swap, another is attempting to do it but it will be his track car, not a daily driven car.

Money talks when it comes to swaps like those, and unfortunately its the reality of this community.
 
#19 ·
So the guy who did the k swap is not a real 3rd genner? *scratches head*

(I'd still do H though, if I was going to do a swap)
 
#24 ·
Ok, so here are the facts, not sure if eurphoric tree wants me to say anything, but he is a customer of mine, his k motor and trans are in my shop right now.

Both he and I measured the motors, both the k and the b21, and outside of the height difference the motor will sit just fine. He has no issue with a hole in the hood and we have already discussed making a custom cowl to cover it all after the swap.

Fact is he got the k motor for an unbelievable price, the wiring and conversion are cheap as I already have the parts in the shop from previous cars. The fabrication, well that's not an issue as I have made many custom mount setups over the years for different applications from VW to chevy to Honda to Toyota. Also, the fabrication time isn't a cost to him, as we both agreed that I would get some free advertisement out of it.

So now the fab time is nil, the parts are available and he got the motor on the cheap, why wouldn't this swap be good to do?

With some tuning this motor can easily make over 200hp and with bolt mods and tuning it can easily hit 220.

The hood is about the only downside, however, like I said earlier, we will deal with that when we get there. One way to reduce the required hood clearance is use the k24a intake manifold as it folds down, not up.

As for the oil pan, well the oil pan of the b21a will sit in the same spot as the k20z3 as remember this is not a k24 which has a huge bottom end.

All in all, this swap will move ahead whether people think it is feasible or not, so I hope the third gen group is prepared. Fact is both tree and I are hoping that this third gen community will support this swap and provide some guidance and assistance if needed along the way.

Also, anyone in here need a running b21a motor with a timgin kit and full seal kit? If so euphoric tree has one for sale that Iam willing to freight to anyone who needs it. 500-700 candian dollars takes it, so pony up if your interested.


Sean, I appreciate your feedback and am grateful to have you in the prelude community, Jon(I tthink its spelled that way), you expertise and knowledge is also appreciated and though we have had our difference over the years, know that I have allot of respect fro you and your opinion. Mustard cat, your drawings will assit allot in the moutning of this engine and I thank you for that. The rest of the third gen group, well, you guy are all pretty awesome, most defiantly more helpful to each other than most car groups, and to me that is some seriously cool shit. I hope that each one of you who may have an idea or a contribution to trees swap speaks up and engages themselves in this particular thread, as I welcome the feed back, as this swap has not received the greatest welcome, although with some work, maybe we all can make it something that others would like to do.

With all that said, keep the opinions coming, as I read them, ponder them and value them all as they help incite and provoke thoughts and ideas regarding this swap.
 
#34 ·
So now the fab time is nil, the parts are available and he got the motor on the cheap, why wouldn't this swap be good to do?
No idea ;-)

With some tuning this motor can easily make over 200hp and with bolt mods and tuning it can easily hit 220.
I think you're underselling the K motor, as future-proof option it has far more going for it than the H.

The hood is about the only downside, however, like I said earlier, we will deal with that when we get there. One way to reduce the required hood clearance is use the k24a intake manifold as it folds down, not up.
I see that as a(nother) reason to use ITBs, have to fit a hood scoop, make it worth it's existence for more than just clearance :)


All in all, this swap will move ahead whether people think it is feasible or not, so I hope the third gen group is prepared. Fact is both tree and I are hoping that this third gen community will support this swap and provide some guidance and assistance if needed along the way.
In fairness I think most would support this and help out if they can. The naysayers are obvious and have their own reasons for that.



Jon(I tthink its spelled that way), you expertise and knowledge is also appreciated and though we have had our difference over the years, know that I have allot of respect fro you and your opinion.
Spell it either way.
I'd rather have some respect than be liked so that's fine by me.
Our differences are of no consequence in the greater scheme of things. Seeing a project move forward is more important to the community(and myself) than two people who have never met, have some words on t'internet.


With all that said, keep the opinions coming, as I read them, ponder them and value them all as they help incite and provoke thoughts and ideas regarding this swap.
At risk of upsetting you, you think more like I do than you might care to admit :lol:
 
#26 ·
This was the guy who was gonna do the b18 swap, but then I had a crashed civic si come into the shop and euphorictree bought the whole swap from him for pennies ont eh dollar. He was gonna sell it to buy a b motor, but then one day we were talking and, decided to take some quick measurements and then after that it was one.

The idea of a k in a ba4 is awesome, and I think it would be great as the ivtec, the true 3 lobe cams, the 6 speed lsd equipt transmission and the over all uniqueness of this swap should render a really cool car once its done.

I feel bad that he isn't going B motor anymore, but look forward to seeing his car parked next to mine and the rest of the crew at the meets in out city. Hopefully, that will be the case!
 
#28 ·
He was gonna sell the k and make some money on it as he got it cheap, but then, due to shitty market up here and poor economy, there isnty much interest in buying motors up here, so then we started thinking about the ba4 k swap.

Then he made this post, and on and on and on.

Really, he was hoping there would be more positive in this thread. Doesn't seem that k swaps are a good thing around here. Oh well.
 
#29 ·
Honestly its really not that its not a positive thing, its really more of a money and hood thing.

While some say they dont mind giving up that hood for a K swap, the reality is that our parts in body panels is Nil....so people are not really into going that far into a swap where it would basically ruin the hood.

I love the H swap personally because I lose nothing and gain everything, but others dont want to lose their lowering capabilities and rather would go lower than gain power.

And then it comes right back to - money.
How much the kit would cost and then sourcing a K is no where near cheap in the US unless its damaged and how often is that happen?

I was expecting more to jump on the B series swap kits but you know were that is right now.

Do I think it would be cool?? Sure.
Would I do it...ehh I can get the same amount of performance out of an H and cheaper to start as well as not losing my nice hoodline etc...

I do want to see your progress here, its just been said so many times and other than that Asia member its really just words.

I hope you guys do go forward with it though since you have the facilites and know how and motor/tranny and stuff to do it.
 
#31 ·
I love the H swap personally because I lose nothing and gain everything, but others dont want to lose their lowering capabilities and rather would go lower than gain power.
Having the downpipe sit even lower than it already does on a Honda is pretty bad, if I read into the issue correctly it's 20-30mm lower. Even with my downpipe at 95mm clearance from the ground it doesn't fare too well against some speed humps etc. On top of that the possibility of losing a point and being fined $117 for ride height being too low isn't super appealing. Just food for thought on that issue.... it's also why I'm very interested to see what Mustardcat's progress on his raised setup amounts to.

Also, I know this doesn't directly relate to the original topic, but when the time for a swap comes for me it's either going to be H22 if it can be raised enough to get more clearance or B20V.
 
#43 ·
Ahemm... I have been helping a lot of people without compensation as well Jon, way before I started down the road of aftermarket, you are just forgetting all of that since you are so focused on always trying to be right and never once admitting you get just as personal as anyone else. And I still do I get the gambit of pms and emails and social media pms like most. So lets back down off that so called high horse of yours dude. :rolleyes:
Same old crap Sean, you always, without exception, start this crap and get all upset when I respond in the same manner. If you tried sticking to the topic in hand instead of always trying to score points on me you wouldn't look so bitter and foolish.
I get personal if you try to insult me, that's your choice.
I'm not at all focused on being right, it's just hard not to be when you're the one arguing.
And I like my high horse, it helps me look down on you.



Not really, anyone can bring something to market if they have the desire to do so. Selling is the easy part (just look at all the shit that sells by the millions for evidence), making something people (and can afford/justify) want is the hard part. - You sound a bit bitter here in this statement Jon. I wonder why??
I have no idea, maybe you should tell me.
Just so as you know, I'm not in the slightest bit bitter, why the hell would I be? I'm just stating a fact.
I suspect you're going to wow us with your great salesman prowess (lol) and I'm meant to be envious of it..... I really have no idea wtf you're going on about. Just looks like another attempt to fog the issue.


- You see I think its the cultural difference between you and I, because you did not understand that I was referring to this debate between only you and I, not the OP. I only stated to the OP that this is not a supported swap and it will be expensive and non supported meaning if something breaks, he has to recustomize everything all over again. That was my point. I gather you did not key into that while reading.
No idea if/how it's cultural.. not even sure what 'culture' you are. But most people here understand me.
I was (and still am) trying to keep the conversation about the thread's topic, you took it off course as usual. I'd say if you don't want to discuss the swap here then don't, if you want to throw petty insults at me then choose a better method/place.


Try not to forget that this is a discussion forum for like-minded people, not just a market place for some. - I have never forgotten that Jon, I simply dont agree with letting people jump off a cliff without being informed. You have your way and I have mine. Ok...good moving on...
This is where we have a problem, you're technical/engineering knowledge is sadly lacking in comparison with many people here, the person who seems to be doing this swap included.
You're telling someone they shouldn't do something based solely on the fact that it's a not a mass market kit or one that you support. It's been said before when you've nay-sayed other's ideas, if that was the case no-one would ever do anything unique or progressive.
I really don't see any cliffs being peered over here, let alone jumped off.




Now can we dispense with the attacking my posts
:lol:
So you can attack me but I'm not allowed to counter your on-topic comments that are unhelpful to the op? Hypocrisy is never far away.


and be of better support to the OP.
Well in that case you could answer the questions I've asked you instead of getting in to the personal crap. But as is often the case you never actually reply to genuinely helpful questions. :rolleyes2:



I know they love to see our arguing but it is boring me now.
So stop then, it's real easy if you have the desire.
 
#44 ·
Thankyou everyone for the input


Same old crap Sean, you always, without exception, start this crap and get all upset when I respond in the same manner. If you tried sticking to the topic in hand instead of always trying to score points on me you wouldn't look so bitter and foolish.
I get personal if you try to insult me, that's your choice.
I'm not at all focused on being right, it's just hard not to be when you're the one arguing.
And I like my high horse, it helps me look down on you.




I have no idea, maybe you should tell me.
Just so as you know, I'm not in the slightest bit bitter, why the hell would I be? I'm just stating a fact.
I suspect you're going to wow us with your great salesman prowess (lol) and I'm meant to be envious of it..... I really have no idea wtf you're going on about. Just looks like another attempt to fog the issue.



No idea if/how it's cultural.. not even sure what 'culture' you are. But most people here understand me.
I was (and still am) trying to keep the conversation about the thread's topic, you took it off course as usual. I'd say if you don't want to discuss the swap here then don't, if you want to throw petty insults at me then choose a better method/place.



This is where we have a problem, you're technical/engineering knowledge is sadly lacking in comparison with many people here, the person who seems to be doing this swap included.
You're telling someone they shouldn't do something based solely on the fact that it's a not a mass market kit or one that you support. It's been said before when you've nay-sayed other's ideas, if that was the case no-one would ever do anything unique or progressive.
I really don't see any cliffs being peered over here, let alone jumped off.





:lol:
So you can attack me but I'm not allowed to counter your on-topic comments that are unhelpful to the op? Hypocrisy is never far away.



Well in that case you could answer the questions I've asked you instead of getting in to the personal crap. But as is often the case you never actually reply to genuinely helpful questions. :rolleyes2:




So stop then, it's real easy if you have the desire.
Hey thanks everyone for the input on this topic, I'm fairly new to the Honda community, fuck I bought 2 of them lol it appears that his has been thought of before. I have come across a rare opportunity where the price was right and what better way to spend some money and push the envelope.

There was a lot of great ideas, and I hope that there will be many more to come. Once I iron out some kinks, I will start a build thread and we will see the project come together.
 
#51 ·
I appreciate it!


Although IMO the Honda J series motor is the best motor Honda has made, especially the j32a2 and the j35a8 from the type s tl.


To each their own, and fact is, this swap will iekly require the assistance of both Jon and Sean as well as others on this site. Franlkly, as much as I know about Hondas, my 3rd gen experience is limited. So, with that said there may be some questions that arise form time to time, and I encourage everyone to be involved, whether debating or not, as it is still stimulus for the swap.


I think euphoric tree will be pleased once the swap if finalized.


Now if we could just track down some ITBs...
 
#50 ·
Yeah right, I was not trying to do that but it always goes this way even after I say lets just let it go.

Hahaha!!! And if you did not read my earlier posts, I said "I hope it gets done..." because so many say they want it and never make it happen.

But silverwrench this swap has been done already and there really is no way around cutting that hood.
I dont personally like losing my hoodline for motor swap, so I would not do it.
 
#53 ·
So, this thread back from the dead, with some really goodness as well.

I recently took a couple AWOL days at work and ran home to finish up some work I had on the go, a Nissan 240 clutch, a PNP and rebuild on a H22 head, as well as a couple oil changes and some tires. Then, late the one night I ralsie di had 24 hours and nothing ont he lift, nothing schedualed for work, so I pulled Jamies third gen prelude into the shop.

I cleane dup the engine bay, removed the power steering pump, lines, resovioir, as well as the distiburot blocks, lines and wiring. I also, loosened the fuse box and got the rest of the engine bay ready to drop the engine in for fitment inspection.

Turns out, the k motor fits nicely into the 3rd gen bay. Sure it sits high, a bt low, but over all the axle angle and fitment isn't so bad.

I took the carrot top mounts, and fit them to the motor, and then checked the engine bay and it turns out the Carrot top EG mounts will work nicely. They need some modification done to them but over all defeintly are able to make work.

Now, with all that said, putting the k engine in ot the 3rd gen bay was easier than putting the B20a/b21 engine into it. Kinda funny how that works.

Some notation:
OEM 3rd gen radiator will not work.
I am using a full 2005 acura rsx harness.
I will be using the oem k20z3 shifter unit with or without e brake.
Oem K series exhaust header will not fit well at all. Need AM one.
A huge hole int he hood will suffice for now, but will be addressed once full mounting is finished.


I will post some preliminary pics up for you fine fellas in a bit here, ince I get settled back into work.

All in all this swap wil be a great one to have done on the third gen, and will likely be easier to do than the h22 swap.

I was surprised at how easy the k motor fit in this engine bay and how much room there really is, minus the brake proportioning valve, it is in the way but not really, but would be allot better if located elsewhere, but that is allot of work so we will see how it goes.
 
#54 ·
Here are some preliminary pictures. I ve gotten the engine bay cleaned up and ready, then the engine stripped down and then the whole setup on some milk boxes, sitting in the engine bay for reference.

The Carrot Top mounts need some modifications, but will work just fine with some tweaking.

My nexty set of days off I will egt more pictures of the munts and the chassis fabrication required to get it alls etup, but here are some pictures just to appease and piss off the third gen community.

I will say this swap will kick ass!




















 
#55 · (Edited)
Yeah there was never any issue with the spacing of the motor while dropping in the engine and tranny.

The H22 swap drops in just as easy, its just getting the mounts tighten down and bolted while keeping the motor in place.

Its actually easier to get to the backside of the H22 than the B20/21.

Cutting a hole in the 3rd gen hood is considered taboo in this community thats why its not a popular swap.

Especially for guys who want to daily drive this thing.

But that was already established.

If I am seeing this right you pushed the motor higher up to get the better ground clearance???
 
#56 ·
For testing purposes, this engine is sitting higher than wanted, ive been kicking the idea of a modified oil pan, to increase oil pan clearance.

In these pictures the engine is straight not tilted as well as is about an inch high as i needed room to slip the mount in and out while i was modifying it.

With a bit of tilt, and a modified oil pan i thino this k kotor will fit nicely.

The axle angle seems to line up really well also, frankly i expected more difficulty than this with this swap, but really so far ive been lucky.

There were two spots where i cut the rear subframe, again just tentative to make clearance for initial fitting. We ill see how it goes!
 
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