08 Civic Si K20 different than a K20A2??

[CAFROG]

The 08 Si K20Z3 Transmission also comes with an LSD, but in order to make it work with an RSX shifter you have to switch out the shifter mech (on top of the tranny) with one from an RSX-S.

You got a swap like I want......I need to talk to you more! In terms of the Z3 trans in our shell, don't you have to tap a hole bigger to get that A2 shift mechanism in?

Thanks for all the info guys. Over the last few weeks, I have been researching the swap a lot. It is friggin' mind blowing how involved it is. Much more to it than I thought with the glances I gave it before. The price for just parts to get the swap up and running is growing everyday lol. Hybrid Racing Mounts, conversion harness, 2.9 DSS axles (gonna run drag radials at least), and (from what it looks like) a hytech replica header will cost me around $1800-2000!!! And thats a package deal.

And then on top of that, I would still need the shifter box, shift cables, Kpro or go home, clutch line, fuel lines, fpr, walbro pump, etc. I am somewhat flexible on buying used parts but mostly would feel better with new parts. I think I wil need to be more flexible as the cost sheet builds. Hoping to have enough $$$ for the motor/trans/mounts/harness/and whatever else I can afford by June (summer break) so I can at least get it started so I keep pinching pennies so its finished and running down the 1/4 mile before August (Fingers crossed)

Pulling the B16 and selling goodies by early April....I will start a for sale thread with the list then

I will have for sale: (b/c the K swap is $$$, I need to sell this stuff first)

Complete JDM B16A longblock w/USDM engine harness/R-12 AC/PS
EG6 OEM mounts
USDM B16A3 Intake Manifold/USDM B series TB
CTR B16B Camshafts in great shape
All 32 ITR Valve Springs (2 per valve)
98 spec JDM ITR header/heat shield(s)/skid plate
Virgin USDM P30 ECU for CA smog certification
Magnaflow muffler&resonator/Trust mandrel bent 60mm exhaust (super custom lol)

Obviously, some of this stuff would be a pain in the a$$ to ship but, for the most part, I will offer this stuff up here first. I would rather pass on healthy, legit parts to this site then have to start another Craigslist Nightmare thread. But, inevitably, I will have to Cragislist some of this stuff.

B16A Transmission already sold to Magana (member here) once I pull it.

Give me your opinions on the value of a stock B16A longblock. Its got good compression, burns no oil (in comparison to my old B18B1 for sure) and it just passed smog not too long ago. I need to get as much out of it as possible lol.

 

[hondafreak513]

Let me know soon on the cams ASAP my friend is about ready to start rebuilding his motor. He might want the ITR valve springs too... At least get me a price on the parts. Maybe get them sold soon so you can get that K-swap going sooner..

 

[Dark93DX]

You got a swap like I want......I need to talk to you more! In terms of the Z3 trans in our shell, don't you have to tap a hole bigger to get that A2 shift mechanism in?

Yes I used three bolts to secure the A2 shifter mech to the Z3 case. Two of the holes lined up, but the third one I had to drill and tap in the Z3 case. You'll be able to see where to drill & tap the third hole when you line up the first two holes, just don't drill too far and go through the case. I used Ultra Grey around the mechanism to seal it up.

Also you'll need to get an aftermarket or A2 throttle body since the Z3 is DBW and an A2 engine harness.

 

[CAFROG]

^^^ Thanks bro. I did find out about the TB swap. Don't I need a adapter for the A2 TB on the Z3 IM?

And I 'have to' run an A2? Okay.....I was hoping there was a way to make it work. Can you tell me what makes it not work? Does the A2 harness plug into everything on the Z3?

The Z3 seems to much more expensive (in comparison to an A2) with all the parts you need to replace.....I'm thinking more and more about a pieced together swap. But its foreign territory for me.

 

[Dark93DX]

Yes to use the A2 (or aftermarket) TB on the Z3 RBC IM you will need an adapter, Karcepts sells them.

The Z3 wiring harness is set up for DBW throttle, thats basically what makes it different. I don't know if its possible to convert a Z3 harness to work with cable throttle, but I imagine its alot of work if its possible. All the sensors on the Z3 plug into the A2 harness, so it works fine, but I did get rid of the plastic cover on the drivers side of the harness so that the plugs would reach the sensors.

My swap didn't come with an alternator or starter so I used A2 parts there.

The Z3 has some small advantages over the A2, it comes with the RBC IM, has a more aggressive intake cam (exhaust is the same I think) and the Z3 transmission has a 4.764 final drive & LSD like the DC5 K20A ITR vs the A2's 4.389 final drive and no LSD. (Also I have "read" that the Z3's intake valves are slightly bigger, but I'm not 100% sure on that yet)

In the end an A2 swap would probably have been a little cheaper and more straight forward, but a K-swap isn't cheap either way. Whether or not its worth it to do a Z3 swap over an A2 is up to you, but the extra effort and cost wasn't that much more when compared with the effort and cost of doing a K-swap already.

I bought my 08 Si Z3 swap locally at the time since it was practically brand new, had an LSD trans and I couldn't find an A2 or Z1 locally at that time.

 

[CAFROG]

Makes sense about the Z3 harness now (fly by wire TB). I heard a Z1 harness 'can' work but needs mod's.

Okay, I think I got this right....now lol. When I add it up....the changes are pretty substantial.
The Z3 swap typically needs a different (A2) ECU, Shift Box, Shift mechanism, Shift cables, engine harness, Throttle Body, and Adapter plate

^^ That's a lot of crap!

Did you run the Z3 ECU with re-flash or a K-pro via 02-04 ECU?

I need to see what a somewhat local dismantler (Redline Recyclers) can get me. I definitely want a LSD transmission. I would feel dumb if I didn't. We all know traction is an issue.

Have you ran drag radials or anything aggressive? I have read the Z3 LSD isn't optimal although I do not know why.

So from my readings and your testimony, the top end of the Z3 is superior. But I also read that the Z3 bottom end and its pistons not being as good as the A2's pistons. I cannot remember the exact reasons but I think it had something to do with the shape of the piston.

Sounds like a Z1 swap is more straight forward and will give me a swap with lower mileage (stereotypically) than an A2 swap and 210hp....but no LSD and a lower final drive (in comparison to the Z3 swap)

How much did you score the Z3 swap for? (before retrofitting it to work in your shell) I'll have over $3k saved by April. Then I part my B series stuff out...save some more and hopefully be K-series running by early summer. Figure I need the swap plus and additional $3k

 

[Dark93DX]

Makes sense about the Z3 harness now (fly by wire TB). I heard a Z1 harness 'can' work but needs mod's.

Okay, I think I got this right....now lol. When I add it up....the changes are pretty substantial.
The Z3 swap typically needs a different (A2) ECU, Shift Box, Shift mechanism, Shift cables, engine harness, Throttle Body, and Adapter plate

^^ That's a lot of crap!

Well it sounds like alot, but keep in mind that you'll have to use an RSX-S ECU, shift box and cables no matter what swap A2, Z1 or Z3 you do (unless you use the hybrid racing shifter). If you want a factory LSD Trans you have to use a Z3 with an RSX-S shifter mech or a K20A trans. The Z1 has the same gearing (except for 6th) as the Z3, just no LSD. The shifter mech I got used from k20a.org vendor forum for around $70.

The only expensive change was the A2 engine harness, I bought mine brand new for $305 from K20 tuned. A used one would probably have been cheaper.

For the TB you can get used A2 ones from vendor forums for around $170 and the adapter plate was $60. I went with an aftermarket TB and then bought all the sensors and brackets to go with it, which wasn't smart cause it cost me me more then simply buying a used TB, but live and learn.

Like I said the Z3 costs more then an A2 swap, but the Z3 has the RBC IM. You can add an RBC IM to an A2 or Z1 swap but it'll add extra cost and you have to modify it a bit.

For the ECU i'm using an A2 ECU with Kpro installed. You can't use the Z3 ECU because you are getting rid of the DBW. If you do a Z1 swap you'll need to have a jumper wire added to the ECU, hybrid racing does this for $145. Also another note on the Z1 or Z3 swap, if you use an 05+ K-series transmission you'll need to do something about the speed sensor, again hybrid racing sells a converter for $200.

I've never heard of the bottom end of the Z3 not being as good as the A2? I know the A2 and Z3 share some internals and are very similar. The Z3 block has a balancer shaft to dampen vibrations. I don't think honda would've made the Z3 not as good as the A2.

I got my swap Engine and transmission c/w all sensors etc for $3K. I didn't pay shipping b/c I picked it up locally. I havent used drag radials on my car, I haven't taken it to a track either, yet.

This was only the second engine swap I've done, but if I had to rank the k20 swaps we talked about in terms of ease I'd say the A2 would be the most straight forward followed by the Z1 and then the Z3.

Here are some links for vendors,

K-Tuned - Where K-Series Innovation Begins
Karcepts, Inc. - Index
Hybrid Racing - hybridracing.com
K20Tuned LLC

 

[CAFROG]

Thanks bro!

K-pro FTW...

I figure 3K about right. Talked to a place I know (recycler) and the guy told me $4K for and A2 complete swap (don't need axles) and after I told him I figure he would be lower.....he said $3700.....but I figure its less than $3200 buying it all separate ($1700 for complete A2 longblock, $800-1000 for a A2/Z1/Z3 Trans, $200 for the shifter box/cables, $200 for 02-04 ECU). I plan on using 2.9 axles and hybrid racing stuff. Already talking to Dave via email. But I wont be able to buy all the necessaries for a while. I can buy the swap in a month if I can get it for $3k or less. Then I figure another $3500 in swap parts. (clutch, header, k-pro, axles, mounts, conversion harness, fuel lines, misc coolant parts, intake, etc)

How'd you deal with fuel lines? Clutch Hydro Line? Fuel pump stock or walbro or?

 

[Dark93DX]

I never added up what the total swap cost was, but your budget sounds about right. As for the Fuel system I used Hybrid racing fuel lines and fuel rail with an Aeromotive FPR. Theres more then one way to do though and some ppl even make their own fuel lines. I used a Walbro 255 fuel pump as well.

For the clutch line I removed the hardline and used the Hybrid racing K-series conversion clutch line.

 

[CAFROG]

Man! You spared no expense! All the good stuff.

I want to make my own fuel lines....and use a stock injector rail...stock radiator....and maybe even stock RSX base axles with the inners swaped out.......for now.....at least.

 

[Dark93DX]

Ya my fuel system wasn't cheap.

You will still have to buy a FPR. Honda Tuning did a K24 budget swap a while back and showed how you can save $$ on a K-series fuel setup --> Manual Transmission Parts - Honda tuning Magazine

I used my stock EG radiator, but I relocated it to the driverside and used a 12" slimfan.

From what I've read the RSX base axles w/ swapped inners works. I used Hybrid racing budget axles ($100/each) to get my swap up and running, down the road I'll probably upgrade though.

 

[CAFROG]

I think I have that issue of Honda Tuning at home lol Gonna look through my stack right now.

I would rather get 2.9 axles right off the bat but I will cross that costly bridge after I get a motor/trans

I found a 27k mile K20Z3 longblock out of an 09 and we're working out a price. He said that motor and an A2 transmission for $2600. But I am not sure if I want that transmission. Gonna check out the motor this weekend, do a compression test and see what we work out.

I spoke to a guy who claims the 1/4 mile times on slicks with LSD and non-LSD (in internally stock K20) are not noticeable. Seems hard to believe though.......It just not logical to me but I do not know a lot about slicks in FWD set ups.

 

[CAFROG]

Also.....did the Z3 knock and other sensors/valves/etc connect to the A2 harness I know you need the Alt and Starter out of an A2 but what about the rest? Looking at a Z3 this weekend!

 

[Dark93DX]

The oil pressure sensor from the A2 harness didn't really fit the Z3 sensor, so for that I soldered the Z3 plug onto the A2 harness. I'm pretty sure I did the same for the knock sensor. You can also use an A2 knock sensor.

All other engine sensors plugged in ok. The sensors on the TB all plugged into the A2 harness b/c you'll be changing that to an A2 anyway.

The only other sensor plug that I changed was the plug on was the Transmission speed sensor, but thats gonna depend on what transmission you use. The A2 plug can be used on the Z3 speed sensor, but you'll just have to shave down one of the plastic guides on the sensor. If you use an 05+ transmission though you'll have to solder in a VSS converter anyway.

 

[Dark93DX]

shit man, I was going through my old receipts and I was wrong about the starter. The Z3 starter DID come with my swap, it just wasn't on the engine itself and was shipped loose. Sorry about the confusion, this was 2yrs ago for me, but after finding my receipt I realised I was wrong. My swap did come with an alternator, but it was also loose and turned out to be from the wrong vehicle. Originally the starter and alt weren't included in my swap, but when I went to pick it up, I asked the guys there if they had them and so they ended up throwing them in for free. The starter was good, but for the alt I bought a used A2 alternator, so thats what I'm using now.

For the Z3 starter the main power wire connected up no prob, the smaller 1P connector gave me a bit of trouble, but I was able to make it work. For the smaller connector some ppl just solder the Z3 plug onto the A2 harness. I have the A2 charging harness as well, but you don't have to use it as you can make your own.

If you buy the Z3 engine it should come with the engine harness anyway so you can use those plugs I mentioned.

 

[CAFROG]

Looking at a Z3 motor/trans this Saturday. We'll see if a price can be worked out.

Its suppose to have a harness on it so it sounds like I'd need an A2 harness and solder some Z3 plugs onto it. No biggie.

 

[CAFROG]

Didn't feel good about the motor and the whole situation. Long story short......I was uncomfortable and went with my gut.....so I shall wait. But I'm cool with it b/c I ain't even close to ready (funds wise) to complete the entire swap.

 

[eg6sir]

just saw this on my local craigslist... just thought i'd let you know

FS/FT:k20Z3 swap A2 converted

 

[CAFROG]

I like the swap and it has gone through a lot of conversions. I do not know why he converted the oil pan, intake manifold, and oil pump....I thought the Z3 stuff is fine but maybe I need to learn more lol Its a little high priced for me too. I can get a complete K20A2 complete longblock (less than 75k on it) with trans, harnesses, shift box/cables, PRB ECU for kpro and axles for less than $3300 at a recycler with a guarantee. I need to wait more anyways......get my B-series stuff sold and save about $2k more and I will be ready to do it all......time is not on my side....no it ain't (Rolling Stones Nemesis lol)