Honda CRX Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
247 Posts
Discussion Starter · #1 ·
im sure this has been covered over and over in other forums, but since ive started browing THIS forum, no other forums are worth it. plus its late and im tired :(

i would like to swap a DOHC head onto my stock '90 SI cylinder block. i dont know what will fit on there, and what would be required to do such a thing. i assume it will need the dizzy and ecu for sure, but dont know what else. im NOT interested in the headache of putting a v-tec head on there... too much wiring makes Stavros a sad boy (i hated doing a dx to si swap in my previous car)

So here are my requests:

1) car the head comes out of (and maybe the engine code too, so it sounds like i know what im talking about later on)

2) parts required

3) details that I might overlook while doing such a job

4) if this swap is worth it?

number 4 is important, cuz i dont want to spend my $$$ on something that will give me only negligible benefits.

i plan on rebuilding the engine as soon as my rings blow (car has high mileage, but im still gonna oil her up regularly) and while i rebuild, i figure i might as well let the top-end breathe a little better, and have a bit more flexibility with my timing than a SOHC can give.
 

·
Registered
Joined
·
5,146 Posts
People say it has been done but until i see in person Im going to say this one isnt happening. It would be more feasible to swap out the whole engine for a dohc one.

Even if you could do it, the machining required would cost too much and be more difficult than wiring up a mini-me.
 

·
Registered
Joined
·
214 Posts
If you don't want to accept only negligable benefits then you are looking at a turbo setup. No head swap is going to make you happy. For about 700 bucks you could get yourself a junkyard homemade turbo setup or drop in a whole dohc zc and only have to change 2 wires. ZC will only get you a couple more horsepower though. If it were me I would turbo that si d16a6 engine.

Something that doesn't quite add up is that you want dual cams for more flexability for power over a single cam. Some people will debate this though. Dual cams can only flexibly give you a negligable power benefit and you need a dyno to do it and adjustable cam gears. Basically there is no easy dual cam head swap for your si engine, your choices are mini me vtec head swap or dohc zc engine swap... . then from there you get into b series engines where you need mounts and harnesses, linkages, axles, and whatnot. Your cheapest route avoiding wiring issues like you said is going to be probably to build that si engine you have. A rebuilt or built engine is going to be much nicer than the condition it is currently in. And if it's built then you can add the turbo later. A turbo is a bit involved though so I am not sure if you want to do that either.

Let's ask this first. How much power do you want to end up with? And have you ever thought about a hybrid transmission?
 

·
Registered
Joined
·
247 Posts
Discussion Starter · #4 ·
im seriously thinking of overhauling the tranny cuz when i changed the oil in it after i bought it... good lord it hurt my eyes to see it. half a litre of black sludge came out. found out why 2nd gear wasnt too happy whenever i shifted into it. when i do take it out and renovate it, i would like to replace my 5th gear with one from an HF so freeway driving is a little more relaxed. ill also replace all the syncros, and check the gears for any damage.

i have been looking at the jackson racing supercharger, only problem is that thing is $3000... and for that much money i could get a bigger powerplant. i dont know how far i want to go with this thing yet, so ive gotta wiegh my options before i put my money down.

jackson racing supercharger looks nice to me because its not as involved as an engine swap, but it will still get me up to around 140 horse with 8psi of boost, if their website isnt lying. just gotta replace all the worn internals... my rings and conn rods would hate me if i put boost on them now.

if anyone has done this modification, or know anyone who has, i just wanted to know how happy they were with it.
 

·
Registered
Joined
·
634 Posts
When you do the transmission overhaul, pay particular attention to the shift forks inside the gearbox. I've got it on good authority (Mista Bone) that you'll bend a shift fork long before you ever need to replace a synchro...

The HF 5th gear does do a helluva job of easing your revs on the highway. It only drops 300-400rpm off the 80mph cruise, but that's a bunch, and you definitely notice it.

Mike
 

·
Registered
Joined
·
247 Posts
Discussion Starter · #6 ·
thanks for the info, ill inspect my shift fork real good when i drop the tranny.

youre right, 300 rpm would make a difference, anything to keep the noise down. gas prices in canada are really high right now too... so thats a real incentive to do the swap
 

·
Registered
Joined
·
214 Posts
When I downloaded the instructions to the jackson racing supercharger and found out you have to cut some stuff and rewire things I thought about how much a pain that kit is as anything else. A turbo would probably yeild more power, depending on what turbo you use of course. I have heard some people are disappointed with the jr supercharger on a d16a6.

If you can get steel shift forks from a newer year car 92 or 96 is when they started with steel forks not aluminum like the l3's have.
 

·
Registered
Joined
·
10,896 Posts
If your CRX is a daily driver and you dont want to mod it any further a JRSC is a good mod. I have driven a JRSC and am considering it right now with the lower price they are selling them for. The JRSC vs a normal B16 swap I would rather have the JRSC it has more power down low and you might give up just a little at high rpm but the jrsc is the better of the two in city driving.
 
1 - 8 of 8 Posts
Top