Ok, guys.. I need suggestions from those of you who have done successful H23vtec swaps.

I am picking up my complete H22 head tomorrow to go on my 93 Prelude Si. I know I need a different ECU, so I'm leaning towards the P72 so I can run a Hondata setup later if I choose to do so. My friend that I'm getting the head from mentioned it was already machined for the h23 block, but I'm somewhat clueless as to what he means by that. I also read alot about the oil squirters on the H22 block needing to be used on the H23.. what's the deal there?

As per bolting the head down, I know I need to do it a specific order as to not warp the head. Should I go ahead and invest in ARP head studs? And for the distrubuter, the h23 one will work fine, correct?

And yes, I have searched this topic over and over, and not only on this board. I have found alot of very informative posts on this swap, but still nothing I'm really looking for. I'm more looking for information on what I'll encounter, not what I need if it goes perfect, which dosent seem to be very common with this frank-install.

 

machined for h23 block.. wtf.. aha oil squirters are designed to keep the piston temps down.. i would do it if u can but if u run forged pistons u dont need them.. i hope u know its alot of work.. good luck.
h23 dist. will work too. watch out wit hthe p72.. if u have a hondata now then its fine but if u run that untuned it will lean out..

 

mchined? maybe they just mean like resurfaced the bottom so the head gasket goes on clean...you always have to clean it up.

Anyways P72 on an H23 VTEC will detonate your motor in no time 2.3 engine with a 1.8L ecu is a baddddd idea.

What pistons are you running? Cause h23 pistons with an H22 head is 9.3:1 CR...

There is an awesome thread on my H23 VTEC and others right here: http://www.preludeonline.com/showthr...threadid=94804

Piston oil squirters are highly recommended if you are running stock honda pistons

 

I was actually hoping you'd respond, satan. I love your car and its progress.. as I keep up with it on preludeonline. Yes, that thread is the 'very informative' one I was refering to.

I knew about the 9.3:1 with the h23 pistons, so I was considering JDM H22 pistons to get into the 10's CR wise. I might end up running nitrous on top of the h23vtec, so I don't want my CR to be too high as it would with the TypeS pistons.

With the JDM H22 pistons, do you still suggest oil squirters? If so, can you tell me where I get them at. I guess I will go with a p13 ecu then, since it seems like I'll run into problems with the p72.

I'm really looking for a detailed list of parts I will need, other than the ECU to properly do this frank swap. I know I might run into problems, but that's something I'm willing to take to get the power I'm looking for.

 

I suggest oil squirters, H22a pistons need them especially since you are revving to stock rev limits...so you need a re-honing of the cylinder block for that...

While you have the block open balancing the entire rotating assembly is a good idea...considering you are pushing the H23 crank and rods beyond stock rev limits (6500). Shotpeen some rods..

Actually if you are taking it apart grab some H23 aftermarket rods if you can...better for handling the nitrous. I recommend a V-AFC at least...

You are only limited by $$$

 

In all seriousness, do you suggest that I just use an H22 block as well? I am getting the H22 head very cheap, and I don't plan on adding the head to the block anytime soon anyway, since it obviously requires things to be done that I can't do yet (downtime wise, not so much money). If I were to be able to pickup an H22 shortblock cheap.. do you suggest I do that instead? It would atleast be a much more direct swap. I know I would still need the H22 ECU, but what do you suggest about the tranny? Damn h22 trannies are high, hell.. more than my head and probably end up running more than the block itself.

If the h23 gearing isn't too bad compared to the h22, I could just use that instead and save myself the troubles. Let me know what you think.

 

Well an H22a block would just be a regular h22a...is that what you're saying? H23 and H22a blocks are the same except for the pistons/crank/rods and the VTEC oiling for the H23 is just plugged, and no squirters.

 

satan- I asked because you're naming off things like honing the cylinders, that I wasn't aware was needed for this swap.. that i'd rather not get into. I was talking about pulling the h23 block and using the h22 block instead.. to go along with the h22 head. I know the block itself is the same, but you're saying 'the crank, pistons.. etc' are different.. which are also the parts that don't like being revved as high as the h22 internals. Wouldn't that mean an h22 block would be a better choice if I want VTEC? I got the head really cheap.. if I could get an h22 block cheap, would that not be a better alternative?

 

yes an H22a straight up is the best idea if you are not planning on going all out.

When you change pistons you have to re-hone the cylinders...and maybe bore out and use oversize (rebuild) pistons. For a more reliable setup just find an H22a block..

 

I have a question about this conversion. Don't you gain hp by the percentage of the displacement increase? That is, if you make the engine 20% bigger you gain roughly the same in hp and torque, right?

If so, I really question the point of this swap. (2.3l / 2.2 l) * 190hp = 198.6hp. Is it really worth $$$$ for 8.6hp?

 

I say go with H22 block and head. It'll save you a lot of future headaches.

 

well no hp does not jump with displacement so lineraly as you are stated, The difference is stroke, which creates torque earlier in the rpm band and the extra displacement can help..

And most people are jumping from 160hp to 190hp+ so it is worth it. But there are just some things you have to do to make sure it works.

 

I still can't see how a 4.5% displacement increase gives 190/160 => 19% gain. I suspect most people add on a bunch of other stuff, masking the gain of displacement by itself, and that negates much of the claims attributed to the 2.3l increase alone.

 

H23 = 160hp NON VTEC
H22 = 190hp VTEC
H23 VTEC = 190+hp VTEC if done right.

What are you talking about? VTEC is what makes the gain, not the displacement!


[Modified by satan_srv, 6:09 PM 1/4/2003]

 

Example, Engine A = 2.2l VTEC (H22A), and Engine B = 2.3l VTEC. We already know that stock, Engine A = 190hp, so what does Engine B equal? I said it's the ratio of the difference in displacement. Why is this wrong? They're essentially exactly the same engine, right? The *only* difference is that engine B has 4.5% more displacement, right? Please explain how increasing the displacement of Engine A by 4.5% gives such huge gains. I still can only see 4.5% gain in torque, hp will have similar gains, assuming the same rpm limits.

 

You're walking all over the proof without noticing it. He said that Engine A, H23 was NOT VTEC. Engine B, the H22, is. The 30hp gain is not from the extra displacement, it's due to the head with vtec. If you took an H22 bottom end and put an H23 NON-VTEC head on it, you would lose 30hp or so, as VTEC is primarily the culprit to the impressive gains seen by his comparison.

 

You're missing it...like buddy said people with H23's have a 160hp NON VTEC engine. Thus putting on an H22 VTEC head is a economical way to VTEC your motor without buying the whole engine.

A stock head swap to an H23 VTEC would actually produce LESS power or equal to the H22 because of the larger H22 combustion chamber drops compression to 9.3:1. However if you use H22 pistons in the H23 block when doing the swap, you will produce slightly more power and retain the 10:1 CR

The main advantage of the H23 block is not merely the displacement. It's the STROKE as I said before. The stroke of the motor causes TQ to be gained earlier in the rpm range, and the H23 block has a very smooth torque curve. it's not about PEAK numbers, but more about the ENTIRE POWERBAND.

Here's the lowdown, here's a simple comparsion of similarly modded H23 non vtec vs. the almighty H22:

HP:

Torque:


NOW, draw a smooth line on each of those graphs. Start using the H23 dyno lines up until it intersects the H22a lines, then follow the H22 line to the redline.

That's what I'm talkin' bout Willis! Down low power and torque, top end scream. I should know. 203whp and 160tq I was feelin it everyday.



[Modified by satan_srv, 3:48 AM 1/5/2003]

 

My friends and I completed this about 3 or 4 months ago, and it was indeed a bit of a headache..... we had a few problems and the car was really slow, mid 15s (1/4 mile) on a 92 4WS prelude.... but finally after finally fixing all the problems last month, except one... it ran a 14.2 all motor... which made my friend very happy.... in my opinion go with a complete h22a motor, or be prepared to get a headache.. but it will be worth it..
my friends mods are the following...
92 h23a, 97 Sh head, DC headers, 95 P13 ecu, greddy exhaust, intake and MSD 6AL...
good luck!!!

 

Is hwe running H23 or H22 pistons? That will make a big difference...

 

Stoker!!!

 

Stroker?

 

OK, I am sick right now and the brain isn't functioning as good as it should. I meant: STROKER!!!!!!

 

It's still basics the more air and fuel you can pack into a cylinder the more power and you will be making. using the 2.3 set up, it increses 102 cc's of more volume which equals about 25.50 cc's per cylinder.