hey whats up guys got a few questions about the F23A1....i kno its not the ULEV setup and it produces 150hp! miles are kinda high and its smoking heavy during high rpm...i wanna do a rebuild but also wanna add some power but another thing that bothers me is emissions...if i boost it it gets converted to obd1 and that will fail me....nitrous wouldnt be a good idea....so im thinking all motor! raise the compression enough where i produce good power for a daily driver and still have the obd2 setup for emissions so i have a few questions.....

-whats a good compression to shoot for and be safe to daily drive?
-would it be okay to get it tuned on vafc since it aint a forced induction setup?
-since it needs a rebuild anyway whats the best brand internal componets i should look into getting?
-what is the best route to get away with the emissions bull we have in maryland?

 

Well if you change the compression and do supporting mods... you are still going to have to tune it to really get anything out of it.

Even if you did raise the compression and stuff and it actually ran right without a tune, I doubt you'd pull much power.

I'm in your same situation in that I won't ever be able to turbo my 98 because of the useless emissions regulations in place in Illinois.

If you REALLY want to up your power without doing any conversion to OBDI, you are going to have to swap.

Could go with an H22 from the newer preludes that is OBDII, a V6 with the six speed from the Acura CL/TL (obviously don't bother with the V6 from our gen because of the automatic), K20, K24... the list could go on. Of course, these are not very cheap options but this is what you have to work with.

I wish you luck.

Oh, and I wouldn't do any tuning with a VAFC. It can be done, but not nearly as well as with most of the standalone engine management systems.

 

i wanted to boost my f23 but i will have the worst luck at emissions....i rather leave this motor in and do something with it....its about that time for a rebuild so i be better off do a internal upgrade.....suggest any retrofit pistons that would be cnsidered a upgrade like h23 pistons or h22 rods? im kinda lost now!

 

I was running 10:1 compression pistons for an all motor setup F22B1. Just by bumping up the compression, you can't mess around with 87octane gas, you gotta go with 93 or higher, or else... car feels like crap.
I think that the F23/F22 are ok for a "daily" ride up to 13:1 or even a 14:1 compression, would need a head gasket that is right for the occasion of course.
If you tune it with a VAFC you're not really tuning it... but only making "adjustments". I bought a vafc myself when building my motor, but realized that a dyno tune (not just a chipped ecu) was necessary to squeeze the horses out of the new setup.
If you are only rebuilding the engine, parts that meet or exceeds the oem spec are what you need. Definetelly gotta open up the engine to really see what you need and what you can reuse.

 

i run 93 octane now as we speak but yes i do wanna bummp my compression up a little bit but not much....did any of u use stock internals from another motor without modification to bump it up or just went on and did the forged internals?

 

I bought forged aluminum pistons and stronger connecting rods for the build.

 

What compression do you want to achieve in terms of psis?

 

There is absolutely no reason to run 93 octane gas in your stock F23. It offers no benefit to our engine (as Honda designed it that way) and you are only throwing your money away. Just trying to help you out.

And as gianinline said, you will still need to tune if you start modding the internals. That means converting to OBDI, which screws your emissions.

 

thats what im trying to find out whats decent for daily driving and not worry about emissions too much...i see alot of people retrofit other oem pistons or rods to bump compression...some mill heads i wanna go in the right direction without spending a million bucks

 

What's your current psi compression?

 

i believe 9.8:1 i could be wrong! i heard the rsx-s pistons bump the compression up too? has anyone done it yet?

 

I've driven my F23 at 10:1cr for a short while on the stock OBD2 ECU. It didn't hurt anything for the short duration, but I can't tell you how reliable that would be for long-term use, or how it would affect emissions.


VAFC would likely be a cheap band-aid for tuning. You won't be able to adjust timing (which you need to do with high compression), and setting your VTEC to engage at 4k rpm like other guys do is useless.


With limited ability to tune, I wouldn't go spending big $$$ on forged components. If the cylinders are still round and in spec, you could just rehone them and install your pistons with fresh rings. If the cylinder walls have any knicks or scrapes, you'd be better off boring .25mm over, and installing some stock +.25mm pistons (purchased from dealer).


Unless you can pay someone to pass you, probably not much, short of converting to OBD1, then converting back to relatively stock and OBD2 for your test.

This is true. At least in comparison to just doing supporting mods without a tune.

H22 is your only affordable option for swapping. It would be a nightmare and a half to convert you I4 to a V6 setup, and K-series swaps will still cost you upwards of 4-5 grand.


x2

The physics just don't add up when you start using any other OEM rod offerings. Same goes for the pistons, with few exceptions like the K20 pistons, though even the K20A3 (base RSX) pistons would raise compression too much if you can't tune the car.

Not true. I've been tuned on 87 octane at 10:1 compression for almost two years now, and made over 175whp on that setup up until just a couple weeks ago.

Those ratios would be way out the question without a fully involved build and stand-alone engine management.


There is always some modification involved. Again, the issue here is being able to tune and adjust timing to compensate for the change in compression. You could probably get away with a little bump in compression and higher octane gas on the stock ECU.


Somewhat true. I have seen cars converted to OBD1 pass emissions test, but the tuner was on the scene to make adjustments, and the test station kept an open mind to allow him to tweak the car during the test. If your test station chooses to fail you based solely upon the car no longer being OBD2, then you can forget about it.

9.3:1 is the stock F23A1 compression. You could mill the head around .030" and bring compression up to ~9.9:1, and maybe be safe running 91+ octane. Milling it .040" would bring you barely over 10:1, but piston to valve clearance starts to become risky in the case of a mis-shift without aftermarket valve train components, and I'm not sure if that would negatively affect emissions. From my experience, ~9.9:1 compression in an F23 with supporting mods and no tune would likely yield around 150whp, depending on the dyno.

 

Good point. Interesting to see that the test station let him change it there.

More referring to the fact that , as you also said, the conversion to OBDI will screw his chances at the test station when they do the OBD system check (which pisses me off that they still do that when they should just be concerned that it passes the sniffer test).

Glad you jumped in on this thread AF. I've noticed you've done a ton of NA work with the F23 and I was interested to see what you'd learned with changing compression around.

 

running 10:1 with 92 unleaded. No problem so far. All stock. Good luck with your build.

 

AF thank you for clearing up a lot of the things on this thread cause ive been reading alot of stuff since being on H-T(you,Mcfred,GHOst,sam,and some guys at O.E.P)you guys are years ahead!!!!!!you answered alot of my question........1cln-eg9 good luck on your quest it can get addictive and expensive im in your area too so if i can be of any help let me know.

i read somewhere my f22b1 com is at 8.8 want to know trying to find out how much i could mill off spare head without p2v compromise in v-tech