Question about building a 400hp+ F23

rexload · May 9, 2010

It may not be as easy as I think...

BUT this is what I am thinking... changing the engine compression from 8.8:1 to say 8.5:1 shouldn't make much of a difference, the ECU will not be able to tell the difference.

Say you did absolutely nothing to the engine besides lower the compression by that amount, the car would still run same as before, it would just lose MAYBE 3-5hp, that's it.

Same with the cylinder head. As long as the camshaft is stock, the ECU will not be able to know that something is different. If the head is ported a little, it will change the flow but probably not enough for the ECU to freak out... especially at idle/low rpm.

rexload · May 9, 2010

nyknick1015 said:
well lets try to make things a little clearer...

im gonna start by saying that it hoestly depends on the location you live in that determines if you pass inspection. I can pass upstate no problem but with NYC emissions, if you have a car that is meant to be OBD2 but is not because you converted it, IT WONT PASS... its all about location thats first.

Secondly the process to switch back from obd1 to obd2 seems plausable, yes you can do it yearly on a regular but the only reason why i dont recommend it is because 1) hours of work just to put it right back on later, 2) by the time that you put it back WHAT IF you throw a CEL, 3) there is a 5050 chance that you are gonna mess up your tune. you put the chance that you put something back wrong and it starts fukign up

Third is because if where u live is like NYC, the machine wont read the ECU unless u drive at least 50-100 miles so the ecu can recollect all the data back.

and finally, if u build your block/head and try to disconnect everything, just to go back to stock, your car WILL WITH OUT A DOUBT run like ****

I personally think its gonna be quite annoying but if u can do it then so be it

Well I don't think it takes hours to convert to OBD2 and back. 15min to change injectors, 5min to change the ecu, 10min to disconnect charge pipe, another 10-15min to change a couple more plugs like the IACV etc.

From my experience you don't need to drive that many miles in order for the ECU to collect all the data, usually a 20-30 min drive is enough.

rexload · May 9, 2010

hotaccord243 said:
Man, So glad i don't have to deal with emissions (not to be an a** at all).

Can you upgrade valves/valve springs on the f23 head and still pass emissions? that will help the head for higher flow for sure.

Either way, yes the F23 head CAN flow to 400+whp, without a doubt. I am going to be going for a re-tune here shortly, and will surpass the 400whp mark in the next month or so. It is very possible, but to make sure that is done right, there is quite a lot of money and time that goes into it too.

Unlike a civic where everything is ready available and ALOT cheaper and you can spend only a couple thousand bucks and run some high power setup without a lot of work....

Yes you are indeed lucky that you dont have emissions inspection

and blah, my Civic has an Accord motor in it, still not that hard to work on

nyknick1015 · May 9, 2010

rexload said:
It may not be as easy as I think...

BUT this is what I am thinking... changing the engine compression from 8.8:1 to say 8.5:1 shouldn't make much of a difference, the ECU will not be able to tell the difference.

Say you did absolutely nothing to the engine besides lower the compression by that amount, the car would still run same as before, it would just lose MAYBE 3-5hp, that's it.

Same with the cylinder head. As long as the camshaft is stock, the ECU will not be able to know that something is different. If the head is ported a little, it will change the flow but probably not enough for the ECU to freak out... especially at idle/low rpm.

not necessarily... you with a lower than stock compression, you might throw a cell for low compression. it might come out as misfire along all 4 cyl. i would get a machine or race shops advice on it.

rexload said:
Well I don't think it takes hours to convert to OBD2 and back. 15min to change injectors, 5min to change the ecu, 10min to disconnect charge pipe, another 10-15min to change a couple more plugs like the IACV etc.

From my experience you don't need to drive that many miles in order for the ECU to collect all the data, usually a 20-30 min drive is enough.

what about the CAT... most turbo setups above 300hp reaches that high because of a cat delete. High flow cat will help but alot advertised as off road use only.

I dont want to sound harsh so dont try to take into offense anything im about to say. JUST BUILD THE DAMN CAR... no more exucses.... like it was said before there is CHEAP/FAST/RELIABLE... there is no way you can have all 3 especially trying to pass emissions. and by looking at your intentions, you are gonna end up spending alot of $$. you might have to just suck it up and build it or buy another project car. but i am saying this now DAILY DRIVERS DONT MAKE GOOD PROJECT CARS

rexload · May 9, 2010

nyknick1015 said:
not necessarily... you with a lower than stock compression, you might throw a cell for low compression. it might come out as misfire along all 4 cyl. i would get a machine or race shops advice on it.

what about the CAT... most turbo setups above 300hp reaches that high because of a cat delete. High flow cat will help but alot advertised as off road use only.

I dont want to sound harsh so dont try to take into offense anything im about to say. JUST BUILD THE DAMN CAR... no more exucses.... like it was said before there is CHEAP/FAST/RELIABLE... there is no way you can have all 3 especially trying to pass emissions. and by looking at your intentions, you are gonna end up spending alot of $$. you might have to just suck it up and build it or buy another project car. but i am saying this now DAILY DRIVERS DONT MAKE GOOD PROJECT CARS

1. I've personally ran a stock F22 ECU on a built ~11.0:1 compression motor, it ran fine. I just needed to get the car from one point to another and kept it under 3000rpm, it drove fine... I've never done it with OBD2 but I seriously doubt a very small change in compression is going to cause a misfire, there would have to be something else wrong.

2. About the cat... it's very simple. Most people don't realize it but you can keep your stock exhaust on a 500-600hp car. All you need is a 3" or 4" downpipe splitting into two pipes, one going to an exhaust cutout, the other going to the stock exhaust. Driving around town you keep the cutout closed, when you want to feel the power, press a button to open the exhaust cutout and you got ZERO restrictions in your exhaust. I built a setup like that for my Civic, works great.

Thanks, I know I need to stop bull****ting and find a clean CG and start turning wrenches!

hotaccord243 · May 9, 2010

rexload said:
Yes you are indeed lucky that you dont have emissions inspection

and blah, my Civic has an Accord motor in it, still not that hard to work on

Yeah but you are talking F22 motor, which is a different animal than the f23. Yes, overall it is the same motor, but the feasibility of parts for the f23 vs f22 is completely different issue. It is MUCH harder for parts for this motor when you are looking for power.

No it's not HARD to work on at all, but you have no idea as far as parts difference between the two.

rexload · May 9, 2010

hotaccord243 said:
Yeah but you are talking F22 motor, which is a different animal than the f23. Yes, overall it is the same motor, but the feasibility of parts for the f23 vs f22 is completely different issue. It is MUCH harder for parts for this motor when you are looking for power.

No it's not HARD to work on at all, but you have no idea as far as parts difference between the two.

IC,

It would be pretty cool if I could build an F22A and be able to pass the OBD2 inspection with it.

Theoretically it should work with the F23A5 ECU... and an F23 or F22B OBD2 distributor...

That would be risky though, I wouldn't want to build an F22, put it in the car, and realize that there is some kind of problem that won't allow me to pass the inspection.

98acclude · May 9, 2010

this debate has alot of good info in it.

and welcome to the boards!

Im kinda stoked to see what you come up with!

EmMinODaGreaT · May 9, 2010

i think you guys are assuming its not going to run right, which it wont be perfect, but you are not goin to be beating on the car, just simply driving to gain readiness to pass obd2 inspections. In this case it will be fine. It may be running a little richer/leaner but as long as the ecu sees all of its items and they are working accordingly it can pass.