Mine is near maxed. I could confirm but I think I'm at 66 psi for my fuel pressure while at idle with the vacuum line connected. This is on my ap2 with the SOS/6 psi kit. I also have a test pipe and bored throttle body.

 

Just took some pictures:

https://www.dropbox.com/s/x5y4jw4j8a...%2046%20PM.jpg

https://www.dropbox.com/s/u1lxdk12a1...%2056%20PM.jpg

 

90 psi is allready a lot of pressure for the stock injector
You want to run the minimum pressure you can to get your target afr
This is why at CT the say 60 psi

 

I ran my stock injectors at 95ish psi at redline for a shitload of miles, they never complained. Technically they are designed to spray to 100psi but obviously less would be ideal, as the closer you get to max psi the more risk of them locking up and that's bad news. Running a safe afr under under 13 would be the more important issue to deal with here. I have found that the injectors will start to crap out when the idle pressure gets to high, and from there the rising fuel pressure rate wont exceed max at redline so its a little bit of insurance I experienced. 3-4 threads showing above the lock nut is typical. When you start going past 68-70psi at idle the injectors will start to crap out and you can tell by the engine idle. You can experiment yourself by cranking down the rrfpr until you hear the engine idle start to miss, then back it off a good full turn from there to get max safe function. Sounds like your getting pretty close to (safe) maxed as is, its unfortunate when you bought a new rrfpr you didn't key in on my advice with getting the ap2 version, you would be able to dial in more fuel, but oh well. At this point your most immediate and costs effective solution may be to put your cat back on as others have mentioned. That should allow you to get idle pressure near 50ish. Or you can try and milk a little more out of the rrfpr now that your armed with a bit more info on what to expect. Maybe 5psi more would be enough to run safe afr. Aiming for low to mid 12's are are fine. You will see a spike well in the 13's at vtec change, that's normal. Its a spike and not sustained, which makes a big difference. You will be rich under vtec, in low 11's. Not ideal for making power, but its safe. Hope you don't see any richer though.

 

Yeah Id say your riding the line Looks like my settings I ran for years. Except I got greedy and incorporated water/meth for more fuel and then added more boost when I figured out I could keep up sizing the nozzle, making it to 11 psi/375whp on factory system, until I ran the motor lean and it finally gave up on me after racing a c6 on the highway. Too much sustained lean load, but was ok giving a gear or two around town. After 3 years and about 50k it caught up to me.

 

Well today is the day i got to give up and put the cat back on ;-(

I adjusted the rrfpr until i had 70 psi at idle and it didnt change a things at wot in vtec with ~95psi. Always low 13s. Never even saw 12s.

The toda hearders and the 3" single must have to much flow ?? I guess???. A friend of mine as an old apexi s-afc II . I might give it a try.

But since i am tracking the car i would rather not be close to the limit. if i can take that rrfrp down a bit and be in the low 12s it would be nice.

So im away this week end but i have a couple of days of next week to work on the car so im gonna try and find that cat under all those s2000 parts and give it a try. Im gonna put some money aside this summer and i think im gonna go with something safer as soon as i can. Slightly bigger injectors since i am not going to add boost ( soon ;-) and the gemu. then i will throw away ( again ) that cat and run the full potentiel of my low boost.

If you guys have any more advice or idea that was never talk about in this topic or that i didnt answered i will be more than happy to try them.

I have to say that the Ct acm hunts my dreams.

Thanks again to all that put efforts into my problems. It is nice to see how much s2ki is a great community , almost as great as our cars. Lol

Cheers

Sylvain

 

Sounds like the cat is an excellent idea, especially if your going to track the car.

Since you mention it, the vafc2 you mentioned your friend having, wont give you more fuel, it can only effectively subtract fuel. It would still be a nice component to add once you get the cat on however, since you can lower vtec for more mid range power, wile this will also smooth out the "hit" of vtec and shock to your glass rear end. You may also notice that before vtec comes in, your afr are richer then optimum, so you can use the vafc to cut fuel in this are for a few more ponies and trq. If the cat drops your afr enough, you can use the vafc2 to trim and fine tune your fuel across the entire rpm range, but you need to be running enough fuel to have something to trim. Ideally when I ran this very set up, I would trim fuel to be 12.5-13afr under vtec and then mid to low 12's in vtec. The vafc will allow you to do this. Without it, you may get in the low to mid 12's above vtec but low to mid 11's under. You will also go rich after 8k so I had -1 to -3 point trim in that area as well, but if your tracking the car it may be best to leave that portion of the rpm alone,as its factory dialed in rich to cool the cumbustion temps at that higher rpm where you will be often at the track.

 

Your right.

I just figured out that the apexi can only trick the air input volatge. I guess at wot there is nothing good about telling the ecu it as less air then it actualy has.

So the only Way to add fuel delivered to the combustion chamber is by adding some injector duty. I wonder was is the easiest way to achive that without having to go nuts with tuning.

I will defenitly try the cat

 

I just don't understand man... I have the same exact setup as you basically... same AP1 Comptech RRFPR, stock injectors, Walbro 255 pump... but I am in the 12's at WOT in VTEC. And I even have my Apexi set to remove some fuel at the top end to keep the AFR curve from dropping down too rich. Something still has to be up with your setup. I am running PLM header, test pipe, and OEM catback.

 

He has a more efficient breathing single exhaust. When your relying purely on fuel pressure, not injector duty, to supply the fuel, small efficiency changes makes big differences when riding the cusp like this.