Giveback

Can factory AP1 360cc injectors handle 7-9psi of boost (Supercharged)?

MorngWoodStewie

Nope.... The bare minimum only puts down 6psi that's with rrfpr anything higher u need inj.

s2konroids

You can get away with 8/9 psi at the very most with the rrfpr, more pressure and you'll effect spray pattern and possibly go static.

Chance S2K

Do yourself a favor and at least get some RC 600+cc, even if you're under 8/9PSI.

yamahaSHO

If staying on gas and low boost, you might be fine with something like these: https://www.s2ki.com/forums/member-s...pters-1165958/

s2000Junky

Stock injectors at max "reliable" 95psi with the rrfpr will max you out right about 310whp, which on the typical Paxton superchargers is 7psi. About 1-1.5psi over standard base systems. When I exceeded that, I introduced water/meth injection and got up to 10psi on the base system, but it wasn't reliable long term, mostly because it was far too reliant on a pre tb emitter to deliver the remaining fuel needed for all cylinders, and even distribution was compromised, as well as putting faith in a rather corky injection system (there are better then what I had). 8psi would have been wiser choice, but I got greedy and loved to push things. That motor ran lean and gave up eventually. Keep it to 1 pulley size smaller above stock if you want to be smart. So base ap2 4.25" on an F20/9k rpm, and a 4" for F22/8k redline for SOS/Comptech systems. Vortech has a larger crank pulley so the blower pulleys run larger for same pressure which I'm not as familiar with.

Spaceman2345

In my opinion you'll be fine as long as you do not go over 9psi. My tuner told me that he just finished tuning an AP1 with a Novi 1200 supercharged boosting at 10psi on stock injectors. The only issue was the top end was detonating, but quick fixed with octane boost. I guess the owner was fine with that. Me on the other hand would not have been ok with that.
As a matter of fact, I'll be downsizing to a smaller pulley soon, ~ 8-8.5 psi pulley, and will be using stock injectors. My tuner said i'll be fine, but anything above 8.5psi would cause stock injectors to fail. The last thing i want to do is upgrade injectors because Cali smog is ridiculous out here. The state/Police have smog station stops, similar to drunk driving checks...IT'S CRAZY! If for some reason the stock injectors on my 00' using CT-E Novi 1220 fail i will stay @6psi.

s2000Junky

You don't want a injector failure, when they fail you lose a motor. 9psi is too much, the rrfpr/stock injector combo isn't capable of supplying enough fuel to get a safe afr at that amount. At least get a water/meth injection kit to supplement fuel and suppress potential detonation. However I don't know how that would work in California.

And I'm surprised that there are any tuners out there willing to push things this far above the known reliable threshold for a customer. I therefore question if they are even that familiar with experimenting with this kit/platform to know better. I know first hand what that threshold is and beyond. Usually they air on too conservative, which makes sense, since they don't want to risk their business practice which a bunch of guys coming back with fried motors. Either way, you will find out exactly what your afr is maxed out at when you run a particular pulley. Just hope you don't learn the hard way, all I'm trying to prevent here. I would strongly recommend investing in a wideband, especially running this close a threshold, as afr will fluctuate depending on the temps. Your fuel requirements will be much more in winter vs summer, so if your tapped out just making it in the summer months, you will be dangerously lean in the winter. there is a sold 1 point difference between say 80F and 50F. so 12.5afr to 13.5afr. If yoru seeing anything over 13afr at redline, your too lean. 12.5-12.8 max. 13afr is ok bellow 6k rpm where there is 1-2psi only. What I'm getting at is this kit requires you to adjust your rrfpr if you want to maintain a safe best performing afr all year around. You cant do that without a wideband. And really therefore a tuner is a waste of money, as this can and would be best performed on the street.

Giveback

Great feedback and information! I'm eyeing 7-8 psi.

s2000Junky

Another thing you will need for 8psi aka 4" pulley on f20 if your running a kit that was designed for the ap1/F20, is a ap2 rrfpr (or a retrofit kit) to convert your existing unit. The ap2 rrfpr has a steeper ramp up rate of fuel delivery because the f22/smaller stock pulley needs more fuel per same rpm but with less rpm/rev limit. Running more boost beyond the 1-1.5psi im recommending (7psi max) will require more rising rate then what the ap1 unit will provide. This also means the fuel delivery/rising rate pressure will cap off/reach max pressure before you hit 9km rpm. Fortunately as luck would have it, on the stock ap1 ecu, it runs too rich from the factory from 8-9k rpms, so it actually works out ok with the net effect in proper fuel curve.