I posted this question to summit, wanted to see if someone here might be able to answer me first. The deal is my stockers were leaking down so I picked up these to throw in. Screaming deal compared to the stock price, little bigger to help support future mods, right? WRONG!!! Had it on a chassis dyno today, was running stock 42 PSI. By the end of my runs I was at 50 PSI and I am still slighly lean. I'm also getting like 30 counts of spark retard above 4 grand. I don't know if I got some bad gas, but some of it is because it's still lean, about half a point lean. I will say I have picked up 50 ftlbs torque at 4500 and about 40 horse at the same, but still getting bad knock. Can anybody help me out here?

plugs arent fouled are they? running em lean will ruin a plug in a heartbeat. i did the same thing to my rapidfires, had the stock inj's and they went bad and i made a 70 mile trip lean the whole way. i changed to 24# accells and had horrible detonation even though i was getting plenty of fuel (BLMs were actually showing rich). finally i clicked in my head i probably ruined my plugs so i pulled em and they didnt really look too too bad. but i changed em and put in some regular ac delcos and bam, instant problem solved.

and to answer your original question, i believe they are rated at the same PSI as gm injectors.

I don't think they're fouled, but I guess it wouldn't hurt to change them. They're only like a month old. I'm kinda PO'ed because a bigger injector you wouldn't think I'd have to go crazy with the fuel pressure. I might try a colder plug too while I'm at it. Thanks for the idea man.

i did the same thing. i went down a heat range from the 45s to the 44s

Cool, I'll do that and try to water inject it, maybe clean some carbon out. Thanks a ton dude.

no problem, be sure to post if it helps.

How did you pick up that many horses?

40 horses...not with just injectors right?

I picked up the power between my baseline and final run by raising the fuel pressure. I started at 42 and finished at 50, but I'm still lean. I'll try a few things, but right now the HP never really peaks. On the last run I had like 175 HP at 3500 and had like 170 HP at 4750 where we shut down. The peak was 180 @ 4000, not much peak. I picked up that power at 4500, and picked up power all the way across, but I'm still getting bad spark knock. All in all though it's not to bad for having 123,000 on the stock longblock.

the 40 doesnt mean he picked up 40 at its peak (like 200hp at 4400 vs 240 at 4400). it couldve been running real crappy at the other engine speeds with not enough fuel so the 40hp gain in some spots doesnt seem too out of line depending on the condition.

Your dead on Sofa King, at the peak I picked up 10 hp, but there was places I picked up 20 and more, and the 40 was at 4500.

I have leaky nasty unclean stock 19 pounders...some good new accel 24s should do nicely you think?

355...cam exaust heads etc...but Ill need a chip...and I cant program em my self..and I dont want to pay for a chip that wont work...wonder if there is a way around that.

it will run a tad rich in open loop, but once you hit closed loop you will be cool. WOT may not be optimal due to a slight richness too but shouldnt affect drivability until you get a chip for the 24#ers. btw, im running the accell 24s and they have been great so far (since october)

I have an adjustable fuel pressure reg...so i may be able to hold off on the chip for a while huh?

getting a chip is a bitch...I dont want to get everything to burn it myself...yet i dont want some company burnign me a "guess" chip.

As said before the only time those 24 pound injectors will cause you to run a little rich will be in open loop when the car is warming up and when your at WOT. Considering a huge part of your driving doesn't fit in those two categories you'll be fine. If this does bug you, DO get a chip burned. Backing off on the fuel pressure too much will cause the fuel to atomize poorly.

I am running SVO 24# on the stock chip and I am almost perfect air/fuel ratio at WOT, as verified by a wide band O2. That was on the dyno though, so I could be rich/lean durring other times. But who cares, WOT is all that matters

Have you tried to get in contact with Acell about the injectors? I can't possibly see them being rated anymore than 46 or what ever stock TPI ones are. With all that knock, something else is going on with your engine.

Summit finally got back with me. First they said 42 lbs then they recanted and said 39.6 lbs. Soooo, I don't think theyare actually 24 lbs injectors. I'm going to do some checks this weekend, make sure my pump is still right and I'm getting the pressure at WOT. If it's all good then I'm going to raise cain, but I want all my ducks in a row before I do, so I'll double check everything first.
Oh, BTW, I think I got the knock out of it, will try to verify that this weekend also with Robert's help.

i have the scanner in the car. by the way, i'll be at vinci hi performance sat from 11-2ish. if you happen to be around my shop in the morning 8-10amish, then your more than welcome to hang out with us.

The other half has to work in the morning. I'll try to go up to Nathan's at 1:30 or 2. Hope to be there around 3 or 3:30. Hook up the scaner and see about the knock. See ya tomorrow

found the problem. fuel pump giving out. had it set at 48psi from the dyno day. he was coming to the www.fl-thirdgen.org north central florida meet. started giving out on him. checked pressure. 40 psi. new walbro going in.

Wheres your place in Orlando?

Im at Golden Rod and University in Winter Park....

What kind of shop?

Robert's shop is on John Young Pkwy, called Tredalign. Come visit fl-thirdgen.org and check us out!

call me at (407)295-7073 i am a suspension and alignment shop.