I got the stock 28.8Lb injectors in my 98 Formula. My Mods are,

LT's, ORY, Magnaflow Cat back
LS6 Intake, !AIR !EGR, Lid

I hooked up my car to HP Tuners and it showed that @ WOT, I was using 88% injectors. I was wondering if this was normal w/ the amount of mods i have? Thanks!!

 

What size are stock injectors? Isn't is like 24 or something. Those are maxed out at high rpm on stock vehicles. 28.8 isn't that much larger. You have a few mods. It's probably normal. I could be wrong, though. (sorry)

Are the lines and injectors free of blockage?

You could also contact the company that makes the injectors. They will be able to tell your. OR pay for a diagnostics (preferably at a speed shop that deals with f bodies) and find out exactly whats going on. If you notice what you deem as a "more than normal' power decline at higher rpms, pay the $$ to a speed shop and get it fixed.

 

The factory WOT tune is VERY rich.... get your fueling nailed down and you will see the DC come down as well.

 

I'm still learning how to tune with it. Ive messed with it and actually added a little bit of fuel @ wot to be safe, I may have added too much???

28.8Lb Injectors came in 98,01,02 and 26's came in 99-00, I dont notice any power decline at higher RPMs, I am the F-body Speed Shop I am doing everything myself on this car, as well as my 90 Firebird which is getting a 1987 Buick Grand National 3.8L Turbo. Im actually focusing all my effort on that now and using the Formula as DD.

 

If you added fuel in your PE table (since you say WOT) take it out... put that table back to stock. Even with your mods the factory calibration would still actually be too rich. Yes, as in giving away HP rich. This isn't 100% as all cars are different, but this is the gross average. Before you can really tune at all (ft tuning is tedious, long, less accurate, and downright archaic) you need a wideband, so grab one before you make any fueling changes to the car. You will thank yourself for buying it.

 

It sounds like we pretty much have the same cars with the same mods, and I am at somewhere in the mid to high 80's also for injector duty.

BTW I have added fuel and timing since the stock tune and have gone faster. If you put full lenghts and and ORY on your car, the stock tune will need to be adjusted to get the full benefit of added power with an aftermarket exhaust system.

 

Its VERY unlikely to need more fuel than the factory calibration for those boltons... MPH in the 1/4 is tough to use as a judge since differences in temp/humidity/wind play a role. Get a wideband and shoot for 12.8-13.0 or get it on the dyno. I agree to get the most that an adjustment must be made, but honestly unless you have done something that really dicks stuff up like a different MAF, you almost certainly need to pull fuel. Get a wideband and find out though.

 

I seen it for myself on the dyno.
00 SS M6 had a factory tune, owner installed full lenghts, ORY, lid, and 160 t-stat. 1st pull the car was really lean on the dyno, and ended up over heating. I dunno what the AFR was cause the dyno wide band wasn't working but I can tell you the millivolts for the O2s was about 820 both sides. i think it made only 265rwhp probably mostly cause it was hot; 2nd pull after giving it more fuel it had 312rwhp. 2nd pull O2s read about 920 millivolts. Keep in mind the huge difference in power numbers is because the car got hot. If the car was getting too much fuel I doubt it would have over 300hp.

As i said before a little tuning after an exhaust system you will see a gain. After I installed the exhaust on my car, I could see that the car was running leaner at the track using HPT scanner, going by millivolts. Gave it more fuel and guess what the car picked up.

In my opinoin and my opinion only you people are wasting your money on wide bands.

 

That's crazy.... you say wideband's are a waste of money but bothered to post about NB readings.... I have seen NB readings move from 790mV to 885mV WITHIN A PULL and the AFR was a consistent 12.8:1 through the entire pull. Hell I can post the log of it... NARROW BAND O2s ARE NO GOOD FOR WOT TUNING. You are making a blind guess if you are tuning off of them. The car you are citing on the dyno is the exception, not the rule, and you may well just be cheating a PE table around a problem if it were that lean.

DO what you guys want to with your cars though... I just wanted to let you know.

 

Look, the mv average seemed low to me, the car was running hotter than it should have been, that right there says its lean. I understand some of you people have no idea on how to tune without computers and wide bands, but let me reassure you it can be done, and has been done since the birth of the internal combustion engine.

You act like you can't tune without a wide band.... Did you ever think how the racing industry made it before wide band ?? plug checks ?? common sense ?? trial and error ??

Let me explain it you you.
Go the the track, make a few base line passes... Give the car more fuel, make 2 more passes. If mph went up you did the right thing now add more fuel again and make 2 more passes. Repeat adding fuel till MPH slows down then go back to previous tune. Or if the car slowed down with the additional fuel, take some out, small incriments. If mph goes up take more fuel out and repeat until mph slows down. Simple as that...
And when you get a little advanced start playing with the timimg, once again small incriments, make one change at a time and test. Sometimes with added fuel you can get away with more timing, to a certain extent compared to stock.

All you people on here think you can't tune without a wide band.... All your wide band number is, is a reference point same with the millivolts, I undstand WB is more accurate. TO ME A WIDE BAND IS NOT WORTH IT.

 

cabech984, sorry to high jack your thread.

What I have learned form this board is to get more than one opinion. Many people on here are ignorant. Don't just listen to 1 person. Also keep in mind, listen closer to people with dyno and track experience than others. I posted my experiences and my opinions, for what they are worth.

I'm done, I'm not going to and bicker with ignorant people. If you would like PM me with any questions about my tune, I'll be more than happy to share my tune with you.

 

That's funny, i was literally about to post this too about a special someone who tunes by NB and how "hot the engine feels"........

 

feels ?? never said feels as in touch. HPT, dash gauge, and a heat gun were used to see how hot the engine was.

Obvioulsy some of you kids have never tuned an engine before there were widebands.

 

Sounds like you are shooting in the dark a little. Get a wide band 02 and a fuel pressure guage on the car and you will be able to figure it out. You should not be driving over those injectors with your changes.

Kurt

 

i tuned my car with narrowbands... got it tuned and running good then bought a wideband... checked my tune and it was a solid 12.8 AFR throught the curve and 14.7/14.8 @ cruise not in PE...

worked just fine for me using narrowbands and smoothing the VE table to where its obviously going to be. tuning is really not too difficult with narrowbands...

 

What is this father/son crap? since when did it matter what your age was buddy? Have you met some of the top hitters in the LSx world? Age does NOT equal intelligence.

Look, the simple fact is, yes it possible to tune your car using NB. That doesn't make it right, or effecient for that matter. There is just no way a NB can consistently represent what your car is doing. This isn't about carb or EFI, this is pure common sense.

Can you tune with NB? Yes
Is it the best way to tune? No

 

I have read the whole thread now, did not realize it was a pissing match. I am out, carry on fellows.

Kurt

 

Like Frost said, the stock PCM commands a very rich mixture. What you want to do is first tune in closed loop, you can use the LTFT's to do it easily since you just have boltons, which makes tuning pretty easy. All you have to do is get the LTFT's under zero, I prefer -2. Then smooth the tables, and use a wideband to tune WOT AFR. For WOT you DO want to have a wideband to get it down right, the stock narrowband sensors are just not designed to operate at AFR's away from 14.7 and are not very accurate once they get away from 14.7. Shoot for around 12.8 AFR. Then see how that DC looks.

This looks like a pissing match here, so im not gonna get too into it.

 

To add to the thread:

My duty cycle is also abnormally high, but after logging and recording my fuel pressure throughout my WOT runs, I figured out why...my fuel pressure drops from 57-58 psi all the way down to 51-52 psi. That will drive your duty cycle up since the injectors will have to stay open longer to compensate for the pressure loss.

There's nothing wrong with my fuel filter (it gets replaced every year or so), and nothing wrong with anything else in the fuel system. I think it is more a function of having the regulator in the tank on these cars, and relatively smally fuel pumps from the factory. I'll be redoing my entire fuel system to see if I can keep this from happening, but it'll be a while before I tackle it.

To detract from the thread:

If you are tuning WOT without a wideband, stay away from my car. That is a bad way to go about tuning with the technology available, at affordable prices to boot. Touting that it can be done and "works great" is even worse IMO...

 

im going to have to agree as well that using the MV scale to make a solid AFR tune is stupid. im using it right now to make sure im in a set area but no way in hell would i not bother to buy a wide band.

corey