KAPLOWW

The car is a 1999 Corvette 650hp LPE TT with HP Tuners.

I have searched pretty extensively, compared stock tunes, and other peoples tunes to the tune in this car.

I have a set of 57lb Siemens Deka PN 3172 injectors laying around from a previous project. 10 of them as a matter of fact.

I was about to ditch these injectors for a set of 60lb'ers, and then read that these injectors are pretty easy to tune with GM PCM's, so I might as well give them a shot since they're just sitting on a bench, and only a few miles short of new.

The car currently has 42lb green tops that are maxed out.

It is also currently running a MAF, I am considering switching to a speed density tune, so I picked up a 2.5bar plug n play map sensor.

Now that we're all up to speed, on to the questions.

Does anyone have experience tuning with these injectors? Positives and negatives?

What are the chances that I could retain the MAF, and run the 2.5bar map sensor with the 1 bar map enhanced table? Worth it? Or should I just go straight to a speed density tune, and call it a day?

I'm pretty new to the GM scene, and very new to the HP tuners tuning format. I've done a bit of reading and have found some good intro to HP tuners guides about.

I have a lot of experiene with aftermarket turbos and EFI tuning, just not this particular flavor.

So far the only thing I've messed with is DFCO, and picked up a couple of mpg.

I really don't want to smoke this motor as the whole purpose of this is to add a little bit more of a safety margin to the fuel system as right now the injectors are running static at WOT.

I'm not real impressed with the tune in this car.

KAPLOWW

Did I ask something the wrong way? 17 views and no responses?

LS1x2

iTrader: (11)

You just asked a lot all at once. You should have any problems with that injector. Go with a 2 or 3 bar map and OS, not 2.5. Whichever you need based on how much boost you will run. Ditch the MAF. No reason to keep it.

KAPLOWW

My thought process on running the 2.5 bar map, on a 2 bar os.

The kpa that the os is seeing is arbitrary, and I'll have 21psi worth of positive pressure that I can compensate for, without losing the resolution of going to a 3 bar.

The kpa displayed will be 80% of what the engine is actually seeing...

Is this correct?

LS1x2

iTrader: (11)

If the kpa is arbitrary, then so is rpm and everything else. I like to have the ecm seeing the same boost as my boost controller. Much easier to tune and diagnose issues. A 3 bar map is $60, and the resolution loss is not going to cause any issues.

I'd think you could max those 57# injectors out at 2 bar anyway. Possibly would take a little more if the ls1 is stock heads/cam/intake.

KAPLOWW

Heads are ported, bigger intake valves, cam is the GT9 lingenfelter grind, and it's a ported Ls6 mani.

Lol

KAPLOWW

Alright, so i've been trying to figure out why the injector flow rate vs KPA would be variable in a car that has a vacuum/boost referenced regulator, and I figured it out.

Its not vacuum/boost referenced.

The vacuum line is pre throttle body. Why on earth would they do that?

They significantly over complicated the calculation of the fueling system by referencing the fuel pressure regulator pre throttle body.

Reference it post throttle body, and now you have a flat rate injector flow.

Is my logic lacking anywhere?

onfire

iTrader: (17)

Before or after tb is a tuner preference...no wrong way. I retuned a buddies LPE 650 a couple of years ago. Went 2 bar sd only since we went to leaded fuel. Biggest thing to look out for is maxing out the stock GT2871r's...on 346ci his starts blowing hot air around 16-17psi...and BP goes up bigtime...good for low 140's in the 1/4 maxed out.

KAPLOWW

Yeah a friend of mine has one 2871r on his A4 1.8t that he maxed out right around 400hp.

So i figured there was max another 150 maybe 200hp hiding in this setup.

KAPLOWW

So am I wrong in assuming the injector flow rate vs kpa would be the same all the way across the board if I referenced the fpr to the intake manifold post throttle body?

KAPLOWW

?????

Bueller?