45.8 #/hr (or 480 cc/min) @ 43.5 psi

This is 52 #/hr @ 56 psi (stock regulator pressure)

Quote:

How do you measure duty cycle on a datalogger?

It's not in the government mandated PIDs but can be derived from the OBD data. It's simply "injector pulse width" in msec times RPM divided by 1200.

or DC (%) = [IPW(msec) x RPM] / 1200

 

I would like to know more about how to monitor injector duty cycle . Is it possible with the zt-2 and a separate harness, or can we get this reading from obd2.

 

Where did you get those numbers for the injector flow rate?

Also, im wondering if the formula you suggested can be put into dashdaq so that it is auotmatically calculated(no sitting there with a calculator for every single rpm)...

 

A couple of Aeroquip Y blocks and an MSD High pressure auxiliary fuel pump, regulator, relay and filter running parallel to the stock fuel filter (w/built in regulator) and problem solved.

 

Unfortunately, it doesn't appear our cars support this PID (IPW). At least not according to the datalogger and software I use. It might be in there and I need to update my datalogger firmware and software.


Maybe the Dashdaq can see it? It would be nice if it was in there.

 

colin, you run this set up for how long? I thought of something similar, but afraid I would flood the system...details please....

 

The weather is improving and I will be doing the crossfire thing soon again.

A/F issues are determined by the amount of oxygen and fuel induced to the cyclinder. Balanced f/a is luck as much as any other thing. Air density and fuel delivery affect the resulting numbers and going lean is a function of the the boost.

We keep adding air O2 but the fuel is going down due to the increased pressure at the manifold pushing back on the pintel of the fuel injector WHICH REDUCES THE EFFECTIVE PRESSURE which is forcing the fuel into the engine.

If you up the pressure you up the deliver with the same injector duty cycle. The computer has a fuel map that alters the duty cycle to allow more fuel and it the map is off, there are lean or rich spots. Adding an external controller to adjust the fuel pressure, will solve the issue and keep a consistant pressure. I have done this and found that it works and Rob is going ahead of me cause I work and have had my cataracts removed which is an interesting issue in its own right.

The stock pump is 60 PSIG and can feed the engine up to about 80 - been there and done that. Went from 17: 1 at stacked to 9:1 which was way too rich. Good now you know how, just have to correct your Kentuckey windage to get - keep it on track. Sadly the FPR in the car is a filter and regulator, great idea for the street but has limitations as it is not adjustable (easily). Adding fuel is as easy as getting a regulator and filter from Needswings or finding one that you like and working out the details to adjust it.

Bigger pumps will allow more fuel and may have higher flow capacity, but again are limited by the factory regulator. This regulator POP'S off the pressure if it gets over the factory setting. THat pressure is set at about 60 PSIG from the factory, I believe that it should be a few PSIG higher from the get go.

Ill be doing the adjustable FRP and let you know how that works in concert with the Zeitronix secondary controller.. The solution is at hand, its just a matter of making it repeatable on all srts without much intervention other than when YOU plug in YOUR laptop to dial the F/A number setpoint.

ENJOY, Woody

 

yes I'm running this but only during wide open conditions. I used a t-tap to the output wire from the ZEX WOT NOS switch under the pedal to control the relay that powers the additional fuel pump, the regulator pressure is set @ 5 Bar. It is working surprisingly well but I still have a few lean spots as Waldig was talking about. I have a new Boost Compensating Fuel Pressure Regulator
summit part number MSD Part # MSD-2222 it is adjusted automatically by using boost pressure but I haven't had the time to install it yet. I'm hoping I'll be able to have both fuel pumps running parallel all the time. BTW. if you do this make sure you use the power from the original fuel pump to power up the relay, if not you will loose all of the safety features (roll over/impact sensor) and you could end up with a X-"fire" bomb.
Another solution would be to just use your stock fuel pump install the needswings fuel filter without the regulator and install a regulator and use the MSDS electronic fuel pump booster summit part number MSD-2351.

hope this helps

 

Our car uses a sort of hybrid OBD-II called DRB-3 in which they only output the PIDs necessary for emissions testing in a format that we can use OBD-II compliant devices with (which is what the DashDaq and most other diagnostic systmes use) and then DRB-3 for actual control and programming of the specific vehicle functions such as ABS, PCM, ECU, TCU etc. This is where the Star system comes in handy as it "speaks" the native language of the car. As far as getting more PIDs to show up, I have been talking with the guys at DrewTech about a posible solution to our protocal problem. Hopefully we can get everything figured out in a timely manner. The ticket isn't to figure it out for the Crossfire but to figure it out for the Mercedes using the ME2.8 ECUs as that is a considerably larger audience than just us Crossfire guys but it will work for our cars because we share pretty much all the electronics with our MB bretheren. Now a different way to look at it would be to use another hardware device that will read the duty cycle of the injectors that outputs a serial data stream for the DashDaq to read and log. I'm looking at a few prossible solutions but it's hard to justify another $150 peice of hardware just so you know how much fuel you're flowing(provided you're monitoring fuel pressure as well) I'll keep everyone in the loop.

 

If this $150 piece would allow dashdaq or zt2 to read duty cycle and tell me if thats why the car is going lean im in.

 

I have my datalogger setup to display fuel flow in GPH. I don't think the Dashdaq has the capability to display it, but you can do your own calculation. Then, once you know fuel flow, you can refer to the post by 70GS455, https://www.crossfireforum.org/forum...el-system.html and reference the nice graph he made to determine your injector duty cycle.

This calculation is a rough estimate only.

Here is what you need to log and the calculations to determine fuel flow:

Log: AFR, MAF and boost (Yes our ECU's determine MAF, but we don't have a MAF sensor. You need to know boost for referencing the graph.)

Density of fuel: 720 g/L (grams per liter) (This is what is used in the software I have. Fuel density varies with temperature and composition. I've seen ranges of 710 - 770 g/L)

Fuel Flow (in grams/sec) = MAF/AFR
Fuel Flow (Liters/sec) = Fuel Flow(g/s) / 720
Fuel Flow (gallons/sec) = Fuel Flow (Liters/sec) * 0.26417
Fuel Flow (gallons/hr) = Fuel Flow (gallons/sec) * 3600

All in one equation:

Fuel Flow (gallons/hour) = (MAF/AFR)/720 * 0.26417 * 3600

Based on these calculations, my car has been flowing around 34 gallons/hr at the top of 3rd gear in the 1/4 mile at 18 PSI of boost.

Referencing the graph in the linked thread, my injector duty cycle is right around 80%. I will need to add a fuel pressure sensor to get even more accuarcy.

 

Actually you could. It's a simple matter of low-pass filtering, or in other words extracting the DC component of the Fourier series, of the injector voltage pattern. And then just data log (record) the voltage. A simple scaling converts it to percent.

You could do it with a simple analog circuit. Take one injector signal, translate the pulse using a convenient (5 or 10 V for example) zener voltage and a resistor, extract the dc component using a simple RC low-pass fliter (1 -2 Hz), and scale that using 100% = Vz (5 or 10V picked earlier). You could use a hand-held DMM reading 5 or 10 volts or one of those low-cost LCD panel volt-meters that reads 5, 10, or 20 volts (100% corresponds to whichever zener voltage). That will give you a real-time readout of dc %.

I'll try to post a schematic in the coming days.

 

I believe it's one of those enhaced, Chrysler-specific PIDs. Surely someone makes a scanner that displays it...

 

This is so frustrating. I come from the turbo buick world where we have solved this...we now have closed-loop control of fueling. The ECM has been figured out, even completely re-programmed to give the user any AFR he wants, selectable in the field (or better, track).

 

Roughly 360 hp : 34 (gph) x 6 (lb/gal) / .57 (lb/hp-hr)

 

There is a closed-loop alky controller which senses wide-band AFR and injects extra fuel (alky, E85, meth, etc). It will regulate and correct AFRs based on the WB O2 reading.

 

Be sure to not activate this during closed-loop control when the adaptives are learning. If so, they will see this as some drift in fueling and store a long-term fuel correction. Then when it goes in to WOT open-loop, this correction will be used to trim back fueling. We learned this the hard way in the early days before we had complete control of the ECM code.