I don't want to go into this anymore , it will just **** off my fuel injection guy.

 

MAX, HOW MUCH FUNNIER CAN YOU BE ? Oh boy... I can't wait to hear from your injector "GUY" on this forum... WOOHOO !!!

 

I must have got it right - he counts the molecules, or is it a radioactive tracer.

Still thinking..

 

Enough P*ssing and moaning already....

Let's try and get back to the subject shall we ?

Does anybody know of a OEM Mercedes injector used on the 3.2 SOHC motor which us non-SRT6 owners can swap into our Crossfires to increase open-loop/WOT fuel delivery ???

A Bosch or M-Benz part number to try ?

A 10-25 percent increase SHOULD address the too lean A/F ratio issue during hard acceleration. During closed-loop driving the ECU would probably use the O2 sensor input to eventually "learn" and adjust the injector duty cycle to achieve lean low emission/good mileage A/F ratios during "normal" driving.

This seems like a pretty low-risk/low-buck way to pick-up 10-20 Hp and protect the top end of the motor from damage from a too lean mixture.

I mean, If the stock injectors are already pretty much "Maxed-out" then there is only so much an ECU reflash can do right ?

Slim

 

just install the srt6 injectors....let us know if that cleans up the lean condition at WOT

 

per HDDP...

"I finally got the specs on the SRT6 injectors from my SPY at Bosch I must say, they have a HUGE flow difference from the NA engine and now I have to figure out how the SC engine is regulating the flow, whether by pulse width or pressure regulator.

NA ENGINE: 17 lbs/hr at 3.8 Bar, or 55 psi/ 14.5 ohms.
SC ENGINE: 51.6 lbs/hr @ 55.1 PSI / 14.5 Ohms based on 380 kPA = 3.8 bars = 55.1 PSI

But, this leads me to wonder if the NA engine would benefit from an injector swap..."

So the SRT6 injectors are WAY TOO BIG to run on a regular naturally aspirated motor.
What I'm still looking for is the Bosch/M-Benz part number of an injector which will flow
SLIGHTLY MORE than the OEM Crossfire injector. Something which will take us from 17 lbs/hr up to 22-26 lbs/hrs of max flow. The 3.2 SOHC V6 was used in some big sedans and in a SUV application. Perhaps one of those part numbers will work. Do I need to start trolling in the M-Benz forums or does anybody around here have an answer ?

Slim

 

I vote you troll the MB forums.

 

I guess that's the plan.

Plenty of heat but precious little light in this thread...

Slim

 

From looking at the injectors it seems quite a lot of other Bosch injectors are very similar, I have some Bosch 0-280-150-901 18.55lbs@43psi, high impedance from a Toyota V6 3.8L somewhere and I think the body is the same as those, just comparing pictures. Too cold to mess with the Crossfire and not enough time but there are lots of injectors around 19-20lbs at 43psi which at 58psi? would be a good bit higher flow than stock.

Give the guys Maxwell suggested in post #27, RC Engineering http://www.rceng.com/ , or the ones HDDP recommended in post #28, Lindertech http://www.lindertech.com/, (or get the Feds to trackdown Maxwells expert - sorry just messing , couldn't resist).

I would guess they will have some ideas and it might save you trawling trash on the MB forums as well as this sad little thread.. Let us know is you find anything useful. Now HDDP is about to depart the NA ranks we need all the help we can get!

 

Slim, I do believe that I posted the information for you to contact Stan Weiss about your injector questions... If he was unable to answer them, then you should contact Linder Technical Services in Indianapolis.

I have had many conversations with both... And they answered all of my questions that you quoted in the previous post... I cannot address this issue as technically and precisely as they can, so I won't even try.

All I can give you a synopsis of everything that has been repeated to me by everyone who is technically proficient on this issue... Add more fuel, then you need to add more air, then you need to provide the engine management to handle both, then you need to make sure it has the optimized outlet size for the exhaust gasses, etc, etc, etc...

And I know I have repeated this statement, which was professed to me by Scott Bingham of Bosch North America. The ME2.8 & 2.8.1 is designed to maintain a constant stociometric state by the signals from all of the integrated sensors. This is approximately 12% leaner than would normally produce maximum HP in the engine, but is designed this way to limit carb emmissions. Every sensor MAF MAP IAT KNOCK TP 02 ECT talk to the ECU which is programmed to cut fuel, add fuel, retard timing, advance timing to maintain it's pre-programmed state.

http://www.autospeed.com/cms/A_1595/article.html

Now, if all of those resources have not answered your question, which was very similar to mine awhile ago, perhaps I can say this... YES, the NA engine will benefit from larger injectors if you have the engine management system that will allow you to do it...

 

Refering to my Turbododge days... This was true in closed loop (14.7 A/F). But since the narrowband O2 sensor couldn't read and relay the ideal range for WOT A/F (11-12), the PCM resorted to a pre-determined injector pulse calculation relative to Manifold Absolute Pressure (which was sadly replaced by MAF in our Crossfires) so a larger injector resulted in a higher volume of fuel @ WOT (to be taken advantage of by the fairly large snail shaped pinwheel toy hanging off the exhaust manifold).


Now, I have some questions I suspect has not been answered yet. But I'll ask them just in case...

Will the stock crossfire PCM adapt to larger injectors and the introduction of more air?
And what % of additional fuel and/or air can we push (or pull) into an N/A Crossfire before we exceed the stock PCM's adaptive range?

I noticed someone speculating about 20% fuel adapt in the PCM. But does the MAF have 20% of range left?

 

FYI - The stock SRT-6 Fuel Injector part number is 68000009AA. ($107.00)

The Dealer is replacing the injector in my #2 cylinder today.

From all the info on this thread, the SRT-6 injectors should (or at least I hope) provide enough fuel at WOT to keep the A/F ratio safe once I install the LET 185mm pulley (20% boost to 22 PSI)

 

Good questions... First let me start by saying that only the NA Crossfire has just the MAF sensor, the SRT has both MAF & MAP.

The PCM is programmed to maintain the optimum air/fuel ratio. This is done by making short term corrections in the fuel injector pulse width based on the O2S output. The programmed memory acts as a self–calibration tool that the engine controller uses to compensate for variations in engine specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the actual air/fuel ratio with the O2S (short term) and multiplying that with the program long term (adaptive) memory calculation, then comparing that to the limit, it can be determined whether it will pass an emissions test. If a malfunction occurs such that the PCM cannot maintain the optimum air/fuel ratio, then the MIL will be illuminated.

FUEL SYSTEM
• Fuel System Similar Conditions Window — An indicator that ’Absolute MAP When Fuel Sys Fail’ and ’RPM
When Fuel Sys Failed’ are all in the same range when the failure occurred. Indicated by switching from ’NO’
to ’YES’.
• Absolute MAP When Fuel Sys Fail — The stored MAP reading at the time of failure. Informs the user at
what engine load the failure occurred.
• Absolute MAP — A live reading of engine load to aid the user in accessing the Similar Conditions Window.
• RPM When Fuel Sys Fail — The stored RPM reading at the time of failure. Informs the user at what engine
RPM the failure occurred.
• Engine RPM — A live reading of engine RPM to aid the user in accessing the Similar Conditions Window.
• Adaptive Memory Factor — The PCM utilizes both Short Term Compensation and Long Term Adaptive to
calculate the Adaptive Memory Factor for total fuel correction.
• Upstream O2S Volts — A live reading of the Oxygen Sensor to indicate its performance. For example, stuck
lean, stuck rich, etc.

In Closed Loop, the PCM adjusts injector pulse width based on the upstream heated oxygen sensor input along with other signals. In Open Loop, the PCM adjusts injector pulse width based on preprogrammed (fixed) values and inputs from other sensors.

 

my eyes and head hurt from reading through this thread, wow, but anyway need an opinion, i will not own this car for too long and i am not looking to make it a race car like i have in the past with other vehicles, but i do want a little more out of it, i have exhaust, soon to be purchasing my intake and ecu tune, possible underdrive pulleys but not sure yet and maybe a sprint booster, but i need to know if the injectors are worth it for me to even look into getting. I mean if i could get 250 hp out of it id deal with it. I have read that puttin the bigger injectors in won't do it without changing the duty cycle somehow and thats even if you can get the bigger injectors it seems. I do not have a way around here of getting a in house dyno tune and that is why i am sending my ecu out to be tuned, so basically is it worth it to me and is anyone ever gonna do it and get some numbers on hp and af. I am not gonna jump at things with this car anymore i have realized there is nothing in the future for forced induction on the na crossfire, nobody seems to be interested in doing it unless you wanna spend 9,000.00 for it then another grand or so to have it installed. hopefully eventually vortech or such will come out with a bolt on charger for 5 to 6k like to usual ones they do, until then i have decided not to go crazy with this car anymore looking around for mods, just make it get out of its own way for now and wait it out a year or so and if not get something else that actually has mods so its easier, lol. sick of the headaches from it already

 

My Theory
Step 1 Replace fuel injectors with 30%? larger.
Step 2 Let ECU adapt to these injectors
Step 3 Modify 02 sensor in a way that the ECU thinks the car is running lean. Volatage conversion in line between 02 and ECU
If the ECU sees a lean condition from the 02 it will adjust again and run what it thinks is the appropriate amount of fuel.
If anyone can figure out how to make this work let me know........

 

Reality:

Step 1: SRT6 injectors. Easy queasy. Good up to 400+ horsepower. Plenty enough for the NA engine.
Step 2: Impossible without a piggyback or explicit ECU programming
Step 3: See step 2.
Step 4: Install pressure manifold to distribute vacuum/boost signal to timing retarding box and piggyback injector controller.
Step 5: Install boost retard, knock detector and timing retard
Step 6: Install piggyback injector controller/MAF Translator/whatever.

 

Isn't this thread about trying to raise the fuel ratio a small amount? SRT injectors? you might as well just run the fuel line directly into the intake And than it will make 4000 horsepower.....LOL

 

lol. I know what you mean. I guess my point is that for the cost of 30% larger injectors from RC engineering or whatever, you may as well get the SRT6 injectors, which are known to make big power and are cheaper.

But the problem is that the ECU only does fuel adjustment based on the O2 sensor in "closed loop" mode. And "closed loop" mode in the cars that I have seen is disabled under WOT and other heavy-load conditions.

I mean, the tactic you mentioned might work for partial throttle cruising or whatever, but for "performance" driving the ECU must be modified in concert with a dyno and other things.

I feel like I'm just stating the obvious for you. I bet you know what I mean.

 

how much fuel pressure does a na crossfire have?, also where should a nozzle to spray nitrous be mounted it has to be after maf sensor and before throttle body, anyone please.

 

Quote from HDDP >>>"Good questions... First let me start by saying that only the NA Crossfire has just the MAF sensor, the SRT has both MAF & MAP."

The 2004 Service Manual begs to differ... see pages 14-42 to 14-43 Also, it is actually on the my engine. Since this is an Sequential Multiport system it uses both the MAP and the MAF.


MAP SENSOR
DESCRIPTION
The Manifold Absolute Pressure (MAP) sensor, is mounted to
the front of the engine on the right side next to the air pump.
OPERATION
The MAP sensor monitors the pressure in the intake manifold. The pressure in the manifold moves a diaphragm
connected to piezo resistors which alter their resistance values. The output voltage of the resistors serves as information
to the PCM about the pressure in the intake manifold.
REMOVAL
1. Disconnect the negative battery cable.
2. Remove the air cleaner housing. Refer to Page 9-608.
3. Disconnect the Manifold Absolute Pressure (MAP) harness
connector.
4. Remove the retaining bolt (1).
5. Remove the (MAP) sensor.
14 - 42 FUEL INJECTION ZH
INSTALLATION
1. Install the MAP sensor.
2. Install the bolt (1).
3. Connect the Manifold Absolute Pressure (MAP) harness
connector.
4. Install the air cleaner housing. Refer to Page 9-608.
5. Connect the negative battery cable.