4.9 Stroker Performance and fuel

[JPIN4LYF]

Ok. I have a Titan 4.9 stroker. Yup, if I had it to do over.... Anyway, there are several very technical questions that I have that I can't find in other threads.
't I have a bored throttle body, Banks header, 47 pound injectors and a cold air intake. I have called everybody I can think of, but I keep running into (i can't do a cherokee CPU) Not many ppl know much about them. And, I've been told that there are like 4-6 possible variations of mopar CPU's.
I found a guy in Cali that can erace and re-write a cherokee CPU as he does for the "jeep-speed" guys, but it is insanely expensive.
My stroker runs very hard and it is really fun to drive. It has a little high rev flat spot that I'm trying to fix.

My speciffic question is this. I think I'm sucking my fuel rail dry. I want to ask if anyine has played with an adjustable fuel pressure regulator and do they work. Also, a wideband O2 sensor or an adjustable map. My motor hesitates a little around 4k to 5k RPM's.

I have been told that if I try to chip this booger that it will only further complicate things. Anything y'all can throw my way would be greatly appreciated...

Oh... BTW. It took 4 engines to get one that would run... yay me.

[SkylinesSuck]

You can't even hazard to guess what's going on with out a wide band 02 sensor. That being said, you aren't sucking your fuel rail dry as long as your fuel pump is in good condition and there are no blockages. The stock fuel pump it more than enough for over 300hp.

[SilverXJ]

x2. To see what is really going on the the AFR you need a wideband. However, this:

47 pound injectors

could be a problem.

[JPIN4LYF]

Ok? What might be the problem with the 47 pound injectors. That is what they told me to get.

And... A wideband O2 sensor is a must then?

[4.whoa]

Most run 24# so maybe they meant 27#? 47# would be right with some really good boost &/or e-85

[unlimitedrubicon]

A six cylinder on gas with 47# injectors is good for ~450hp. Any less demand (hp) and you will not be able to pull enough fuel out with the stock computer.

[JPIN4LYF]

A six cylinder on gas with 47# injectors is good for ~450hp. Any less demand (hp) and you will not be able to pull enough fuel out with the stock computer.

Holy smokes Imma tard Yam man,. Bosh 27 pound injectors....

[Cheromaniac]

My speciffic question is this. I think I'm sucking my fuel rail dry. Do you know that for sure?
My motor hesitates a little around 4k to 5k RPM's. There could be other reasons e.g incorrect plug gap, valve float.

[JPIN4LYF]

I talked to Chuck at Titan the other day and he has a possible solution. There is a guy in CA that can write a specific map on the cpu that will align the vehicles componets with the needs of the larger motor. It'll be shortly after the first of the year before I dig up the coin, but It's on it;s way.
I'll post results.

[JPIN4LYF]

I have investigated every piece of tech info that I can find on every forum and race manual in print. In my quest for knowledge I spent some time with some rece-heads. Something they suggested was checking the EGT to gauge whether the motor is running lean or rich. It is running wicked lean. The EGT was like 1320 degrees. I have cooked 3 headders and threw all the blame at them.
I'm going to try a reprogrammed CPU to see if I can't get this joker dialed in. I ordered an EGT gauge to try to monitor changes.
I'll post results.

[amcinstaller]

checked your compression lately?? that seems rather hot id be interested whats happening in the cylinders too

[lafrad]

High compression usually runs LOWER egt's.

I would make sure you have the timing right. cooking headers usually means that you are running the timing with little or no advance... and the "fire" is still burning when the exhaust valve opens. This can also happen when you get misfires, so check your coil. GO to a GOOD quality OEM coil and a new distributor. make sure you are running spark plugs that are appropriate for the compression ratio.

[yuppiexj]

Using EGTs to determine A/F ratio is not going to give you the best data.
Lot's of people do it, but you are only given anecdotal evidence as to the true mixture.

If you're already going to weld a bung in the exhaust for a sensor probe, put in a wide band O2 sensor.

[the_wrench116]

Using EGTs to determine A/F ratio is not going to give you the best data.
Lot's of people do it, but you are only given anecdotal evidence as to the true mixture.

If you're already going to weld a bung in the exhaust for a sensor probe, put in a wide band O2 sensor.

"2nd"

[amcinstaller]

High compression usually runs LOWER egt's.

with that much heat in the exhaust i was wondering about ping and perhaps burnt pistons or valves. that seems way too hot to me. so, LOW compression