Ive read that Evo's will run a lil fat after a fuel pump upgrade , anyone no how much fuel to pull out ?

Thanks in advance

 

I would not pull any out until you can see a wide band reading. I sure there is almost no need for retune.

 

Thats kinda what i was thinking,,,,, but i hear of reflashes that ask if you have a upgraded fuel pump or not . But thanks man.

 

Well at higher RPM the fuel perssure drops so you have to run a little less timing because you don't have enough fuel to avoid knock. Again I would not realy worry about a retune.

Eric

 

It will run fat after a Walbro 255 HP upgrade. I don't know how much richer it will run or how much extra to take out. But I can tell you it does run richer at any boost level over 3 psi. If I were guessing I would say you could take out about 4 to 5% more fuel on the top end to stay somewhat close to where you were before the fuel pump upgrade. You will notice the car is slower after the pump upgrade, that is do to the over rich condition. I don't have a wideband, but I was datalogging O2 voltage after the pump and noticed the higher voltages.

Brian

 

Maybe i was too lean , b/c it run a lil better after the pump upgrade (maybe its in my head) .

 

Brain,

Not to sound mean or like a jerk but your are not going to have any sort of a valid reading from any factory o2. So you voltage logging does not mean anything. Plus I have yet to find a true real time data logger they are all off a bit.

Also 4%-5% is a bit of fuel even on a S-AFC. That's enough to have motor damage. Tops on my car with a full exhaust I was only able to pull 8% at 5500 rpm of fuel. That gave me a nice 11.7 to 1 AF on a wideband.

The pump should run a bit richer but not enough to have a completey retune the whole AF.

My Best
Eric

 

Matt it's not in your head the ECU see less knock nosie and has advanced the timing because you know have enough fuel to support it.

Ing advance is very important to making constent repeatable power.

Eric

 

Thank's Brain and Eric I think it was at evomoto's "how to " install a fuel pump they said something like 5-10 more fuel psi .

 

You can most certainly ascertain good information from a narrowband O2 voltage. Can you tune down to the nearest .5 A/F point??? The answer is a most astounding NO!!! You can however tell how rich or lean you are running. I can tell you with 100% certainty that if you are running 1.00 volts or higher on the narrowband O2 voltage, you are definitely running richer than 11.7 :1 air fuel. When my car was running stock ECU, I would run 1.00 volts above 4k rpm. After the Dynoflash, the O2 voltages dropped down to .96 volts. I ran it this way for about 4 months. Then I installed the 255 HP pump. After this the car would run 1.00 volts and occasionally would run so rich, that it would go up to 1.02 volts. I have since tuned the car back 5% across the board with my HKS Super AFR, and I am back to the .96 volts that I was before the pump upgrade.

BTW, at the track, running race gas, I was pulling out 18% to 20% up top. This was getting me .88 to .90 volts. I tune this way currently, and my car has run pretty well with this method. 12.2 @ 118.4 mph. Stock turbo, intercooler and injectors.

It is not as accurate as a wideband, but it does give relevant and reliable information. My pocketlogger recieves 19 samples per second and I can see the changes in MAF voltages when I make changes on the AFR. I think the datalogger is working fine.

Buschur gives information for tuning the SAFC referencing O2 voltages. He seems to think it works well too. I have a Techedge in my Supra and I love it, but I don't in the Evo yet.

Another, thing to keep in mind when tuning with O2 voltages, the O2 voltage will change as the sensor heats up. It will change as much as .02 volts without having a change in air fuel. So its accurancy and consistency is at .02 volts at the best. That is not that accurate, but if that is kept in mind, you can use it very effectively when tuning.

And, I didn't think your post was being a jerk. Maybe a little "close minded", but thats okay in my book. Everyone has their opinions and now you know mine.

Brian

 

why not invest in a wideband now though? the LM1 is only $350!.. find a cheap old laptop and you're in wideband heaven!

 

I saw some place that has the LM-1 for a little under $310. I found the link to it, but I can't find it again. Anyone know where that link is?

Brian