Help Went to the Dyno Today! 307hp and 325tq

[lead09]

So we spent 3 hours making runs and tested the fuel pump and the maf to see if it was pegged because the tunner could not tune out the lean condition that occured at around 4300-4500rpm. We did not go past 5000rpm cause it was too lean.

We did make alot more horsepower compared to the previous owners run (I'm using the same tuner as the previous owner). I also made 5.5psi of boost at 5000rpm so I should be seeing over 6psi at 6000rpm. The upgrades from the base run are 130amp alt., upr boostmasterpipe, 90mm lightning meter (from 76mm C&L).

Note the fuel ratio leaning out. He had no problem controlling the fuel below 4300-4500rpms. Fuel pressure was good and stable during the run. We bumped it to 60psi and it ran richer but still leaned out. MAF read 3.8v at at 5000rpm, so it is not pegged. The only thing we can think of it the injectors are plugged. I don't have any history on the injectors so they might be.

Should I be looking at some 42lb injectors? I hoping 330hp and 350ftlbs....

 

[luckythirteen13]

what fuel pump are you using?
did you try running fuel pressure at 42psi and adjusting pulse width? your fuel pump may have had trouble with the high volume and high pressure.

i recognise this post from mustangforums.com

 

[Cman88]

I'm not sure I am reading the chart correctly, but if I am, the car appears to be running quite rich (11.0:1) below 4,300, then leaning out considerably. I have yet to try my hand at tuning the 5.0, but I tune boosted Hondas to 11.8:1 and that is even considered a little on the rich side. Running it as lean as 13:1 is a little risky in my book. Even for low boost.

 

[poneypower89]

11 is a good boosted 5.0 tune while at in boost at WOT. its not TOO rich. Of course, climbing above 12:1 in those high RPMS can and will be costly.

Things that would help

1) are you still running an FMU?
2) are you still running the stock fuel pump?

 

[88Stang331]

11 is a good boosted 5.0 tune while at in boost at WOT. its not TOO rich. Of course, climbing above 12:1 in those high RPMS can and will be costly.

Things that would help

1) are you still running an FMU?
2) are you still running the stock fuel pump?

Unless they put a 255lph pump in his car stock, i don't think he is

first of all, i would probably reccomend 42lb injectors as that seems to be the injector size of choice for average boost...5-10lbs. Your fuel pump shouldn't be the problem, maybe try cutting the fuel pressure down like he said and see what that does for you.

 

[$uperstang]

Well you have a Lightning MAFS that is calibrated to 42lb injectors and you have 30's this is a big NO, NO! Get the 42's or better yet get a Pro-M meter calibrated to 36'lb injectors and new 36lb injectors which would be perfect for your set-up. Just my opnion, but it is a damn good one!

 

[lead09]

I'm running a 255lph pump. That was also an upgrade from the previous tune.

We ran at 40psi and 60psi fuel pressure. At 60 is got richer but still leaned out.

The MAF is not cal'd for anything. Injector size is done in the computer. The lightning meters a cheap (less than half of what a pro-m would cost me) and consistenlty accurate.

 

[$uperstang]

I'm running a 255lph pump. That was also an upgrade from the previous tune.

We ran at 40psi and 60psi fuel pressure. At 60 is got richer but still leaned out.

The MAF is not cal'd for anything. Injector size is done in the computer. The lightning meters a cheap (less than half of what a pro-m would cost me) and consistenlty accurate.

Injector size is calibrated in the computer? Dude you first must understand the IMPORTANCE of getting a matching meter and injectors. TRUST me this is where your problem is. But hey if you don't want to take the advice then continue to battle your problem and spend more money trying to figure it out and you will see in the end that I was right all along.

 

[Hickfied]

The injector size IS calibrated in the computer, then only thing the AF MAF companys do for the new MAF is adjust the signal it sends to match a diff set of injectors, if he had the car tuned for the injectors with the MAF, he wont have a problem.

 

[$uperstang]

The injector size IS calibrated in the computer, then only thing the AF MAF companys do for the new MAF is adjust the signal it sends to match a diff set of injectors, if he had the car tuned for the injectors with the MAF, he wont have a problem.

True it would be calibrated in the computer if he had a custom chip, But I do not see mention of a custom calibration here.

 

[352Ford2]

Do you have a boost sensitive fuel pressure reg? I think that might fix the whole issue of running fat on the bottom end and lean on hte top end.

 

[lead09]

Superstang, didn't mean to rub you the wrong way.

Yes it has a chip. We made a bunch of runs and he had no problem controlloling the a/f below the 4300rpm. He did mention from the get go that it was behaving strangely to the different things he tried. He mainly tunes mustangs and has done a lot of lightning metered cars and he comes highly recommended. He only tunes and does not sell parts so he isn't trying to screw me.

I'm not sure what regulator is on their I will have to check when I get home. I have a fuel pressure gauge and it was steady at both 40psi and 60psi. What does a boost sensitive regulator do differently?

I appreciate all the advice.

 

[352Ford2]

a boost senstive FPR increases fuel pressure according to boost, so you can run a more consant a/f ratio
they work really well and would be the first thing I did to try and fix it.
their are all sorts of ratio's but most are 1:1 so for every 1 pound of boost you get another pound of fuel pressure