Almighty-Si

OK heres the problem guys. My friend has a 98GT and we had just installed a Vortech kit on it. It's a S trim non-aftercooled kit. With the kit came a 4:1 FMU and T-Rex inline pump. It didn't come with any kind of chip or larger injectors, which had me a little puzzled. I'm by no means a Mustang tuner but I have a boosted Honda (I know but I'm not one of those guys who thinks they can beat everyone just cause I have a muffler and lights on my car) and when I installed the kit I had to retard the timing per pound of boost. Which is why I thought that this kit would come with some kind of chip but according to some people (the place he bought that charger from and a couple of friends that have boosted Mustangs) they said with the FMU and T Rex it would be just fine and that is not the case.

Today we took a little trip to have the gears installed. While we were there, he got a little curious as to how much power he was making and I thought it would be a good idea to see his power curve and Air Fuel curve and he had it thrown on the dyno. Well the guy strapped it in and everything was looking fine right up to about 4800rpm where the air/fuel ratio started to get really lean and when he got to 5500rpm I s**t myself and yelled for him to shut it down but he took it to 6000rpm and all I could think was melting pistons as the air/fuel ratio at 6000rpm was 17.5 !

I know that he needs injectors as the 19lb/hr are not doing the job. I was thinking something along the lines of 24lb/hr injectors but now my concern is running to rich down low. So I guess that my question is, if he installs the 24lb/hr injectors, would there be some sort of way to lean out the bottom end? Also, would he be able to lose the FMU with the larger injectors or will he still need it? What are the options?

Thanks in advance guys !

eteddie

I am also having fuel delivery problems at 1500-1800 RPM's with my 98 GT after installing a Vortech SQ, no intercooler, AFM Power Pipe, 80 mm mass air flow. Here is my story......</P>


After I had installed the complete kit here at home,the car was taken to a local speed shop with aninfloor dyno. A custom chip was burned, car was tuned, air/fuel ratio was adjustedwhile spending about $600 worth of dyno time to get it there. They needed to install a bleeder fitting off of the FMU to get the air/fuel where it needed to be. It also only had the t-rex pump and the Vortech FMU that was supplied with the kit from the factory. I also wanted them to install an X-pipe during my initial visit, but they ordered one for a manual trans whereas mine is an automatic, no install during this initial visit. </P>


About a month later, the correct pipe showed up but they could notinstall it on in time for us to hit the dragstrip, therefore, I had my cousin install it at his local muffler shop, pretty simple. Car seemed to run just fine for about a week. This is when I started having the fuel delivery problem.</P>


The car lunges and lugs at the RPM's I had stated above and the pipes are comletely black as well as the back of the car with soot. I have been told to put bigger injectors in it, a fuel pump in the tank, lose the Vortech FMU and so on and so on........</P>


I am lost and am not willing to have our local dyno shop keep working on it at $100/hour. Just tonight I was told that because I no longer have the catalytic converterson it (Bassanni off road X pipe) I need some sort of sensors on it so the computer knows the cats are not there. </P>


Any help would be really appreciated...........I know dragbikes inside and out but am only learning with these Mustangs......thanks in advance, ed.</P>

awwimer

i was allways under the impression that black pipes where running rich. If you where going lean then you would have the fuel problem at higher rpm under more boost. Do you have a rich lean gage or fuel pressure gage? Let me know and also would like to here dyno results.