Injectors versus FMU??

HIVOLTJ

HIVOLTJ

Project Old School
OK, a few questions. I had my heart set on a Vortech SQ S-trim kit, can't get all the pieces together, so now I'm looking at a Powerdyne BD-11 setup, stock pulley for now, so should make 6psi on a stock-ish truck I believe. Would injectors be a lot better for driveability than an FMU? The guy also has some Ford Racing 42lb. injectors I can buy or an FMU. Will the 42's be too much for 6 lbs of boost? I'm sure later I'll be swapping pullies for more boost. I've heard FMU's can be finicky to tune. I do plan on swapping to a Vortech S-trim at some point in the future when I can. I do plan to get a Tweecer or Moates quaterhorse + wideband, what else will I need for this powerdyne? An inline fuel pump? BTM and/or ignition upgrade? What all is needed to get started at 6 psi? I'm trying to get the BD-11 setup for <$1000, but it's for a regular F-150, so I would have to build all the piping. (I know where a scroll can be traded straight across for the one I need)

Advice please?

Josh
 
I would just go ahead and get the 42's so that when you upgrade to an s-trim it will be already there.
 
Right now I am running 42's I had a fmu in the truck and hated it. One thing you will need for the 42s is a tune. But at least it opens the door if you are looking for more boost down the road.
 
Yes and Yes boys, I'm thinking the same, but mainly wondering what else I would need besides a tuner, and if the driveability will come out good w/ the 42's at lower boost levels. I don't see why not, but wanted to make sure.
 
Main thing is a tune! With a good tune drivability is greet. you will also need some type of fuel pumb booster or the 2 pump trick.
 
You will get your best drive ability out of a 19lb or 30lb injector. With the 19s you will need a fmu, with a thirty you will not on a PD and stock engine with the right tune. A 42lb injector should be the choice if you think you will upgrade to a strim or more hp, but you will not quite get the idle quality as the smaller injector, however it will still pass emissions if you retain your egr/cats and air pump.
SS
 
Super Glide said:
You will get your best drive ability out of a 19lb or 30lb injector. With the 19s you will need a fmu, with a thirty you will not on a PD and stock engine with the right tune. A 42lb injector should be the choice if you think you will upgrade to a strim or more hp, but you will not quite get the idle quality as the smaller injector, however it will still pass emissions if you retain your egr/cats and air pump.
SS
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Steve, I've HEARD that when the inline and FMU come on, it is a nightmare to dial in the fuel curve? Any truth to that? I've heard it's very on/off with an FMU instead of a nice smooth fuel curve if that makes any sense?
 
You will get an increase of fuel pressure when the inline kicks in. It seems like an increase of about 6-7 psi on my truck was the norm. This will cause the truck to get a little bit more rich because it's putting more pressure on the injector.
 
Diabolic said:
You will get an increase of fuel pressure when the inline kicks in. It seems like an increase of about 6-7 psi on my truck was the norm. This will cause the truck to get a little bit more rich because it's putting more pressure on the injector.
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Same thing with me. I went with the 42lb injectors and a Tweecer R/T. I found that Ive got a bit of idle hunt at startup but after it gets warm she runs great. I kept my fuel pressure at 40 lbs in the rail via regulator. when the inline kicks in it pushes another 2-5 lbs in. It does run a bit rich (11.5-12 AFR at WOT; 13.5-14.8 otherwise during normal driving).
 
I have my in-line (t-rex) set to come on with key on. I tried a 2 psi hobbs switch, but my pump would never come on. So, I ditched the switch. Even if you don't want your pump on all the time you could do it just for tuning purposes. Are there any reasons not to have it run all the time. Mine has been working this way for over a year.
 
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