Right now I have a vac line from the manifold to the SFMU. I need to have 24psi static to get the right fuel but I get 13psi at idle and it runs rough. When I unhook the vac line and idle it at the static 24psi then it smooths out. Can I just run the signal line from the compressor so it idles at 24psi and the static is also 24psi. It should still rise w/ boost since it's connected to the compressor outlet. Any thoughts on doing this?
#34471, "RE: Running FPR signal from turbo?" In response to Reply # 0
sounds like a good idea, since the vacuum signal would never go below 0 psi. i've never heard of it being done, but give it a try... it sounds like it sound work fine to me.
#34472, "RE: Running FPR signal from turbo?" In response to Reply # 1
Hmmm, I wouldn't recommend referencing the FPR vacuum source from the turbo. I guess it would work, but I believe it will be more accurate to run it off the manifold. There should be a slight difference in boost pressure when measured at the intake than at the turbo compressor side. I really don't have any detail explanation or understanding on that.
___________ Kon C
"Sometimes, a man has to do what a man has to do."
#34473, "RE: Running FPR signal from turbo?" In response to Reply # 2
How about.. when you're pushing a single shopping cart, it doesn't take much pressure to push it along. But when you're pushing a big long chain of shopping carts, it takes a lot of pressure to push them all. You're still pushing the single cart in the front, but with all these other shopping carts behind it its harder.
The air in the intercooler piping "stacks up" like the carts, so the shorter your IC piping and less IC volume, the less air "carts" the turbo compressor has to push ahead.
That's why for instance a SMIC has a rated "pressure drop" of about 1psi, and a large FMIC has a pressure drop of 2-3psi. I assume pressure drop is the difference between compresser outlet and manifold PSI.
Anyways probably the same reason you always get more pressure out of a short garden hose as opposed to 300 feet of interconneted hoses. Friction or something?
#34474, "that's one ofd the reasons for having a s-fmu" In response to Reply # 0
on the s-fmu, there are 2 screws. one says vac, and the other says presure or boost or something besides "vac". well, the one that says VAC is the lower pressrue limit. you can turn that to raise your lower limit to whatever you want without affecting the rest of your curve. the rest fo the info about it is in the instructions.
A.D.P. "...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all." bring it on............
A.D.P. "...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all." bring it on...........
#34476, "RE: that's one ofd the reasons for having a s-fmu" In response to Reply # 5
I think the main issue here is you are running the injectors at too low of a pressure. 24 psi static (13 psi under vacuum) seem too low for proper injector function. I would investigate something to let you run higher pressures. Like using smaller injectors or just letting your car run richer at idle. It sounds like you are asking the injectors to fire at such a low pressure, that they aren't spraying right.
Corbin
'95 ESI-T HRC+FMIC+ETC...
Gimme fuel...Gimme fire...Gimme that which I desire
#34477, "RE: that's one ofd the reasons for having a s-fmu" In response to Reply # 6
Well I screwed that vac screw all the way in and out and it didn't change at all.
Corbin- I'm the one that just sent you the money for the injector bungs. So that's how I'm working to solve the problem I'm just not happy at all w/ my current setup.
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I'm just not happy at all w/ my current setup.