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I've Got A Dyno To-do List

  • Thread starter Thread starter 90GTFIVO
  • Start date Start date Oct 18, 2012
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90GTFIVO

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Apr 28, 2011
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Oct 18, 2012
#1
  • Oct 18, 2012
  • #1
I have a supercharged 5.0 and have finally found what seems to be a very reputable Foxbody dyno/tune shop in Columbus, OH. Talked to the owner today and gave him my list of mods on my 90GT. He recommended I make some changes/upgrades before I bring the car in. As a few on here already hit on, I need to beef up my fuel pump from 190 Lph to 255 Lph and my 24# injectors to 42# or 60# (if price is comparable). This will allow me to do away with the FMU.

I'm new to all this and a couple things. He mentioned something about 40# based pressure. No idea what this means, can anyone help?

Few other things I picked up on from reading about the V3 SCi:

I currently have a 75mm mass air meter. If I up the injector size, do I need to have the mass air re-calibrated?

How important is it to upgrade my ignition system?

I read where it would be wise to change plugs to 1 heat range colder than stock. I'll probably go ahead and do this since it will be fairly inexpensive.

If you have any suggestions on what injectors to buy and best place to buy them (cost), let me know. Thanks!
 

Bullitt347

I have been doing it wrong this whole time
15 Year Member
Mar 23, 2007
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Oct 19, 2012
#2
  • Oct 19, 2012
  • #2
The 40 psi base fuel pressure is the starting point. Without an FMU the fuel pressure regulator will typically (if stock) raise fuel pressure by 1 psi for every pound of boost. With the 42 lb/hr (or 60 lb hr) injector set at 40 psi base (engine idling vacuum/boost hose off) fuel pressure, then at 10 psi of boost the fuel injector will see 50 psi and add enough fuel to keep the engine happy. Of course the dyno will be the best place to change the fuel pressure to allow for optimal air/fuel readings at WOT/max boost. And naturally the MAF will have to be calibrated for the larger fuel injector, either thru a different sample tube (like a C$L meter) or thru the ECU map for the MAF.
 

pearlnotchback

5 Year Member
Dec 18, 2011
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Tennessee
Oct 20, 2012
#3
  • Oct 20, 2012
  • #3
can you run 42lb injectors with an FMU?
 

90GTFIVO

Active Member
Apr 28, 2011
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Carroll, OH
Oct 22, 2012
#4
  • Oct 22, 2012
  • #4
I will not use the FMU when I upgrade injectors.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
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Oct 22, 2012
#5
  • Oct 22, 2012
  • #5
Duplicate thread in Tech.

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