Is the 5 bar fuel pressure regulator a worthwhile upgrade on a GIAC stage 4 TT? I have heard different opinions- some say it isn't needed until GT640 and above, while I have also heard that it makes a difference on stage 4 under full acceleration. Any opinions much appreciated.

 

I had it on my stage 3 set up.... I also have a AEM afr
dial on my dash... and it improved my afrs dramatically.... my current SG stage 5 has it as well.

 

I was told i didnt need it on my Stage 4.

 

OT- Mark, appreciate all the info you gave me over the phone the other day- very helpful.

 

I personally would do a few pulls on the chassis dyno before making the decision. Dont throw more fuel at the car unless it needs it. Do a pull. Post the A/F ratio charts and show us what it is doing. You dont have to reveal the HP/TQ numbers.. just the A/F ratio under load/boost.

What we have found: the car *may* pick up some bottom end torque. But each one of these kits react differently to more fuel.

Typically Garret (GIAC) will tell us to ad a 5BFPR


B

 

im runnning 1.3 and 1.4 bars constant and I NEED the 5 bar. I have the AEM AFR guage so i know afrs all the time.

 

It also depends on the programing.We use a 5 bar FPR on all are kits over 500hp.

Neil

 

It seems that the programming is the key. The GIAC tuners/dealers I've heard from don't recommend the 5 bar FPR at stage 4. It is not until GIAC GT640 and above that they use it and tune for it. While other tuners (PSI,FVD for example) use and program for the 5 bar FPR in their 500/600hp kits.

 

In the test's that we have conducted the 3.75 FPR max's out around 500hp. Most european tuners use the Maha dyno and give a lot lower hp number than say the Mustang or Dynojet. ie our 550 kit put down 620 on a Mustang dyno.

Neil

 

It never hurts to run a little rich... but if start pushing 1.2 or 1.3 bars u definately need a 5 bar regulator... no matter what tuning package ur on.. trust me... ive been there twice. I actually took out the 5 bar on my stage 5 package and looked at my afrs( I have a guage in my car)... and it jumped to mid 12s at full boost from 11.8s... and If one thinks it hurts the car... no way.. not at those boost levels. My evo 8 that pushes 35 psi of boost runs high 10s to mid 11s thru the power band.... nice and rich- just the way I like it. the leaner u get the more heat in ur cylinders, detonation, and POW!

 

Amen brother. Lean melts pistons.



B