How streetable are the #72's or #83's with first gen DFI

[WIKEDV6]

My buddies daily driver (2003 Caddy CTS with the GN powertrain) maxed out the #55. He is using the old Gen DFI. What he doesn’t want is to sacrifice his gas mileage. Right now he gets 18-20 mpg in the city with his #55. What are the gas mileage most of you guys are seeing with #72’s or 83’s in a daily driver.

TIA
Prasad

 

[Reggie West]

Gas milage is going to depend on how you have the car tuned.

72s idle really well and they can be leaned out to get decent fuel economy. It will require one guy driving and another tuning those cells that are for light load/cruising.

Bear in mind that 72s work with a batch fire box but that is about the maximum size injector that it will be able to drive.

83s or anything bigger require a VIC box to drive them. It is the same old story. Bigger this requires bigger that and then once you hit this level you just have to have bigger everything else.

 

[norbs]

No matter what you do, your going to have to change the oil every 500 miles or so, since the idle will be rich, and contaminate the oil, using any large injector idling alot, so just keep that in mind. Even with the seq felpro i am running into this problem

 

[bruce]

Originally posted by norbs
No matter what you do, your going to have to change the oil every 500 miles or so, since the idle will be rich, and contaminate the oil, using any large injector idling alot, so just keep that in mind. Even with the seq felpro i am running into this problem

What size injectors, and cam are you running?.

 

[norbs]

83 injectors and a pte 224 billet roller which i am changing to something else

 

[Superskwrl]

Originally posted by norbs
No matter what you do, your going to have to change the oil every 500 miles or so, since the idle will be rich, and contaminate the oil, using any large injector idling alot, so just keep that in mind. Even with the seq felpro i am running into this problem

I have never heard of this problem, have others you've talked to also had it?

 

[norbs]

I have a few friends, with big injectors, and its quite common to get a alot of fuel down low, even with a conservative fuel map. Your trying to get the injector to work at a very low PW, and at those low numbers the spray patern is not that accurate. I always change the oil after 500 miles anyway of hard driving, its insurance.

 

[BigChinooks]

With 72lb inj's and gen 6 dfi with a vic i do not have any problems at all.
You really have to spend time at getting your tune down though!
Norbs,i thought you had f.a.s.t.?