its a 87 s4 turbo 2

running 9psi of boost, walbro fuel pump, thats it for engine related mods.

so for some reason when i step on it at night it flys, it pulls really well, but during the day it doesnt have that power like it should.

now I wonder with the walbro during the day its sending more fuel b/c its getting more voltage than it does at night with everything on(lights, music with subs) and leaning it out.

any other possibilities?

 

colder air is more dense then warm air and will produce more power


is your pump rewired or on the stock wiring ?

Rotary > Pistons

 

yeah but the difference...is well...night and day..lol.

stock wiring.

i mean even my sr s13 wasnt like that, it could be hot as hell and still have power.

 

idk , havent boosted mine yet so I can't tell ya im still on break in

but if you're running lean its not a good thing.

have you upgraded anything besides the fuel pump as far as fuel system/ecu?

if you're leaning out whether from loss of voltage and/or from boost creep you'll want to find out.


I'm not sure how but you should test voltage on your fuel pump under load and see if its where it should be.

personally Im not running subs or anything because I know the stock s4 alternator is rather weak.

Rotary > Pistons

 

its not really "leaning out" but i'm thinking b/c of the added pressure of the fuel pump its lowered due to the drop in voltage, but i'm going to drive my car during the day with my lights and **** on and see what happens. I just think its running rich to begin with.

 

Pick up girls with a smaller *** in the daytime..it will even out..

 

unfortunately for me the only *** i'm hauling is mine lol.

 

Lack of AC is my problem. My fiance is from New Hampshire and she won't set foot in my car in the summer.

 

AC just makes your car slower and suck up more gas, I'd rather save money and open the windows and sunroof in my fc

Rotary > Pistons

 

You need to rewire your fuel pump so it's CONSTANTLY getting 12volts instead of 9 or whatever it usually gets. Plenty of writeups on this site.

Good luck!

 

I still gotta do that on mine but haven't since I'm still on break in

Rotary > Pistons

 

i'd wonder about intake air temps, ie heat soak

 

even at stock boost it was like that.

 

are you sure its staying at 9psi and not creeping

Rotary > Pistons

 

yeah its holds a steady 9

 

if you're concerned about fuel you should be testing things.

get or borrow a wideband and monitor AFRs in the evening and during the day and compare. a wideband should be on every turbo owner's requirements list. even if you have no way of making fuel adjustments it will still show you the health of your fuel and engine management systems.

 

+1

I want to get one of these for my car.

Turbo cars require much more special care and.attention to last

Rotary > Pistons

 

yeah its def on my list, I am going to rebuild first, looking around for kits and prices, also i think ive fixed it, took off the UIM and cleaned the grounds with some sand paper and its running alot better in the upper range. so i think it was an issue with my secondaries.