Setup:
Hahn Racecraft Stage II with Side Mount (7/8 psi)
Vortech SFMU 3.62 with hard spring
Stock Injectors

I was wondering if anyone bumps up their fuel pressures in the winter season. I would think that in colder weather you would make more horsepower and could possibly run lean on pressures that you would normally run in the summer.

I was running 50 psi at idle and recently bumped it up to 55 psi today to compensate for the winter. A base line increase should increase your total fuel pressure under boost - that is my thinking. I'll monitor my A/F gauge and see what change it makes. Just curious if anyone else does this. By the way, I am in New Jersey and last night was one of the coldest nights in three years! Figured I should do some adjusting.

Comments are always welcome,
Kurt

yeah i noticed i was hitting almost 1600 egt's the other day on a long pull in 4th..usually is a bit cooler. Its damn cold here, so i know its leaning out. Its never a bad idea to run a little more fuel. Luckily the colder air helps to keep back detonation when running a bit lean. I did raise my fuel pressure a bit for boost.

Colder air = more dense = more oxygen molecules = more power = more fuel requirement = a big smile on your face :D

Ok, this is going to sound dumb, but how do you change the fuel pressure? Just by adjusting the FPR or what? If so, how do you adjust it? If not, then what do you do? Just trying to learn here guys. Thanks.

Thanks for the responses. I took the car out yesterday and on my Autometer blinky light A/F gauge, the car stays right in the center of rich in third gear. I've also noticed that crusing at 55-60 mph, my EGTs are around 1200-1225 depending on engine load (hill or not). Those temps are about 25 degrees lower than before which is always a good thing :). I do want to take the car out today and boost in second gear as this is where I was going lean.

It is very easy to adjust fuel pressures. I am using the Vortech SFMU instead of the HRC supplied regulator - the cartech. The cartech is brand new, never been installed, and still in the box. I've heard of too many problems with this regulator so I stayed away from it right from the start.

On the top of the Vortech SFMU, there is an allen key screw and jam nut. You simply loosen the jam nut and turn the allen key screw in to raise pressure and out to lower pressure. You will need to tap into your fuel line and temporarily install a fuel pressure gauge to get the exact fuel pressure reading.


Here is a quick install guide and pictures of my setup:

I have a 96 Eclipse GS that does not have the original FPR on the fuel rail. My old FPR was under the car near the fuel tank (passenger side wheel). I followed the instructions that came with the HRC kit and removed the Schrader check valve from the fuel rail, attached the hose barb fitting, and the fuel injection hose. Now this is where it gets different.

Additional Parts:
- 3 foot 1/4" fuel hose
- 1/4 NPT Tee with 3 1/4" NPT to 1/4" Hose Barb Fittings
- 1/4 NPT Pipe Plug (this came with the Hahn Kit)
- The Vortech SFMU has -6 AN fittings so you will either need to buy two conversion fitting (one for the IN and one for the OUT on the vortech) that has -6 AN Female to NPT (The -6AN will go into the vortech). I did not buy the fittings as I had access to a machine shop. I simply removed the flare from one side of the -6 AN fitting to make it flat, drilled it out to slightly smaller than 1/4", and then threaded the inside of the fitting to 1/4" NPT. This allowed me to attached 1/4" NPT 1/4" Hose Barb fittings.


Installation:

After running the hose from the fuel rail I attached the other end of the 1/4" fuel hose to the 1/4" Hose barb fitting on the tee. I then ran the other end of the tee to the IN on the Vortech SFMU. You now have one more port on tee to use to connect to the fuel pressure gauge from Hahn. You can then run the fuel pressure gauge under the hood an onto the front windshield for testing (just latch the hood, do not close it as it will pinch the fuel hose). Here is a picture to clear it up. You will also have to run the out of the Vortech SFMU to your return line to the tank. Remember to use teflon paste fo a leak free seal and to plug the tee once testing is complete.

(P.S Sorry if the pictures don't load. The webserver is apparently having trouble. Try again later if you don't see the pictures.)