Wally39

I want to go from my 3.6 pulley to the 3.4 pulley. What all do I need? Smaller belt? Different tune? Better fuel pump? or can I just swap the pulley? Everything is from JDM.

Herknav

Call JDM and they will tell you everything you need.

Screamin Yellow 06

With the 3.4" pulley you'll also need a 107.5" belt assuming you also installed all the other pulleys that were partof the saleen install (some people don't use the plastic idler pulley that comes with the kit because of noise). With the 3.4"pulley you should see 8psi on a regular basis zooming around town and around 9.5psi at max rpms.

I would also assume that there would be a tuning tweak required as well to get the correct/optimala/f ratio.

I have all JDM stage two stuff already with my saleen including the 3.4" pulley and their tune. I took it to adyno tuner a couple weeks ago. Although it was running well the tuner was able to tweak a little more out of the tune (about 30 addition hp). He said that the JDM canned tune for this set up was pretty conservative (rich).They obviously like to stay on the safe side since every car might be a little different.

I would recomend getting the belt and pulley from whomever you want (least expensive) and then let a tuner tweak it if you have that option. A tweaked tune from JDMwould also work but I just wanted to let you know that theres probably more gains to had if you got it dyno tuned.

RedFire281

I would also recommend a KB Boost-A-Pump at the very least unless you want to spend some real money and buy dual GT or GT500 fuel pumps. Check out Brenspeed. You might also want to consider boost and fuel pressure gauges if you don't already have them.