I am done with engine/power mods for my Evo, so I want to finalize my fuel system. Currently I am flashed for 93 octane (and I now live in Cali so I can only get 91), and I have the following mods:

RMR 3" DP, Cat-back, IC piping, intake and intake piping (stock cat)
Power Enterprise boost controller/gauge (currently set to 1.25 kPa ~ 18 psi)
Lots of dress-up or non-applicable stuff

I have a Walbro 255 lph fuel pump, but it is not installed yet. I am wondering if any of you guys who have experience can tell me if I should do more than just add the pump and get reflashed. For example, do I need bigger injectors, etc.? I would think not, esp. since I'm going to be running the stock turbo for a while. The only other thing I'd like to do is put in better headstuds so I can run a little more boost (maybe up to 1.5 kPa ~ 22 psi).

Please post your suggestions and keep any flames to yourselves. If you are a n00b, please don't post unless you have extensive experience. Thanks in advance!

Chris

 

You don't need bigger injectors to run the Walbro, but you most likely need to be re-flashed - although the extra volume may make up for the octane difference in you fuel map. I'm running the Walbro with only exhaust, intake, mbc, and emanage for mods. I put mine in for a bit of a safety cushion since I track the car a lot and didn't want to have the stock pump leaning out on me at 100% throttle and 135 mph. Plus I'm set if I ever want to do cams and injectors later on.

Headstuds aren't a bad idea if you're already in there doing cams or something, but I wouldn't think you'd need them just to run 22 psi. The stockers aren't *that* weak.

 

Just do the walbro. It's easy also, check out evomoto.com for a tutorial.

If you really want to know how much fuel you'll need, in AEM EFI Basics it has all the formulas for injectors and fuel pumps (But since your not running a larger turbo you don't need to waste your time).

 

Thanks for the tips, guys. My concern with the injectors was because I've read a lot about how the stock injectors end up getting 100%+ duty cycles. Any other info?

 

i have similar mods(and run 21psi at the track on 100 octane) and with my utec i have never seen my injector duty cycles reach anywhere near 100%. it is rare that they break 80.