I'm looking at the new fuel pump hanger that Radium has released for the Evo 1-6. Does anyone have this hanger for the 7-9? I'm curious if a smaller fuel pump like the Walbro 255 would fit in it. According to the Radium website they have a list of pumps that are compatible but the smallest is a 340 lph AEM and even that is overkill for my build.

 

Following along as considering this for my V, if 340 is the smallest radium says, I would just go with the recommendation.

 

The 340 is the dimensions as a walbro 255

 

Yeah I'm kind of in agreement, I just have no need for a pump that big and I have no desire to upgrade my FPR or fuel return to avoid problems with an unnecessarily large pump. But I will install whatever to get a pump hanger that does not require me to drop the fuel tank to install another fuel pump again.
I've seen pictures and they look pretty close. The Walbro 450 is also the same length as a 255, just wider (from the looks of it). But I can't for the life of me understand why Radium wouldn't test fitment for probably the most popular pump installed on the Evo. FWIW I contacted them to ask and they gave me a stock answer about not being able to test compatibility with every single pump. Pretty lame.

 

The AEM 340 and Walbro 255 are externally identical. That was the while point of the AEM 340 pump. That was the "standard" pump pattern for a ling time before the shorter EvoX style pumps and fatter base Walbro 450 style pumps came out. Theres no need for radium to "test fit" a walbro 255...

 

There are two AEM 340 lph pumps that exist with different dimensions, the one that Radium lists as being compatible is noticeably larger than the other (which is the one commonly used in the Evo 7-9). I assume you are talking about the smaller one.

https://www.my4dsc.com/aem-50-1220-v...e85-fuel-pump/

 

If it uses the EvoX pattern pump, just put single aem 340 in it and run it. You're way over thinking it.

 

Maybe. Would you say I need to do the battery hardwire for a pump that size or is the stock wiring okay?

 

if you do the radium hanger you might as well hard wire the pump

 

From what I have read here, if you do the hardwire you're more likely to have FPR overrun at idle/cruise, but if you don't then you run the chance of high current draw from the pump overheating the wire harness. Not sure which is worse/more likely.

 

On an 8/9/X the wiring is adequate for pump gas with an AEM 340. Idk about a 1-6

 

Just to update this thread for the record:

1) It is common to overrun your factory FPR with a hardwired fuel pump. Even on pumps as small as 320/340 lph this seems to be common on any build still using the stock FPR. This is probably because of the bypassing of the stock electrical system which undervolts the fuel pump at idle/cruise. There are ways to maintain the factory undervolting system using a switching system or you can try to replicate the system using a Hobbs switch to lower voltage at low boost pressure. None of the commonly used hardwire systems (STM/Radium/etc.) use these systems however, so if you hardwire without trying to maintain the factory undervolting you should be prepared to replace your factory FPR and fuel return system.

2) The maximum current draw for an AEM 340 is going to be significantly higher than the factory Evo fuel pump, about 15A vs about 10-12A. The Walbro 255 is closer to the stock pump's current draw.
https://www.roadraceengineering.com/...pflowrates.htm
https://www.efisystempro.com/image/c...PqyB7PeAKmib6b

3) I haven't seen anyone post of fuel pump wiring damage with a Walbro 255, but it seems to be something that does happen with larger pumps with greater current draw. It's not a problem that's unique to the Evo, this happens on many cars when you go big on the fuel pump.
https://www.evolutionm.net/forums/ev...l#post11401857
https://www.evolutionm.net/forums/ev...s-evo-8-a.html

4) Given the above you could probably use factory wiring information (gauge and length) to calculate the exact amp draw limit for your fuel pump at which you should not use factory wiring, but my assumption is that it is in the 15A region give or take a few amps, right about where the AEM 340 is at higher demand.

Feel free to correct me on any of this, I've looked at a bunch of older threads here and elsewhere and I'm summarizing so maybe I am leaving out important things or missed something.

All that being said I think I am going to get the Radium hanger and try installing a Walbro 255 in it. The 255 isn't a huge investment and maybe it'll help someone else. These hangers are going to be popular among older gen Evo owners even at stock power for the sole reason they remove the asspain of having to drop the fuel tank to replace the pump.

 

To install this don't you still need to drop the tank on a V or VI ??
Can a 255 do E85 ?, I will be going to flex fuel when I am ready for this kit.

 

You will still need to drop the tank for the hanger install but after that point if you need to replace the fuel pump you won't need to do it again. There is a great video on youtube from a channel called Uzumaki Garage that goes through dropping the tank.

Walbro 255 is pump gas only, no E85.