dual 255's or single 450 walbro
 

Rigth now.. im between these 2 setups... i will use 93oct low boost and VP fuel (q16) for high boost... i want 600-650 hp on high boost...

The single 450 walbro will do The work for the 93 oct and high boost ?

Or i need dual 255's?

single

450 no question. 255's are too ****ing loud.

So With a single 450 i can archieve 650whp without problems?

single 450! good for 900hp

On pump gas you should be able to achieve that without issue. I am using a 450 with a fp red on ethanol, but i dont like how they draw so many amps. Its starting to melt my 30amp relay, so im going to go to 10G wire on a 40amp relay.

Does this pump just drop in or do you need a custom fitment? What about the OEM FPR, is it overrun or does it handle the extra fuel?

Thanks!

I'm in the same boat as you so I bookmarked this a while ago.

https://www.evolutionm.net/forums/ev...evo-8-9-a.html

I think I saw Buschur say something along the lines that an OEM FPR and rail is good to 700 whp. Could be wrong though....

The factory return line is the problem. It is simply too small to drain the extra fuel. An aftermarket FPR can't fix this.

But then again, this pump cannot deliver anywhere near its full capacity with factory feed/return lines or the flimsy factory power/ground wiring.

To be on the same page here, quoted hp figures of U.K DynoDynamics and Mustang Dyno U.S, of 560whp or 700 flywheel aproximate hp, is very do-able on single 400 walbro fuel pump even if you use ethanol, 450 is an overkill and as previously stated the main issue is the stock lines as pushing a properly done setup of 1000hp cabability on stock fuel lines on the above specific dynos one will reach to the inevitable conclusion that at around 750-800hp flywheel power lies serious insufficiency of fuel , especially on ethanol, thus the excess flow of a 450 walbro goes to waste.








Marios

So what you recommend ? Im confused rigth now

The single 450 pump (Walbro 267) will suffice in your setup with decent headroom if you upgrade the wiring and preferably the fuel lines (both feed and return) as well.

I only made 613hp on E85 with a single 450. Pump was close to maxed out. chamelieon has achieved high hp with a single 450 using a wire upgrade as mentioned. Without wire upgrade you'll need dual pumps, either one external and one inline or Busher's double 255 setup.

The issue isnt power, its overrunning the regulator to me that is the issue. A stock 450 isnt better than dual 255s in parallel anyway, it requires lines and a regulator as Ted has pointed at least twice, and it still flows less.

When you math it out the 255s are still a better deal and drive better with less other mods.

Hardwiring either 400 or 450 walbro is needed for peace of mind. Although I am sure there are setups out there that have done 650 flywheel on pump fuel on the above mentioned dynos without hardwiring the 400 walbro pump, but in order to take full advatntage of the cababilities of the above pumps and for peace of mind as I said it is better to hardwire them.



To make things clearer to those who have not understood my stream of thought, around 800 hp ( i repeat quoted figures are of the specific dynos) is possible on stock fuel lines on pump fuel or other oxygenated premium high octane fuel, on a hardwired 400 or 450 walbro, with the second being able of even more. Above 700hp one needs to change FPR and fuel rail, and above 800hp fuel lines also.


If one just drops in the 400 walbro he can do on a properly done setup around 680-700 flywheel hp on pump gas or any other fuel equivalent apart from corn juice-ethanol or a combo of the two such as the E85, even if he uses the stock FPR and stock lines.






Marios