M35 Fuel Pump

[conan7772]

I'm really enjoying driving around in this and especially the near dead silence within the cabin, all except for the exhaust of course which I don't mind.

Any know the flow rate of the OEM fuel pump and it's awkw capacity ?

Really don't want any pump whine if I can do without it.

cheers

[joshm35]

Put it under the car

[Daleo]

I hid mine in the fuel tank.

[Brick]

I hid mine in the fuel tank.

You sneaky bastard

[Ben C34]

Pull the fuse.

[conan7772]

wise guys hey

[joshm35]

Get a midget in there with a bike pump

[Reprieve]

Iv had the dw300 deatschwerks pump in tank and a walbro 255 in tank, The walbro is just a little louder the DW. The DW only lasted 2.5ish years

[datmoo]

Iv had the dw300 deatschwerks pump in tank and a walbro 255 in tank, The walbro is just a little louder the DW. The DW only lasted 2.5ish years

Isn't it spelt doucheworks? Sorry, I couldn't help myself.

[BoostdR]

I'm running a RACEWORKS 340LPH E85 Safe pump in the std housing. Small amount of filing to the bottom cradle cap clip holes to lengthen the assembly. OEM wiring with 20A fuse.

*needed direct 12v to initially purge the pump

[scotty nm35]

So they fit in Matt? I saw they were longer and would require cutting compared to the Walbro.

Did you run a direct power feed? I doubt the Raceworks/Proflow/Chinese e85 pumps will like the low voltage on idle/cruise for long.

[BoostdR]

No they don't fit easily but are do-able.

What I think is a small amount of mods would not be as easy for the average enthusiast, I'm sure you would have no issue's scotty.

They are definitely longer which is why the bottom assembly cap required modifying to enable the assembly to clip together with the pump installed. The original pump rubber bottom cap doesn't fit, I used some less density rubber provided with the pump which takes up less space. The plug is required to be rewired, the bottom keyways and fuel filter captive washer post need shaving. OEM fuel filter is a little loose, now held on by the assembly bottom cap and foam.

It did require a 12v direct feed initially to enable the pump to purge. Haven't had any other issues, flow at idle voltage was ok. I asked about running OEM low voltage prior to purchase and was given a green light as the windings are different in these pumps compared to others...possibly why it is physically longer. I suspect voltage during cranking to be reasonably low anyway...food for thought.

Time will tell if it remains reliable, it's only been in for a couple of weeks.

Comes with a 2 year warranty

[conan7772]

Ok, So I've got a Walbro 255 sitting on my shelf still.

Is it still worth installing it if I choose not to tune ?

I'm looking at everyone's dyno results and the peak power it way too late for what I want.

I guess that's part of auto transmission.

[joshm35]

Sell it to me

[scotty nm35]

Ok, So I've got a Walbro 255 sitting on my shelf still.

Is it still worth installing it if I choose not to tune ?

I'm looking at everyone's dyno results and the peak power it way too late for what I want.

I guess that's part of auto transmission.

Your stock pump is 15 years old, I know I would be changing it... It will require decent wiring, a fuse and relay to install properly, Walbro pumps don't like the low voltage supplied during cruise and idle.

Just remember, peak power in some cases might be almost triple the stock power and 30+psi, most highflows would still outflow a stock turbo by around 3000 revs. Plus when looking at the curve, having the torque converter locked Vs unlocked makes a fair difference. In manual mode it's trying to lock, in drive it is unlocked. All my results are skewed to look laggy, as the converter is locked, where as I drive on the street with the lockup clutch disconnected for better response and gearbox longevity.

[conan7772]

thanks Scott, great explanation there.

My main question is, assuming I'm running 19 to 20 psi with the Walbro installed, will the stock ECU keep good AFRs ?

[conan7772]

I've been told the factory maps only go up to 17psi, so any more, will the ECU keep tune or just dump fuel ( protection mode) ?

[scotty nm35]

Well, other than the MAP sensor boost cut, the rest is based off airflow, so every car will be different. Bump up the boost and see how she runs, shouldn't be too hard to find the sweet spot.

If you are running a highflow, that boost level may be less than stock.