rossi_p

iTrader: (26)

Hi chaps,

I currently have the usual Walbro fuel pump upgrade on my Type R and and looking to upgrade the entire fuel system.

I have most of my ideas in place re fittings, swirl pot etc but I will be looking to run a fuel pump from a swirl pot. Most people seem to go for the Bosch or another Walbro, or maybe a duel pump setup. However, I've been browsing around and have found these rather nice Fuelab pumps.

Buy*280 l/h at 45 psi (Injection) Prodigy Fuel Pump*-*Fuel Pumps*at*GPR

Basically, I'm curious as to why I haven't seen anybody use these an an upgrade instead of the Bosch or Walbro.

Is it due to the price? Are they not compatible for some reason?

Many thanks in advance
Rossi

joz8968

iTrader: (13)

A fair question.

Probably because the Walbro is:

a) An established ubiquitous mod

b) Works fine, no hassles

c) Very cheap (should be paying no more than £90 - but can get 'em c.£60)

d) Direct OEM pattern replacement (fits in place in minutes)

e) I assume 255 l/h is more than enough fuel flow for the majority of Scoobs out there? At least up till REALLY high power applications (where you'd best move to a twin out-of-tank set-up).

After all, that Fuelab one only flows an extra 9.8% more fuel than the Walbro, but you have to pay almost £200 more for the privilege!


As you can see, the Walbro has a lot going for it

rossi_p

iTrader: (26)

Cheers for the feedback.

As far as I understand it, the Fuelab one will pump all its fuel at a constant pressure (45psi) compared to the Walbro.

I'm not debating the excellence of the Walbro, just wondering why, for higher power applications, that only the Bosch ones are used when they have the same flow rate as the Walbro (although at a constant 8 bar).

I think that on my application, I am near the limits of the Walbro so am looking into using the Walbro to feed a swirl pot and then an in-line pump (such as the Fuelab or Bosch) to move the fuel from there.

Lateral Performance

iTrader: (20)

If comparing the flow of fuel pumps, it must be done at the actual max pressure you will run.

The max pressure will vary depending on set up, but you need to add fuel pressure at atmospheric, with max boost.

On average this will be between 4.5-6bar (65- 87psi) total.

It's not uncommon for a Walbro 255lt pump to struggle on a well set up MD321T, or similar and generally, I would recommend the Walbro Hi flow kit that I sell.

The Bosch, and Fuelab pumps are very good, but overkill at these levels.


Mark.

joz8968

iTrader: (13)

Right Mark, so to work out your intended max fuel pressure, you take the pump's idle pressure at atmos (typically 3 bar), and then add your relative boost pressure. So because I'm running 1.15bar relative boost, then my max fuel pressure will be c.4.15bar? Is this correct?

Lateral Performance

iTrader: (20)

Yes, that's right. I used 3 bar + 1.5bar as a start, because that's typically where MD321's would be run from.

joz8968

iTrader: (13)

Danke.

rossi_p

iTrader: (26)

Thanks Mark,

My MD321T currently peaks at 1.7bar.

With this in mind, a fuel pump upgrade is definitely worth while.

Out of interest, how much is your Walbro high flow kit? What is in the kit?

Sc0oby

is it possible to run upgraded fuel pump without remapping yet? has anyone felt any over fueling with this situation?

rossi_p

iTrader: (26)

Not sure fella.

I'd also be interested to know if I would need to remap after changing rails, pump, fpr, swirl pot, filter, fittings and hoses.

STiFreak

iTrader: (4)

I don't think the problem will be with the mapping, but if you are still running the OE fuel pressure regulator, you might overwhelm this, which would cause you hassles.
To be honest, I am not sure if this will only be a problem if you are running greater than stock fuel pressure? Sure Mark can confirm.

joz8968

iTrader: (13)

Yes, what max fuel pressure can the OEM FPR handle, before being overwhelmed? An important question I think, as it dictates the max boost you can run using it, which would be helpful to know.

Mark?

Lateral Performance

iTrader: (20)

The factory reg' is set at 3 bar @ atmospheric, so that's the pressure it will handle.

"Flow" is the issue, where a bigger pump flows more than the reg can bypass, and in effect the fuel backs up, and pressure increases beyond the 3 bar.

This should be avoided, as it's inconsistent, and the reg' can end up failing.

If I were changing reg', pump, rails, etc', I would definitely have the fuel map tweaked.

joz8968

iTrader: (13)

Right. So taking my car, I have the 255l/h Walbro, OEM FPR and 1.15bar relative boost. Am I okay?

If I were to fit 440s and a FMIC later - I think the boost would be upped to c.1.5bar or thereabouts - then would the std FPR still be okay?

Lateral Performance

iTrader: (20)

Assuming you haven't changed anything since Simon mapped it, it should be fine !

It should be, but your mapper will be able to confirm at the time.

Sc0oby

can anyone confirm if i could run a hks gt2835 on stock 440cc injector but plans is just limit boost at 1 bar. have all the usual supporting mod at pump/power fc/front mount/exhaust.