Hello all,

Now that I've successfully hooked up my larger turbo, and got a clutch to hold down the power, I've noticed that I'm running out of fuel. The larger turbo means I have to shift up earlier as I go up the gears, because there just isn't enough fuel. 1st maxes out over 6500 rpm, 2nd is at 6000 rpm, 3rd at 5000, and I have to shift to 5th at 4000.

So now I need more fuelling. I'm thinking of a Walbro 255 lph universal pump, and some injectors in the 650-850cc range. I have a standalone EMS, so idling shouldn't be too much of an issue. If it is, I can just use the standard injectors on a daily basis, and go big for 'special occasions'.

This is the pump I had in mind -- Fuel Pump, Walbro 255LPH Internal - 034 MOTORSPORT

... and these are some of the injectors I had in mind.

79 LB, 830cc Lucas Fuel Injector, High Impedance - 034 MOTORSPORT

Racetronix-Siemens_Injector_Sale-55h

I'm looking at these websites because they seem to be a lot cheaper than the rest, and I can always ask someone to carry them, so shipping isn't an issue.

I'm only wondering if any/all of these parts that I've found will actually fit onto my car. It's an AUM, if that helps.

Cheers and TIA

The pump is ok but the injectors look a little big. What power are you expecting?

Well, I'm now looking at 350ish whp. I've been told that any more, and I can safely bid my gearbox goodbye. My issue is that I'd rather buy large injectors now, and control duty cycle than discover that when I do get to 400 odd hp these injectors aren't enough all over again.

Be very careful running your car as it is. You will be running very lean which may cause engine damage. Most who fit a larger turbo also go for a larger MAF as well as injectors. If i were you i would look at what size injectors others who have similar power to you are running.

What turbo is it?

Well, I'm now looking at 350ish whp. I've been told that any more, and I can safely bid my gearbox goodbye. My issue is that I'd rather buy large injectors now, and control duty cycle than discover that when I do get to 400 odd hp these injectors aren't enough all over again.

350 whp is well past the standard gearbox capabilities. What turbo do you intend to use to get 350 whp?

and internals if they havent been done.....what else have you done to the car apart from strap a bigger turbo on???

Be very careful running your car as it is. You will be running very lean which may cause engine damage. Most who fit a larger turbo also go for a larger MAF as well as injectors. If i were you i would look at what size injectors others who have similar power to you are running.

What turbo is it?

I'm running a standalone EMS with its own onboard MAP sensor, so the MAF is redundant in this case. Also running an aftermarket FPR in series to bump up fuel pressure, but that barely helps. My wideband is showing around 11 at peak boost, so I'm guessing AFRs are safe enough to avoid leaning out.

What turbo is it?

350 whp is well past the standard gearbox capabilities. What turbo do you intend to use to get 350 whp?

A TD05 16G big bore.

and internals if they havent been done.....what else have you done to the car apart from strap a bigger turbo on???

FMIC, EMS, FPR, and some coilovers, though they aren't really relevant here.

Racetronix got back to me about these injectors Racetronix - L107 - 63 lb/hr Siemens High-Z Fuel Injector MT= and say I will need a 3/8" spacer or washer under the fuel rail to fit these. Does that sound about right?

Can't really spring for a new gearbox :( so I guess I'm going to have to scale power down by 10% atleast.

I guess I'm going to have to scale power down by 10% atleast.

It will quite happily throw a rod at 350bhp if it's still got the standard internals, aiming for 325-330 would work out safer

To be safe you should look to run 280-300bhp and under 300lb/ft at the fly wheel on standard internals and gear box. Your injectors are way to big for any of these applications.

a nice modern cheap 4-nozzle high impedance injector comes from the Astra VXR, good for 350bhp

Bosch Part Number 0280156280, GM Part Number 55556798

flow rate is 470cc @ 3 bar or 495cc@ 3.3 bar

Plenty on Ebay if you search for "vxr injectors", you shouldn't need to pay much more than £100 for a new set

For these standard (75mm or so long) length bosch style injectors you will need to space the fuel rail up a bit to get them in, round about 10mm from memory.

So now I'm going to scale it down to under 300 whp for the time being, let's see if it runs alright with the new injectors and fuel pump. The VXR ones seem like a good (read cheap!) idea, so I think I'll stick with them.

Anyone have any experience with the Walbro pump?

we race the TT in my avatar in a local circuit saloon car championship - the engine is essentially standard BAM (came out of a Leon Cupra Cup car) with GT3071R turbo, big FMIC and aftermarket management.

It makes 340bhp at 1.4bar on those VXR injectors and a Bosch "044" fuel pump, we hold a 7000rpm rev limit. We've done a full season of 10 races and 3 full trackdays in this spec (most of previous season with the original K04) and been problem free. We use the Leon 6-speed 2wd gearbox with a ceramic paddle clutch which has also been trouble free. We've toyed with the idea of changing to 5-speed box as it is hugely lighter, but all advice has been that we would break it.. so the 6-speed stayed.

Your build sounds interesting, turbo seems a good choice too! where did you get the manifold and downpipe in the end to fit this?

Got them custom fabbed.

we race the TT in my avatar in a local circuit saloon car championship - the engine is essentially standard BAM (came out of a Leon Cupra Cup car) with GT3071R turbo, big FMIC and aftermarket management.

It makes 340bhp at 1.4bar on those VXR injectors and a Bosch "044" fuel pump, we hold a 7000rpm rev limit. We've done a full season of 10 races and 3 full trackdays in this spec (most of previous season with the original K04) and been problem free. We use the Leon 6-speed 2wd gearbox with a ceramic paddle clutch which has also been trouble free. We've toyed with the idea of changing to 5-speed box as it is hugely lighter, but all advice has been that we would break it.. so the 6-speed stayed.

Does that Maestro Turbo still race at Castle Combe? I seem to remember it giving an Audi A4 a run for it's money a few years back. Best bit was seeing a real mini beat a chubby BMW mini! The saloon cars were the most entertaining thing to watch all day.

Do you ever race at Thruxton?

Yea the Maestro still runs on occasion and does well - unfortunately he got tangled in a big shunt a couple of months back and did a lot of damage, but was intending to put it back together. We only do the CC championship, never had the car at Thruxton sadly.