Squeezing more power out of an already maxed out 11mm bosch pump

[Paul_13]

Need to try and squeeze more fuel out of my 11mm which has pretty much been maxxed out. It's boosting around 35psi and it's clear on boost. I've got a nice free flowing system and intercooler. 

Bits I've already done :

I've turned it back a spline on the arm
Modified the arm to allow it to travel round further. 
Idle screw is fully backed off and fuel screw to suit
Pretty harsh lda grind, plastic limiter washer removed

Just wondering if there's any other internal pump mods I can carry out. Going to strip the pump and rebuild it at some point

[bashbarnard]

Bang it back another spline. Have you actually cut the bit on the pump where the throttle limiter screws in. As youll notice itll knock against that otherwise. Cut that bit and youll get more. Can also change the delivery vanes as well. From memory i think terrano ones will also give a bit more as well. Few bits for you to think about there


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[Paul_13]

Terrano 2 delivery valves. Was going to try and get a set.
I'll knock it back another spline, see how that goes

[Paul_13]

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[bashbarnard]

Cut it off youll get more travel may have to do something about the manual cut off as well although ive never had an issue with that bit

[Piggy]

Check throttle pedal position vs arm position... I would put money on not having enough travel in the pedal to go full throttle...

especially due to the position of the cable on the throttle arm

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...not mentioned gov'nr mod unless I missed it... you shimmed that puppy hard?

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Also, about the splines, I managed knocking back 3 splines on my 11mm in the end.

You say the 11mm is maxxed out... as in, more max fuel and the revs hang?

[zx_volcane]

transit gov cradle has shorter throw on it iirc - don't have to much about grinding the pump, get more lever movement for same pedal movement.

[Piggy]

Yeah good shout

[Dave]

Delivery valves are a must, I used to use the Transit delivery valves gives heaps more fuel, you can actually grind the stock ones down too, just have a few spare incase you f*ck it.

Transit cradle, harsh Govmod, 11mm head, advajnce piston grind, you can modify the LDA swining arm inside to allow a further throw when the LDA drops, this will give you more on/off boost fuel. Grind out the inlet ports, add an extra 2 slices into the valve pump,

Have good free flowing fuel lines, and filter (probably best sack stock filter off).

There are heaps more mods you can do get at it with the grinder.

You must have a fairly heroic setup be be maxxed out with an 11mm pump, good one! Get an internal pump gauge on there so you can see what its doing - if your pump is clean it would be good to know what IPP is, and if it drops after a hard pull. Mine used to pull hard, then empty itself IPP die and have to play catch up with the fuel lines.

[darrenjlobb]

What LDA pin is in it? A totally stock pump with 11mm head and LDA pin is normally enough fuel to blow Coal from Cornwall to scotland....

[Paul_13]

[welshpug]

moving the cable clamp fitting closer to the pivot will change the ratio.

[Paul_13]

Could you elaborate on the advance piston grind please

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moving the cable clamp fitting closer to the pivot will change the ratio.

Cheers, did that last night. It catches on the stop lever. It's at a funny angle cos of the boost pipe

[zx_volcane]

Could you elaborate on the advance piston grind please

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moving the cable clamp fitting closer to the pivot will change the ratio.

Cheers, did that last night. It catches on the stop lever. It's at a funny angle cos of the boost pipe

You can remove material from one end of the advance piston to enable it to move further and gain more advance - although tbh without a test bench you don't know if you're getting full advance as it is.

There are advance piston cover spacers available off the shelf which achieve same.

Roller wear on the case can be an issue too if you push past stock and there are grooves in the pump you can wind up with the cage getting stuck.

You're in the dark though with these mods as to what you're gaining, what they're doing - without a test bench.

Same with any lever / lda mods - bit too heavy with the grinder or in the wrong place and you will loose control of idle, or smoke control ..etc ..etc

Not convinced on DV valves, don't think they're much of an issue on IDI motors.

[Chris_90]

Delivery valves are a must, I used to use the Transit delivery valves gives heaps more fuel, you can actually grind the stock ones down too, just have a few spare incase you f*ck it.

How do you go about grinding the standard delivery valves just out of intrest?

[zx_volcane]

Delivery valves are a must, I used to use the Transit delivery valves gives heaps more fuel, you can actually grind the stock ones down too, just have a few spare incase you f*ck it.

How do you go about grinding the standard delivery valves just out of intrest?

I'll bet a fiver it was with a 9 inch grinder knowing Dave

[Dave]

Delivery valves are a must, I used to use the Transit delivery valves gives heaps more fuel, you can actually grind the stock ones down too, just have a few spare incase you f*ck it.

How do you go about grinding the standard delivery valves just out of intrest?

I'll bet a fiver it was with a 9 inch grinder knowing Dave

Hehe Tom you do have more of a systematic approach to pump mods. The DVs on my first pump did make a huge difference to fuel delivery. As long as you don't kill the seat there is only gains to be had if you see how restrictive the origice is on original ones round stock DVs

[Paul_13]

Going to knock the arm back a spline and I'm off to a scrap yard on Saturday to find some Terrano delivery valves

[Paul_13]

Will unscrewing this as shown allow me to increase fuel?

[Mattcheese31]

well i'm just thinking coz that pic is back to front but yes, if the idle came down which i think it will, you can squeeze a bit more out yes

[Paul_13]

It's not back to front?!
That's the front of the pump. The stop lever is shown

[Mattcheese31]

It's not back  to front?!
That's the front of the pump. The stop lever is shown

ahh shit, there's me thinking it was the idle, thought it looked weird, in that case no, i don't think so mate, can't see why that would make a difference, wouldn't that raise it if anything? 

[Paul_13]

Need to turn the boost down its doing 45psi in 4th :/

[Mattcheese31]

Need to turn the boost down its doing 45psi in 4th :/

nice, you got uprated head studs n shit?

[Paul_13]

Yeah arp's

[Mattcheese31]

Yeah arp's

was gonna say, my tdo4 lifted the head at about 26psi lol

[Paul_13]

Just picked up the 9mm spare bosch pump I had and give it a go at rebuilding it

[Dum-Dum]

Having a look at your pics i have a few suggestions.

You still have both hot and cold idle screws, certainly the hot one can go and will allow you to add more fuel and bring the idle down.
You also still have the minimum throttle stop screw and its out a turn or 2, again, remove this entirely and again it'll drop the idle and let you bring the fuel up. Likewise you can remove the bit that hits the minimum throttle stop from the arm with a grinder so you have even further minimum travel.

I might be mistaken but your lines look like they are only 8mm, upgrade to 10mm with a proper sized filter. The outlet from the tank is 10mm on the 306.

[Paul_13]

I'll have a look at that.

10mm lines and a fuel filter off a train engine