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Supercrown
25-05-11, 10:18 AM
Hi guys

Anyone know much about fuel pump upgrades for the TD42?

Iíve currently got the wastegate clamped shut on the truck and have wound the fuel screw in to the point where I have had to wind the idle adjustment right out to keep the revs at idle down.
It will make just over 22psi under heavy load Ė but of course the limiting factor in a diesel is the fuel flow Ė itís not the same as running 22psi in a petrol motor.

It goes pretty bloody well, but now I want to start leaning on it good and proper.

From here I believe I need to begin modifying the fuel pump.

In addition, as I wind more fuel into it, the EGTs will go up, so I figure some water injection may be the go to drop the inlet charge temp and hence EGT. Anybody done WI on a diesel to combat EGT?

nine2nine
25-05-11, 11:11 AM
It is a GQ or GU fuel pump? Factory turbo or not?

Supercrown
25-05-11, 11:46 AM
GQ, non turbo from factory.

nine2nine
25-05-11, 12:01 PM
I nice upgrade might be a GU fuel pump then. They have a 11mm plunger instead of a 10mm plunger and a fuel limiting diaphragm that limits fuel at low boost allowing you to run heaps more fuel without any overfuelling off boost or at low boost. I think the GU pump is good for an extra 20-30rwkw from memory.

If your real serious you can rebuild your pump to take a 12mm plunger, but i know very little about this.

Adding water is much the same as a petrol, you can keep adding it until it starts to run rough, then take some out.

myliberty
25-05-11, 12:18 PM
Look at exhaust manifold pressures also. Might need a bigger turbo.

Do you know what egt you are at now at full load?

You might have 22psi, but if you have 60psi in the exhaust in order to make it, you're doing it wrong.

myliberty
25-05-11, 12:20 PM
and as above, go straight for a 12mm pump rebuild with matched injectors and you'll always have enough fuel.

Supercrown
25-05-11, 12:35 PM
Haven't taken any backpressure readings as yet - but the turbo is a bit oversized and is pretty lazy coming on compared to a factory set-up.

Up till this stage I've only been lightly messing with it, but now intend to get a pile of data and go from there.

Intersting - a bit of web research suggests that a 50/50 meth/water mix can result in better overall combustion and more power (the methanol assists the diesel burn similarly to LPG injection)

So I go for a GU pump + the 12mm plunger mod then?

What does 'matched injectors' mean for a diesel?

nine2nine
25-05-11, 12:42 PM
You can put the larger plunger in your current pump, but you really need the boost compensator otherwise it will pump out serious black smoke until its on boost.

What year was the engine built? Aparently from mid 93 to the end of the GQ's, they put holes in pistons with only moderate EGT's. If its before, then your good to go.

Is it intercooled yet? Putting the FMIC on mine made a massive difference to its top end pull.

Supercrown
25-05-11, 12:53 PM
Yeah - it's got an RX7 topmount and a GU scoop.

http://img263.imageshack.us/img263/236/p4300008a.jpg

It's a '90 I think, so has the heavier pistons.

Haven't had an EGT probe on it yet, next job is fitting a permanent EGT guage.

There seems to be one school of thought putting the EGT in the dump pipe, and one of putting it in the collector. I would have thought the collector is the correct spot.

nine2nine
25-05-11, 01:01 PM
I have mine in the exhaust manifold just before the turbo. Much better, responds way quicker and it much more accurate as each turbo will lose a difference amount of heat through the turbo. 700 degrees before the turbo and you're sweet.

Putting it in the dump is just easier, as most aftermarket dumps come with the fitting.

This is the gauge i have and its awesome, easy to read at a glance, fits anywhere, and will go up 100degress in a second if i blip the throttle.

http://www.auberins.com/index.php?main_page=product_info&cPath=5&products_id=139&zenid=1b6cf09cc9e005f44cef75787b6a1210

nine2nine
25-05-11, 01:08 PM
And this is the sensor that goes with it

http://www.auberins.com/index.php?main_page=product_info&cPath=3&products_id=69

Just have to tap a thread and screw it in.

Supercrown
25-05-11, 01:36 PM
Fuck me that's cheap.

I'll be fitting one of those to the Crown as well.

Cheers brother!

bigmuz
25-05-11, 01:49 PM
Dunno if backpressure hurts a diesel like it does a petrol engine given that pumping losses are already huge from the compression.

I never understood why once you hit a certain point on the fuel screws the idle wouldn't come down- like there is a limited range in the fuel rod or something?

JZK25
25-05-11, 02:27 PM
Pretty sure exhaust manifold pressure is not going to be a problem with that manifold and exhaust housing.

myliberty
25-05-11, 02:38 PM
I just bought 3 of those gauges for mine. EGT, Boost, Head temp.
*edit: and they arived in the post today :D

Get them in kits (sensor and gauge together) here: http://www.auberauto.com/

Compressor looks small to me, but if your EGT's are good with the pump wound right up then you just need more fuel to get more out of it.

Supercrown
25-05-11, 04:05 PM
So - is it correct to say that the biggest issue with diesel engines keeping the EGTs down?

Provided I can control EGT, I can continue leaning on it?

The turbo on it is from a diesel generator - the compressor side is about the right size, bit the exhaust is a bit big. To combat the lag I just blanked off one of the turbo split pulse entries, and it brought the boost threshold right into the sweet spot for the converter.

Once this turbo blows I'll go for something with a bigger compressor (GT30-35 size) and a small hot side.

Looks like a GU fuel pump is the go too.

nine2nine
25-05-11, 04:38 PM
That would be correct.

These motors are meant to be reliable as daily drivers with up to 200rwhp, so you got a fair bit to play with. If response wasn't a massive issue a gt3076 with a 12mm pump would be ideal.

I think getting a pump rebuilt with a 12mm plunger and the injectors set to suit is around $2k if you price around.

A stock GU pump is good for around 150rwhp on 33's, and GQ pump around 120rwhp from memory.

myliberty
25-05-11, 05:31 PM
with regards to injectors, all they do is clean them and set the opening pressure.
it's important to match the whole set in terms of opening pressure.

GU turbo pump will give you less/no smoke off boost.
If you don't mind a bit (lot) of black smoke while it spools up, then GQ pump will be fine.

bigmuz
25-05-11, 11:48 PM
EGT relates directly to the temperature of the exhaust valve and seat and turbine and therefore is the critical number.

If it is too hot- you blow more air in to make it cooler. Sounds trite but I believe that it is a very reliable treatise.

Cplus
26-05-11, 12:08 AM
i didn't actually realise you were messing with this you nutter :)

vet 180
26-05-11, 05:07 AM
water meth on diesels works better than in petrol motors due to the way diesel and meth ignites. the td42 is the perfect motor to give it a crack on. I wouldn't recommend it for anything that blows head gaskets easy.

Supercrown
26-05-11, 11:00 AM
EGT relates directly to the temperature of the exhaust valve and seat and turbine and therefore is the critical number.

If it is too hot- you blow more air in to make it cooler. Sounds trite but I believe that it is a very reliable treatise.

Yeah - that's exactly my logic for allowing it to feeboost.

My theory is -


clamp gate shut to allow to freeboost

Wind up fuel pump till I run out of idle speed adjustment (idle screw is right in now - idle arm is resting directly on idle screw stop)


This means system makes as much boost as it can, which means as much air as possible is running through the motor for the given fuel flow, which should keep the EGT down.

The power it makes should be same as if I actually had the boost capped - (as in a diesel, the amount of fuel is directly what governs power, but the additional air keeps the mixture lean and cool), but the EGT should be lower.

(on diesels, when you get near stoichometric is when the EGT skyrockets)

QUALIFIER : If I put a thread asking how to rebuild a diesel in the next few weeks howerver, my theory may not have been quite correct.

Supercrown
26-05-11, 12:21 PM
Looking about, a GU pump is up to $2k.

I think that a nigger rigged LPG injection system is likely to be massively cheaper.

Go go Macguyver LPG system.

15UZU
26-05-11, 09:32 PM
word of warning from someone who`s been there and done that, after leaning on the smoke screw in the pump,when you first start the engine afterwards have an intake pipe off and something clean,strong and non bendy (i use a bit of 7 ply wood) within arms reach- safest way to play is with the engine idling and bit of wood handy to choke the engine if the pump starts to run away.

you`ve been winding the smoke screw in,and using the idle screw to bring the rpm back down,right,
if you lean on some smoke screw too hard you can usually get an engine to "run away" on the pump (dump bucket loads of fuel in and free rev),and if your not in the cabin,or have a turbo timer fitted in a cunty spot,you won`t be able to kill the engine before it hits about 1 bazillion rpm.

have a block of clean wood handy and spin the screw with the engine idling,when you run out of idle adjustment,back the smoke screw off a bee`s dick and lock it there.. if it runs away,block the intake. it`ll smoke like a bastard but it`ll keep the rpm down a bit and eventually choke the engine to a stop.

hrt5l
26-05-11, 10:41 PM
Looking about, a GU pump is up to $2k.

I think that a nigger rigged LPG injection system is likely to be massively cheaper.

Go go Macguyver LPG system.

There was a gu pump on patrol 4x4.com for $1k, probably sold now but they come up every so often

vet 180
27-05-11, 04:02 AM
How much does it cost to do the 12mm upgrade out of interest?

Supercrown
27-05-11, 10:34 AM
word of warning from someone who`s been there and done that, after leaning on the smoke screw in the pump,when you first start the engine afterwards have an intake pipe off and something clean,strong and non bendy (i use a bit of 7 ply wood) within arms reach- safest way to play is with the engine idling and bit of wood handy to choke the engine if the pump starts to run away.

you`ve been winding the smoke screw in,and using the idle screw to bring the rpm back down,right,
if you lean on some smoke screw too hard you can usually get an engine to "run away" on the pump (dump bucket loads of fuel in and free rev),and if your not in the cabin,or have a turbo timer fitted in a cunty spot,you won`t be able to kill the engine before it hits about 1 bazillion rpm.

have a block of clean wood handy and spin the screw with the engine idling,when you run out of idle adjustment,back the smoke screw off a bee`s dick and lock it there.. if it runs away,block the intake. it`ll smoke like a bastard but it`ll keep the rpm down a bit and eventually choke the engine to a stop.

Cheers.

Yep - you are describing exactly what I've been doing (minus the wood and running away bit obviously)

I shall make any adjustments from here carefully then (with the intake pipe off and wood in hand) - although I believe I'm at the limit of the pump as it is - any additional fuel screw and the idle RPM will be too high.

15UZU
28-05-11, 10:59 AM
don`t get me wrong,i`m not saying its definatly going to happen,just be aware it can.

an associate of mine wouldn`t listen to my advice when he was hotting up his old mans tractor (long story, don`t ask), anyhoo, he maxxed the smoke screw with the engine off,hit the key and the revs went through the roof straight away,i`d decided to stand next to it and be ready to flick the fuel cut lever on the pump,having an expectation of what was about to happen.

after the brown pants moment, he listened.

TTerror
06-06-11, 10:27 PM
Can anyone explain why diesel pumps are so expensive and why building them seems to be a bit of a black art here in aust?

myliberty
06-06-11, 10:41 PM
cause there aren't a lot of tractor mechanics about, and the ones that are good are busy fixing tractors.

da9jeff
06-06-11, 10:42 PM
my guess is: high pressures = tight clearances = not alot of room for error. So you pay a bit for a bloke that knows his shit.

bigmuz
06-06-11, 10:58 PM
Cause you can't log mixtures like with petrol and you have to modify a really complex mechanical system to alter the amount of fuel it delivers for a given rpm and throttle opening and boost.. And if you dyno it and it isn't right you have to pull the whole ting to pieces and modify some tiny ports and slots to make it better..

15UZU
07-06-11, 01:08 PM
can log mixtures by EGT probes in each runner of the EX manifold,great way to fine tune

mechanical injector pumps are pretty easy to understand once you get you head around how they work, but yes lots of fine tolerance expensive bits to fix if bad shit happens

Buco_73
07-06-11, 02:23 PM
I have been messing with several diesels of late. And loads of fun.
Try this, setup a regulated electric fuel pump feed to the diesel mechanical pump. Start with 5psi and test. Heaps of guys do this shit in the US and it works. Just don't go nuts on the fuel pressure, start off slow and work your way up. Some nutters run 70psi. I've been wanting to do this on my setup, but at 17psi have plenty of fuel left. My issue is I can't get any more boost eve with waste gate fixed shut, turbo is too big for engine. RB20 turbo on a Navara TD27.

http://www.parleysdieselperformance.com/products/fass-hd-series-220-gph-high-performance-fuel-delivery-system-for-2008dash2010-ford-6dot4l-powerstroke

bigshipengine.jpg
07-06-11, 06:58 PM
So what do you do Buco, leave the electric "Booster" pump running all the time or have it set to operate at a certain load point or boost pressure etc?
If its running all the time dosent it mess with the normal fueling when the extra fuel isn't required?
Trying to get my head around it.

Buco_73
07-06-11, 08:10 PM
Good question. With a turbo mechanical diesel pump, I'm sure you can take enough fuel out with the electric running all the time and the boost compensator will do the load (turbo boost) fueling.

Now you bring up a great point I did not think of with a NA mech pump, would be interesting to have some sort of rising rate reg or variable voltage on the electric pump.

So you could have the elec pump run on minimal voltage and adjust the mech pump so you are not chugging fuel for no reason, then as positive mainfold pressure could could have full 12V to elec pump with pressure reg or both. Would be interesting to setup and test with low tech methods. Less shit to go wrong.

Wow, we are going back in time 15 years or so, when turbo fuel enrichment was a black art...lol

"Put a hob switch on it mate.."

nine2nine
07-06-11, 08:45 PM
Mechanical pumps have a return line, so the excess fuel just gets returned to the tank. The electric pump is just to make the pump life easier as it doesn't have to draw fuel, but instead has positive pressure.

Buco_73
07-06-11, 09:21 PM
Mechanical pumps have a return line, so the excess fuel just gets returned to the tank. The electric pump is just to make the pump life easier as it doesn't have to draw fuel, but instead has positive pressure.

Not quite a true fuel return. The fuel return in a diesel system is called a "leak off" and "over flow". The fuel that is returned is used to lube the injector moving parts hence the little low pressure return line off each injector and the pump housing. And is a small amount compared to a petrol setup.

Increase in pressure at mech pump = increase in fuel amount. Volume displaced is the same, pressure is greater hence more fuel. No different to a petrol EFI system. Rising rate reg with boost = more fuel. It is just crude and a global fuel trim.

You can also get your injectors high flowed. I was going to get mine done, but at the time I was told the TD27 injectors are the same size as the QD32. 2.7L = 3.2L, and my mech pump would supply plenty of fuel even for the QD32 boosted. So did not bother.

bigmuz
07-06-11, 10:38 PM
Correct- the bleed is a mechanical orifice so squeezing fuel in may help.

It may also piss fuel everywhere and create a trainsmash/ debacle.

jellis
08-06-11, 01:48 PM
this intrests me.
i have just rebuilt my 4jb1t out of an isuzu mu and wondering what mods i can do.
I have got 3 inch pipe waiting to go on it,
she was running 16psi before the rebuild just not sure how much boost it would be able to handle, fuel screw was played with a bit but propaly not enough.

15UZU
08-06-11, 10:48 PM
hobbs switches can be a bitch to set up,

i`ve got one of these to go on the hilux when
i bolt the monster pump on when it (eventually) arrives
http://www.fassride.com/shop/fuel-pumps/adjustable-fuel-pumps.php

also, with some mechanical pumps, its easy to change the relief spring and valve ( VERY exact sized ball bearing) to fuel it up a bit. not one for amateurs tho

ls400x
09-06-11, 10:12 PM
I think the lift pumps give best results on pumps with worn internal vane pumps, or, where there are leakes in the line between tank and IP allowing air to be sucked in. The vane pump is a positive displacement pump so the lift pump should not cause a great change.

for VE style IP pumps have a read of: http://legionlandrover.com/manuales/tdi%20tunning%20instructions

ls400x
09-06-11, 10:21 PM
Also, massive changes to the IP inlet pressure due to lift pumps may give changes to pump timing as this is related to thepressure after the vane pump, which is also a function of shaft speed.

In short, big IP inlet pressures may artificially advance the injection timing.

ls400x
09-06-11, 10:29 PM
Increase in pressure at mech pump = increase in fuel amount. Volume displaced is the same, pressure is greater hence more fuel. No different to a petrol EFI system. Rising rate reg with boost = more fuel. It is just crude and a global fuel trim.



I'm not sure that is entirely correct as the fuel is an incompressible liquid and the pump is positive displacement, pressure is developed by the resistance to flow.

x
10-06-11, 08:15 AM
I'm not sure that is entirely correct as the fuel is an incompressible liquid and the pump is positive displacement, pressure is developed by the resistance to flow.

Beat me to it.

Isn't diesel not compressible?

ls400x
10-06-11, 09:38 AM
I couldn't find a copy of the Bosch VE injector pump technical overview .PDF but it's worth a read to.

Outerlimits forum has some good discussion on td42 IPs involving people who work on IPs for a living. The vw diesel forums also have good information because the older ones used VE pumps.

Ih8mud forum, also some good applicable theory.

ls400x
10-06-11, 10:01 AM
Beat me to it.

Isn't diesel not compressible?

Incompressible, yes. The result of more delivery pressure cannot be compared with a petrol engine. At some nominal load the IP will deliver x volume of diesel to the injector, the resistance to flow of the injector will determine the line pressure. In a petrol engine for x injector open time, the volume passed will be determined by the line pressure that is set by the regulator.

As an analogy think manual grease gun, it's going to deliver say 1g of grease per pump regardless of it's inlet pressure or what it's attached to, assuming no air is mixed in and no leakage past the piston.

Buco_73
16-06-11, 10:13 PM
Both petrol and diesel are considered incompressible fluids. Engine oil is, so is brake fluid. But they all operate a various working pressures that vary greatly. Even at zero pressure (rel), they are at atmo pressure.
So a diesel fuel injector opens at a predetermined pressure, if we increase the total working pressure of the system, basically what we have changed is the injector open time. Basically if at pressure X the injector opens, we need to supply a fuel pressure of X+1 to deliver enough fuel for combustion and injector will close once the pressure drops to just bellow pressure X. If we increase the pressure to X+2 the injector will be open for longer and deliver more fuel. Given that volume flow is a function of pressure, more fuel is being injected.
Diesel mechanical pumps control volume and duration not timing. Timing is static. The counter weights (governor) determine the fuel volume at rpm (mapping). We are talking about a very basic system here, no high tec gear. Unthrotled operation where only additional fuel allows the engine to rev up. Only the new electronic systems with common rail setups vary the injection timing dynamically.
Correct me if I'm wrong.

Supercrown
16-06-11, 10:58 PM
Yep - all liquids can be considered incompressible for practical purposes.

ls400x
18-06-11, 08:10 PM
Both petrol and diesel are considered incompressible fluids. Engine oil is, so is brake fluid. But they all operate a various working pressures that vary greatly. Even at zero pressure (rel), they are at atmo pressure.
So a diesel fuel injector opens at a predetermined pressure, if we increase the total working pressure of the system, basically what we have changed is the injector open time. Basically if at pressure X the injector opens, we need to supply a fuel pressure of X+1 to deliver enough fuel for combustion and injector will close once the pressure drops to just bellow pressure X. If we increase the pressure to X+2 the injector will be open for longer and deliver more fuel. Given that volume flow is a function of pressure, more fuel is being injected.
Diesel mechanical pumps control volume and duration not timing. Timing is static. The counter weights (governor) determine the fuel volume at rpm (mapping). We are talking about a very basic system here, no high tec gear. Unthrotled operation where only additional fuel allows the engine to rev up. Only the new electronic systems with common rail setups vary the injection timing dynamically.
Correct me if I'm wrong.

You could be right but I'm not sold on your theory. The way I see it is that the shot delivered to combustion chamber will be near enough to the displacement of the plunger.

I wish I had a copy of the VE operational literature at hand. From memory combustion event time is fixed, therefore injection has to advance as engine speed increases to get peak cylinder pressure occurring at the correct crank angle. This is achieved by cam plate or follower (probably follower, I cant remember, it sounds more practical) controlled the body pressure of the IP determined by the vane pump and regulating valve. I would say that the pump controls injection volume and timing and the duration is only determined by the engine speed and cam plate.

I'm not sure how the timing is controlled further on the td42ti pumps.

bigmuz
18-06-11, 08:30 PM
Buco is wrong. Supplementing the input pressure will only increase the output a small amount.

The pump outputs a fixed chamber of fuel per injection event and increasing the pressure of the fule into the pump won't increase the amount of fuel in the chamber as fuel is incompressible. It would remove any air bubbles or pumping losses into the chamber but these are almost zero unless something is broken.

You also need to read up on diesel injectors Buco- they are simply a valve with a preset pressure that they crack off the seat at to then inject fuel through a very small orifice in a very fine mist. They aren't involved at all in determining injection quantity or timing.

bigmuz
18-06-11, 08:34 PM
To increase the amount of fuel you need to increase the stroke of the pump or the size of the chamber. Once you set the pump to it's maximum stroke you are out of easy solutions.

Big truck diesels use buttons in the pump to decide how much of the stroke you have available based on hp requirements and how hard you want to run the things. In a low duty thing like a ferry or local truck you would only use half the possible stroke to stretch maintenance and reduce fuel usage. In an interstate truck you would use more of the pump to try and keep your average speeds/ driver happiness up.

So there are engines rated at 350 hp and 500 hp that are identical other than the pump settings.

bigmuz
18-06-11, 08:36 PM
In fact the paxman diesel in the state rail xpt I used to work on was rated at 2500hp but you could have that engine in a patrol boat rated to 5500hp with only a pump mod and a few hundred extra revs.

Buco_73
19-06-11, 03:12 PM
I see, the vane pump pressure controls the timing and the governor controls the fuel mapping. Asked a few diesel guys and was told that a TD27 has a fixed injection timing. According to them the counter weight governor maps the fuel curve and that there is no timing control. Interesting. So I see that so called experts don't seem to know as much as they assume they do.
So can the timing be remapped?

ls400x
19-06-11, 08:21 PM
This should answer some questions.

http://etc.gnarlodious.com/Vanagon/Bosch_Pump/Bosch_VE_Pumps.pdf