240: IPD High Output Pre-Pump

[VolvoScout]

Is there any advantage in getting the IPD High Output Pre-pump Upgade Kit for a stock B230F?
(https://www.ipdusa.com/products/5799...lvo-Ipd-111016)

Or does it make more sense to just get the regular pre-pump?
https://www.ipdusa.com/products/5993...3507436-101250

[lookforjoe]

On stock setups that have a pre-pump and external main pump, there is zero benefit to running a higher output in-tank.

[RoadRacer4Life]

I'd personally go with the high output pump.. the stock pump is a very weak pump and prone to failure.

[lookforjoe]

Originally Posted by RoadRacer4Life

I'd personally go with the high output pump.. the stock pump is a very weak pump and prone to failure.

Given the age of the cars, any stock part is now prone to failure That alone is not a rationale for higher output on a stock setup. Given that the parts he is referencing are aftermarket, not even OEM supplier, who knows how long they will actually alst.

[oldschoolvolvo]

Originally Posted by lookforjoe

On stock setups that have a pre-pump and external main pump, there is zero benefit to running a higher output in-tank.

I agree (for a stock n/a LH2.2 / 2.4 setup).

Anecdotally...I am using the high output pump with a Kjet main pump without issue, but this really moves way more fuel than is needed for a n/a LH setup, I believe it starts to aerate / heat the fuel when the tank gets low.

[the_hairy_baboon]

I have a 1983 245 Turbo where the pre-pump only works when you hit it, but currently the flexible outlet hose is cracked so needs replacing. Thinking of replacing the pump as well, but what's not clear is whether the upgrade kit has to use the short bit of black hose or whether it can take the flexible outlet hose which is designed for more flex.

It seems from the instructions that the upgrade pump mounts in a different way (i.e. held in place by the hose) so needs the stiff hose to hold it there versus the stock pump sitting in the cupholder and taking the flex hose because it can twist around some when the motor kicks on. Is that the correct analysis? (Also noting the fact that the upgrade kit comes with a seal, filter, clamps...)

[2turbotoys]

I like replacing both pumps with 1 in tank pump, like a DeatschWerks DW200. I just removed the pressure pump (under car pump) and connected the fittings together. Less parts to go bad. Ya, it's more fuel than you need, but it just returns to the tank so who cares.

[Radtap]

Originally Posted by 2turbotoys

Ya, it's more fuel than you need, but it just returns to the tank so who cares.

Future proofing for a +t

[oldschoolvolvo]

Originally Posted by the_hairy_baboon

It seems from the instructions that the upgrade pump mounts in a different way (i.e. held in place by the hose) so needs the stiff hose to hold it there versus the stock pump sitting in the cupholder and taking the flex hose because it can twist around some when the motor kicks on. Is that the correct analysis? (Also noting the fact that the upgrade kit comes with a seal, filter, clamps...)

Yes, the upgrade pump is attached to the sending unit by the supply hose only.


(upgrade pump attached, stock pump on the right)

[the_hairy_baboon]

I ended up going with the upgrade kit but managed to keep using the holder from the original pump by letting the pickup move maybe 3-5mm further down - this gave clearance on the return pipe and also means that the new pump isn't just dangling by clamps, there's a nice sturdy friction fit on the old bracket so between it all there shouldn't be any more issues.

Chasing the bung nut off with a screwdriver and hammer is easy, but chasing it back on is much more difficult. Definitely lubricate the sender top/bung nut interface, but you really need an even rotational torque to get it to sit since the new o-rings are quite sturdy and hard to compress.

[Radtap]

The truck is wedge a flathead between the locking ring and the ring on the tank and twist to walk the ring back in position. Or just buy the tool.

[84B23F]

Originally Posted by 2turbotoys

Ya, it's more fuel than you need, but it just returns to the tank so who cares.

People who drive in warmer climates will have higher tank vapor pressure, and most likely vent more gasoline to atmosphere. Returnless Fuel Systems reduce vapor loss...and keep tank's gasoline cooler.



Return-Type Fuel Systems
A return-type fuel system is one that is designed with a fuel pressure regulator that diverges the fuel pressure based on the power of vacuum suction from the engine’s intake system.

Returnless Fuel Systems
A returnless-type fuel system is one that is designed to use the powertrain control module (PCM) to regulate fuel delivery. A fuel pressure sensor mounted to the supply rail of the fuel injectors allows the powertrain control module to keep an eye on the fuel pressure. If the fuel pressure and flow starts to decrease as a result of increased engine speed or load, the powertrain control module will make up for the drop by increasing the injector duration and/or operating speed of the fuel pump.

https://www.autorepairindy.com/blog/...-fuel-systems/

[FreeEMSFred]

I don't know about that replacement, but the stock little pump I pulled out of my 960 that was totally dead from being completely physically worn out after 200k miles or so (over 300k km) does not have a separate return line from the main pump and instead has a very low pressure bypass at the pump end such that if they feed line to the main pump is full it simply pumps it through the bypass directly into the tank.

Having said that, I replaced it with a BMW 750i in-tank pump that does not have that bypass feature and is therefore in series with the main pump helping it out and this has worked flawlessly down to being able to over fill the tank above spec by several litres :-o

The Volvo two pump system is a work of genius really - the feed line to the main pump has a large vertical descent and large internal diameter - it's a surge tank built into your car from the factory. The in-tank pump's only job is to keep that feed line full so the main pump *never* sees air.

Given the return from the rail does not go to the inlet of the main pump and does go back to the tank the in-tank pump must be able to match the main pump for flow, but at basically zero pressure (except in my case). Because zero pressure it's very little to no heat as it's a very easy job :-)

But to answer the original question: on a stock B230F - no, zero point in any upgrade, just get a replacement unless you have big plans for the car that aren't so big as to warrant a totally different fuel system design.

My 2c at 1am after working on a rebadged and totally stripped Ford with a sweet T6 whiteblock in it all day

[FreeEMSFred]

To clarify, overfilling tank by several litres = it kept running smoothly and without any hiccups until SO empty that refilling required more than the car is supposed to hold re reading my post afterward I realised that read weirdly and wasn't clear - sorry.

[84B23F]

Originally Posted by FreeEMSFred

The Volvo two pump system is a work of genius really

SNAFU (Situation Normal, All Fuc.ed Up): 1975 240 CIS came with a single external pump, which in warmer climates, vapor lock would happen, so they had a recall to install a new fuel tank with an internal low pressure pump that feeds external pump.

When fuel is sent to engine compartment, it will heat up, and then return to fuel tank. 1975 240 CIS setup had a fuel filter on top end of firewall, so it was warmed up via engine heat. If fuel filter had been relocated to underneath vehicle, like in later vehicles, this might have resolved most all heat issue.

So, with time, there was two design changes...internal low pressure fuel pump in tank, and filter relocation.

Anyone know which year they relocated filter?

[FreeEMSFred]

All that may be true, but that large ID hose to the main pump is no accident and is awesome

[84B23F]

Originally Posted by FreeEMSFred

but that large ID hose to the main pump is no accident and is awesome

Just a guess, larger ID allows any hot gasoline bubbles the chance to rise up vertically and be converted back to liquid. Function of in-tank pump was to compress gasoline for reducing gasoline bubbles. The boiling point increases with pressure

[FreeEMSFred]

Maybe except that the fuel fed to the large ID hose is fresh fuel from the tank not hot fuel from the rail, so it's highly unlikely to be boiling or even remotely hot unless the tank is nearly dry at which point you've got bigger problems.

For the surge tank effect to work the in-tank pump must out-flow the under car pump - however because the factory in-tank pump operates at near zero pressure it's easily able to flow a lot of fuel relative to its size and do just that.

When my intank pump was dead the thing would run normally most of the time but when you got on it hard it would cut out, guessing maybe it was drawing air in under vacuum with the in-tank dead as a restriction rather than helper. But either way replacing the intank with a bigger badder high pressure one worked great :-)

[84B23F]

Originally Posted by FreeEMSFred

Maybe except that the fuel fed to the large ID hose is fresh fuel from the tank not hot fuel from the rail, so

How hot does it get in Saudi Arabia?

Summers, from June to August, are hot, with daytime temperatures in the shade exceeding 100 °F (38 °C) in almost all of the country. Temperatures in the desert frequently rise as high as 130 °F (55 °C) in the summer.

Volvo Cars are sold there...


>in-tank pump....able to flow a lot of fuel

Reid Vapor Pressure for gasoline varies on what's blended, but gasoline is boiling at 100 °F (38 °C)


Well Yeah, with some in-tank pressure of 8 to 10 psi at 100 °F (38 °C), gasoline (liquid or vapor) will flow to a less pressure area.

[Marvelous3]

I put a dw200 pump in the tank of my na 240. Threw that whole under the car pump away.

[84B23F]

Originally Posted by Marvelous3

...dw200 pump in the tank...Threw that whole under the car pump away.

For a local vehicle, that's OK, but not for a vintage vehicle driven transcontinentally, or places within. Been more than one person who changed out a pump on a trip where vehicle stopped.

[Marvelous3]

Originally Posted by 84B23F

For a local vehicle, that's OK, but not for a vintage vehicle driven transcontinentally, or places within. Been more than one person who changed out a pump on a trip where vehicle stopped.

So, the red wagon in my sig has a DW300 in the tank with no under the car pump. It's been driven from Atlanta to NYC and back a couple of times. It came from Ohio to Atlanta when I bought it. I'd say it works just fine with the single pump set up.

[84B23F]

Originally Posted by Marvelous3

I'd say it works just fine with the single pump set up.

Stuff Happens - Brother in law bought new Yukon some years back, and fuel pump shot craps within several thousand miles, some 60 miles from home. Dealership picked it up.

[84B23F]

Originally Posted by FreeEMSFred

fuel fed to the large ID hose

Fuel within a metal pipe does not expand the pipe with say 10psi of pressure. But, within a typical rubber hose used, gasoline can expand the hose with say 10psi of pressure.

At 130 °F (55 °C) in an open container, gasoline will be boiling, with vapor rising. Within a rubber hose, this increased pressure can represent vapor, which rises upward in the hose.

[Kjets On a Plane]

The 2 pump thing is partly a warm weather vapor lock thing, yeah.

That said, the D-jet 140s worked pretty reliably with the gravity fed single under car pump next to the tank.

But then they moved the tank closer to the axle/farther from the back of the car & gave it an expansion chamber for the USA market in addition to the usual charcoal can (in 140s this was a mess of stinky hoses & lived in the trunk).

The k-jet cars ran at higher pressure than the efi cars ~70-84 psi, depending. The ‘74-‘76 ‘recall’ tank iirc originally had a sort of side-feed spout like the 140s (been so long since I replaced one).
Starting in ‘77 (& to retrofit the earlier cars) they combined the sending unit & lift pump & return into a baffled bucket that only lets sloshing fuel in gently (tho at the bottom maybe over hot pavement).

Some of it is a cost compromise, some of it is needing to come up with a safer tank farther from the rear of the car, some of it is higher operating pressure of the CI/K-jet, some of it is to prevent vapor lock with minimal frothing, stirring, total volume thru-put & heating of the fuel with what they had to work with at the time.
Without going to a bladder like a Prius / airplane & single pump/return-less system with digital control, they did the best they could with what they had at the time more or less?

The filter lives in the engine bay on the CI cars partly because the pump/accumulator takes up the whole under car tray, but it’s not on the exhaust side or likely there much hotter than hot pavement?

On the MBZ CI cars the tank is a above the two large external/easily serviced quality Bosch main pumps in series more like the D-jet 140s were behind the back seat trapped between layers of metal out of the cabin oriented vertically, w/expansion chamber shielded from sun or hot pavement.

This works better than the Volvo sorta band-aid lift pump + slightly overworked main pump & metal tank over hot pavement. But the Volvo wagon has a flat load floor w/tank fwd from the back of the car & solid axle too & is a cheaper simpler car that forgives neglect better in the USA market.

Turbo k-jets cars the 700T (or moral equivalent) lift pump works well & keeps the main pump from being so overworked. Don’t let the tank run low/into the red on the gauge & it’ll last indefinitely on the cool cloudy weather no hot pavement cars.
The quality of the pre-86 lift pumps or those generally in the 240s leaves a bit to be desired.
When they went to EFI on the 200 series they ran pretty low pressure (2.5 Bar vs. 3 bar from the get go on even the N/a the 700s) / keep the work load down on the engineering compromise 240 tank.

Without significantly altering the tank design, or returnless digitally/precisely controlled somehow, 2 pumps it kinda has to be for optimal operation with the CI /generally in some ways in the 200 chassis w/‘77+ style tank.

1995-only 940t uses the 850/70 style single in-tank pump in the USA market, but the tank/baffle is also different & plastique.

I still prefer gravity fed/external pump like the MBZ or 2 pumps in the 240 chassis if you’re using the ‘77+ style tank to hacking a single onto that poor sender & return line setup to really froth & stirr it up in that confined bucket/sender setup, tho.

People love to hack weird stuff into these cars or think one (especially domestic junk) pump is some great panacea tho?

Idk why Volvo even bothered offering the cars in unusually hot climates?