Front mounting 306 diesel fuel cooler

[boggs]

Due to my car being stupidly low I managed to rip off my fuel cooler I am thinking of front mounting it behind the grill. Would there be any benefits of this? Could it cause any restriction due to the extra piping needed, although I didn't think restriction would really be an issue on a return line feed. Also are there any fuel cooler upgrades out of any other cars I could use while I'm there? I could even run two 306 hdi coolers as I have two spare, again is restriction an issue on a return diesel line. I have heard I can over cool diesel so that it isn't optimum temperature for performance, although it has an R70 pump as well as a 1.6 fuel pressure sensor (1800 bar) so the fuel will be hotter than usual.

Thanks in advance for any advice

[Poodle]

I can't see any problem with that, it would probably cool the fuel better thanks to the higher airflow, as you say. It would need fairly good protection mind, you wouldn't want a stone going through it on the motorway. :/

[toseland]

I can't see any problem with that, it would probably cool the fuel better thanks to the higher airflow, as you say. It would need fairly good protection mind, you wouldn't want a stone going through it on the motorway. :/

It should be fine as poodle says but care should be taken specifically regarding crash safe zones

This leaves basically in front of and behind the engine block as your options.  Possibly if you relocate the battery or put it behind the headlight on one side (drivers maybe?)

As a rule of thumb 45degC is about where you want the fuel temp. Lower will increase performance marginally and but importantly above this the performance losses will be swift and generous.

It absolutely needs to be away from the radiator as the ambient radiated temperature, as well as heated airflow past the rad will be higher than 45degrees.  Also you need to consider it cooling the fuel too much.


Depending on how you go about doing it you need to consider the ambient temperature and the affect the fuel system components have on the fuel. In the UK it will tend to have a cooling affect, whereas in warmer temps it will tend to be a heater by comparison. 

I think maybe your best bet would be to mount to the bulkhead or in front do the pedal box if you can glean enough room, be sure to ensure adequate airflow and if you notice a drop in performance then you might need to rethink the design and location

[JTaylor2005]

What is the reason behind having to have cold diesel? I would have thought hotter would atomize better in the cylinder? Or is it a lubricity thing and needing a certain thickness to keep pumps and injectors happy?

[boggs]

I can't see any problem with that, it would probably cool the fuel better thanks to the higher airflow, as you say. It would need fairly good protection mind, you wouldn't want a stone going through it on the motorway. :/

It should be fine as poodle says but care should be taken specifically regarding crash safe zones

This leaves basically in front of and behind the engine block as your options.  Possibly if you relocate the battery or put it behind the headlight on one side (drivers maybe?)

As a rule of thumb 45degC is about where you want the fuel temp. Lower will increase performance marginally and but importantly above this the performance losses will be swift and generous.

It absolutely needs to be away from the radiator as the ambient radiated temperature, as well as heated airflow past the rad will be higher than 45degrees.  Also you need to consider it cooling the fuel too much.


Depending on how you go about doing it you need to consider the ambient temperature and the affect the fuel system components have on the fuel. In the UK it will tend to have a cooling affect, whereas in warmer temps it will tend to be a heater by comparison. 

I think maybe your best bet would be to mount to the bulkhead or in front do the pedal box if you can glean enough room, be sure to ensure adequate airflow and if you notice a drop in performance then you might need to rethink the design and location

Thank you both for your replies when you say it absolutely needs to be away from the radiator do you mean just not behind it? In front of it would be fine apart from the crash safety issue? Despite the crash zones I think I'm going to front mount it if it will give me the most cooling. Also are you saying I can't loose any performance from over cooling diesel? Just power will be lost from not cooling it. I live in N.Ireland so our climate is cold nearly all year around so I doubt it will act as a heat soak but will it suffer from heat soak from being in front of the radiator. I was even considering using two fuel coolers as I have a spare so thought I may as well as long as I won't loose any power by over cooling diesel?

Thanks again both of use

[Ruan]

Pressuring to 1350bar heats it up severely, however there is a bimetallic strip thermostat in the filter housing which will stop it being sent around the fuel cooler and therefore being over-cooled.

[boggs]

Pressuring to 1350bar heats it up severely, however there is a bimetallic strip thermostat in the filter housing which will stop it being sent around the fuel cooler and therefore being over-cooled.

What would happen with the unused diesel since it won't be sent down the return route? I'm confused now

[Ruan]

Sorry, actually other way around, it selects whether the diesel is pre-heated by the coolant before entering the fuel filter housing if the fuel in the filter housing is too cool (the diesel that is cooled on it's return to the tank is the return flow from the pressure regulator in the filter housing)

[boggs]

Sorry, actually other way around, it selects whether the diesel is pre-heated by the coolant before entering the fuel filter housing if the fuel in the filter housing is too cool (the diesel that is cooled on it's return to the tank is the return flow from the pressure regulator in the filter housing)

Thanks for that information. Pretty technical for me but basically I'm guessing I can't loose any performance by over cooling my diesel on the return line? Cant is a big word actually more like I don't have to worry about loosing any performance by running two front mounted diesel coolers as I have another spare. Also again does anyone know of any cars with bigger/better fuel coolers that would be a good use. I will be using 3/8 inch pipe to put the cooler inbetween the return line as it fits tightly over the 6mm standard return line with some jubilee clips. I know this because I ripped the damn thing off and replaced it with a bit of 3/8 inch pipe. At the minute I'm running no diesel cooler could I be causing any damage or just loosing a bit of power?

Thanks again

[toseland]

No, but in the UK you don't have the considerations of extremely hot, or cold, climes.

In front would be fine..


Hotter diesel is thinner Jay which means it's also less dense and more difficult to meter..

Interesting articles published on it somewhere I'll dig for it

---

And lack of cooler means you will lose power pretty rapidly after the optimum.. provided the fuel isn't too cold then it should be fine. The minimum you would want to achieve would be about 20degrees. 45 is the optimum.

[boggs]

No,   but in the UK you don't have the considerations of extremely hot, or cold, climes.

In front would be fine..


Hotter diesel is thinner Jay which means it's also less dense and more difficult to meter..  

Interesting articles published on it somewhere I'll dig for it

Thank you again. Front mounting two HDI coolers it is then the last question this would obviously cause more restriction but does that matter in a return line?

Being N.Ireland 98% of the time its cold wet and miserable.

[toseland]

The cooler isn't particularly restrictive

[JTaylor2005]

Our Bimetalic strip opens to allow diesel through the heater. This guy on the landy forums reckons his opens to allow the hot diesel to go through the cooler on the way back to tank? If this how it's actually setup it could be possible to create an thermostat valve to cool the return diesel and an under temp valve which would open the heater. So when its too cold it goes through the heater. When the return is too hot it opens and goes through the cooler. If its not too hot it returns to tank down a normal pipe?

https://www.landyzone.co.uk/land-rover/f...rix.50748/

[Ruan]

Our Bimetalic strip opens to allow diesel through the heater. This guy on the landy forums reckons his opens to allow the hot diesel to go through the cooler on the way back to tank? If this how it's actually setup it could be possible to create an thermostat valve to cool the return diesel and an under temp valve which would open the heater. So when its too cold it goes through the heater. When the return is too hot it opens and goes through the cooler. If its not too hot it returns to tank down a normal pipe?

https://www.landyzone.co.uk/land-rover/f...rix.50748/

That's already exactly how it works, apart from there's no need for the 'return via normal pipe' as the thermostat simply blends the blends the supply to the filter housing to get the temperature right - it selects whether it sends more through the exchanger or whether it only pulls from the tank which will just mix hot and cool and the bimetallic strip will shut off each supply as required.

[Piggy]

I think you are way too concerned about details that are not yet requiring modification...diesel cooler/airbox/fuel lines.
Plus. The cooler is usually not lower than the subframe... So if you are that low...that too low, no?

[JTaylor2005]

Got ya. So all the diesel goes through the cooler on return. Then as it comes into the engine it gets heated or bypassed around the heater. Fair enough. Just seems like a waste of energy heating the diesel and wouldn't that require the coolant to be up to temp as well?

[boggs]

I think you are way too concerned about details that are not yet requiring modification...diesel cooler/airbox/fuel lines.
Plus. The cooler is usually not lower than the subframe... So if you are that low...that too low, no?

The reason for all these modifications is because all of these components had to be replaced so why replace them normally when I can upgrade them. I do know what your saying. I'm from N.Ireland so if you know what height we have our 306s at you will know the diesel cooler won't fit below. The car had a stupid cone filter so I replaced it i was looking a standard 306 box from a breakers they only had an xantia one so I was curious if it was an upgrade after fitting it. My fuel lines are ripped to shit and have joins everywhere so I was thinking I may as well 12mm line the whole thing while there so I'm also curious will this be an upgrade. My fuel cooler wont fit under without loosing it on speed bumps again so I may as well front mount it which I'm also wondering will it be an upgrade. I'm not going and doing all of this for no reason. And no I'm not raising the car haha

[boggs]

The cooler isn't particularly restrictive

That's true it looks pretty straight through, just out of interest could restriction cause power loss on a return feed do people ever upgrade return pipes seems to be just fuel feed pipe.

[Poodle]

One cooler will be plenty, especially with the extra airflow it will receive mounted up front.

The return line is only used to return fuel not injected, so as you up the power (inject more fuel) your return line will actually require less flow capability.

[Dum-Dum]

TBH I wouldn't worry about stones going through it too much, I've never seen an oil cooler popped that way and worst case scenario if it does is that you loose a tank of fuel, hardly the end of the world.

I'd use a mocal oil cooler behind one of the fog lights (with the fog light removed).

Possibly something like this.
   
   
   
   
   

[pug306driver]

Is the fuel warmed to help stop the waxing problem ?

[maxaret]

I am with Piggy - if your car is low enough to be worried about damaging components then really it is perhaps too low !
I have never understood the advantage of lowering cars more than (say) 30mm - if the roads in NI are anything like some of them are here in scotland - no way would i want to reduce ground clearance too much.
I have always been a little 'anti fashion' anyway LOL,where I used to work down south we always used to have a laugh at the guys with the extreme lowered cars who were grounding the underside on every speed bump etc.

[JTaylor2005]

I am with Piggy - if your car is low enough to be worried about damaging components then really it is perhaps too low !
I have never understood the advantage of lowering cars more than (say) 30mm - if the roads in NI are anything like some of them are here in scotland - no way would i want to reduce ground clearance too much.
I have always been a little 'anti fashion' anyway LOL,where I used to work down south we always used to have a laugh at the guys with the extreme lowered cars who were grounding the underside on every speed bump etc.

My personal take on lowered cars is based on whether or not you can get out of the way of ambulances + fire engines. If you can't get your car up a small kerb or over a speed bump when a ambulance is stuck behind you then it's just daft.

[Ruan]

Is the fuel warmed to help stop the waxing problem ?

Combination of reasons - partially same reason as oil is warmed to help lubrication of the diesel injection system, reduces ignition delay and therefore combustion performance, stops waxing in cold climates during driving (obviously if it's waxed already you're stuffed).

[boggs]

I am with Piggy - if your car is low enough to be worried about damaging components then really it is perhaps too low !
I have never understood the advantage of lowering cars more than (say) 30mm - if the roads in NI are anything like some of them are here in scotland - no way would i want to reduce ground clearance too much.
I have always been a little 'anti fashion' anyway LOL,where I used to work down south we always used to have a laugh at the guys with the extreme lowered cars who were grounding the underside on every speed bump etc.

Its that low the underside had to have sheet metal fitted the whole path way of the fuel lines I live in N.Ireland you know how we treat our 306s here its the only fashion we know for them as low as possible the torsion bar is fully down with the bumpstops cut so that they are just long enough to stop the banging/knocking. No I won't raise it I'm ready for all of your death messages now haha

[boggs]

I am with Piggy - if your car is low enough to be worried about damaging components then really it is perhaps too low !
I have never understood the advantage of lowering cars more than (say) 30mm - if the roads in NI are anything like some of them are here in scotland - no way would i want to reduce ground clearance too much.
I have always been a little 'anti fashion' anyway LOL,where I used to work down south we always used to have a laugh at the guys with the extreme lowered cars who were grounding the underside on every speed bump etc.

Its that low the underside had to have sheet metal fitted the whole path way of the fuel lines I live in N.Ireland you know how we treat our 306s here its the only fashion we know for them as low as possible the torsion bar is fully down with the bumpstops cut so that they are just long enough to stop the banging/knocking. No I won't raise it I'm ready for all of your death messages now haha

[maxaret]

Hey Boggs - sounds like you guys are not as boringly practical as me LOL