Flat plate heat exchanger fitting to an xantia?

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falling-out-with-my-car
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Flat plate heat exchanger fitting to an xantia?

Post by falling-out-with-my-car »

Hi,

Has anyone ever fitted a flat plate heat exchanger to an xantia for the burnning of vegatable oil? and if so what size elbows did you use to connect the water connections to the heater matrix on the citroen xantia and where did you get them from please?

Many Thanks in advance Nigel.
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Post by KP »

best to ask on the veggie oil forums to be honest.

Are you mounting on the bulkhead or ontop of the gearbox??
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Post by MikeT »

Hi Nigel, may I ask if you want to burn it or just heat it up? If the latter, there's already a heat exchanger built into the fuel filter (assuming it's an XUD?) which is regulated to about 80 I think.
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Post by falling-out-with-my-car »

Kp, I am mounting the FPHE on top- of the engine their is a perfect braket already in situ ready to take it.

Mike T,

the inbuilt water heated filter housing doesnt get hot enough quickly enough and the veg oil doesnt maintain that heat all the way to the pump.

The FPHE on the other hand heats the oil much hotter much quicker and maintains the heat at optimum temperature, this is particularly important in the winter, I already have an inline electric fuel heater but I want to fit an FPHE as well, my computerized bosch pump is not liking the viscosity of the veg oil I cannot alter the timming to correct this as the engines ECU sets the mixture and throttle idle speed.

the next best thing is to make the veg oil more fluid so that it behaves much like diesel.
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Post by KP »

To be honest you will lose a lot of heat into the IP and the injector pipes anyway in winter as the air flowing straight through the cold rad and intercooler will just flow straight onto the IP and the pipes and lose any heat you put into the SVO.

best to just cut it with a little bit of diesel. Diesel is best used every now and again anyway as i've heard that the SVO hardens up the rubber seals and doesn't lubricate the inner workings of the pump as well as diesel so a regular bit of diesel in there will help anyway. never did my xantias any harm and i ran near 100% most of the time other than when temps dropped below about 5 at night and then it was about 2-5 litres of diesel per tank full.
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Post by f00lzz »

falling-out-with-my-car wrote: my computerized bosch pump is not liking the viscosity of the veg oil I cannot alter the timming to correct this as the engines ECU sets the mixture and throttle idle speed.

the next best thing is to make the veg oil more fluid so that it behaves much like diesel.
Hi. What symptons are you getting to conclude that the pump isn't coping with the oil viscosity?
My 1999 1.9TD is running fine on 100% SVO with no heater mod.. could it be that the heater in the filter isn't working?

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Post by falling-out-with-my-car »

Has no one fitted an fphe to an xantia? no idea of the fittings needed etc?

Im going to fit one without loking for other ideas that might be causing problems.

the fuel heater is heated by the circulation of hot water and yes its getting hot but the surface area of the bottom of a tiny plastic pot isnt enough to heat the veg sufficently thats why I asked about fitting an fphe.

never mind I'll ask one of these conversion companies instead.

regards Nigel.
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Post by f00lzz »

Not heard of anyone needing to fit one, that's why I asked about the symptoms..

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Post by MikeT »

falling-out-with-my-car wrote:my computerized bosch pump is not liking the viscosity of the veg oil I cannot alter the timming to correct this as the engines ECU sets the mixture and throttle idle speed.


I know how frustrating it is when replies don't answer your questions and question your motives but we do have your best interests at heart, hence the alternative suggestions. No offence meant and all that.

What car is this for as I assumed you have the Bosch semi electronic but these don't control mixture? As for timing, yes, it would be nice to be able to alter it to accomodate cold SVO but it's not that much of a problem, I just hold the revs around 1500 while I select gear and release handbrake and all's fine.
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Post by falling-out-with-my-car »

Mike, No offence intended matey, I was just under the opinion that somebody on here must surely be using an FPHE in an xantia.

Ive got the information from dieselveg now but I am slightly confused by it.

they say they use Tees to make the connections into the heater matrix lines, which doesnt make a lot of sense to me.

I would have used elbows one on the flow and one on the return, this way the heated water would be pumped around the FPHE connecting it to tees simply relies upon heated water getting to the FPHE by convection.
Now I really am puzzeled.

I am convinced that my Bosch pump will last longer in the long term by fitting an FPHE it may save costly work later on, ( I have already seen my Dads Mk1 xantia bosch pump leak) fortunately a tank of diesel resealed the pump seals, my Mk2 xantia engine still hunts running a blend of 5% rug with veg oil filtered to 1 micron, even after a long hot run.

the advice to fit an FPHE has come from a lot of people they suggest that the cold oil is causing this problem, if the oil was heated before the the bosch pump it would be thinner before being pumped through the pump & injectors, apparently this will also extend injector life running on veg..

The FPHE would be fitted after the xantias own fuel filter supplying hot oil directly to the pump. the xantia filter apparently heats the oil to 70 degrees C but only if you are idling with a hot engine, running at speed the cold oil hits the fuel filter and cools the filter housing and heat is lost,esspecially in the winter, the fphe will reheat the oil before it goes to the pump. apparently stopping this hunting I am experiencing when the engine is hot but the fuel is cold and to thick.

Anyway there does seem to be arguments for and against this method of pre-heating the fuel as it is one of the least expensive routes to give it a try I thought I would give it a go and made up my mind to try it out. I am not a great believer that electric heaters produce much gain esspecially in the winter, I already have an electric inline fuel heater and it doesnt really heat the fuel up enough 50 degrees F which is pretty poor really.

regards Nigel.
Citroen Xantia S2 1.9 TD estate 189K soon to be broken for parts Jan 2017 headlamps & radiator fan assembly already spoken for & A 1987 Citroen 2CV6 special just for fun.
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Post by MikeT »

I agree on your elbow vs T argument, as I too would have thought an elbow is what's needed, as using a T means there's little to no control over which direction the coolant would take?

I think the fact no-one has admitted to using FPHE on this forum speaks volumes about it's usefulness. The factory built-in fuel heater system is probably a little underwhelmed by the thicker fuel but over time, as most of the pumped fuel is returned to the tank it's overall temperature will increase to the regulated spec. If it gets to the fuel filter warm enough, the little thermostat closes to ensure it doesn't overheat the fuel and therefore the pump and this is where I see danger in bypassing this regulation.

I find that too many people simply copy what others are doing if they believe there's a benefit to be had, usually without doing any scientific testing to prove it's effectiveness. Probably not the best analogy but I see it as akin to turning up the radio to drown out unusual noises. It works! But it doesn't address the actual cause, just the "perceived" symptoms. Meanwhile the underlying cause is still present and possibly causing yet more problems or damage. (Not to mention the new dangers of having the radio on too loud and all the disadvantages that can bring.)

As for the Bosch pump, they are very robust pieces of engineering, granted with fine tolerances but I am not concerned in the least using clean SVO through it.

Yes, contaminated fuel will cause big problems - just look in my blog at the pump I stripped! Yes, nasty chemicals used in processing WVO might attack the seals and cause more problems, but I am not aware of SVO being directly responsible for any damage at all. Many have suspected it but not one piece of evidence have I seen.

Yes, a thicker fuel may exaggerate and highlight already present deficiencies that have gone unnoticed when using diesel fuel but it doesn't cause them IMO. Yes, the slower burn rate will have an effect of retarding the timing but to what degree (if you'll excuse the pun)? All it does is cause a bit of hunting and maybe a puff of light smoke on cold starting but once up to temperature, aside from the smell of chip shops, I couldn't tell what fuel it was running. It certainly hasn't damped the power output on mine, that's for sure. The MPG I'm still measuring but it's looking good so far.

What I'm getting at is if you're having problems when hot, then there's underlying problems that heating the fuel won't fix, hence the majority advice on this thread is to not waste your time and money. Obviously, it's your car and you will do what you think is best, hence your request for help in setting up this FPHE. Unfortunately, it seems there's little to no help forthcoming on that topic, sorry.
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Post by falling-out-with-my-car »

Thanks Mike,

I have been advised by a plumber today that is how domestric household radiators are plumbed in and it should work fine although I can still see it somehow working better using elbows and only connecting to one flow pipe from the heater matrix not both pipes, I still feel that using tees is the easiest way to tempt an airlock into being, afterall you can bleed a domestic radiator when it develops an airlock because it is connected with tees, you cant bleed an fphe.

I used to run SVO in my 1.9TD xantia and got an average urban mileage of 60mpg on a long run at 60mph I got 68 mpg but many others will dispute that anyway.

at least SVO isnt full of detergent that big oil companies claim clean your engine when all they really do is dilute the fuel so that they can make more money from it.

I am playing around with adding small amounts of 2 stroke oil to veg oil at the moment it has stopped the smoke at start up and the engine does seem a lot quieter than it was,, acceleration also seems to be smoother than it was.

regards Nigel.
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Post by evilally »

Hi mate, I run a FPHE on my 405 1.9TD. I found while the XUD does run on 100% oil with no mods, it is better to do some simple ones. Under normal driving conditions you might not notice, but if you spend much time past 3,000 rpm you should notice an real improvement. My standard car really suffered after 3,500rpm but now will go all the way to the red line :o

I removed the filter housing as it lets in air, just a fact of the bad design exagerated by thick fuel. I've replaced this with a Delphi sandwich type which can be picked up cheaply. The filters are also bigger, better flowing and cheaper. I've just picked up a box of 10 genuine Delphi filters for £18, so it's more than paid for itself. You can also get a head with a built in heat exchanger which might be neater.

Image

I've got a biotuning FPHE. It heats the oil to 70-80 degrees. One of the big advantages here is that hot oil is returned to the tank, which keeps everything clean and the contents of the tank liquid. After 32k on WVO, I haven't had the strainer gum up or any blockages on the lines like a lot of people seem to. A FPHE means there is no risk of the fuel filter waxing in cold weather, as I had happen prior to fitting it when my car ground to a halt on the dual carriage way :shock:

The way I see it is it's not a lot of money and you can remove and refit to your next veg car, or flog on ebay and get most of your money back.
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Post by MikeT »

Nigel, I agree about additives diluting fuel content. I believe they now add an oxygeniser to petrol so instead of expensive fuel, you're getting air added which is free. Not dissimlar to me buying bacon when some of it is actually water :twisted:

Yep, as long as your FPHE is above the supply, the hot water will want to rise up to it. I'm not sure how I'd implement one to be honest. I'm still leaning toward T's at this point though.

I have read nothing but praise for 2-stroke oil and again, I'm wondering if it's the result of a poorly pump being rejuvenated by a much thinner lubricant. It's often said it increases mpg significantly but I know nothing about it's fuel values, yet, so can't comment.

Best results from 2-stroke trials often came from owners of the non-electronic pumps, with dynamic advance that relies on the differential pressure of the fuel between the intake and vane pump. To me, that's a big clue where the problem might lie.

evilally, thanks for those details.

As I suggested earlier, perhaps your troubles were merely exaggerated, not caused by SVO?

On 100% SVO, I do spend ample time beyond 3K as peak power is around there. 5K is the highest I've dared taken it to though which I believe is well into the red line? It has never suffered any of the problems you report.

Even when there was solid ice on the windscreen, I was starting and running on at least 80% SVO. Not the smoothest of idle but once slightly warmed up, it made no discernable difference bar the smell and pyschosymatic hunger for burgers :roll:

What I find most surprising is, I assume, your car started and got to you to the dual-carriageway before it waxed up? I'm surprised because I would expect the fuel heater to be effective by then.

It's certainly the first I've read of waxing causing a breakdown (that I can recall).

Good point about the investment side of a FPHE. I shouldn't really have said it might be a waste of time and money because I'm normally one of the first to encourage experimentation. :oops:
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Post by evilally »

Mike, perhaps it's the difference between SVO and WVO. WVO is generally a bit thicker, and is even thicker still in cold weather. Also fats can drop out, which the heat exchanger melts. Perhaps it's also the luck of the draw with these older cars and what sort of condition the fuel system is in.

However, I ripped the standard housing to bits, replaced the bottom O ring with a brand new genuine part, and sealed up all the other bits permamently with araldite. Although this made a decent improvement, and the car maybe even drove fine, I could still see air in the clear lines I had installed when I opened the throttle for a sustained period. The culprit was the top lid in the housing, which you can't really do much with. This is why I gave up, and chucked it in the bin!

Another good test is to connect an electric tyre inflator to the end of the fuel line. I presurised the system to about 15psi, and listened for air escaping. There were no leaks and the system held it's pressure, therefor there was no way the -7psi vacuum caused by the pump would be an issue.

Getting rid of air ingress is better for the pump, and also decreases emmisions as I noticed. The car was a lot less smokey after modification.

I should also mention, the heat exchanger under the filter housing needs its thermostat modified to run full time. If you take it out and look at it, you will see it only directs the fuel through the heat exchanger when open, at all other times it goes directly to the filter.
'96 405 1.6 GLX with 306 GTI engine on Cat cams @ 195bhp

'05 RenaultSport Clio 182 Cup, 102k

'97 406 1.9TD, 314k.
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