Fuel Cooler...

StingrayRT

Veteran Member
Joined
Jul 20, 2005
Location
Slovakia
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AUDI A6 2.7Tdi Avant Quattro
fuel cooler on PD is necessary........pressurizing fuel inside the PD injectors create huge amount of heat this heat need to be removed to keep fuel temperature as cold as it can. Second - fuel goes thru cylinder head and remove some part of heat generated in combustion process.......better fuel cooling means better heat management.......
 

named tintin

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Jan 21, 2007
Location
quebec, canada
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golf tdi
All PD engine and automatic (VE4/11) have a fuel cooler on the return line, even some PD motor, have an auxiliary fuel cooler (cooling water/fuel) with an electric pump and temp sensor to activate the pump when it's too hot.

Just by curiosity the last year I send an email at Bosch France (in french)

Here the translation of the answer I got: (poor translation)

''Hello, You did not communicate the type of vehicle, nor the type of embarked EDC. On certain TDI functioning with the injector-pumps, there is an exchanger assembled on the return to cool the gas oil. This in order to preserve the equipment assembled in the tank (unit of drawing up) and to as prevent as one finds oneself with gas oil accumulated in the tank at a too high temperature. These systems the temperature of the fuel influences the beginning of repression as well as the flow of repression, its thermal regulation the return and on the feeding circuit is important.

Greetings, technical aid.''

Beginning and flow of repression = timing and amount of fuel.
 

FlyTDI Guy

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Nov 3, 2001
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PNW
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'01 Jetta GLS
named tintin said:
...temperature of the fuel influences the beginning of repression as well as the flow of repression...
Interesting terms... On what basis do you interpret that as meaning timing and fuel quantity??? (just a question, not disputing)
 

named tintin

Veteran Member
Joined
Jan 21, 2007
Location
quebec, canada
TDI
golf tdi
iIt's a bad translation of the french term: Début de refoulement et débit de refoulement, the real word are: Start of delivery or start of injection, and Injection quantity.
 

TdiRacing

Vendor
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Aug 19, 2003
Location
Baltimore, MD
TDI
2006 Jetta TDI Cup
Here is how mine is for now. Will change it when I get my new engine installed. One on the left is fuel cooler and the one on the right is Oil. I have mine on the return line. I drive in cold weather, so do not want to gel my fuel in winter.

 

LNXGUY

Top Post Dawg
Joined
Jan 10, 2004
Location
Barrie, Ont, Canada
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'05 Jetta TDI Wagon
I picked up a simple FRAM tranny cooler from the local autoparts store for about $40CAD. Perfect for all your fuel cooling needs.
 

MAXRPM

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May 7, 2008
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US
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00 Jetta and 99.5 Golf, 2015 Passat TDI,BMW 2
KROUT said:
I did it myself. I just used a flat piece of steel and mounted it to the cooler and used the factory bolt whole for the old inner cooler. I have the bumper off I will take a pic.

Krout, this forum does not let me see the pics. it is asking me to register then it says that I am already registered, so I can not see the pics, I would like to see your cooler mounted, I will be doing this mod in my car, . what brand of cooler did you get?
 

TornadoRed

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2003 Golf GL 5-spd, red; 2003 Golf GLS 5-spd, indigo blue; 2003 Jetta TDI wagon, Candy White; 2003 Jetta TDI wagon, silver
MAXRPM said:
Krout, this forum does not let me see the pics. it is asking me to register then it says that I am already registered, so I can not see the pics, I would like to see your cooler mounted, I will be doing this mod in my car, . what brand of cooler did you get?
Your login to http://pics.tdiclub.com is the same as to www.tdiclub.com . You do not have to register again, but you have to login again.
 

SuperJ

Veteran Member
Joined
Apr 11, 2006
Location
Waterloo, ON
TDI
2006 Jetta TDI
I'm pushing 80 deg C on hot days here in Ontario with a decent amount of fuel in the tank with the stock cooler.

Any idea how low I could get it with a fuel cooler, fuel in the cylinder head/pd injectors seems to be formula for hot fuel.

Does the fuel always flow through the PD cooler? or only when it's above a certain temperature?

Are there any after market thermostatic T's set to maybe 50 deg C to control cooling? (I don't think my MkV has the ALH style T on the filter).
 

majesty78

Veteran Member
Joined
Dec 7, 2007
Location
Austria/ Europe
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Skoda Superb 3T5 CFFB
SuperJ said:
Does the fuel always flow through the PD cooler?
Yes it does.


And by the way, a big european Mercedes tuner, named 'vaeth' developed a fuel cooler working with the AC of the car. It cooles the feed down to about 10-20 degrees celsius, but they want about 800 Euro for it...this are good 1300 dollars...


Greets, Alex
 

TDikook

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Joined
Jun 15, 2003
Location
Biloxi, Ms
TDI
'06 Golf Anthracite Blue
Im bringing this up from a long slumber. has anyone done a cooler on both ,to the engine and from the engine, to determine which is better? I am searching and might do both. a small two pass cooler going to the engine and a bigger cooler from the engine. but I am still looking into it.

anymore insight into this I would most appreciate

Eric B
 

Fix_Until_Broke

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Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
If you have to pick one, do the one after the engine. The fuel coming from the injection pump is the hottest fuel and will be the easiest to cool with ambient air. Putting a cooler on the way to the engine won't hurt, but won't be as effective as the one after.
 

Farfromovin

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Joined
Apr 9, 2005
Location
Ventura, CA
TDI
03 Golf 2dr- PD150 6m
Kook, if what your asking is "should I install a second cooler?", I would recommend that it's probably overkill. I have an OEM cooler and a tranny cooler and I'm just debating on which to install. I went to the dealer and got some prices/pn's for the necessary fuel lines and that stuff is very expensive. I may just use a tranny cooler in front of the radiator on the return side after the thermo T. But, you already have one...

--edit-- KROUT installed his on the feed and return and didn't notice any differences between the two.
 

SheeB

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Joined
Jul 8, 2007
Location
Ottawa, ON
TDI
2001 Jetta GLS Manual
ak47tdi said:
I have a Kerma widget instead of the stock thermostatic tee. Wondering if i should go back to the stock tee before a mod like this?

I always wondered weather i was doing more harm than good when i go to the track with a 1/4 tank or less.
I am in Canada and will installing shortly the Nicktane filter head using my CAT2 filter. The Nicktane setup deletes the thermostatic tee so I will be able to test this scenario next winter ;) I would think though as the fuel is winterized anyways, and I am religious with the PowerService that there should not be any issues. Bring on the -30C :D
 

dieselpower04

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Joined
Jun 26, 2007
Location
Outside Tampa, FL
TDI
2004 Golf GLS TDI (sold)
Farfromovin said:
Kook, if what your asking is "should I install a second cooler?", I would recommend that it's probably overkill. I have an OEM cooler and a tranny cooler and I'm just debating on which to install. I went to the dealer and got some prices/pn's for the necessary fuel lines and that stuff is very expensive. I may just use a tranny cooler in front of the radiator on the return side after the thermo T. But, you already have one...

--edit-- KROUT installed his on the feed and return and didn't notice any differences between the two.
No difference in a fuel cooler? The fuel gets hot and gets cooled before returning to the tank right?
 

TDikook

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Biloxi, Ms
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'06 Golf Anthracite Blue
After I installed my two Fuel coolers, I took logs. there was hardly a difference, there was one, but I don't think it was noteworthy, a degree or 2 difference. but it did bring the temp down quicker after hard runs. I don't think I would do it again, instead, I would add an oil cooler.
 

GgOTi

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Dec 23, 2007
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LA, CA
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2003 Golf TDI (Mickey) | 2011 335d-RIP | 2010 Jetta TDI (Merlin)-Returned to VW | 2001 Jetta TDI (The German)-SOLD
I am in Canada and will installing shortly the Nicktane filter head using my CAT2 filter. The Nicktane setup deletes the thermostatic tee so I will be able to test this scenario next winter ;) I would think though as the fuel is winterized anyways, and I am religious with the PowerService that there should not be any issues. Bring on the -30C :D
I am considering doing this as well. Seems to be the best setup really. However, I am a little apprehensive to eliminate the thermostatic tee. Granted, I am only in Ohio, but we get some good winters. I will be very interested to see your results. Please keep me posted.
 

TornadoRed

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2003 Golf GL 5-spd, red; 2003 Golf GLS 5-spd, indigo blue; 2003 Jetta TDI wagon, Candy White; 2003 Jetta TDI wagon, silver
I am considering doing this as well. Seems to be the best setup really. However, I am a little apprehensive to eliminate the thermostatic tee. Granted, I am only in Ohio, but we get some good winters. I will be very interested to see your results. Please keep me posted.
The thermostatic-T is not that useful. For example, assume that your fuel is not suffiiently winterized. Your engine starts, and for several minutes all is well as hot fuel is returned to the filter. Then the thermostat opens or closes or whatever it does, and cold partially-gelled fuel flows into your filter... and the engine dies.

Several minutes and much cranking later, ambient heat under the hood warms the fuel slightly and the engine starts and runs... for another minute or two. And then it dies.

If gelled fuel is going to be a problem, I would rather have that problem in my own driveway than five-minutes' away from home.
 

TornadoRed

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Shoot! Just when I thought I was done modifying my Jetta TDI, I find this thread about a fuel cooler. Pretty tempting to go for it before the next New England Dyno Day in autumn.
It has to be more useful for those in the Deep South and Desert Southwest, than in New England.
 

Honeydew

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Florida
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13 Passat DSG
rocketeer928, also consider the stock fuel cooler from an automatic ALH or a PD as an option. That's what I went with:
 

loudspl

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Osakis, Minnesota
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02 ASV w/ 02J
How about a fan-forced one like this from B & M? Would it be worth it if positioned right?


I have the stock ALH cooler and hot weather really takes it toll on power (or so it seems)
 

TornadoRed

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I have the stock ALH cooler and hot weather really takes it toll on power (or so it seems)
I think hot intake air is a bigger drag on summer performance, as it reduces the effectiveness of the intercooler. During Formula 1 broadcasts on Speed, when they give air temps of 80-85°F, typically the track temps are 115-120°. On a hot highway, in mid-day in the South, with air temps of 105-115°, road temperatures could reach 140-160°.

That heat, radiating off the asphalt, must have a greater effect on combustion efficiency than the few degrees' change in fuel temperatures.

Additionally, if the fuel temperatures are already ~110° when you start your trip, you would have to travel several hours before the fuel temp would climb much higher. The best you can hope for with a fuel cooler would be to keep the fuel from getting much hotter than 110°. But the air temps would affect performance no matter how far or how long you drive. And the air temps would limit the effectiveness of a fuel cooler, too.

Thus, it would seem to me that a fuel cooler can have only limited effectiveness, even in the most extreme conditions. And even less effectiveness in more temperate climate zones. The only exception would be if you plan to drive several hours at a stretch, during which time the hot fuel being returned to the tank could raise the temperatures there by many degrees.
 
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TDikook

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Biloxi, Ms
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'06 Golf Anthracite Blue
I will address this again. the Fuel cooler on a PD is not that substantial. the supply fuel and the return fuel mix in the head to give a uniform temperature. on an ALH, a cooler would be a good idea before the IP as heat kills. but again, when I had TWO fuel coolers, one going to and one coming from the block, the difference was minimal(but there was a difference) I would invest in a quality oil cooler before I went down this road again.
 

Farfromovin

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Ventura, CA
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03 Golf 2dr- PD150 6m
If I had a rotary, I'd fit a cooler on the return. After the 11mm (or 12) cranks that fuel pressure it's HOT on the return. I'd have the cooler on there to help keep the tank from heating up sending even warmer fuel to the IP and to protect the in tank lift pump. Just my .02.
 

TornadoRed

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If I had a rotary, I'd fit a cooler on the return. After the 11mm (or 12) cranks that fuel pressure it's HOT on the return. I'd have the cooler on there to help keep the tank from heating up sending even warmer fuel to the IP and to protect the in tank lift pump. Just my .02.
I'd like to see some data on how rapidly the rise in temperatures in the fuel tank, where hot fuel returning from the engine is mixed with fuel at ambient temperature.

Also, how effective is a fuel cooler going to be if the air blowing through the cooler is 100°F or 130°F or 160°F? The hotter the day and the hotter the "track" temperature, the less effective the fuel cooler will be.
 
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