www.tdiclub.com

Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You




Go Back   TDIClub Forums > VW TDI Discussion Areas > TDI Fuel Economy

TDI Fuel Economy Discussions about increasing the fuel economy of your TDI engine. Non TDI related postings will be moved or removed.

Reply
 
Thread Tools
Old March 27th, 2011, 07:02   #76
josh8loop
Veteran Member
 
josh8loop's Avatar
 
Join Date: Sep 2009
Location: Vero Beach, Fl.
Fuel Economy: 45 MPG City with the previous 01M, 5-speed 60+ MPG City. Always searching for ways to make it better!!
Default

DF,

Thanks for the update on the ARP studs. I'm sure you are glad that they are installed at least.
__________________
2002 VW Jetta TDI 5-speed(completed 01M-5-speed swap at 155K miles) 60+ MPG City.
Experimenting with the "Hybrid" 205 Deg F T-stat:
http://forums.tdiclub.com/showthread.php?t=306799&page=4
Now have Nokian Entyre Low RR tires!
josh8loop is offline   Reply With Quote
Old March 27th, 2011, 07:11   #77
josh8loop
Veteran Member
 
josh8loop's Avatar
 
Join Date: Sep 2009
Location: Vero Beach, Fl.
Fuel Economy: 45 MPG City with the previous 01M, 5-speed 60+ MPG City. Always searching for ways to make it better!!
Default

All,

I ended up installing the modified thermostat yesterday, and doing some testing. I used a friends Vag Com to monitor temperatures during the test. The temperatures with the modified T-stat reached 103 Deg C, which is about 217 Deg F, and was still climbing. This concerned me greatly, and I ended the test. Before I installed the modded T stat I had known that the rear bypass section of it was uneven by about 15 thousandths. The press tool I had made was not quite square as I don't have a lathe here. I am thinking this made the difference, and plan on trying to square up my tool, and try it again. The modded T-stat should keep it around 94 Deg C(205 Deg F)
__________________
2002 VW Jetta TDI 5-speed(completed 01M-5-speed swap at 155K miles) 60+ MPG City.
Experimenting with the "Hybrid" 205 Deg F T-stat:
http://forums.tdiclub.com/showthread.php?t=306799&page=4
Now have Nokian Entyre Low RR tires!

Last edited by josh8loop; March 27th, 2011 at 08:37.
josh8loop is offline   Reply With Quote
Old March 27th, 2011, 11:21   #78
dieselfuel
Veteran Member
 
Join Date: Dec 2008
Location: ohio
Default

Josh,

Yes, I'm glad to have the ARP's installed: Peace of mind..., lol!

Wow, 217+F! Too bad. With Evans HDTC, 210F would be perfect, imo.

Thanks and keep us posted,
__________________
2003 Jetta TDI 200,000 mi. Horrible fuel milage? Check your thermostat: http://forums.tdiclub.com/showpost.p...49&postcount=7
dieselfuel is offline   Reply With Quote
Old March 31st, 2011, 09:34   #79
josh8loop
Veteran Member
 
josh8loop's Avatar
 
Join Date: Sep 2009
Location: Vero Beach, Fl.
Fuel Economy: 45 MPG City with the previous 01M, 5-speed 60+ MPG City. Always searching for ways to make it better!!
Default

Fellas,

I am in the process of having my press tool aquared up a bit at work. Should be done in the next few days. This will allow me to re-press the T-stat together squarely this time instead of having a slight wobble to the bypass section. I will probably also pick up a new T-stat O ring even though the one in their now is only a few mths old. I also need to source the 4mm x 32mm "O" rings for the coolant line quick disconnect fitting on the top & bottom of the radiator and replace them as preventative maintenance. With any luck I should be able to test the modified T-stat again in the next couple weeks. On thing I noticed as was expected at the higher coolant temps, the coolant system was indeed pressurized higher than normal by the feel of the radiator hoses.
__________________
2002 VW Jetta TDI 5-speed(completed 01M-5-speed swap at 155K miles) 60+ MPG City.
Experimenting with the "Hybrid" 205 Deg F T-stat:
http://forums.tdiclub.com/showthread.php?t=306799&page=4
Now have Nokian Entyre Low RR tires!
josh8loop is offline   Reply With Quote
Old March 31st, 2011, 19:40   #80
Ski in NC
Veteran Member
 
Join Date: Jul 2008
Location: Wilmington, NC USA
Fuel Economy: 48-52 typical
Default

After breaking into cooling system, air gets into system, hides in pockets. and some gets dissolved into the coolant. When it heats up, solubility goes down and the coolant off-gasses. This raises pressure in system and hoses get hard.

What I do on any cooling system I do major work on, is to run system with no cap on and let engine run up to full temp (on tdi, that means fans cycle on). This tends to expel non-condensible gasses through the bottle cap. Do this and then pressure does not get so high in normal thermal cycles.
__________________
2001 Jetta TDI 5sp Stock 201k mi
1981 Rabbit IDI 4sp Sold at 339k mi
1990 S-10 4.3 4wd 5sp 154k mi
1986 VW Pathfinder 1.6 45hp Marine 4700 Hrs
2001 Cummins 8.3 420hp Marine 1660Hrs..REFIT DONE!!
Ski in NC is offline   Reply With Quote
Old April 1st, 2011, 06:33   #81
josh8loop
Veteran Member
 
josh8loop's Avatar
 
Join Date: Sep 2009
Location: Vero Beach, Fl.
Fuel Economy: 45 MPG City with the previous 01M, 5-speed 60+ MPG City. Always searching for ways to make it better!!
Default

Ski,

Good point, especially when performing these non traditional tests with higher temps. I ended up using a vacuum source to help with the refill. Seemed to work out nicely both times I used it. I just wish there was a better way to drain coolant other than removing the lower oil cooler coolant line. That makes for a very messy drain, and I end up loosing coolant inventory. Wish there was a modification for a quick drain on that lower coolant pipe like the one on the lower radiator.
__________________
2002 VW Jetta TDI 5-speed(completed 01M-5-speed swap at 155K miles) 60+ MPG City.
Experimenting with the "Hybrid" 205 Deg F T-stat:
http://forums.tdiclub.com/showthread.php?t=306799&page=4
Now have Nokian Entyre Low RR tires!
josh8loop is offline   Reply With Quote
Old April 1st, 2011, 09:54   #82
Tom W.
Veteran Member
 
Tom W.'s Avatar
 
Join Date: Dec 2005
Location: Raleigh, NC
Fuel Economy: Getta 49MPG IDI 60MPG Passat 34mpg
Default thermal efficiency

Generally, the higher the temperature, the higher the thermal efficiency of the engine( more HP, better MPG). Remember Smokey Yunick's Adiabatic engine?
Some are using waterless coolent to boost their temps. http://www.evanscooling.com/
I don't know if the coolent is compatible w 1.9 TDI or not- I use this in my Jetta 1.6 diesel and my Chevy. I use it because it eliminates all possibility of corrosion, and because there is no longer pressure in the system- which means if I have a leaky hose, I don't loose pressurized coolent- the coolent just slowly drips out. This stuff has actually saved me three times from overheating.
__________________
Chemically cleaning your turbo: http://forums.tdiclub.com/showpost.p...8&postcount=48

canadiangrizzly's Diagnosing limp mode: http://forums.tdiclub.com/showthread.php?t=179589

GoFaster on loss of power:
http://forums.tdiclub.com/showthread.php?t=75959
Tom W. is offline   Reply With Quote
Old April 1st, 2011, 11:23   #83
dieselfuel
Veteran Member
 
Join Date: Dec 2008
Location: ohio
Default

Ah, Tom, you're the one using the EVANS!

How did you drain out all of the G12? I understand there can be no more than 3% water with the Evans. Did you use the Evans pre-treatment?

Thanks,
__________________
2003 Jetta TDI 200,000 mi. Horrible fuel milage? Check your thermostat: http://forums.tdiclub.com/showpost.p...49&postcount=7
dieselfuel is offline   Reply With Quote
Old April 1st, 2011, 12:45   #84
Tom W.
Veteran Member
 
Tom W.'s Avatar
 
Join Date: Dec 2005
Location: Raleigh, NC
Fuel Economy: Getta 49MPG IDI 60MPG Passat 34mpg
Default Evans

I'm not using Evans in the Getta, but I have been using Evans in a bunch of my vehicles- started using it in 1996, in a new chevy Astro.
I also converted my 1.6 diesel Jetta in 2001, and several other vehicles. Still own the Astro and 1.6 Jetta, and Evans has quite literally saved both vehicles from the scrap heap by preventing catastrophic cooling system failure.

I don't know if it is compatible with my 1.9TDI Getta. I didn't convert Getta because I wasn't sure I wanted to keep her. Still don't know If I'll keep her. (Getta's a lot of fun, but it's a bit too much car for me-I like to drive slow-my wife says I like to "putter along" )

On one hand, I love Evans, because it works exactly as advertised- zero pressure, zero corrosion, zero maintenence, and I never have to worry about overheating again.

Downside of Evans: It is REALLY expensive, I cannot get it locally, so I have to pay/wait for shipping , and probably the # 1 problem with the stuff is that it is a real PITA/impossible to get all of the old coolant out of your system. I would not spend the time/effort to convert a vehicle, unless I was planning on keeping the vehicle forever(but that's just me).

What I did to remove the old coolant/ convert to Evans: Park the vehicle on a steep decline(pointing down hill), removed the upper and lower radiator hoses as well as the thermostat, got my two burly boys to help me rock the vehicle, and then rigged an air pressure hose to the engine block top to blow out as much coolant as possible. I did not pop out the freeze plugs in the block, because I couldn't figure out how to do that without pulling the engine (space was too tight).
I then filled w Evans, and drove with the expansion tank cap/radiator cap loose. I think it took abt 3 months to actually boil off the water that remained in the system. You know when the water is all gone, because you can tighten the expansion tank cap/radiator cap, drive till up to operating temp, and then squeeeeeze the upper hose- zero pressure!

Evans has some new stuff for flushing/pretreatment - probably what I will do when I convert wife's Nissan.

I run all my vehicles with stock thermostats,- I know from personal experience that you can run Evans way past the temp gauge red line safely, but I never did it intentionally. Both times it was because I had lost a water pump, and was far, far away from a service station.
__________________
Chemically cleaning your turbo: http://forums.tdiclub.com/showpost.p...8&postcount=48

canadiangrizzly's Diagnosing limp mode: http://forums.tdiclub.com/showthread.php?t=179589

GoFaster on loss of power:
http://forums.tdiclub.com/showthread.php?t=75959

Last edited by Tom W.; April 1st, 2011 at 12:50.
Tom W. is offline   Reply With Quote
Old April 9th, 2011, 10:07   #85
Tom W.
Veteran Member
 
Tom W.'s Avatar
 
Join Date: Dec 2005
Location: Raleigh, NC
Fuel Economy: Getta 49MPG IDI 60MPG Passat 34mpg
Default Running at higher temperatures

This has me thinking- did some more research. Smokey Yunick's Adiabiatic engine. http://schou.dk/hvce/ http://www.rexresearch.com/yunick/yunick.htm
I think we can apply some lessons here:
Smokey converted several normal Chrysler and Chevy engines, so we know that normal engines can be run at extreme temperatures safely. The fuel/air mixture was 1,508F when compressed, just before combustion. I think it is safe to assume Smokeys engine temperatures were far beyond anything anyone here has considered, and these engines apparently ran just fine.

I did read he was using jet engine oil for lubrication- Mobil Jet engine oil has an effective operating range of -40F to 400F. 400F? Wow!

What would happen to thermal efficiency by bumping the coolant and oil temp to 300F from 190F? Our little TDI's are already so thermally efficient, I am not sure you could get up to these temperatures.
__________________
Chemically cleaning your turbo: http://forums.tdiclub.com/showpost.p...8&postcount=48

canadiangrizzly's Diagnosing limp mode: http://forums.tdiclub.com/showthread.php?t=179589

GoFaster on loss of power:
http://forums.tdiclub.com/showthread.php?t=75959
Tom W. is offline   Reply With Quote
Old April 9th, 2011, 11:47   #86
dieselfuel
Veteran Member
 
Join Date: Dec 2008
Location: ohio
Default

Tom,

The only thing that concerns me is, the headgasket.

Coolant temp 300F? I don't think I'd want to go over 230F.

I'll read that link when I've got more time.
__________________
2003 Jetta TDI 200,000 mi. Horrible fuel milage? Check your thermostat: http://forums.tdiclub.com/showpost.p...49&postcount=7

Last edited by dieselfuel; April 9th, 2011 at 11:47. Reason: typos!
dieselfuel is offline   Reply With Quote
Old April 9th, 2011, 20:04   #87
Tom W.
Veteran Member
 
Tom W.'s Avatar
 
Join Date: Dec 2005
Location: Raleigh, NC
Fuel Economy: Getta 49MPG IDI 60MPG Passat 34mpg
Default

I'm not so sure the headgasket would be an issue, as they are metal. Dosen't seem to have been a problem for Smokey. Hmmmm. One more thing to ponder.
Here's another thing- Smokey was using gasoline engines- which have a pre-detonation issue at higher temps. Diesels don't have that issue. Wonder if there is any more info on how Smokey handled the thermal stress on the engine?
__________________
Chemically cleaning your turbo: http://forums.tdiclub.com/showpost.p...8&postcount=48

canadiangrizzly's Diagnosing limp mode: http://forums.tdiclub.com/showthread.php?t=179589

GoFaster on loss of power:
http://forums.tdiclub.com/showthread.php?t=75959
Tom W. is offline   Reply With Quote
Old April 9th, 2011, 22:18   #88
dieselfuel
Veteran Member
 
Join Date: Dec 2008
Location: ohio
Default

I see Smokey passed away in 2001. I wonder who now holds his patent?
__________________
2003 Jetta TDI 200,000 mi. Horrible fuel milage? Check your thermostat: http://forums.tdiclub.com/showpost.p...49&postcount=7
dieselfuel is offline   Reply With Quote
Old April 10th, 2011, 07:32   #89
Ski in NC
Veteran Member
 
Join Date: Jul 2008
Location: Wilmington, NC USA
Fuel Economy: 48-52 typical
Default

Patents last a maximum of 20yrs so it is probably expired.

Years ago I did a little research on "adiabatic" engines. Of course none are truly adiabiatic, as even without a cooling system there is heat transfer between process fluid and metal.

What seemed to be concluded (and memory may be a little foggy on this) is that thermal efficiency was not really increased much, but the amount of heat lost through exhaust increased to cover what normally was rejected in the cooling system.

Most of the design work involved keeping moving parts from burning up. That problem was solved on conventional designs long ago.
__________________
2001 Jetta TDI 5sp Stock 201k mi
1981 Rabbit IDI 4sp Sold at 339k mi
1990 S-10 4.3 4wd 5sp 154k mi
1986 VW Pathfinder 1.6 45hp Marine 4700 Hrs
2001 Cummins 8.3 420hp Marine 1660Hrs..REFIT DONE!!

Last edited by Ski in NC; April 10th, 2011 at 07:34.
Ski in NC is offline   Reply With Quote
Old April 11th, 2011, 10:06   #90
Tom W.
Veteran Member
 
Tom W.'s Avatar
 
Join Date: Dec 2005
Location: Raleigh, NC
Fuel Economy: Getta 49MPG IDI 60MPG Passat 34mpg
Default

So, how much of an improvement can be achieved in raising coolant temps?
Auburn University http://www.pavetrack.com/PAVE/Evans%...t%20Report.pdf has reported that increasing the thermostat from 190F to 215F creates a 3% MPG improvement in commercial diesel engines. Wonder what it would do for our TDI?
If you wanted to run a 215F thermostat in your TDI, you would need to figure out a way to override the cooling fans coming on until 230F.

Evans has tested both gas and diesel engines, and ther research indicates that most engines can be operated at a sustained engine temp around 260F, with spikes up to 300F. The only problem they have found is that some valve springs might loose some of their spring pressure at temperatures of 260F and higher. So, if you are planning on operating your engine above 260F for sustained periods of time, you would probably want to upgrade your valve springs.
Bottom line, operating with a 215F thermostat is not that big a deal, as long as you are using a waterless coolant.
__________________
Chemically cleaning your turbo: http://forums.tdiclub.com/showpost.p...8&postcount=48

canadiangrizzly's Diagnosing limp mode: http://forums.tdiclub.com/showthread.php?t=179589

GoFaster on loss of power:
http://forums.tdiclub.com/showthread.php?t=75959

Last edited by Tom W.; April 11th, 2011 at 11:43.
Tom W. is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
higher boost = higher blowby.... now a solution oldpoopie TDI Power Enhancements 116 August 4th, 2015 20:19
Higher the price = Higher the MPGs Joe333x TDI Fuel Economy 2 March 13th, 2008 18:02
36 mpg's on 2002 5 speed / tracking mpg's days-like-this TDI Fuel Economy 23 July 21st, 2002 01:04
Higher Altitude = Higher Boost? :confused: Stealth TDI TDI Power Enhancements 4 July 10th, 2001 09:42
Higher Profile Tire for Higher Gear Ratio? VelvetFoot TDI Power Enhancements 7 June 14th, 2001 22:00


All times are GMT -7. The time now is 11:15.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
1996 - 2017, All Rights Reserved
Page generated in 0.18388 seconds with 11 queries
[Output: 143.29 Kb. compressed to 120.78 Kb. by saving 22.50 Kb. (15.70%)]