Modified Thermostat for higher MPG's...

Riflesmith said:

I have had Evans in since last June. All is well. I converted the pressure cap to a zero pressure system at that time. This allows any residual water in the system to slowly escape the system, leaving only Evans behind.

Click to expand...

How did you convert the cap?

G3TDI said:

How did you convert the cap?

Click to expand...

Gently pry the black plastic center with o-ring and it will pop out. Then drill two quarter inch holes on an angle from the inner "wall" to the outside world, but not through the top of the cap. Probably a poor explanation, but simple to do and it still effectively keeps dirt out of the system.

When I converted to Evans, I just drove with my pressure cap a little loose for a few months. The residual water vapor escaped, not the Evans. I would occasionally tighten the pressure cap and go for a drive, in order to see if I had any water left in the system (water will pressurize the system). I've used Evans since 1996.

dieselfuel said:

I can honestly say, my TDI has never run better than it is running today.

Later in the year, I'm replacing the intercooler with an aftermarket one I bought off e-bay from ILoveTacoTaco. And late summer/early fall, I plan on adding a 17/22 turbo.

df

Click to expand...

I'm running a big FMIC and a 17/22- I have to say that I had a LOT of lag with a FMIC and the VNT15(more than 1 second). With the 17/22 I get very little turbo lag(maybe 1/4-1/2 second). There really isn't any performance improvement with the FMIC. Maybe if I was racing it would be different, but for daily driving, a bigger intercooler actually decreases performance a little bit because it does cause some turbo boost lag. Bigger intercoolers only are useful if you are driving under sustained boost for over 2+ minutes.

SilverGhost said:

Well, two cautions I would throw out there for everyone. If you are doing performance mods like bigger nozzles and turbos I would stay with factory t-stat temperatures. You have a much smaller margin for error if something breaks or tune is not perfect. Also both the factory and aftermarket lower the cooling temperature for power. VW actually builds a couple models with variable t-stat to get the best of both.

Second we see a lot of the other plastic parts in the cooling system break down when the engine gets hot or overheats. At the shop when we see large cooling fan failures, they precipitate t-stat and water pump failures. Also the coolant flange, heater core hose barbs, the cross over pipe on VR6, tees and elbows in the radiator hoses get brittle and break easily.

Maybe a good suggestion for long term durability would limit max temp to 200-205F. That is still a healthy bump from 185F of the stock t-stat. I'm not saying that all the pipes and plastic will just explode, but when you do work on the engine all the plastic parts will snap easily.

Jason

Click to expand...

Good caution there about the plastic parts-I agree whole heartedly! I ended up replacing just about every coolant hose and coolant pipe O ring I could find since I was in there and was experimenting with higher temps. Always good to perform preventative maintenance since these vehicles are getting a bit long in the tooth nowdays any how This is all very experimental-some are running temps that I wouldn't necessarily be comfortable with, but they know the risks involved.

As far as tunes and running much higher power outputs and running high temperatures-I'm not so sure about that one. We know most power increasing mods tend to reduce life of the engine at expense of increasing performance. I would hate for higher temps(205-209 Deg F) to get blamed for damage caused directly from excessive hot rodding. To each his own however.

G3TDI said:

You're saying this isnt really a 205F thermostat?!
http://www.stant.com/modules/partLocator/view_diagram.cfm?id=14252

Click to expand...

You mention the 13252 I listed in the original posts documenting the process of coming up with the "Hybrid". That was the non cliff notes version It would have been better if you skipped directly to this page and post number 59:


http://forums.tdiclub.com/showthread.php?t=306799&page=4


After initial visual comparisons I used a 13352. Basically, purchase a 13379, remove it's rear section, buy a 13352, and apply the rear section from the 13379 to the 13352 and end up with a 13352(205 Deg F) with a rear bypass section just like the OEM but at a new higher temperature. Use caution and have a ScanGage on the car to monitor temperatures just in case.

TDIMeister said:

As I understand it, the problem of employing the Stant 13352 is that it is fundamentally different in appearance to the original-fit 13379, so the technique of hybridization is to take the innards of the 13352 to the 13379 (sorry that I don’t use the jargon of the thread). So if I may ask the stupid question, josh8loop made reference in his post in early 2011 regarding P/N 14252. Visually, it looks like what the 13379 should be with the lower circular plate and lower spring. Can’t this part be used instead and forget about hybridizing?

Click to expand...

Sorry so long to get back to you on this. The 13252 was only mentioned in the initial development(non cliff notes version). I ended up using a 13352 and 13379 in the actual materialized development of the "Hybrid" T-stat. Again, sorry for the delay in replying and the confusion

josh8loop said:

After initial visual comparisons I used a 13352. Basically, purchase a 13379, remove it's rear section, buy a 13352, and apply the rear section from the 13379 to the 13352 and end up with a 13352(205 Deg F) with a rear bypass section just like the OEM but at a new higher temperature. Use caution and have a ScanGage on the car to monitor temperatures just in case.

Click to expand...

Yeah I just did this now and installed it yesterday however it puzzles me what function that part you swap over exactly does?

Anyone know why some thermostats have that "rear section" (hat) and some don't? Just want to fully understand what it does..thanks!

[EDIT] I used that SEARCH button and voila http://forums.tdiclub.com/showthread.php?t=166243&page=2

Reason for this was I wanted to know how critical the distance (of the swapped over hat) was from the main part but as it turns out it does nothing when cold (does NOT seal anything) so it's not super critical.

Tom W. said:

When I converted to Evans, I just drove with my pressure cap a little loose for a few months. The residual water vapor escaped, not the Evans. I would occasionally tighten the pressure cap and go for a drive, in order to see if I had any water left in the system (water will pressurize the system). I've used Evans since 1996.

Click to expand...

Ok thanks well I am installing EVANS into a car/engine and setup that has been into pieces and been out since two years ago and replacing all hoses the radiator and heater core so I think I won't have any residue water

G3TDI said:

Yeah I just did this now and installed it yesterday however it puzzles me what function that part you swap over exactly does?
Anyone know why some thermostats have that "rear section" (hat) and some don't? Just want to fully understand what it does..thanks!
[EDIT] I used that SEARCH button and voila http://forums.tdiclub.com/showthread.php?t=166243&page=2
Reason for this was I wanted to know how critical the distance (of the swapped over hat) was from the main part but as it turns out it does nothing when cold (does NOT seal anything) so it's not super critical.

Click to expand...

I can't say I agree with your last statement. The issue I have with it is the rear section distance criticality. Most of the T-stat operational time is spent some where between here and there and not necessarily fully extended(rear bypass section fully closed off)-that is a condition that should rarely occur. Just like any properly designed control valve setup it should operate somewhere from 40-70% travel while reaching desired target process values. That allows some fudge factor to control non normal thermal transients. From some results from others on this Forum that have experimented with changing the rear section spacing and observing results I can say that you might get away with .030-.040" variations, but the end goal should be to stick with the same designed dimensions as closely as possible using standard workshop tools. Without data logging equipment it may be difficult to graph temperature fluctuations resulting from bypass section dimensional differences. Also, From those experiments it's clear that even if the rear bypass section has a slight tilt to it the functionality won't be affected to a great extent. Again do your best to assemble the "Hybrid" to the dimensions of the 195 degree ALH stant T-stat and you will be fine.

josh8loop said:

I can't say I agree with your last statement. The issue I have with it is the rear section distance criticality. From some results from others on this Forum that have experimented with changing the rear section spacing and observing results I can say that you might get away with .030-.040" variations, but the end goal should be to stick with the same designed dimensions as closely as possible using standard workshop tools. Without data logging equipment it may be difficult to graph temperature fluctuations resulting from bypass section dimensional differences. Also, From those experiments it's clear that even if the rear bypass section has a slight tilt to it the functionality won't be affected to a great extend. Again do your best to assemble the "Hybrid" to the dimensions of the 195 degree ALH stant T-stat and you will be fine.

Click to expand...

I don't even remember myself now what those words of mine meant, I might have been looking at some alternative thermostats that could fit/work "off the shelf" however I did follow your recipe in the end

Haven't started the engine yet though

G3TDI said:

I don't even remember myself now what those words of mine meant, I might have been looking at some alternative thermostats that could fit/work "off the shelf" however I did follow your recipe in the end

Haven't started the engine yet though

Click to expand...

I gotcha-I do that too Best of luck when you do run it!

Tom W. said:

When I converted to Evans, I just drove with my pressure cap a little loose for a few months. The residual water vapor escaped, not the Evans. I would occasionally tighten the pressure cap and go for a drive, in order to see if I had any water left in the system (water will pressurize the system). I've used Evans since 1996.

Click to expand...

meaning Evans won't (pressurize the system)? If do so I even need to drill a hole in the cap?

No you do not need to drill the cap you can just keep the cap loose till all the water is out of the system.

would this mod work on a 09 CR and would it benifit me? also is there anyone out there that has tried it on a CR?

I've checked in VCDS and I my temp is 105-108c now that would be 221-226F

Has anyone noticed additional smoke from having a high temperature t-stat?

I've been forever trying to get a custom tune straightened out. I say it smokes too much, and the tuner says he's turned the pump voltage down to the 120 HP range.

Could the temperature be retarding the timing and leading to it smoking?

TDI4evah said:

Has anyone noticed additional smoke from having a high temperature t-stat?

Click to expand...

Nope, if anything the opposite but then I wouldn't know cause I put this hybrid thermostat in on a fully rebuilt engine with new turbo and IP, but I can't see ANY smoke.

TDI4evah said:

I've been forever trying to get a custom tune straightened out. I say it smokes too much, and the tuner says he's turned the pump voltage down to the 120 HP range.

Click to expand...

Voltage?

TDI4evah said:

Could the temperature be retarding the timing and leading to it smoking?

Click to expand...

What color is your smoke?

TDI4evah said:

Has anyone noticed additional smoke from having a high temperature t-stat?

I've been forever trying to get a custom tune straightened out. I say it smokes too much, and the tuner says he's turned the pump voltage down to the 120 HP range.

Could the temperature be retarding the timing and leading to it smoking?

Click to expand...

Sounds almost like the IQ needs adjustment. I think on aftermarket tunes, they end up being outside the 3.0-5.0 range...sometimes around 6.0? I know that finally getting the IQ right on our Mk3 pretty much eliminated the smoke we had with that one.

I've got the IQ turned up around 8-10 already. Any more and it'll be hard to start, particularly this time of year.

As for the car:

10K miles on a rebuilt engine
stage 2 cam
VNT17 turbo
DLC764 nozzles

The mileage is right about where it was stock (45 in a wagon), it's got loads of power now, all-in-all I'm pretty happy with it. Except for the smoke level - with the foot to the floor it'll have maybe a dark puff and a blue haze, or maybe a big black cloud. It depends on which tune I use, what fuel, and I'm not sure what else.

I was just wondering about the ECU retarding the timing if it thought the engine was overheating.

Growler said:

I walk up to the counter at my favorite auto parts store, and ask for a high temperature thermostat for a 1986 (to get into the mk2 Generation) 1.8L gasser jetta or Golf.

it is the same size as our ALH stat, and get an O-ring for the same and you walk out of there for less than $15 and get temps at ~200 degrees +/- 3 in my experience on two ALHs.

Click to expand...

Will that fit the AFN engine? I need to replace my thermostat and planning use a higher temp thermostat. But which one should I use if I use standard coolant? I don't need to make any modifications to that one?

The temperature drops (engine temp) if I go full on the cabin fan. So I guess it's cooling too well.

yNG WITH DOU ARE "DANCI

Wahler 4256.92D50 works perfectly in my AFN, temperature readings between 90c-93c.

G3TDI are you not seeing a start of injection retard once you pass 92C ?
Edit: Just been through my AHF and AMF maps and now cannot find the table where I noted a timing retard around 92C. I'll keep looking but suspect it may have been in a 2.0 CR map I was looking at.

I am trying to do the exact oposite to my 2.0 PD 16V engine (BKD) for economy and eliminating that slightly shaky idle that these engines are notorios for once they reach 90.
Also with the tune it is running now, it easily reaches 96 deg during wots (actually immediatly after) and I can see the instant consumption at cruising rising a lot during that high temp period of a minute or two.
I want to try an 82 deg thermostat (hopefully low enough).
Mako, are you the same guy from ecuconn?

Same one.

My 2003 Jetta was destroyed in an accident in January. Picked up a 2002 Jetta in February. Was able to develop some data with it. Did decide that the thermostat that was in it was in terrible shape (really didn't get up to anything more than 180*F on the Scanguage). Before a long trip, I got a chance to swap out a modified thermostat. Scangauge showed that I maintain temps usually around 206 to 214F now. I think the highest that I have had has been about 221F...long pull up mountain in Georgia/Tennessee. I use Evans coolant.

My 2003 jetta had a much taller fifth gear. I was using a .658. Stock fifth in the 2003, but the MPG is about the same at very regularly in the 53 to 55MPG range. I haven't done my regular change to Redline MTL in the gearbox on my 2002 Jetta, and I usually recognize an MPG bump with that.

The taller gear was nice, but, Dollar for Dollar, the thermostat change has been very good. Hoping to get the trans oil changed before we move in August so I can generate some data...especially since my commute distance will also change.

i have a question it might seem a little weird but bear with me ok.

i understand that a hotter engine will burn a little cleaner (finer spray mist
thus increasing mpg and power)
but why increase thermostat temp?
Would it not be better to put a stock or cooler thermostat and increase the
temp of the diesel being injected for a finer spray?
that way no increase load on the oiling system.

i seen gasser use this but i never seen or heard of it in a diesel.
they heat the fuel line with aircraft fuel line heater to increase the
fuel temp.

The hotter temps also reduce the oil viscosity reducing it's drag in the bearings - this is more likely the most significant contributor to increased MPG/efficiency.

I've been running the higher temp gasser stat for over a year, I see 201-219 on scan gauge.
I've been killing fan control modules (3rd one now) in such a matter that the A/C compressor does not run anymore. I'm not in anyway sure that my electrical failures are related to coolant temps, or my swap wiring, dealer servicing until I owned it, or just a VW thing.
I'm just posting here to see if anyone else has similar issues.