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Jon_slider
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Joined: April 11, 2007
Posts: 5091
Location: Santa Cruz, Crowdifornia
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 Posted: Tue Nov 18, 2014 4:45 pm Post subject: |
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Some of the variables between the five vehicles include
1. tire size (IMO R&P is compensation for tires, but R&P does not reduce the added work to turn a taller tire)
2. Vehicle weight loading, including on top. Both of these increase the work, and heat.
3. Skid plates. Check if that is a factor with the hottest van. I believe it is fully clad.
I agree the trans radiates motor heat. More work = more heat.
Fwiw I don't think a tranny cooler is required with stock tires and stock skid plate.
Again IMO, increasing tire size is a precursor to engine upgrade, and R&P upgrade. Iow, the motor and R&P are not primary variables, it's tire size that is a source a extra heat.
I now believe full coverage tranny skid plates are responsible for +20f tranny temp. (With no cooler)
Whether tranny heat arrives as radiant from the motor is immaterial to me. In fact I do believe tranny temps ARE increased by motor temp. My concern though is to not accumulate heat in the tranny.
I do also believe that gear faces, especially small ones on 4th gear, create heat. But more importantly, I believe lubricating 4th, main bearing, and R&P are significant benefits of tranny oil circulation.
For reference, on flat freeway at ~68mph, using cruise control, I see tranny temp 85f over ambient.
I encourage using an over ambient reference, not just tranny temp raw data.
IMO, Hans skid plate is smaller than mine, and probably adds less than the 8F my 14" skid plating.
This is Hans'
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Waldi
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Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Tue Nov 18, 2014 4:57 pm Post subject: |
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Difficult say any sure without knowing if oiling plates and exact r+p ratios and tire dimensions.
But it seems like your TDI runs cooler trany than the gaz engines. |
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Waldi
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Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Tue Nov 18, 2014 5:35 pm Post subject: |
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| Jon_slider wrote: |
Some of the variables between the five vehicles include
1. tire size (IMO R&P is compensation for tires, but R&P does not reduce the added work to turn a taller tire)
2. Vehicle weight loading, including on top. Both of these increase the work, and heat.
3. Skid plates. Check if that is a factor with the hottest van. I believe it is fully clad.
I agree the trans radiates motor heat. More work = more heat.
Fwiw I don't think a tranny cooler is required with stock tires and stock skid plate.
Again IMO, increasing tire size is a precursor to engine upgrade, and R&P upgrade. Iow, the motor and R&P are not primary variables, it's tire size that is a source a extra heat.
I now believe full coverage tranny skid plates are responsible for +20f tranny temp. (With no cooler)
Whether tranny heat arrives as radiant from the motor is immaterial to me. In fact I do believe tranny temps ARE increased by motor temp. My concern though is to not accumulate heat in the tranny.
I do also believe that gear faces, especially small ones on 4th gear, create heat. But more importantly, I believe lubricating 4th, main bearing, and R&P are significant benefits of tranny oil circulation.
For reference, on flat freeway at ~68mph, using cruise control, I see tranny temp 85f over ambient.
I encourage using an over ambient reference, not just tranny temp raw data.
IMO, Hans skid plate is smaller than mine, and probably adds less than the 8F my 14" skid plating.
This is Hans'
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R+P ratio and tire size are the same for the revolutins of the pinion.
So it is the same having a taler gear ratio and small tires, or a short with big tires.
I am sure there is no significant temperature difference between the 4th gears.
And i can only speak for my gearbox which had good bearings after 200k km on a 100hp and 200nm torque engine. Pulling heavy trailers.
I dont need extra oil circulation. |
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Christopher Schimke
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Joined: August 03, 2005
Posts: 5391
Location: PNW
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| Posted: Tue Nov 18, 2014 5:40 pm Post subject: |
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| hans j wrote: |
me: 142* - ALH TDI with brand new SA trans - 215/75-15 tires with oiling plates and 0.73 4th gear
Jahbah: 158* - Subaru 2.5? with stock transmission Probably no oiling plates and I think 215/75-15 tires?
Carterzest: 149* Vanistan with stock transmission Probably no oiling plates and I thought 205/70-14 tires?
Christopher Schimke: 174* - Stock engine with stock trans but 1x taller R&P Oiling plates = yes, full mag box, 5:43, stock 1-4 gears, stock skid plate and 29.1" tires
Frankensubysyncro: 171* - not stock anything with 2x taller R&P 30x9.5 15" BFG Mud tires according to his signature and probably has SA oiling plates
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I just updated my info in Hans' quote above (in red) to reflect that I do have oiling plates and the tire diameter is 29.1", not 29.4".
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Jon_slider
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Joined: April 11, 2007
Posts: 5091
Location: Santa Cruz, Crowdifornia
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| Posted: Wed Nov 19, 2014 9:30 am Post subject: |
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IF ambient was 62F, the following are tranny temps above ambient (all vehicles are syncros)
Hans: +80F 27.8" tires, diesel
Carterzest: +87F 25.3" tires, waterboxer
Jahbah: +96F 27.8" tires, subaru 2.5
Frankensubysyncro: +109F 29.5" tires, subaru 2.5 (I believe this van has the most extensive skid plating of the group, and the tallest lift)
Christopher Schimke: +112F 29.1" tires, waterboxer (I believe this was the heaviest van)
And for reference, freeway temps (not the same trip as the 5 above),
Jon_slider +85F 30.5" tires, 5000 lb Van, diesel, lifted to the max, 21" ride height.
Syncro Jael +86F 27.8" tires, subaru 2.2, about 19.5" ride height.
note on ride height, taller vans have more wind resistance, use more fuel, and likely make more heat to do the work, than a less lifted van.
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Jake de Villiers
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Joined: October 24, 2007
Posts: 5911
Location: Tsawwassen, BC
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| Posted: Wed Nov 19, 2014 9:43 am Post subject: |
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| Christopher Schimke wrote: |
| Jake de Villiers wrote: |
Good data, Hans. Could you put numbers to those "1 x taller" and "2 x taller" R&Ps?
Thanks! |
Hey Jake! I'll save Hans the trouble.
1x = 5:43 R&P
2x = 6:17 R&P |
Thanks Chris and Hans, too. I was just wanting to make sure that 4.57 R&P didn't put me in the 'running too hot' camp. It sure looks like its the taller tires that's the culprit, eh?
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Jon_slider
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Joined: April 11, 2007
Posts: 5091
Location: Santa Cruz, Crowdifornia
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| Posted: Wed Nov 19, 2014 11:10 am Post subject: |
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| Jake de Villiers wrote: |
| I was just wanting to make sure that 4.57 R&P didn't put me in the 'running too hot' camp. |
You are not out of the woods yet. Taller gearing, whether by R&P change or taller tires, both have the same effect.
But hard to say without more info... motor, tire diameter, van weight, lifted, syncro, skid plate armor, roof racks?
fwiw, your R&P is equivalent to a 26.8" tire (+6%) with a stock 4.86
Maybe invest in an IR Thermometer, so you wont have to guess:
http://www.homedepot.com/p/Ryobi-4-to-600-Degree-N...ffZ1z1180y
you also need to measure ambient temperature:
http://www.walmart.com/ip/Taylor-1523-Indoor-Outdoor-Thermometer-and-Hygrometer/24727251
where to measure tranny temps:
All the following quotes from this excellent thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=5...p;start=80
| hans j wrote: |
| I measured the five vans when we drove down to Solstice though. Measured just in front of the diff ribs, where AA is placing temp sensors. |
| pedrokrusher wrote: |
163 near temp gauge
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| Jon_slider wrote: |
Analysis comparing tire size
Compare Jahbah to Carterzest, 9% Larger tire, and 7% hotter
compare Frankensubiesyncro to Carterzest, 15% Larger tire, and 15% hotter
compare Christopher to Carterzest, 14% larger tire, and 17% hotter
in addition to tire size within 2% of Frankensubiesyncro, Christopher was heavier, and had the most stuff on the roof
left to right, Hans, Jahbah, Carterzest, Christopher and Frankensubiesyncro.
It would seem that tire size is the primary variable, and that wind resistance, weight and horsepower are secondary variables
note that Christopher and Carterzest were both similarly heavy, and both had roof racks, yet Carterzest ran much cooler
Also note that even though Carterzest had stuff on the roof and was heavier than Frankensubiesyncro, who had nothing on the roof and was lighter, Carterzest ran cooler, with his smaller tires. |
One implication derived from tire size is that higher rpms are more efficient at producing horsepower, which makes less heat. The tendency to want to drop RPM is counter productive.
It may help to include speed at 4000rpm reference, for gas vehicles. Example, stock VW spec is 71mph@4000rpm
a van geared 10% taller, such as with 215x75x15 tires, would see 78mph@4000rpm, AND would run hotter.
I would be curious to know the speed at 4000rpm for your 5 speed, and its tranny temp compared to your 4 speed.
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Waldi
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Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Wed Nov 19, 2014 11:22 am Post subject: |
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Good data Jon.
So stock is 4,85 and 1x taller is shorter gear ratio 5,43 ?
I was thinking taller is taller 
In my view there is no physical reason why big tires should cause higher trany temps on same over all ratio.
Yes, wide tires and at or mud tires need more power and this will cause more heat on engine and gearbox.
But the same tire in 205-14 and 205-16 with same over all ratio can not cause higher temps. Even i think the 16 run easier.
Less revolutions on pinion cause less oil movement and efficiency of the oil plates and so less cooling.
Would be also interesting to have clutch housing temps from TDI and Gas engines. |
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Jon_slider
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Joined: April 11, 2007
Posts: 5091
Location: Santa Cruz, Crowdifornia
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| Posted: Wed Nov 19, 2014 11:53 am Post subject: |
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| Waldi wrote: |
| 1x taller is shorter gear ratio 5,43 |
no, thats backwards
taller tires, e.g. 215x75x15 is +10% (taller), are offset by shorter R&P. The 5.43 is -12% (shorter) than the 4.86. This combo produces gearing -2% (shorter) than stock. 70mph@4000, for reference 71mph@4000rpm is stock for gas.. I use that as a reference for diesel, but at 3000.. for diesel, I like to aim for 68mph@3000rpm, in my personal experience.. with a 140hp 2.5 AEL Tdi
What is your diesel motors' gearing producing for speed @3000rpm?
| Waldi wrote: |
| In my view there is no physical reason why big tires should cause higher trany temps on same over all ratio. |
I agree in principle, but my observations run contrary to my expectations. I don't know why yet. Large tires may be revealing other correlated modifications, such as increased wind resistance on expedition style vans, lifted, increased weight, with lots of gear on the roof and inside, and more than one person, as was the case for the hottest running Syncro, Christopher.
And by the way, All my tranny temp discussions are based on high speed use freeway travel of minimum 65mph. At that speed my van makes much more heat than at 55mph or less. So your earlier comment that you don't see any main bearing burn on the pinion shaft, may be due to your low speed travel? Also, you are not a syncro, and lack skid plates that contain heat, not only under the transaxle for those of us who add custom plates, but also under the motor.
Offroad Protection adds heat, and weight.
Lubrication aside, I agree that the tranny is radiating heat whose original source is the Motor. I agree a fan on the bell housing would be a practical avenue of tranny cooling to investigate.
Reducing heat to the tranny may only be necessary for heavy vehicles that do high speed travel. The coincidence may be that these vehicles are heavy, have stronger motors, taller tires, and put greater loads on their transaxles, than a 2wd diesel pulling a trailer up a mountain at slow speed, not sure. You would need to start by contributing temperature and tire size data 
| Waldi wrote: |
Less revolutions on pinion cause less oil movement and efficiency of the oil plates and so less cooling.
Would be also interesting to have clutch housing temps from TDI and Gas engines. |
I don't consider the oiling plates a cooling function to the overall internal temperature of the gear oil. And their effectiveness as lubrication improvement is disputed.
> Less revolutions on pinion
this may put the motor in a lower rpm range where there is less horsepower available.. thereby producing more heat. I consider tall gearing a heat maker. The hottest syncro, had a 5.43 R&P plus 29.1" tires, making the combined gearing, only slightly taller than stock, +3%, or 73mph@4000rpm, waterboxer
tire size also has a mass component, larger weight, further away from the fulcrum (axle), so require more work to turn.. more work, more heat.
In terms of diesel vs gas, I agree bell readings will be helpful. Please post your data, including operating parameters, location of temperature reading, and pics are always great!
Link
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hans j
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Joined: May 06, 2006
Posts: 2715
Location: Salt Lake City UT
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| Posted: Wed Nov 19, 2014 12:12 pm Post subject: |
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| Waldi wrote: |
Good data Jon.
So stock is 4,85 and 1x taller is shorter gear ratio 5,43 ?
I was thinking taller is taller
In my view there is no physical reason why big tires should cause higher trany temps on same over all ratio.
Yes, wide tires and at or mud tires need more power and this will cause more heat on engine and gearbox.
But the same tire in 205-14 and 205-16 with same over all ratio can not cause higher temps. Even i think the 16 run easier.
Less revolutions on pinion cause less oil movement and efficiency of the oil plates and so less cooling.
Would be also interesting to have clutch housing temps from TDI and Gas engines. |
It was my mistake to call it a taller R&P initially. It is shorter, but I wasn't thinking it through and probably only calling it taller because the numbers are larger.
The same overall tire diameter isn't going to change anything regarding gearing, but in this case there are different size tires involved with different R&P.
Updating this list with my trans specs with blue:
| Quote: |
me: 142* - ALH TDI with brand new SA trans - oiling plates = yes and full aluminum box 4.86 R&P stock G-1-2 and 1.18 3rd, 0.73 4th. No decoupler, 50% skid plate covering trans, full skid plate on engine. 28.7" tires,
Jahbah: 158* - Subaru 2.5? with stock transmission Probably no oiling plates and I think 215/75-15 tires?
Carterzest: 149* Vanistan with stock transmission Probably no oiling plates and I thought 205/70-14 tires?
Christopher Schimke: 174* - Stock engine with stock trans but 1x taller R&P Oiling plates = yes, full mag box, 5:43, stock 1-4 gears, stock skid plate and 29.1" tires
Frankensubysyncro: 171* - not stock anything with 2x taller R&P 30x9.5 15" BFG Mud tires according to his signature and probably has SA oiling plates |
I think it would be interesting to see a comparison on rotations of the tire at the pavement for the different vehicles measured. I'd also like to work up a printable chart that can be used when in a convoy. That should take a lot of guess work out of what numbers to fill in! I plan to have something ready like that for Syncro Solstice when there should be multiple variations of vans driving together, same day, same conditions.
And I do think Chris' van was heaviest, but I have weighed mine on race scales and it comes in at 5200 lbs fully loaded with two people.
Also I was in front of the caravan. I've noticed less stress on the car (better fuel economy) when I follow other cars. Speed was about 65mph for a while then dropped to 60 mph (specific details are in the other thread I think).
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Waldi
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Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Wed Nov 19, 2014 12:24 pm Post subject: |
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Hans, please istnall a decoupler with a bit harder fixed visco.
First i think you will say after the install, why didnt i do it before, second i think the temps will go a bit down and the mpg will rise.
Ps:
I finished today a syncro box for Stefan Herzberg. Do you want to buy a ZA |
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Jon_slider
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Joined: April 11, 2007
Posts: 5091
Location: Santa Cruz, Crowdifornia
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| Posted: Wed Nov 19, 2014 1:16 pm Post subject: |
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| hans j wrote: |
The same overall tire diameter isn't going to change anything regarding gearing, but in this case there are different size tires involved with different R&P…. |
coldest to hottest, added calculated speeds for use to verify:
Hans: 142F +14% 4th. +10% tires, = +24% diesel 66mph@3000rpm, I call that -7% (short)
Carterzest: 149F +0% tires gas, 71mph@4000rpm= 0% (tall) overal
Jahbah: 158F +10% tires, gas 78mph@4000rpm= +10% (tall) overal
Frankensubysyncro: 171* -27% R&P, +17% tires, = -10%, he may have a .7 4th +18%, if so, gas 77mph@4000rpm +8% (tall) overall
Christopher Schimke: 174F -12% R&P, +15% tires, gas 73mph@4000rpm = +3% (tall) overall
Christophers blue van on right has +15% larger tires, and runs +17% hotter, than carterzest brown van on the left. It might have nothing to do with tire size, maybe just the weight of the van is the determinant of its temperature... I wish I knew what these 2 vans weighed..
example, if Christophers rig is 17%, heavier than carterzest, then Christopher runs 17% heavier AND hotter, tire size be damned..
hottest on right
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Waldi
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Joined: February 28, 2014
Posts: 1752
Location: Germany
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| Posted: Wed Nov 19, 2014 2:16 pm Post subject: |
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The stock r+p ratio for a 14 diesel was 5,43 or shorter 5,83.
I think it is not good to compare different engine revolutions and speeds on the trany temp.
Ah, my van is a syncro. 4,85x0,78
As i told i change my tires due to using.
With trailer 205/65-16
Without 205/80-16
My usual speed on highway is with trailer 90 and without 110km/h.
While even with a conversion (no turbo) gazer it is very importand to go down with the gear ratio with big tires, there is not necessary on a conversion diesel.
Reason to relation on revolutions x torque=power
Danger to the trany are full diesel torque under 2k revolutions
And there is a point on speed where high revolutions lead to high trany temps because the engine and trany goes on full load.
So we con not genaraly say higher pinion revos cool better.
But we can say high torque on low pinion revols make more heat and cool less.
Edit:
I have the original diesel engine skid plate.
The diesel engine is originaly also covered at all.
I remove in summer the cover for better cooling but not the skid plate.
Another edit:
Shit i am still in the old term. When i maintained my gearbox after 200k km, 30k ago, i have changed the 4-th to 0.82.
It is a nicely shorter step from 3-4 better acceleration when pulling the trailer. |
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Syncro Jael
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Location: Utah
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| Posted: Wed Nov 19, 2014 2:40 pm Post subject: |
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On one of our last trips to Oregon/Washington we happened to stop at a road side scale. Our Syncro weighed 5745lbs with all our gear, 2 adults, 2 dogs, and loaded for BEAR.  I am stock 4:86 RP with 215/75/15 (27" tall) tires. I run a decoupler also that may contribute to less stress/less heat build up in the transaxle. I have a skybox, LED bar, Yakima Basket on top that I know makes me less AERODYNAMIC than stock. Along with a lift of 19.5" that puts all this crap higher in the jet stream. So I know my EJ22 Subaru and transaxle gets to work a little harder than most.
I too am running an all aluminum tranny from AA with oiling plates installed. Hopefully this next Solstice I can run with Hans and the pack down to Moab and get in the results too.
I do believe the air scoop aids in keeping my tranny cooler out on the highway and am still interested in a cooling system on the next tranny.
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pedrokrusher
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Waldi
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| Posted: Thu Nov 20, 2014 12:58 am Post subject: |
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| Syncro Jael wrote: |
On one of our last trips to Oregon/Washington we happened to stop at a road side scale. Our Syncro weighed 5745lbs with all our gear, 2 adults, 2 dogs, and loaded for BEAR. I am stock 4:86 RP with 215/75/15 (27" tall) tires. I run a decoupler also that may contribute to less stress/less heat build up in the transaxle. I have a skybox, LED bar, Yakima Basket on top that I know makes me less AERODYNAMIC than stock. Along with a lift of 19.5" that puts all this crap higher in the jet stream. So I know my EJ22 Subaru and transaxle gets to work a little harder than most.
I too am running an all aluminum tranny from AA with oiling plates installed. Hopefully this next Solstice I can run with Hans and the pack down to Moab and get in the results too.
I do believe the air scoop aids in keeping my tranny cooler out on the highway and am still interested in a cooling system on the next tranny. |
I think the 4,85 with your tires and weight/shape is too tall for the gazer. |
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Syncro Jael
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Joined: December 19, 2013
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Location: Utah
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| Posted: Thu Nov 20, 2014 5:54 am Post subject: |
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Waldi,
I agree that I am geared too high and loaded too heavy for the EJ22 gasser. I'd have to drop some serious coin to change RPs front and rear. I also don't want to loose the ground clearance and looks of taller tires.
There always seems to be a trade off somewhere?
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Subaru EJ25 Forged Frankenmotor, Triple Knob.
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Syncro Jael
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Joined: December 19, 2013
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Location: Utah
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| Posted: Wed Jan 07, 2015 3:02 pm Post subject: |
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We just went on a great road trip and I documented some tranny temps.
Across Nevada desert 60-65 mph mostly flat ground, ambient 22° tranny temps 90-105°. Going slow under 5 mph on unpaved roads (trails) the tranny heated up in the 130° range with ambient temps in the low 30°'s. As soon as I got some airflow under the van on paved roads it went down in the 120°'s.
Cold morning 7° F tranny never got above 95°. Pretty knotchy shifting in 1st and 2nd gears until the tranny temp got to 84°.
The rest of the trip the tranny held to it's normal 80-85° above ambient temps.
Coming over the pass into Victorville in a snow squall the tranny temp went down below 80° - that is the low mark on the gauge.
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