cooling observation

[T1 woodywagon]

I did the tbi to 2.5 T1 swap a couple of weeks ago in my 88' reliant wagon. So after driving it now for awhile I noticed it seems to cool more efficiently than my tbi set-up. Everything is the exact same, except for the reverse coolant flow of the 89' donor motor. The motor size is the same, same rad, and same used coolant. I run a mechanical temp gauge in my car so I am always looking at it.Plus my old motor was good too it never ran over 170. Did the reverse flow really make that much difference?

[Reaper1]

170*F !? That is TOO cold!! The computer still has the engine in closed loop trying to warm it up, unless you've tweaked the cal. Even if you did, that is still too cold! At least get the coolant up to 180*, preferably 190*. Oil temps should be over 200* for daily driving around under normal operating temperatures.

[shackwrrr]

Newer engines aren't reverse flow, the impeller just spins the opposite direction. The housing and impeller are more efficient though. 170 is too cold, at temps that low water can still condensate in the oil causing the oil to become acidic.

[T1 woodywagon]

I bought my 2.5 tbi feb 2012. As of feb 2013 I had put 18,600 miles on it. I commute back and forth to my job 1400 miles round trip, every few weeks plus all the road miles going to the different work sites. I can drive 410 miles on a full tank of gas in wagon. Thats pretty good for an all original 25 year old motor and car. The car had 80,000 miles on it when I bought it. When I put in the turbo set-up I installed .91 transfer gears with the 2.86 turbo ring gear. I want to see if that helps on those long commutes. I run a 160 degree thermostat in my daily driver. In my woody wagon I drag race I don't even run a thermostat, and I've made probably over 100 runs at mission raceway testing tons of different engine parameters. when you compete in drag racing and expect to go 6-7 rounds on race day you have to have 100% control over engine temps at all times.

[GLHNSLHT2]

I agree with Reaper, 170 is too cold. Now are you just running the 89+ water pump or are you truely reverse cooling the engine?

[T1 woodywagon]

I swapped in an oem 89' 2.5 T1 motor and trans from an 89' lebaron vert. The only change on the motor is the 89' TII garrett, and the .91 transfer gears in the trans. Later I might try a 89' tbi converter, and of course I will get the splines changed in the converter. My focus with this set-up is for the mostly freeway driving, and commuting I do with my car. I probably average 75 mph when I commute and drive to work sites. I also have 16" GTC lace wheels and mvx 205/65/16 mounted on them.

[Reaper1]

I bought my 2.5 tbi feb 2012. As of feb 2013 I had put 18,600 miles on it. I commute back and forth to my job 1400 miles round trip, every few weeks plus all the road miles going to the different work sites. I can drive 410 miles on a full tank of gas in wagon. Thats pretty good for an all original 25 year old motor and car. The car had 80,000 miles on it when I bought it. When I put in the turbo set-up I installed .91 transfer gears with the 2.86 turbo ring gear. I want to see if that helps on those long commutes. I run a 160 degree thermostat in my daily driver. In my woody wagon I drag race I don't even run a thermostat, and I've made probably over 100 runs at mission raceway testing tons of different engine parameters. when you compete in drag racing and expect to go 6-7 rounds on race day you have to have 100% control over engine temps at all times.

Sounds like you are getting around 25mpg. Not bad at all :thumb:, but within range with the set-up you have. I agree that is great for a 25 year old car.

If you want to run your engines that cold, that's your choice. We are just indicating that you are most probably leaving power and economy on the table, and are certainly shortening oil life. Though, I admit it's speculation because you most probably don't have a way to monitor oil temps, however, it is a VERY educated opinion.


I swapped in an oem 89' 2.5 T1 motor and trans from an 89' lebaron vert. The only change on the motor is the 89' TII garrett, and the .91 transfer gears in the trans. Later I might try a 89' tbi converter, and of course I will get the splines changed in the converter. My focus with this set-up is for the mostly freeway driving, and commuting I do with my car. I probably average 75 mph when I commute and drive to work sites. I also have 16" GTC lace wheels and mvx 205/65/16 mounted on them.

The '89-up common-block engines are standard cooling, so besides the water pump design change, the cooling system is the same. If you are focusing on freeway economy, then I'd suggest going with a lock-up TC transmission and controlling the lock-up clutch with a simple switch like a lot of diesel guys do. Simon (turbovanman) has this type of set-up in his van as well. I remember him syaing something about how well it worked, but I don't know that he is currently using it.

[contraption22]

170 degrees is too cold. 160 degree thermostats are not good for street use. You need at least 180, preferably 195 in a car that sees a lot of highway miles.

[T1 woodywagon]

Thanks for the reply guys. I enjoy reading the opinions. I forgot to mention I was driving the same 88' 2.5 tbi car for 10 years before I bought my new one last year. So I also have very educated and real use data. I've ran them all 195*, 180*, 160*, and no thermostat. In that 10 years and thousands of miles I've logged and collected data from each set up in a large number of parameters. And my real world user conditions have put me at a 160* thermostat. I would probably drive more than 20,000 miles a year on my set-up, but I also use my dually as well from april to november every year. I run royal purple 5/20 synthetic, and 1 liter of lucas oil synthetic stableizer in all my vehicles, and have gone 15,000 miles between changes on my original reliant. Not sure what kind of milage and usage you guys are doing with your cars. Also when I make the commute with my car it is loaded up pretty good because I leave home 2-3 months at a time.

[Reaper1]

Have you ever had the oil analysed? That will truly tell the story on what contaminants are in the oil, and how much.

Out of curiosity, what parameters/figures lead you to your choice of thermostat?

[T1 woodywagon]

I'd like to respond so give me a little time. My wife just gave birth to our son 6 days ago, and its lunch now for him then to the doctors this afternoon, I'll post after dinner. Thanks

---------- Post added at 12:56 PM ---------- Previous post was at 12:51 PM ----------

I just thought, maybe in the meantime you show me from your data that you have collected that 160* is so bad, with oil analysis, decreased power, milage and such.

[Reaper1]

http://www.jcb-conseils.com/uploads/1256109595_noria_moisture.pdf

1st page, under #4. "Low jacket-water temperature and intermittent operation may prevent the water from easily vaporizing out of the oil compartment."

The entire thing is a good read, however.

---------- Post added at 05:34 PM ---------- Previous post was at 05:28 PM ----------

http://www.bobistheoilguy.com/engine-oil-analysis/

This is a friggin AWESOME resource for oil information (and now other things it seems). In this article it states that oil viscosity is typically tested when the oil is at 210*F. If the oil isn't that hot, then it isn't at operating temperature, and there is less of a chance for water to evaporate (which is also discussed).

[Reaper1]

http://www.carnut.com/ramblin/cool3.html

Here's a visual aid on engine coolant vs. potential power an engine wear.

---------- Post added at 06:03 PM ---------- Previous post was at 05:57 PM ----------

http://speedtalk.com/forum/viewtopic.php?f=1&t=27948&start=15

While not a true study, and more opinions, it does offer feedback on both power and engine longevity.

One last point to make...one word: thermodynamics. It is the basis for heat transfer. Understand it, and then you will start to understand the benefits of engine temps warmer than 160* (though I'm betting the engine IS running warmer than that simply because that is only the "advertised" opening point for the thermostat)

[T1 woodywagon]

Reaper you miss understood me, I meant your personal data from your own vehicle with regards to decreased power, milage, and oil analysis when using a 160* stat compared to 180* or 195*. I scanned over the links from other general findings you suggested. Right in number 4 it says MAY prevent the water from easily vaporizing out of the oil compartment. and then under water %, the last sentence says "an occasional long highway drive is good for your oils health. Plus the fact I drove an already 15 year old 60,000 mile car an additional 10 years and easily over 100,000 miles mostly with a 160* thermostat supports my point quite firmly. Remember were talking a 100 hp car here. When I drive to my job I do it in one shot over an 11 hour or so period, good constant temps all the way. I think that helps. I don't even know why I would even consider getting an oil analysis done when I'm pulling out over 400 miles on a 25 year old high milage engine with a 160* stat?

[Reaper1]

Yes, I've had a coolant temp sensor go out. Basically it makes the computer default to closed loop, just like if the engine is below whatever the open loop switch-over point is. The car got significantly worse millage, and ran like crap.

I changed from a 195* thermostat to a 180* in my 8v Shelby Z. I was after the best of both worlds (economy and power), and I was following a trick that was supposed to work in the 3.0. One day I was doing some research on thermal efficiency of an engine and found that having it warmer should actually yield a more efficient engine all around. So, I swapped back to a 195* thermostat. The car got a bit better fuel millage. I've been to track days with it, and even running it hard for 20 minutes at a stint, it never ran hot.

Look, if you want to go against convention, go for it! I'm not going to sit here and bash this horse to death over a car that isn't mine. I'm just trying to spread information. What you choose to do with it is your deal.

I'm happy you get decent millage out of your car and that it is faithfully serving you well! That's awesome and I'm not taking away from it. I wish you another happy 100+k miles! :thumb:

[GLHNSLHT2]

So what's your actual MPG? Reaper somehow came up with 25 but I'm not sure what he's calculating that off of. If the TBI engine never got above 170, what's the turbo engine getting too that has it "cooling more efficiently"?

[T1 woodywagon]

I am too scared to tell you guys now.

[Reaper1]

So what's your actual MPG? Reaper somehow came up with 25 but I'm not sure what he's calculating that off of. If the TBI engine never got above 170, what's the turbo engine getting too that has it "cooling more efficiently"?

He's saying he can go 400 miles on a tank of gas. I'm figuring the wagons got the 16 gallon tank, instead of the 14 gallon tank. 400/16 = 25. If it is the 14 gallon tank, then we are looking at 28.5mph or so. I will admit I find that hard to believe if no other mods support just the thermostat change.


I am too scared to tell you guys now.

Why? I have personally told you that I'm not trying to take away from your success, but that it simply goes against convention.

[T1 woodywagon]

I was just joking about that. Guess I should have put an lol in there. I'm not big at texting or typing. After I did my swap and was driving in local lower mainland traffic during good weather I was monitoring the temp gauge. In stop and go traffic with the fan it would drop to about 135*-140* thats 20*-25* lower than normal for me, so thats why I asked the original question. Reaper, I travel to Tacoma from time to time so next time I'll swing by and show you the machine.

[Reaper1]

I was just joking about that. Guess I should have put an lol in there. I'm not big at texting or typing. After I did my swap and was driving in local lower mainland traffic during good weather I was monitoring the temp gauge. In stop and go traffic with the fan it would drop to about 135*-140* thats 20*-25* lower than normal for me, so thats why I asked the original question. Reaper, I travel to Tacoma from time to time so next time I'll swing by and show you the machine.

Do you have a manual switch on the fan? The reason I asked is because the OEM calibration turns the fan on around 210*. There are 3 situations that I know of that will turn the fan on otherwise (2 assume the car has A/C):

If the A/C is selected to be on, the fan will cycle with the A/C clutch.
If the defroster is selected, the A/C will cycle to dry the air out and hence the fan will run.
If the SMEC/SBEC senses the outside air temp is such that the radiator warming up could possibly cause condensation on the radiator to boil off and cause steam, it will turn the fan on to suck the possible steam under the car so the driver isn't alarmed by it.

I would love to see the car. I'm always open to meeting other TM'rs!! :D

[T1 woodywagon]

Yes my car is an a/c car, but anytime I have the defroster selected it cycles every 11 seconds, and the fan stays on for 7 seconds. I saw your masi thread too, looks very professional.

[Reaper1]

That sounds right. The A/C cycles with the defrost selected to dry the air being blown on the windsheild. The fan gets cycled when the A/C cycles.

Thanks on the Masi. I'm hoping to get it shipped to me within the next couple of weeks. I still have a bit to do on the car before I can put it in, and that stuff requires a welder. If I go the route I'm currently thinking of going, this will be a very unique build within the TM community. ;)