180 VS 160 degree thermostat

[turbojkt]

I've always had a 160 degree thermostat in my Turbo Regal but a good mechanic friend suggested running a 180 if it is street driven a lot. He says the oil would stay cleaner longer, and I have noticed that my oil gets very dirty very fast.

How much, if any, would a 180 increase detonation?

Anyone have any ideas or suggestions on this subject??

 

[scottyb]

Change the oil more.

I can't homestly answer your question about detonation, but remember that almost all aftermarket chips are designed for 160 thermostats. In addition, they usually operate the cooling fan based on this. Even when it's cold out, a 180 stat will make the fan run constantly.

 

[87gninpa]

i run a 160 all year round here in the northeast and i think its mandatory. dont know about your oil, but mine stays clean for 3k until i change it, dont think a thermostat would have anything to do with that. and as for the detonation, with a 180 your car will run hotter, but i dont think it will directly "cause" detonation

 

[Rayk]

An engine running at 180 deg will definitely detonate more at a given boost level than one with a 160 deg. The whole purpose of the 160 is to be able to run higher boost than stock. Change oil more frequently if you want max performance out of your combo and run the 160.

 

[Ormand]

An engine running at 180 deg will definitely detonate more at a given boost level than one with a 160 deg

Would that be 40% more, or 0.00363% more? And either way, how did you test it? How do you figure the per centage? Is it mor detonation, as in more often, or more detonation, as in stronger?
There is some historical basis for the 160 thermostat. Maybe it has to do with Camaros, running a 302 and a Holley carb. And most of the chip burners, as mentioned above, set the fan based on a 160. But there doesn't seem to be much technical basis for the 160 vs 180. NASCAR stockers, running at 800 or 900 horsepower, are usually above 200 degrees. The 20 degree difference in T-Stat setting will NOT translate into 20 degrees lower temp at the top of the piston, or the edge of the exhaust valve, or the tip of the spark plug. Those are the "hot spots" that might trigger pre-ignition (not the same as detonation, but bad, anyway)
Turbo Tune, in Greensbore, NC, volunteered their dyno for me to run tests, with both T-stat settings, but I never followed up. It would be interesting to see the results, but it would also be hard to run the test, without other variables affecting the results.

 

[Rayk]

Originally posted by Ormand
Would that be 40% more, or 0.00363% more? And either way, how did you test it? How do you figure the per centage? Is it mor detonation, as in more often, or more detonation, as in stronger?
There is some historical basis for the 160 thermostat. Maybe it has to do with Camaros, running a 302 and a Holley carb. And most of the chip burners, as mentioned above, set the fan based on a 160. But there doesn't seem to be much technical basis for the 160 vs 180. NASCAR stockers, running at 800 or 900 horsepower, are usually above 200 degrees. The 20 degree difference in T-Stat setting will NOT translate into 20 degrees lower temp at the top of the piston, or the edge of the exhaust valve, or the tip of the spark plug. Those are the "hot spots" that might trigger pre-ignition (not the same as detonation, but bad, anyway)
Turbo Tune, in Greensbore, NC, volunteered their dyno for me to run tests, with both T-stat settings, but I never followed up. It would be interesting to see the results, but it would also be hard to run the test, without other variables affecting the results.

Yes, it would be interesting to run some tests to develope some reliable data to substantiate the effects of the block temp vs cylinger temp vs knock. I don't have any specific data for my statement but will tell you that, years ago, I installed a performance chip in my first TR without changing out the stock T-stat or blocking the intake manifold water lines and I could not crank the boost up past about 15 or 16 without noticable (audible) knock. After installing the 160 and blocking the water lines with no other changes I was able to run about 17 psi boost with no audible detonation. (don't know about inaudible knock). So, I'm satisfied based on unscientific results that the 160 is necessary for "optimum performance". I should also mention that I live in Central Florida where inlet (MATs) are higher than in other parts of the country so maybe that has an affect on my situation. It's an interesting topic and one that some controlled testing could add credibility to.

 

[bruce]

Like lots of things, it's a matter of tuning.

Using a 160 does add some more fuel into the equation.

180's help to increase the cylinder head clamping.
Raises overall engine effeicency.
Reduces piston skuffing, on oem engines.
Better gas mileage.
Lower emissions.
Boiling the condensation out of the oil more completely.

Downsides to the 180, for a properly tuned engine....
1. I can' think of any, other then a few degrees hotter piston dome.



Some years ago, I did some back to back passes, with 195, 180, and 160 thermostats, with carbs (SBC, 355 CID) set up for each operating time.
I'd also experimented with ESC modules for fine tuning the system to be able to run as much timing as possible, and stay right up again the Knock Sensor.
The results were all within what I would consider in normal errors from run to run.

I've run a 180 in my GN without a hitch for years.

Like I said in the opening sentence, the tune has to be right.

 

[VinsGN]

I’ve got a mostly stock 87 GN and planned on replacing the Stat with a 160 degree unit and bypassing the TB coolant line. When I posted a couple months back various members said there would be no ill effects with the changing to 160 degree unit. But now, from this post there’s talk about head clamping issues and cooling fan turn on times. Should I continue with this mod? Your suggestions are greatly appreciated.

PS: I’m running the stock chip / 3” DP and 3” exhaust / Walbro 340 / Acufab adjustable fuel regulator.

 

[Rayk]

Originally posted by VinsGN
I’ve got a mostly stock 87 GN and planned on replacing the Stat with a 160 degree unit and bypassing the TB coolant line. When I posted a couple months back various members said there would be no ill effects with the changing to 160 degree unit. But now, from this post there’s talk about head clamping issues and cooling fan turn on times. Should I continue with this mod? Your suggestions are greatly appreciated.

PS: I’m running the stock chip / 3” DP and 3” exhaust / Walbro 340 / Acufab adjustable fuel regulator.

I'm curious as to why you've chosen to run the stock chip with the "recipe" mods you've done to your car. Perhaps you like lower boost and higher timing? As for long term effects of running a cooler thermastat, my WE4 has over 165,000 miles on the original engine, heads, and manifolds and almost 200 1/4 mile passes. I installed the 160 stat at 77,000 miles and my engine is still very solid with 25psi oil pressure at idle and still runs strong.

 

[Ormand]

I'm with Bruce- tuning makes the difference. If you have an "off the shelf" chip, which is set up for a 160 T-stat, then the fan turn on temp will be lower than stock, maybe something like 175. If you use this chip with a 180 T-stat, then the fan will run all the time. Some people don't mind this, others do. But if you have the right chip, such that the fan and other parameters are matched to the engine temp, then I think the advantages of the 180 are clear.
As far as I can tell there are no disadvantages to bypassing the throttle body coolant passages. It's just one more potential leak.

 

[VinsGN]

Originally posted by Rayk
I'm curious as to why you've chosen to run the stock chip with the "recipe" mods you've done to your car. Perhaps you like lower boost and higher timing? As for long term effects of running a cooler thermastat, my WE4 has over 165,000 miles on the original engine, heads, and manifolds and almost 200 1/4 mile passes. I installed the 160 stat at 77,000 miles and my engine is still very solid with 25psi oil pressure at idle and still runs strong.

Ray,

To tell you the truth I’m a little leery messing with the computer. I don’t feel my knowledge about the car and a computer controlled car, for that matter, is at a level where I feel comfortable making the next step. Although I do plan to up grade the chip I’ve been trying to safely do “little” changes to prepare for the chip up grade. Am I totally lost?

My Buick history is in Nailheads, tune the carb by ear and set the timing, done. A far cry from the Turbo motor.

 

[Rayk]

Originally posted by VinsGN
Ray,

To tell you the truth I’m a little leery messing with the computer. I don’t feel my knowledge about the car and a computer controlled car, for that matter, is at a level where I feel comfortable making the next step. Although I do plan to up grade the chip I’ve been trying to safely do “little” changes to prepare for the chip up grade. Am I totally lost?

My Buick history is in Nailheads, tune the carb by ear and set the timing, done. A far cry from the Turbo motor.

Fair enough. Changing the chip is very easy but if you've never done it, It can sound intimitading. If you want to change it, you can post and get lots of help to walk you through the process. I think there might also be a tutorial on GN/TType forum. You'll notice a nice performance increase with the extra boost and fuel you'll get with a good street chip.

 

[bruce]

Originally posted by VinsGN
I’ve got a mostly stock 87 GN and planned on replacing the Stat with a 160 degree unit and bypassing the TB coolant line. When I posted a couple months back various members said there would be no ill effects with the changing to 160 degree unit. But now, from this post there’s talk about head clamping issues and cooling fan turn on times. Should I continue with this mod? Your suggestions are greatly appreciated.

PS: I’m running the stock chip / 3” DP and 3” exhaust / Walbro 340 / Acufab adjustable fuel regulator.

The thermostat sets the min operating temp., the fan enable temps set the *normal* operating temp..

If your using the stock chip, IMO, leave it alone. BTW, there are a number of chips that are better then the stocker.

Bypassing the TB hoses, can under some circumstances allow the throttle body to ice up, and cause the throttle to *stick*. A snap of the throttle losens it, but can be puzzling the first few times it happens. Normally that's not a problem, but it is something that can happen.

Like I said, for me, the 180dF thermostat is just fine. Others will argue about it increases the possibility of detonation. If the engine has a bunch of miles on it, I'd say leave it alone.

 

[Race Jace]

Originally posted by bruce


180's help to increase the cylinder head clamping.
Raises overall engine effeicency.
Reduces piston skuffing, on oem engines.
Better gas mileage.
Lower emissions.
Boiling the condensation out of the oil more completely.

although these things are true. the disadvantages are higher under hood temps this will result in higher intake temps if the filter is under the hood.
this will also reduce rubber hose and seal life.

if these were normally aspirated engines or non adjustable boost pressure systems (supercharger) then the 180 might be the way to go.

On our cars, you can make more hp, make every under hood componant last longer and increase reliability if retaining the 160 T stat.

 

[bruce]

Originally posted by Race Jace
although these things are true. the disadvantages are higher under hood temps this will result in higher intake temps if the filter is under the hood.
this will also reduce rubber hose and seal life.

if these were normally aspirated engines or non adjustable boost pressure systems (supercharger) then the 180 might be the way to go.

On our cars, you can make more hp, make every under hood componant last longer and increase reliability if retaining the 160 T stat.

While true on a race car, his isn't.

20dF on a hose makes little to about nil difference in life expectancy. Better purging of the oil moisture is alot more paramount in the grand scheme of things, for a street car.

If one's the least bit concerned about under hood temps, the biggest bang for the buck is a Barrier Coated set of headers, and Barrier coated THDP. Along with removing the rear welting across the back of the hood to aid in venting the hot under hood air.

The contribution of the exhaust system totally overwhelms the coolants contribution, of a delta of 20dF.

 

[Race Jace]

Originally posted by bruce
While true on a race car, his isn't.

20dF on a hose makes little to about nil difference in life expectancy. Better purging of the oil moisture is alot more paramount in the grand scheme of things, for a street car.

If one's the least bit concerned about under hood temps, the biggest bang for the buck is a Barrier Coated set of headers, and Barrier coated THDP. Along with removing the rear welting across the back of the hood to aid in venting the hot under hood air.

The contribution of the exhaust system totally overwhelms the coolants contribution, of a delta of 20dF.

have you ever experomented with these coatings and recorded any underhood temperature change? We have and even though we have just everything under the hood coated on our cars. We tried to measure the difference and could not find any reduction underhood temperatures reguardless of manufactures claims.

Changing the T stat will change the temp at least the 20 deg seen on the water temp gage. (we have measured this) and is significantly cheaper than $400-$500 in coatings.

Wraping your headers with thermal wrap will do the most for underhood radiant heat but these significantly reduce header life.

 

[Steve V]

Great thread guys!!My GN has the THDP wrapped with header wrap,how can this shorten it life?Sorry if it's a stupid question.

 

[bruce]

Originally posted by Race Jace
have you ever experomented with these coatings and recorded any underhood temperature change? We have and even though we have just everything under the hood coated on our cars. We tried to measure the difference and could not find any reduction underhood temperatures reguardless of manufactures claims.

Changing the T stat will change the temp at least the 20 deg seen on the water temp gage. (we have measured this) and is significantly cheaper than $400-$500 in coatings.

Wraping your headers with thermal wrap will do the most for underhood radiant heat but these significantly reduce header life.

Yes, I have.

Well golly gee, a themostat is cheaper then a Thermostat?.
You brought up under hood temps, the most effective way is with heat management of the exhuast system.

Like so many things, cheap is only a short term answer. Thermal warp is just way too cheap of answer, IMO.

 

[bruce]

Originally posted by Steve V
Great thread guys!!My GN has the THDP wrapped with header wrap,how can this shorten it life?Sorry if it's a stupid question.

Take it off would be my advise. That wrapping makes an excellent absorbant for oil, fuel, atf, brake fluid etc.. Not to meantion with high EGTs you can ignite it, with those fluids soaked into it.

Oh, and with enough use, it will crystalize the pipe, and make it unrepairable.

 

[VinsGN]

I have not performed any tests or experiments but…. My stock headers and 3” DP are ceramic coated and I have felt no reduction in under hood temps. My conclusion is these cars just get hot as hell!

When it comes to the 160 stat member’s views really get polarized. On a race unit it’s clear as day (at least to me) that a 160 stat is the way to go, but for a stocker it’s still unclear to me. By going to a 160 stat and bi-passing the coolant to the TB I was hoping to reduce engine temp and intake charge. My concern is I use the car to go back and forth to work on nice summer days and stretch its legs from time to time during a little street showdown, but that’s it, no winter duty. I just do not want to run into problems with blowing head gaskets, erratic idle, open and closed loop problems, ect... or failing CT emissions.

I do have 113K on the car but I’ve replaced the head gaskets (Felpro), used ARP bolts / dual row timing chain / HV oil pump / new water pump / all basic tune up and ware items have been replaced.