Foosh

That just shows what the cooling system was intended to maintain whether it's a 160 or 180 stat. GM intended the engine to run at least above 180, and usually above 190 while at speed.

All a 160 stat does is stay open more often (generally all the time), but the overall capacity of the cooling system remains the same. Again, once a 160 or 180 stat opens, it's exactly the same cooling system.

It might make some sense for the drag racers out there, who want a few more ponies at launch time. For everyone else, it's pretty irrelevant.

Zig

if it's open all the time, wouldn't that be the same as running without one ?

capacity yes, effects no.

Lankhoss

From what I have been told, the thermostat shouldn't affect the operating temperature, except when it gets really cold....it may run cooler. However, it will help prevent the car from getting too hot, since the thermostat is opening sooner. It seems to be working, since I was running the car hard out at the track in blistering hot heat....and the coolant never got above 220.

And what I was trying to say about the oil vs. coolant temperature is I have ONLY seen the oil get hotter in EXTREME conditions. But 99% of the time the oil is cooler. I'm not sure if the person that was posting about the oil temperature meant that it gets hotter in extreme conditions only, or during normal operation.

Bill's ZO6

This is a reply to 4enjoyn. The dyno test before the additions for rear whell numbers was 450.5 rwhp and 423.4 torque. After the additions: 484.4 rwhp and 466.4 torque.

Zig

are you saying you picked up 33.9 rwhp and 43 rwtq from simply replacing the thermostat.

that has got to be the best bang for the buck mod. i've heard of.

therm. $20, gain 33 and 43, that's less than $1 per rear wheel ft lb. gain.

Foosh

I'm sorry, but that part in bold just doesn't make any sense. It shouldn't run any hotter than 220 with a 180 stat either under the same conditions. I've never seen mine hotter than that while running hard with a 180 stat in blazing heat.

Again, when a stat is open, it's open and that's it, it's done. The 180 stat will not close again while you're continuously running the car, so it's doing the same thing as the 160--allowing full coolant flow.

I do acknowledge that if you are a drag racer, and per Ranger's advice, you want to keep the car under 200 before you hit the staging area, a 160 stat will give you more time to work with. That seems to be the primary advantage. But, GM wants the LS7 running at about 190-200 optimally. That's better for optimum oil temp (hence better lubrication) and less wear and tear on the engine. That's why they put the 180 in it, so it would get to that temp more quickly.

People make the mistake of thinking that cooler is automatically better. You may get a little extra HP for a short period of time, but there are other issues associated with running cooler. The vast majority of engine wear takes place on start up, and until the oil is up to an optimum temp. The 160 stat causes that process to take longer......not good in my book.

RADAR B8

Foosh

Does the LS7 have a 180 thermostat?

Foosh

Yes.

Slim Shady

I just installed the 160 stat and it flows to much. The fluid does not stay in Radiator long enough to cool. It stays around 180-185 then once in stop and go traffic it shoots to 199-210 and never goes back down. I even see 216-221 at times. I had it installed at West Coast Corvette and John thinks the problem is as stated above. I am changing it out to a 176 stat to see if it helps? I will update after install on Thursday.

Foosh

Yep, in stop and go traffic 215-225 is normal, depending on how much stopping and how much going. No thermostat is going to have any effect on a situation, where little or no air is moving over the radiator. You could run no thermostat at all and it would be the same. The stat is irrelevant.

Now if you were to find a higher CFM capacity fan to move more air over the radiator, you might be on to something. Nonetheless, too cool is not good.

Slim Shady

I did boost up the fan speeds to 55% at 188.5 degrees. I can still go to 70% at 188.5. What about recovery time? How is it effected with different thermo's? With stock Stat it recovered quickly. Now it seems to not come down once over 200 degrees?

Foosh

Slim, the type of stat should not affect "recovery time" at all. It sounds like something else is going on? How do you know for sure that changing the fan speed programming had the effect that you think it did in stop and go traffic?

In any event, when the car is moving at a good clip, even the fan is rather irrelevant. Once the oil heats up, it's gonna keep the block temp higher since oil is denser than coolant and takes longer to cool down.

Zig

ageed, a cooler therm. (lower temp therm 160 vs. 180) will 'saturate' the coolant sooner. the coolant will retain more heat and be unable to return to it's 'normal' operating tempurature as quickly as the 'stock' or higher temp therm.

the only way heat is removed from the 'coolant' is by airflow through the radiator.

if all other things are equal, fan operating speed, water pump flow rate, car movement (air movement through radiator), etc. the lower temp therm. will have a longer 'recovery' time.

see my post in the other thread about this subject for more information.

i just didn't want to type it all over again.

http://forums.corvetteforum.com/show...7&postcount=43

http://forums.corvetteforum.com/show...0&postcount=45

Slim Shady

I think I get it. I am going to try the 170 or 176 stat to see if it helps with the recovery. If no change I will go back to stock.

Halltech

I get the same temps here in WI. Before the thermostat I saw 198 to 205 most of the time.

I also have the first two slots on the fan in my program tuned to 55% fan speed. that is 188.5 degrees and 190.

DntXme

I just put in the 160 thermstat. Anyone know the torque specs for the two bolts on the housing? Please help

Norm_427

Could someone who has changed stats out of a C6 Z06 look to see what temp the stock thermostat has stamped on it? My 05 LS2 was stamped 86 C which = 187 F. I'm pretty sure the new Z06s are in the 190s F.

Norm_427

Anyone?

DntXme

Mine says NTCL 86C. any word on the torques specs for theose bolts? Other qquestion is there any particular orientation required for the thermostat..meaning rotion wise, I'm pretty sure I did not put in in updside down

Norm_427

I think that you're asking this: the "rotation" of the stat sitting in the housing doesn't matter.

I don't think you're asking this Q: I'm sure you noticed which way the spring / sensor part of the stat was when you removed the original. (It's been a couple of years but I believe that it can only go one way ... the long spring / sensor goes into the block.)

Torque: I don't have a shop manual but maybe someone will come on with that info. Sorry. I think it's around 25 lbs.

Thanks for the temperature info. I'm suprised that it's 86C or 187F. Is your Z an 06?