ULTIMATEORANGESS

iTrader: (4)

a well reputed tuner in this area thats built hundreds of LS motors recommends a 160 TSTAT.


i havent had any problems and my heat is fine.

dailydriver

Also, that super low oil temp will NOT allow the oil to thin out (ESPECIALLY with the very thick/heavy weight/low viscosity index oils soooo many on here are so fond of) to operating temps, thus actually losing (to oil friction/drag/load on the oil pump) the few horsepower their tuners went seaching for with timing advances/fuel trim manipulation/etc.

BarneyMobile

iTrader: (4)

Yeah.... those few degrees of timing only made a 50rwhp difference in my car. Theory < Practicality.

JetMech442

iTrader: (1)

Yeah, under WOT the coolant temp does increase. When the Tstat is full open, your engine temps are regulated by airflow through the radiator(wether by vehicle speed or fan-on operation). Lets say your driving at 210F and then you go WOT for a while. The cooling system should be able to reject anough heat to keep the coolant from exceeding 225F. Now, lets say you're driving around at 160. Now you go WOT and eventually the system reaches 225 just like the other car, except inthis case the thermal stresses are much greater because of a 55 degree temp swing instead of 10 degree. This isn't good to thermally fatigue components. Aside from the fact that at normal driving the 160 leaves the piston/wall clearance much greater than designed.

Barney, I'm glad you havn't had any issues with your 160. I'm just providing a point of view from the design side of things. At the middle of every engine design cycle we put theory to the test with 500 hour thermal cycles, 3000 hour harmonic durability tests and then send vehicles out to Davis Dam and Death Valley to beat the hell out of the cooling system. As it turns out we had a few tstats delivered witht he wrong set points, and I can tell you operating outside our design targets caused us to fail 500 hour thermal cycle. Theory is put ot the test when you offer a warranty on the systems you design.

I'm pretty surpised that you got 50 HP from timing advancesover a 190 tstat. was that with or without your 125 shot? I'd like to compare the 50 hp with the 160 to anyone else that has a similar setup using a stock tstat. That would help a lot of people decide weather the power increase is worth the theoretical risks of going lower.

The Alchemist

iTrader: (19)

If running at 160 degrees got you better power, or made the motor last better, don't you think that a group that specializes in extracting as much power out of a v-8, and needs it to last, like, I don't know, NASCAR, thought that running a motor cooler would make more power, than you would never see them boiling over?

Power is heat, and the more heat you pull out of a combustion cycle, the more power is lost through the coolant system, with the one caveat of uncontrolled combustion, ie knock and detonation.

I really don't care if people want to run 160's, hell, run a 130 or 110 degree thermostat. Fact is, if you could run the motor at 300 degrees, and have the metallurgy to handle it, and the fuel to run without pre-ignition, like e85 or diesel, you'll have a much more efficient, and powerful motor.

Again, drink the coolaid, don't drink it, take the blue or red pill, whatever.

BarneyMobile

iTrader: (4)

I never said my tstat made more power. I was refering to an earlier post about "tuners looking for a few more degrees of timing." And to the comment about a 125 shot , my setup made 531/487 N/A with 33* max timing. It only made 480/464 on 28* so lets do the math here..... I come up with 51 rwhp difference minus the "125 shot".....

JetMech442

iTrader: (1)

Perfectly said^.

redtan

iTrader: (5)

Yeah but that extra 5* of timing were not really due to the 160* thermostat. Like I and jetmech said, coolant temperatures at WOT (where this discussion is) is mostly controlled by the flow of coolant through the radiator and its ability to remove the heat.

It doesn't matter if you have a 160* or 186* thermostat in there, at long periods of WOT the temps will go as high as the cooling system's capacity to cool. Yes the first thermostat will keep the coolant cooler while cruising, thus providing an initial benefit of having a cooler engine. But once the engine temperature catches up and goes past that then it doesn't make a difference what thermostat.

For example, say at WOT your cooling system can keep the engine temperature at a constant 200*.

Car A has a 160* thermostat and car B has the stock 186*.

Initially car A is running 170* coolant temps while car B is running 192*. They both go WOT and within seconds both of those coolant temps will start to creep up and get to the 200* level that the cooling system is capable of delivering. At the end of the run, both of those are running 200* coolant temps regardless of what thermostat they are running, thus both should be able to run the same * of timing. The only benefit of car A is that at the beginning of the run it has cooler temps and can run slightly more timing. But by the end, they are both on an even field.

JetMech442

iTrader: (1)

Thats seriously impressive. I'm assuming that only a 160 Tstat can get 33 degrees and a 190 gets 28. 50 HP is a serious difference for only 30 bucks.

Here's my guess at the situation:
I assume that you can get 33 degrees of advance as long as the coolant temps stay below some target(lets say 200). If your running 10-11's at the strip , then there isn't enough time for the coolant to get this high, so you can reap the full benifit of advanced timing from the lower starting temp. If however, your using this motor at the track where you are on/off the throttle for 10-15 minutes at a time, temps would probly equalize at 210-220 and knock retard would kick in.

If someone wants to run a 160, lets help them minimize the potential durabuility issues and ensure they keep knock retard from kicking in. The Tstat opens at 160, and is full open generally 20 degrees later(180). To allow your radiator have a crack at controling temps first(and prevent the Tstats from cycling), the first stage fans should come on 10 degrees later(190F) and the 2nd stage at 200. IF your cooling fans and radiator are capable of maintaining roughly 200 degrees, then you could minimize thermal cycling AND prevent knock retard. There would still be the issue of operating outside the designed temp range, but at least people have the information to choose what they want to do. Anyone else have ideas, or experience running these lower stats?

MeentSS02

iTrader: (11)

That's a bridge too far.

I bolded the most important part...the amount of timing you can put in a tune depends on the heads/cam you choose. Some combos can take up to 33* of timing (like yours), but if you try that with a stock heads/stock cam LS1 or LS6, your PCM will be having a friendly chat with the knock sensors. If I recall correctly, a stock LS6 in a Vette has around 22* of timing under WOT conditions in the stock calibration, and people have tried adding more timing with no gain in power. That combo just doesn't like that much timing. Heads/cam cars are a different story.

I just don't want people skimming random posts and thinking that simply swapping to a 160 stat will allow them to add a ton of timing on an otherwise stock car.

dailydriver

EXACTLY!!!^^^

Maybe that is great for a single 10-12 second blast down the strip, or a single dyno pull to get a peak reading for bragging rights.

BUT, in the real world (daily street use, open tracking/road course use) I'd rather NOT have that peak just to be able to claim power superiority, and have more longevity/reliability for the LONG RUN.
(But I guess I'm the exception on here, as I got rid of my UD crank pulley/damper as I thought it was just NOT worth the very few rwhp it was supposedly good for. This car currently has 160K miles on it and I'm going for 500K+! )