Ok, i would like to upgrade my thermostat so that it opens before 180 degrees like the stock one. Is there one that opens at like 160 or something so my engine doesn't feel heat soaked??? Which one will fit? thanks

 

Nismo has a 160* thermostat, but it costs well over $120, as I recall.

The 350Z thermostat is set for 170*. It looks like this, but you need to block the oil-cooler hose. I use one on my 3.5. It's pretty cheap.

 

^ so the 350z thermostat should drop right in on a DE-K

 

Why not just modify yours with a spacer/washer? I think Jime did a writeup thread on it, might be in the stickies.

 

After you
Or you could:
http://forums.maxima.org/showthread.php?t=157602

 

i am running a nismo t-stat on my vq35. All that was needed to make it work was a coolant hose from a late 4th gen max.

 

Are you guys with cooler t-stats monitoring your coolant temps while cruising on the street or highway? If it gets too cool it can accelerate cylinder wear and/or carbon deposit formation. Cooler is better to a point. Beyond that point you're doing more harm than good.

 

I'm not monitoring yet - but it never gets to cool down anyway !!!

 

I have, and it doesn't.

 

At what temp does yours open and what temps are you seeing during highway cruising? I'm genuinely curious.

 

I think I read in the other linik that after he modifed it he put it in a pot of boiling water and had it almost at exactly 10 degree difference. He also did a fan mod to go along with that to cool off between runs at the track.

 

I have a 150 Nismo Tstat. I see about 165-170 while cruising on the highway.

 

Eek. Too cool for me. Thanks for the response though.


Anyone else?

 

I never have heat soak anymore (especially with phenolic spacers) and a cooler VE is much more consistant and has less chances of detonation. Gas mileage didn't change at all when I installed this Tstat a year or two ago. In fact, it might have gotten better. As long as the coolant temp is above 150, AFR isn't changed at all.

If it is hurting the motor, I don't care too much. Anything to gain performance.

 

I set my T-stat around 160, temps while cruising are similar, give or take a couple degrees. I also have the EU set to kick the fans on at about 168, the combination produces a consistent car with temps always in the 160-168 range, heat soak is of little concern and the mileage is good still.

 

It's not the mileage so much I'm concerned with.


Hope I'm not preaching to the choir but apart from possible cylinder wear and carbon deposit formation, an engine that runs too cool can even affect power by allowing less of the thermal energy released by the combustion process to transfer to the piston. "Heat soak" is only one side of the equation. Each engine has its own operating temperature sweet spot for making the most power, and it's not always as cool as you'd think.

 

I don't believe that's a concern at 160-168F. You're only talking 15-20* cooler than stock. There were no signs of that on my 110k mile engine, and it's been torn down completely. No excessive carbon, and crosshatching still in great shape. And I put that engine through a lot of high revving, racing abuse.


In theory yes, with significantly lower temps, but not in this case. I'm 100% positive that 3.0 engine was not losing any power in that temp range. In fact it ran better than with the stock range.

As for mileage, that should only get noticeably worse if you drop the temps so far you trigger the stock ECU out of closed loop into open loop, and/or into cold enrichment.

 

Well, as you know, the temp at which the thermostat begins to open doesn't always necessarily equal the operating temps one will see while driving depending on the type of driving and cooling system efficiency. For all intents and purposes, actual coolant temps during a particular driving condition > thermostat rating. Again, it's not the temps during hard driving that I'm referring to. It's the temps the motor sees the rest of the time while cruising. Just wanted to clarify. If most of one's driving is hard and the stock cooling system can't keep up with the stock thermostat, then I'm all for a cooler one. (Cost aside, I'd actually suggest going with a better radiator/coolant solution in that case before a cooler thermostat but that's for another discussion.)

But that's good to know about your motor. One question though, how long had the motor been run with the cooler t-stat? These issues tend to be long-term.

During these runs (dyno or 1/4 mile) what were the actual coolant temps? And how did you quantify the engine running better?

Understood.


Then there's the oil temperature issue... Since water vapor is a natural byproduct of combustion, some of it will end up in your crankcase and it will condense when the engine cools. If the oil isn't reaching 212* it won't boil off when you run the engine again.

Sorry if I'm being too picky or overthinking this. I tend to be pretty detail-oriented.

 

That and you always say get an Al rad.

I know that you guys know this, but long as you're above 160*F, you'll be ok (closed loop/open loop)

 

My current solution to the cooling issue is a 5/8" orifice vs a thermostat. My temps run in the 170-180 range and can be brought down very quickly by manually putting the fans on hi. I usually leave the fans on until I get to the staging area, then I shut them off and switch them back on after I cross the stripe.

On the highway temps stay in the 175 area. I prefer the orifice as I always know what state its in and I have never known an orifice to fail.

 

Oh yeah. I keep my fans on and heater blasting also up until I'm ready to stage. Also, I don't have an AC condensor. Ever since I removed that, the airflow the radiator gets has gone through the roof! Even with a 150 Tstat, with the AC condensor in place, on some days, I'd see coolant temps in the 190+ range. That is what it was with the stock Tstat on a normal 80 degree day. But now, the radiator gets so much more airflow and my coolant temp is strictly dependant on the Tstat rating.

I recently had the stock 180 Tstat in place and my coolant temps were consistantly at 190.

So if you want cooler temps, remove the AC condensor.

Also, back when I had the condensor in place, I needed cooler temps in order to do my bracket racing when I lived in hot Las Vegas. I found out with the VE, it's MUCH MUCH more consistant and faster if I launch at 160 degrees instead of 180+. Sometimes I had trouble getting the temps back down to 160 after a 1/4 mile pass. Sometimes, they would make me hotlap to the next round if I won. So, a fellow bracket racer told me about a product by Pro Blend called "Stops Overheating - 40 Below". That stuff is amazing! I did a pretty extensive study with the VE in 110 degree Vegas heat and it significantly lowered my coolant temps. But ever since I moved back to NC and removed my condensor, I've never had cooling issues. So I've had no need to use 40 Below since my Vegas days.

I also studied Water Wetter and found out it's a complete WASTE OF MONEY! My coolant temps didn't lower my more than 1 solid degree.

Here's the thread that I posted my review in, if anybody is interested:

http://forums.maxima.org/showthread....0666&highlight

 

There are 2 T-stats on our motors FYI....

I got a Nismo one for the "main" T-Stat. Before I would see temps around 180F on the highway but that was when it was much warmer than it is now.... In the 45F temps I see my coolant at about 160F. My heat doesn't blow as warm as it used to eighter.

My oil temps on the other hand are about 180F after a loooong drive. I got the T-stat to keep the engine temps down on the track. With the stock T-stat I would get up to 230F after 25 min of WOT all the way to fuel cut around the track. Nismo T-stat dropped that down to 215F under WOT. Last track event I did the ambient temps where about 75F and my oil temp got up to 280F after 25 min. I'm putting a oil cooler with a thermostat on the car, I hate to see my oil temps with the turbo now... especially after 25 min session on the track.

 

Ya, that t-stat thingy on top of the block area on the opposite end.

230*F is right at the sensor limit IIRC(0.0V). Doesn't the ECU get mat at that point enter a failsafe - like mode?

 

That only applies to DE-K's.

But +1 to you using a colder thermostat for track use where your current cooling solution couldn't keep up under strenuous driving conditions. Those 160* coolant temps while cruising disturb me though.

 

We all know DE-Ks PWN :P

I run aftermarket gauges in my car where I monitor my engine temps, oil pressure etc.

I did notice my MPGs did go down a bit as of late... and it was RIGHT after the thermostat replacement. In reality, I wouldn't be worried bout 160-170F temps, just run diff oil. I went to 5W30 vs 10W30 and the oiling issue shouldn't be a problem.

I do not like my oil temps on the track, with all the high RPM use I am upgrading the oil pump to a RevUP while I got the motor apart this winter. Its getting fresh timing chains, some chromed out goodies also and fresh set of cams Response is what I'm after on the track, with BETTER than OEM reliability.

Our cooling systems are pretty good actually, SR20s tend to have water cavitation issues once past 6000RPM on the track. UDP is a MUST for those who do track, or you have to do cool down laps. Nissan might have been on the verge of bankruptcy but they built a killer engine. I love my VQ30

 

answered my own question by reading your earlier post

 

Gingerman = Speed Trial USA
It was approx 80-85F outside that day.
Ran 25 min sessions in mostly 3-4th gears- sometime dipping into 2nd to get around slower cars which would slow me down enough that required 2nd gear to power out of the corners.

210F all the time, in the last few laps the temps creeped up to 215F but would dip back down if I stayed in 3-4th gear. NEVER did they go above 215F.

Oil temps where in the 260-280F range the whole time.

I ran 5 sessions of approx 25 min each = 125ish minutes. My car runs kinda rich also, I got a small exhaust leak (which you can't even hear) that throws off my AFRs on my PLX M300. Corrected AFRs where about 11:1 the whole time.

It was a very sunny day that started out in the 70s and went up to mid 80s. I got to test out the Quaife and Brembos that day. I'm happy with the way the car is doing- but it could use another 100-150WHP to really shine on the track. Even with my "power deficiency" I was still pulling in laps that where .5 second faster than a E36 M3 with basic bolt ons and slicks. Late braking and LSD is what makes the Maxima shine !

 

Nice, what sort of lap times were you running? What tires were you on?

 

I do not remember the lap times, my friend was clocking us and comparing....

I couldn't get the correct wheels for my car to clear the brakes.... so I was on my street tires. Toyo T1Rs, which are alright but Gingerman chews up your tires like crazy. I was on a fresh set, and my sidewalls are a bit chewed up.

There was a C6 Z51 on the track that day, and we played tag Outpowered me on the straights, but I would PWN him in the braking and powering out of the corners.

Why are all Vette driver's cocky ? I had Mustang guys chill with me, Honda and BMW guys talking... yet the Vette driver didn't wanna talk to a guy with a family car he couldn't shake off for 25 min.

 

I think you are...

Tons of street tuning runs, quarter mile runs, hwy trips to and from places, all datalogged and/or monitored in real time with the EU have shown me my temps always stay consistently in the 160-168 range, depending on where I have the fan control kick in. The combination of T-stat + EU fan control works well in all weather, for my climate, which in the summer is in the 90's F. (Note that I don't drive the car in the winter though).

 

Heh, I just haven't seen enough evidence to justify significantly lowering the engine operating temp in light of the potential drawbacks associated with it. Engine internal clearances were specified with a certain operating temp in mind when considering the rate of thermal expansion of the materials involved, among the other things I'd mentioned. I'd take a more modest drop in average operating temps personally. Wouldn't want oil temps to stay below 212* during normal driving conditions either. Perhaps the 350Z thermostat would be the ticket.

 

I have not seen any evidence that my motor is being hurt in anyway by lowering the temps. If it is, then that's fine by me. In my experience with the VE, the advantages of running a lower temp significantly outweighs any potential disadvantages on the track and on the street.

 

We will just have to agree to disagree then, yes?

 

I'm ok with that. It's just that I don't know the facts about how it could be damaging to my motor. All I have to go by is the testing I've done in my car. I can't tell if it's hurting my motor or not. My trap speeds go up considerably when I launch at 160 versus 190 and my 60 foots and ETs get much more consistant. I mention 60 foots b/c back when I was bracket racing a couple years ago, I never had traction problems. The 60 foots were dependant on the motor's ability to rev smoothly from 1800 to 4K. Sometimes it would bog terribly. I got rid of all these problems by launching at a lower coolant temp.

I have no way to test the long term effects of this. Honestly, I don't care if it's hurting my motor long term. I'm about to spray a 150+ nitrous shot so I know that's not healthy for the motor.

Also, I do use 5w30, so that will help a little when I race my car on a cool engine in 40 degree temps.

 

At the temps I'm running, any drawbacks are negligible IMO. If you were doing a lot of racing you might be more sold on the benefits...





It's all good...

 

I have found that if my motor does not reach at least 160 deg. than it seems to run rough and not as smooth as when it reaches 180 deg. but no matter what the coolant temp is, the oil temp is always over 200 deg.
Also the Nissan cooling system is somewhat differant in that it pulls the cooled water from the radiator through the thermostat where a Ford or Chevy pushes the hot coolant through the thermostat to the radiator. It seems that it would be harder to control temps from the incoming coolant than at the exit of the coolant.

 

In reality all the people here who have said lower T-stat is the way to go- do not drive much on the street. And they did the T-Stat to lower the engines hot soak ability... AND they race their car in one way or another SO thats why they did it. On a DD lower T-Stat would suck.

My Max for instance doesn't like to be run on a COLD engine, after oil temps are in the 150-180F then she makes full power.

Even if my engine is runing only 160F coolant temp, my oil temp is always around 170-180F when I am crusing on the highway. It just takes a bit longer for it to get up to those temps. But with the way I drive the Max (I drive it rarely now cause of the cold weather being hard on my FLTA2 JICs) I tend to bring her up to hot oil temps kinda quickly. Few quick bursts from 70 to tripple digits and I'm runing 180F oil temp

 

I would hope that people who do this race more than they DD. Like I said, in a hardcore racing context (road racing and such) I'm all for a cooler thermostats to maintain the lowest of stock-like temps (i.e 185-ish), not a net reduction of operating temperature. Then again, everyone's got an opinion. Mine is no more important.

^^^ Another reason cooler thermostats are no good on a DD car (at least during cooler months where ambient temps are below the dew point). The fact that oil temp needs to be raised to at least 212* to get rid of moisture that has accumulated is fact and well documented.

 

+1 to this. The thermostat should be on the hot side, IMO. More proactive and precise coolant temperature control that way.

 

I just noticed that the OP hasn't touched this thread since. Probably saw the monster he'd created and .