Could it be possible to modify the stock thermostat so that it opens up at a lower temperature like the Nismo one? Is it just a different spring rate or something?

 

Good question, I was thinking the same thing?

 

The Nismo unit is just a different spring rate but if you somehow manage to get the actual thermostat unit apart I doubt its going back together. The Nismo thermostat is such an overpriced rip off IMHO. The stock unit is $15. A simple spring change makes the Nismo $150. There is no other difference then the spring and yes I have held them and inspected them side by side. Theres a reason why I decided to run without a thermostat at all.

 

Couldn't running without a thermostat at all actually make the car run hotter? The hole for the water to go through the thermostat is much smaller than the opening left when you remove the thermostat, thus if you take it out, the coolant could be flowing through the system faster and spending less time in the radiator being cooled.

 

Think about it backwards too...it's also flowing through the engine faster leaving less time for it to get as hot...

 

Removing the thermostat (freeflow) use to be an old school solution to fixing overheating problems in older cars in the summertime. I'm not sure if it applies to the G/Z but it's an interesting question.

 

Running with out a thermostat is not recommended, although MIAPLAYA likes to think so... We experimented with this while data logging with the VPRO, and the motor took a long time to come up to ideal operating temp in the winter (NY METRO AREA) and once it did, it ran 15-20 degrees hotter... Tuners explanation was there was nothing to slow down the flow of coolant, and the cooling system wasn't being used as design.

Anyhow, do what you want; it just didn't work out for us.

 

Right, but inevitably over time, the fluid will heat up and tend to run hotter as Philthy's account above states.

Only reason I thought of that is I'm having an overheating problem with my '00 Mazda; the damn thing is boiling the coolant and for the life on me I can't figure out why. Found out whoever I bought it from (on a cold day, so no problems) had removed the thermostat (old school solution as mentioned above) and so people told me that was the problem; that the coolant was flowing through too fast and not getting enough time in the radiator to cool down. I put in a new thermostat and it's a little better, but still boiling the coolant. Pump is obviously working, radiator is not obstructed and looks undamaged, so I don't know what the hell the problem could be...

 

I heard somewhere the Z32 Twin turbo thermostats are just like ours except they open at a lower temp. Anyone have any info? Its a good alternative to buying a NISMO which is a rip off.

 

That would be sweet. Hope someone confirms this suspicion.

 

Could you essentially make a billet thermostat and use a different spring. Wouldn't have to be exactly the same design. It would just have to work and bolt up to the block basically.

 

Just buy one used on the forums for like $50

 

I know you can find them cheap on the forums but if you could find a way to convert the stock ones you could make some killer money.

 

The C5 guys were modding their stock thermos by placing a small shim at the end of the thermostat. It was a very popular way to mod the stat to open at a lower temp. Check out this link:

http://teamzr1.com/modstat.html

 

Well contrary to your logging mine has shown a difference. Cruising water temps are DOWN 15 degrees to 180 F at the outlet pipe to the radiator. On boost highway running temps are 185-195. In 101 degree weather in San Diego with the AC on max going uphill to get home from the last car show I saw coolant temps as high as 203 but no higher. Thats with periods of on boost and off boost. Only one time have I seen higher then 205 with the thermostat removed and that was 106F ambient temp long on boost run uphill followed by bumper to bumper traffic with AC on high. Even at Battle of the Imports last year at Cali Speedway temps were 105F. AC on blast, on boost runs followed by cool down temps never crested 205. That is with thermostat out. With thermostat in the car ran 195F at cruise low speeds. 195-200 on boost highway. 205 or higher at the track ALL THE TIME.

Cliffnotes: My temps went DOWN on average 15 degrees from before by removing my t-stat.

 

Could be your rad cap isn't holding enough pressure. The whole point of pressurizing the cooling system is to aid in increasing the boiling point of the water. If the cap is not holding the right amount of pressure your boiling point has dropped. Try a new or higher pressure cap.

 

Removing a stock thermostat on a vehicle is going cause the engine to take a little longer to get to operating temp but I’ve heard this done before where its real hot all the time (like here). You would not want to do this in New York or Chicago.

I’m not so sure that this will cause the engine to run hotter because now there is a big open hole where the thermostat was and fluid will “go by” faster. There are other more restrictive places that the coolant has to go through.

Personally I think if your car is having cooling problems, I would remove the thermostat way before spending $150.00 on a Nismo Thermostat that was made in China for $2.50

 

Heres a link to the performance nissan site that has the nismo thermostats, the 350z thermostat opens at 68 degrees and is much more expensive. The 300zx thermostat opens at 62 degrees and much much cheaper.

We need to confirm that they are interchangable.

 

I completely agree that the Nismo thermostat seems to be a complete waste of money for what you get. I have two complete motors which means I have one extra motor to fool around with. I guess I am going to try playing with the thermostat on the one that is not in my car and see if I can not figure out a way to upgrade it or something.

 

My next question is it would seem that you could benefit in two different ways. Having a larger opening (i.e. no thermostat at all) and a thermostat that opens at a early temperature. Maybe if I get bored I will just look into making a whole new thermostat that has a larger opening yet has temperature operation so that you can get up to operating temps quicker for us guys in the North.