Folks:
I recently installed a Lund tune which kicks the High speed fan on at 189 degrees. Currently the stock T-stat is in the car (192 deg), so I am looking for a replacement so the fan doesn't run continually. (a notable side effect, the constant running of the fan and intercooler pump seems to keep the IAT2 values pretty low @ <115-120 degrees).
I have read a dozen threads on this, and the general consensus is to use either the Reische 170 deg T-stat, or go with the 180 deg Napa THM-190, Murray 4138 or Motorad 354-180. Those that went with the latter, claim no issues in real world experience.
I prefer the slightly higher temps, since it gets cold down here in Texas (but I don't drive it under about 50 degrees, as the Cup 2s dont like the cold). BUT - One thing that recently caught my attention was some comments from Reische as follows:
"One thing you can say about the GT500 cooling system is that it works very well. It can still dissipate a great deal of heat even if you run a thermostat that doesn't close the bypass. In order to do this you have to run the fan for longer periods of time to cool the rad output more so when it mixes back in with the bypass you'll get a lower ECT. Many GT500 owners ran improper SOHC and 4.6 DOHC thermostats for years with no problems, however the benefits of running a proper t-stat are more stabilized lower temps and increased electrical efficiency while also increasing the life of the cooling fan. Of course the overall efficiency of the cooling system is improved so under severe conditions it will be able to dissipate more heat but the majority of owners will never take the cooling system to it's limits.
Many people thought the NAPA 180* (which is a 4.6 DOHC t-stat) was the correct thermostat because the diaphragm size and the overall height were the same or very similar. However the bypass on that thermostat functions in a totally different way making it incompatible with the 5.4 DOHC's hot-side setup. As far as I know my unit is the only low temp thermostat made specifically for these cars. "
Anybody have experience switching between the 170 Reische and "correct" 180 stats? (According to Reische, the 170 stat will run hiflow to radiator around mid-180s or so.)
Also - the main gripe about the 180 t-stats is that they are Hot-side vs Cold-side bypass. I dont quite understand the difference nor why its important for proper function.
Thanks much
I recently installed a Lund tune which kicks the High speed fan on at 189 degrees. Currently the stock T-stat is in the car (192 deg), so I am looking for a replacement so the fan doesn't run continually. (a notable side effect, the constant running of the fan and intercooler pump seems to keep the IAT2 values pretty low @ <115-120 degrees).
I have read a dozen threads on this, and the general consensus is to use either the Reische 170 deg T-stat, or go with the 180 deg Napa THM-190, Murray 4138 or Motorad 354-180. Those that went with the latter, claim no issues in real world experience.
I prefer the slightly higher temps, since it gets cold down here in Texas (but I don't drive it under about 50 degrees, as the Cup 2s dont like the cold). BUT - One thing that recently caught my attention was some comments from Reische as follows:
"One thing you can say about the GT500 cooling system is that it works very well. It can still dissipate a great deal of heat even if you run a thermostat that doesn't close the bypass. In order to do this you have to run the fan for longer periods of time to cool the rad output more so when it mixes back in with the bypass you'll get a lower ECT. Many GT500 owners ran improper SOHC and 4.6 DOHC thermostats for years with no problems, however the benefits of running a proper t-stat are more stabilized lower temps and increased electrical efficiency while also increasing the life of the cooling fan. Of course the overall efficiency of the cooling system is improved so under severe conditions it will be able to dissipate more heat but the majority of owners will never take the cooling system to it's limits.
Many people thought the NAPA 180* (which is a 4.6 DOHC t-stat) was the correct thermostat because the diaphragm size and the overall height were the same or very similar. However the bypass on that thermostat functions in a totally different way making it incompatible with the 5.4 DOHC's hot-side setup. As far as I know my unit is the only low temp thermostat made specifically for these cars. "
Anybody have experience switching between the 170 Reische and "correct" 180 stats? (According to Reische, the 170 stat will run hiflow to radiator around mid-180s or so.)
Also - the main gripe about the 180 t-stats is that they are Hot-side vs Cold-side bypass. I dont quite understand the difference nor why its important for proper function.
Thanks much