I’m wondering if a 160 deg thermostat might be a better choice than the factory 180 deg piece on an engine that’s got a few miles and not to spec in terms of CR and vacuum. I think this because my engine feels strongest shortly after cranking.

Let’s say an engine at cold temp produces a compression that’s ~10% lower than spec and a vacuum that’s ~20% lower than spec and at op-temp there’s further degradation. Will the cooler thermostat result in less metal expansion/deformation and therefore less degradation of the BSFC.

 

I have wondered this as well. Thanks for posting this question.

 

Are you sure the OEM t-stat is a 180 and not a 195? I was told that the factory t-stat was a 195, so I put a 180 in my FD.

 

i use a mustang gt thermostat it opens at 160...

 

Mine is an FC Tii. Spec is: initial open 177-182 F, fully open @ 203 F.

 

Interesting...I wonder if there are any negative repercussions to running the motor that cold? If not, maybe I'll pick myself up a 160 deg t-stat!

 

from what i've read on the subject (both here and other places) the only drawback is extra fuel consumption. i don't think i've ever got an idea of how much more fuel is generally consumed though.

 

Gotcha...rx71king, what mustang t-stat did you get? What year/engine/etc? I'm thinking about picking one of these up...

 

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Yes fuel consumption is increased normally hence an increase in BSFC. But my question is directed more towards a "loose" turbo engine that no longer produces a CR or vacuum reading anywhere near spec. Where the engine's condition is such that by using a cooler T-stat the expansion/deformation might be less (specially under full load) preventing the BSFC going exponential.

This is something that obviously needs to (or has been) proven on a dyno.

 

54mm 86 to 95............it opens at 160. buy the time i get out of my driveway it at 180 and my fan kicks on. so for summer time it a head start on cooling......he seid extra fuel consumption ..

 

Ok, so I picked up a 54mm 160 deg t-stat from a Mustang...The only thing is it's slightly larger than the OEM t-stat, and thus the OEM gasket won't fit into the housing. Did you just RTV the new t-stat when you installed it?

I used RTV grey...Going to let it set up overnight before starting it.

 

You guys may want to consider doing some research before blindly installing parts on your cars

http://www.importtuner.com/tech/impp...wer/index.html

 

1) I've already consulted 2 reputable builders before doing this, and

2) I'm not doing it to gain power.

I'm doing it to run the car colder in the summer time...Besides, if I lose any power I'll spend the whole 10 minutes to put the OEM t-stat back in.

 

What kind of summer temps are you seeing? I'm usually around 86-87 IIRC.

 

Lucky bastard. :P It depends on the day, really. If I'm LUCKY I'll see those temps when I'm cruising (actually, at idle and on level ground I'll see those temps, but if I encounter a hill or run the A/C forget it). Also, keep in mind I've got a Fluidyne rad, 50/50 mix (I know I could run more water in the summer), and my fans coming on @ 180.

See, the major problem is when we get into the hot months and I want to run my A/C. Being that the condenser is immediately in front of the IC, the air is significantly hotter passing through the radiator if I'm running the A/C. The scary part is that the temps will climb and climb and climb if I'm running the A/C. I've never let it get over 105, but I do believe they'd climb steadily if I let them...

The way I figure it, if I get a jump start on cooling with a 160 deg t-stat it won't get as hot. It's at least worth a shot, right?

 

A/C? I junked that (along with P/S) back in the summer of 2001 when I lived deep in the heart-a Texas

I used to show up for formation with my BDUs soaked in sweat, and all my soldiers thought I was nuts

 

What year 7?There is 2 different t-stat sizes that will fit FCs depending on the series.

 

LOL....Yeah, A/C is one thing that I won't junk. :P I don't use it much, but it comes in real handy on some of those hotter summer days.

Joey, I don't recall what year I had the guy look up at the parts store, to be honest. I just went with the 54mm 160 deg t-stat as instructed by rx71king. It said 54mm right on it, so I'm sure I got the right one.

 

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Oh sorry, just saw you were asking about what year my RX-7 is...

It's a 93.

 

sorry man for some reason i thought we were talking older rx's....your themostat is 32mm 89 to 95 with out gasket.......i should have read more carefully ...i am such a ***...

 

Haha it's cool man. This t-stat seems to work fine though? It's installed, and I started the car today to let it come up to temp...Came up to temp just fine, the t-stat opened, and I have no leaks. Is there any reason I should pull it back out?

 

100 degree days are pretty common here in west Texas. I'll be putting in a cooler T-stat at that time. Did we ever find out what temp the factory T-stat actually opens at? That's what I currently have now. Based on what I'm seeing with my engine on the test stand, I think it starts opening at 180 and isn't full open till around 195.

 

Some ppl are claiming it's a 180 degree t-stat from the factory, but the t-stat that was in my car when I first bought it was definitely a 195. Idk if this is true for all FD's, but I know my (possibly original?) t-stat was a 195...There shouldn't be any problem with leaving this 54mm 160 in there, right? It's not leaking, and seems to be working just fine...I did have to make my own gasket, but it wasn't that big a deal.