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-   -   Has anyone used a lower temp thermostat? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/has-anyone-used-lower-temp-thermostat-262385/)

7racer 08-02-04 08:31 AM

Damon,

just would like to keep the car running cooler in the hopes to prevent overheating and hot spots like what occured with SleepR1

I'm just too uneducated in the thermal efficiency of these engines...that is if the PFC has a temp adjustment (I believe it does), and the 13b runs just as efficently at 170 degrees F as 180....can't I attempt to run cooler temps?

that's why I asked the question about what the 2nd gens run in regards to temps, without a turbo....are their thermostats also 180?

pomanferrari 08-02-04 08:31 AM


Originally Posted by BATMAN
WOuld the FD pass smog (meaning that it runs normal A/F ratios by being in the warmed mode) if the temps are 168-175 degrees?

Somehow the engine seems to be stronger for me when it's just slightly warmed up.

If it's heat soaked there is some loss in power via butt dyno.


Batman, why are you even asking these questions? How can you even afford to play with your car when your job as a caped crusader has been outsourced to India?

And whatever happened to the buttplugs that you championed so vociferously?

obviousboy 08-02-04 08:45 AM


Originally Posted by DamonB
A lower thermostat is not going to lower coolant temps. The only thing the lower thermostat is going to do is take longer for the engine warm up. Once warmed up the car will run just as hot as it did before. The thermostat has no control over coolant temps; only the warm up period.

It is a bad idea to remove the thermostat completely. With no thermostat there is no restriction in the system and coolant will flow too quickly. This means the coolant won't spend enough time in the radiator and cooling will actually be reduced when pushed hard. If the car is for racing and has no need for a thermostat then you just add a "washer" in place of the thermostat or you gut the stock one. Both of these will still provide a restriction which will slow the flow of coolant.

The stock ecu will not even open the double throttle until 180F I believe it is. I never run my car hard (street, track, anywhere) unless I see at least 180 on the temp gauge.

this is the biggest complaint i have about my car...it takes FOREVER to warm up....

DamonB 08-02-04 09:13 AM


Originally Posted by 7racer

just would like to keep the car running cooler in the hopes to prevent overheating and hot spots like what occured with SleepR1

The thermostat doesn't control engine temps once it is open. The thermostat controls engine temps only when it is closed: It allows the engine to warm up quickly by trapping coolant in the block and not allowing "cool" coolant in. Once the thermostat is open you have coolant flow through the system and temp will be controlled by the radiator and how hard the engine is being stressed. Once open the thermostat has no impact whatsoever on peak coolant temps.

7racer 08-02-04 10:58 AM

I hear you....it just seems with all the upgrades like the 99spec front, dual oil coolers, that I am able to keep the temps cooler....


just for daily driving and cruising on the highway....is it that bad to sve 10 degrees of heat to the engine and components in the bay?

Damon, I know I won't win this arguement as your right as to what you said....just my last little niave question:D

BATMAN 08-02-04 11:06 AM


Originally Posted by pomanferrari
Batman, why are you even asking these questions? How can you even afford to play with your car when your job as a caped crusader has been outsourced to India?

And whatever happened to the buttplugs that you championed so vociferously?

weak attempt to hijack this thread.

Where is ur master? u know, the one that butt raped u in the other thread and u couldn't rebuttal him intelligently. U might have use for these butt plugs, not for the FD, but for ur septic orfice. It's even got threads in place for a more secure feeling since ur anal cavity echoes more than a Manfagcisco Gay Area Canyon.....

http://www.sportbikes.net/forums/ima.../gayfight2.gif

https://www.rx7club.com/forum/image....ine=1029557984 = low budget avatar with "pomangraphics"

BATMAN 08-02-04 11:11 AM


Originally Posted by 7racer
I hear you....it just seems with all the upgrades like the 99spec front, dual oil coolers, that I am able to keep the temps cooler....


just for daily driving and cruising on the highway....is it that bad to sve 10 degrees of heat to the engine and components in the bay?

Damon, I know I won't win this arguement as your right as to what you said....just my last little niave question:D


I see DamonB's point, but if the temp drops 10degrees that still should help.

I only see the logic in a thermostat if u happen to live in an area that has extreme winters that dips in the freezing point.

DamonB 08-02-04 11:41 AM


Originally Posted by 7racer
I hear you....it just seems with all the upgrades like the 99spec front, dual oil coolers, that I am able to keep the temps cooler....

Cooler than what? 200F is just fine!!! You don't WANT to go cooler than that when pushing the car hard!!

This is not a case of "more" being better. You don't want to cool the car more unless you have a temp problem. 200F-220F is NOT a temp problem!!!!

adam c 08-02-04 12:05 PM

On a normal 70 degree day, driving down the freeway, my car will stay around 180. Its nice that it runs fairly cool. However, there are times when I wish it had a 190 t-stat. The car runs better when it is a little warmer. I like the cooler temps because I think they are easier on everything, but it would be nice to have the car ready to perform at its best on the freeway. I have been considering a 190 t-stat, but have not made a decision to do it ...... yet :)

KevinK2 08-02-04 01:12 PM


Originally Posted by DamonB
The thermostat doesn't control engine temps once it is open. The thermostat controls engine temps only when it is closed: It allows the engine to warm up quickly by trapping coolant in the block and not allowing "cool" coolant in. Once the thermostat is open you have coolant flow through the system and temp will be controlled by the radiator and how hard the engine is being stressed. Once open the thermostat has no impact whatsoever on peak coolant temps.

only last statement is true.

FD T-STAT 101

BASIC OPERATION:

FD t-stat will crack open when coolant completing a loop thru the engine hits 180F. Cruising at 70 mph in the winter, peak bulk coolant temp will be at or even a little below this point.

The T-stat will open in a linear way up to wide open at about 195F, allowing a progressively higher % flow thru the rad. At moderate load and car speed combo's, stable temperature conditions can be found in this range, esp in cool weather.

About 195-200F is good point for rad fans to come on, with wide open t-stat. Miata switch, pfc, parking lights do this well. OEM is 221F ... good for emmisions tests, but too high for me.

Once the fd '3-way' t-stat is wide open, an extented disc closes off the the warm-up bypass loop in the wp housing. Now all coolant goes to rad (and heater core), for most effective cooling.

WOT at the track. Now the warm-up bypass is closed t-stat is wide open. Like you impled, t-stat may be acting like a restrictor, depending on it's flow area vs other restrictions in the flow path.

RELATED TWEAKS:

Rad, heater core, and AST are mostly in parallel, so hot coolant will only pass thru one of these. Aluminum AST's should have a .07" pill in the inlet hose, like the oem ast restrictor, to reduce coolant bypassing the rad. Might also consider a manual valve in heater core hose, to nearly close off during summer track events and force more coolant through the rad, and thru the exh side of block (credit cam worth).

T-stat removal will usually increase flow to rad/eng (if bypass is also plugged) and help cooling, unless very high flow induced pressure in the block was needed to supress excessive local boiling in egw systems. See link for Nascar cooling system supplier:

http://www.stewartcomponents.com/htm...t/techtip3.asp

HIGH FLOW T-STAT:

by robertshaw and mr gasket are available for other cars, even with a 3-way stat (mr gagsket 9-43015). would need to study if one would work right in FD. For track use, with real temp gauge, would be informative to drill a ring of holes around the oem tstat, as big and as many as possible. This is like runing no stat, but still having the bypass valve that prevents gross bypass of the rad. could briefly block off rad/mouth to help with warm-up. If it cools better, then a proper 3-way high flow stat should be persued for street/track use.

1FooknTiteFD 08-02-04 08:58 PM

i run the billion thermostat, it keeps my water temps at 68 degrees celsius when cruising, my water temps are super low when i drive hard too. Overheating is definitely not a problem

jpandes 08-02-04 11:27 PM

So, is setting my PFC to turn on the Rad. fans at 86 C(186.8 F)? That't what mine are set for.


Would 90 C (195 F) be better?

adam c 08-03-04 12:12 AM

I think turning the fans on at 186 is too low. I wouldn't set them below 200. I have the fan mod on my car. I like to turn them on several minutes before I arrive at my destination. That way they have time to bring the engine temps down to 180, which is where I like them to be when I shut down the car.


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