i have a 2002 f250 with 5.4 and i know that the with the ford lightning one of first the mods your are to do is to put a cooler thermostat in. i was wondering if i should change out my thermostat which i think is a 190 or 225 to a 160 or 175 to help with performance?

it seems like it might help- what does everyone else think, or is there anyone that has done this?

thanks
Rich

 

What is that going to do to the computor? It is going to read engine not reaching temp and will it will do what? Set a code and stay in closed loop. Besides that it is not going to help the life of the engine. My 2 cents

 

If anything, I'd go no lower than 180 or so...but I agree with kotzy.

Your truck will run rich and your mpg will suffer.

 

You should only mess with the thermostat when you have other mods that stand to gain from it and the ECM has been programmed for it. I know it's not a mod, but the stock Lightning does have a blower that your truck doesn't. Probably not the best thing for the Lightning, but somebody must have seen an improvement with a change or reprogrammed it to take advantage of the change.

-Kerry

 

So what modifications would benefit from a lower temperature thermostat? and tune for it with a burned chip or custom programming?

 

I've got a blower and my tuner said a 180-degree t-stat would give me a few HP.

But I'm still running the factory t-stat.

 

Dave - The modifications that may benefit from a t-stat change to a lower temperature would be a higher compression rating or forced induction equipment... basically a supercharger in the modular engines' case. Both of these mods create heat due to the energy given off by compressing the F/A mixture even tighter than originally designed. This is particularly true of roots style blowers, since this particular style has the side-effect of raising cylinder temps when adding the air charge more than any other kind of supercharger. By putting a colder t-stat in (dropping from a 190 to 180 for instance) will allow a slight bit more boost and/or allow you to improve your timing. These changes will equate to more power output when properly tuned for. I recommend a dyno shop and wide band F/A meter for the optimum results, so yes, a custom tune.

The engineering behind the material used in the engine has been taken into account with a stock set-up. You want to make everything with the engine happy for the best performance and longevity. Try to keep the temperature difference between the oil, the metals, and the coolant all within a band. Taking one of these a little out of the band may not grenade the engine, but it may not get the mileage it once did or last nearly as long - swapping in a t-stat just because you heard it'll help you get more power will help you achieve the goal of a replacement engine. In the case of a large power adder, internal engine components may have to be or have been changed to help with the longevity issue. For example, the Lightning's 5.4 uses forged pistons, the N/A 5.4 does not.

In no way am I implying that swapping out a t-stat is the reason a piston gets melted, but, along those lines, it may have assisted in the process.

IMO, changing out a t-stat is not worth the effort for a stock engine. It's another cheap attempt at power that just ain't there.

-Kerry

 

I agree, it will just run a little richer and wear the engine faster!!

 

Not to mention it'll assist in fouling up your cats. Another side effect is more unburned fuel. You could also fail your sniffer emissions check.

-Kerry

 

Leave it alone unless you are running lots of spark advance (tuner on 93 octane) or a blower.

With the Superduty, the thermostat is usually a 195, which is just about perfect. Years ago, they used to put high temp thermostats in engines (like Jeep) running at 215 degrees just to get emissions down. With those engines, sure, a lower thermostat would certainly help things. But with the Ford modulars, 195 is dead-on.

 

So.... my factory thermo is a 195? Never have changed it. But "Buster" is running cool and I think it may be stuck. This is the only place I have found referencing the correct? temp for factory specs.

Buster: 2000, F-250, 5.4, Super Duty ext cab, Long Bed, 5 sp. manual

 

Someone who tunes these trucks would be able to tell you with 100% certainty, but I would be willing to bet that 195°F is indeed the stock thermostat opening temp.

 

You should strongly focus on other ways to increase your performance. A thermostat change itself is not going to give you anything that you will feel/see. As you said about the lightning series, there are other mods that are done along with running a cooler thermostat.

 

It will run no richer.
The PCM determines that the engine is at normal operating temp at approx 150 degrees.It will take no longer to reach this temp with a 170,180,195,225 degree stat.
JL

 

Most of Ford's performance vehicles use a 180 degree stat, including the Police package crown vic's.

You can bump the timing a bit without the detonation, but when I did it, without bumping the timing, I lost a bit of fuel mileage around town. Didn't seem to make much difference on the highway. And during the hot summer months, the engine temp will go up above 180 anyway, so may only help during the winter.