[updated:LAST EDITED ON 17-May-02 AT 01:44 PM (EST)]Has anyone went to a cooler thermostat on the 300??? Any changes??? I used to run a 160 in my 4.3 @hevy. It made a big difference. Just wondering..TY

 

What do you mean by "...it made a big difference."

I put a 180^ thermostat in my 86 Mustang 5.0 HO and that was a mistake. My computer controlled engine lost power, lost gas mileage and is a cold bugger to boot.

Unless you have a reason for wanting to change it out, it's a really bad idea to change the running temperature on modern engines. If you're doing it for performance reasons, don't. Spend your money on a fuel system magnet instead.

 

On my chevy, installing the 160 put the computer into a permanent warm up state. My gas mileage was nothing to brag about but I had a noticable amount of power. It did not kill the truck either. I put about 80k on it with the 160 in it. Because of the difference I saw in my other truck, I am interested in the idea for my Ford.

 

"Spend your money on a fuel system magnet instead. "

Heh, you talking about those nifty little magnets they sell in JC Whittney's? I think I'd put one of those on right after a "Tornado" intake insert

 

I apologize for the sarcasm, the fuel magnet thing. You're asking sincere question in a legitimate search for better performance, so I'll try to be more constructive.

I don't doubt that your Chevy truck ran better in open loop mode, but defeating the Ford's computer to get an improvement in performance seems like a bad idea. I've read through Probst's book on Ford EEC IV fuel injection and realized that you can do a lot of harm by modifying the engine controls without an understanding of what they do, including the EGR, the 'smog' pump, the thermostat, and the MAF, just to name a few. When everything is working as designed, the system is a work of art; max power, max longevity, max reliability, and min pollution at no expense to power. It's really danged clever once you understand it all. They even make an adjustment for time/mileage - as the engine gets older they modify the parameters to compensate for worn rings, leaking valves, stretched timing chain, etc.

Yes, I don't doubt that the engine make more power in open loop mode, but it goes to open loop when you mash the throttle anyway, so why not reap the benefits of closed loop when you're coasting through the parking lot and save the engine for the stop light? Specifically, in 'warm up' mode, the air diverter valve is directing air to the thermactor ports where the extra oxygen is combining with the extra fuel and burning inside your exhaust ports. That would make your heads a little hotter. I could go on and on, but the point is that if the computer is holding back performance, try reprogramming the computer.

Although it has taken 15 years for people to get comfortable with computers in their cars, there are now a variety of programs that allow alteration of all of the data lookup tables for your EEC IV. That's cool. BTW, there's discussions of computer parameters and which program is the favorite over on the [link:www.corral.net|corral's] discussion boards.

Best of luck,

 

pcmenten : Thanks for the info and taking the time to explain. Thats why I was asking. When I did that whole thing with my chevy I was 17 and did not know much about cars. I do a little more research now before I do anything like that. Thanks -Chris

 

I've done the 160 and 180 in my truck. The 160 does allow it to get out of warm up, at least it did on mine. The 160 will not allow the heater to work properly and renders the temp gauge useless because the needle won't move more than 1/8" or so. Even in the summer when it's 100+ degrees it doesn't get to normal on the gauge. With the 180 the truck seems to be smoother, the heater works, and the gauge gets to a point where it's information is useful. I've had the 180 in for over a year and have found it to be the best compromise.

 

I agree with keeping the standard degree thermostat in computer controlled vehicles unless other well-planned-out modifications are completed as well.

pcmenten, can your readings explain why the EGR restrictor plate works so well for so many people with higher-mileage EFI I-6's? I'm glad to hear you seem to consider it tops out of the myriad fuel injection systems that have been used to fuel gasoline engines (though 'd think if that was really the case, there'd be an appreciable amount more HP coming out of the 300 cubic inches - not a ton as to make it unreliable long-term, but its displacement vs. performance seems like it's starved for fuel). I'll have to read up on it myself.

 

Hi GammaDriver,

I still need to learn more about tuning the EEC IV system, but I believe that it can be used to tune a 300 for 250 hp without trouble. It seems to me that it is critical that a person starts with an engine with minimum quench height and a modern, fast burn cylinder head. I'm not familiar with the late model intake manifolds but I assume that they are long runner jobbies. If it can be rigged for SEFI then all you need are some reasonable headers, 1 5/8" seems right, and some software to tune the look-up tables.

I also don't know if the late model 300's have roller cams, but I don't think that's critical. The roller cam will give you extra low-end torque but a 300 already has plenty of low-end torque.

As far as the EGR problem, I wonder if a vacuum brake thingie would fix that problem. What I'm refering to is a little device that delays the vacuum signal. I've got one on my MGB and I know it's used elsewhere.

Best regards,

 

Hmm, a vacuum brake sounds like a neat idea.

From what I hear our heads have a problem since they have some type of emmision ports in them, otherwise they'd be a great head.

Thanks for the reply.