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R/TBlues
Dodge Dakota
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2/07/2004
17:27:39
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 Subject: RE: 180 thermostat
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Trukguy,
As a matter of fact, I have done all that already and I have backed up my schooling with experience at both the drag strip and the circle track. The reason I was inconstant with the 195stat was the fuel I was running and if you read all of my post you would have caught that. Once I found fuel with no ALCOHOL in it, I was back to running 14.7's. I keep mentioning Diesel and Alcohol engines because both of these fuels are much more sensitive to temperature than gasoline. Gasoline is very forgiving and tolerates a lot wider range of engines than alcohol or diesel. To better understand gasoline engines you need to have studied alcohol and diesel engines. A cold engine makes less HP. I haven’t had my own engine dynode, but I have been in a dyno room where they dial in an engine. To properly tune an engine you have to bring it up to temp first. With a temp sensor and air fuel sensors mounted as close to the exhaust port as possible you adjust the fuel/ratio to where you generate the most HEAT without leaning the engine out too much. They adjust everything on the engine to generate the highest temperature possible in the exhaust without detonation and that is where the HP graph consequently peaks. You can go too lean and melt the pistons. By installing the 180 stat on a PCM controlled engine you richen the fuel mixture and the exhaust temperature goes down which results in less HP. Go to ANY competent engine builder that has an engine dyno and they will have an exhaust temperature and air/fuel ratio analyzer to help them dial in the fuel ratio. They do NOT run the engine cold with rich fuel mixtures. The leaner you can run the fuel mixture the cleaner and hotter it will run.
History Lesson:
Before the EPA tightened it's grip on emissions Chevy, Dodge, and Ford were running their engines as lean as possible (mid-70's to mid 80's). Ford was the leanest with like a 16.5:1 ratio. The problem was that a lean hot combustion makes excess NOX emissions and that depletes the OZONE layer. So, the EPA mandated the reduction of NOX emissions. An exhaust system that could convert the extremely high NOX emissions was too expensive and would require that the converters be serviced every 50,000 miles. So, they opted to run a 14.7:1 air/fuel ratio instead. This was at the price of less performance and poorer fuel economy. Now you want to go to 12.5-13.5:1 by running the engine to cold. GO FOR IT!!!
Since you don't believe me or WYOTECH........
Another informative article on this topic is in the FALL 2001 Issue of Mopar Now. They explain the same thing. They also explain how you can hook a temp sensor on the exhaust manifold to make adjustments to the air:fuel ratio. They also explain that the hotter the exhaust temp the more HP your making. I guess all these experts know less than you do about making HP.
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Trukguy
Dodge Dakota
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2/07/2004
17:53:20
| RE: 180 thermostat
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You don't get it do you? You completely disregard the facts in hand. Run your truck at the track when it's cooled off and run it when it's hot. Come back here and use some sort of reference to somebody else that supposedly knows what they are talking about to try and explain why your truck went slower when it was hot. That will be the truth of the matter and your talk about diesels and alcohol won't mean a thing. You keep talking about exhaust temp without understanding what happens with hot intake temps that result from a hotter running engine. What you keep failing to understand is that the engine isn't going as rich as you say it is because of the temp change. You are getting more air into the engine when it's cooler because you don't run into the reversion problem. You get more timing thanks to the PCM. It does add fuel, but with more air and timing you make more power. Since you haven't had your truck on a dyno to see the A/F numbers change, you are taking it for granted that it goes that rich. It doesn't. Don't take my word for it or read it in a magazine. Like I said before, spend your own dime and put your truck on a dyno and check. You might just be amazed at what you find out. Who knows, you might even learn something for yourself without having to read it in a magazine, on the net or on TV.
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R/TBlues
Dodge Dakota
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2/07/2004
19:52:34
| RE: 180 thermostat
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That statement is partially true. I'm assuming that most people on here are running a cool air induction. I mentioned that already. Therefore, under-the-hood temps won't affect the incoming air temp. The 180 stat might lower the incoming air temp by 1 degree. Then again, it might not lower it at all. We were originally referencing the 4.7L on this thread. It has a composite intake manifold with no water or exhaust passing through it. Therefore, it's not going to affect the incoming air temp enough to make any difference. It might on the R/T because it has an aluminum intake and aluminum transmits heat and therefore heating the incoming air. Cooler incoming air is very important. I never said it wasn't. In fact I presented the BTU=HP equation and it's the difference between the incoming air:fuel and the exiting exhaust temperature that makes HP. The 180 stat doesn't lower the HP by itself. The rich fuel mixture condition the PCM creates lowers the exhaust temperature. Example: 100deg incoming air temp and 800-degree exiting exhaust temp will make more HP than a 50-degree incoming air temp and a 700-degree exhaust temp. Increasing the amount of fuel to just 13.5:1 instead of 14.7:1 will drastically reduce the exhaust temperature. Typically, the exhaust temp will fall 100 degrees for every ratio you drop. (14.7:1 vs. 13.7:1). The same holds true in reverse. If you raise the air:fuel ratio to 15.7:1 you will raise the exhaust temp. The best scenario would be if you could run a 160 stat with 16:1 air:fuel ratio. BUT!! We don't have control over the air fuel ratio. The 160 stat would allow you to run a leaner air:fuel and the result would be a much hotter exhaust and you would see substantial HP gains. Unfortunately, these are PCM controlled motors that won't allow us to adjust the air:fuel ratio. Therefore, we have to run them HOT. I don't like it either. It's the facts though. I can make more HP with a carbureted engine and a 160stat that I can a factory PCM engine for the simple reason that I can control all the fuel and ignition parameters on the engine. You can't do it on these engines.
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R/TBlues
Dodge Dakota
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2/07/2004
21:49:45
| RE: 180 thermostat
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Did anybody watch NARCAR's BUD-SHOOT-OUT tonight?
Wellllll, With 19 laps to go, a caution came out and Terry Labonte added tape to cover his grill because his car was ONLY RUNNING 200 degrees. They added tape to RAISE the temperature. Rick Hedrix has had the reputation for having the most powerful Chevy engines in NASCAR. They run their engines between 210 and 220 degrees. I guess Rick Hendrix isn't an expert on temperature vs. horsepower. How many NASCAR championships does he have?............. HP=BTU, BTU=the difference between incoming air temp and exiting exhasust temp.
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Trukguy
Dodge Dakota
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2/07/2004
22:07:02
| RE: 180 thermostat
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You are not listening. Do you honestly believe that YOUR truck will speed up and become more powerful if you ran it at 220 degrees? Does anybody else believe your truck will speed up and become more powerful at 220 degrees? They add tape to the grill opening to increase downforce and improve aerodynamics. They could afford to allow the temps to raise a little more without damage and needed the downforce more. Do you have a NASCAR engine in your truck? Do you have a cowl induction system forcing cold air into the intake at 190 mph? Do you have external oil coolers? Do those NASCAR guys have a speed density control system on their engines? You're talking apples to oranges. I wonder why the entire NHRA field tows their race cars to the line instead of firing them up and letting them idle for a while and really build some real HP generating heat? You are still pissing on your own leg.
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R/TBlues
Dodge Dakota
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2/07/2004
22:41:13
| RE: 180 thermostat
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You obviously didn't watch the race. They said they were running TOO COLD in front of over 1 million viewers on national TV. They said they were running 200 deg. and needed to run hotter. They said nothing about down force. Of course down force is the number one reason for running tape. That's unless your running cold. Then raising the temperature becomes the number one reason to add tape. When the engine is running at a cool 200 you add more tape. You not only get more HP you get more down force. Dude I know, trust me. I raced dirt track for 5 years in a Limited Late Model running ALCOHOL! Alcohol is much more sensitive to temperature than gasoline. I ran no grill at all. I controlled the engines temp by richening the air/fuel ratio and adjusting the timing. The difference between 180 and 210 on an alcohol engine is about 1HP per degree.
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btomcik
Dodge Dakota
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1/20/2005
11:52:10
| RE: 180 thermostat
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Sorry to bring up an old post, but I found this info interesting off of this guy's website:
http://www.paysonarizona.net/MyProjects/ProjectDak/Project_Dakota_06_T-StatSwap.htm
Update (02-19-04) : A month ago or so I almost had to take the Dakota into the dealer for something so I swapped the 195 t-stat back in first. Well I found what my problem was so didn't have to take the Dakota in. But, I didn't notice anything at all from running the 180 or 160 t-stat vs. the 195 I put back in and then reading about the occasional milkshake these engines like to develop in the cool area of the oil fill cap (in cold weather) I decided to leave the 195 t-stat in. These 4.7 V8's do NOT have a heated intake from the coolant like old school engines. The PLASTIC intake stays very cool anyway so the colder t-stat is a waste when you can't even tell the difference with the BUTT-DYNO. If I was running boost, it may be a different story for pre-detonation reasons. I took one for the team by trying both the 160 and 180 t-stats. No check engine light or any problems. But no power increase so I would recommend you to NOT bother with this mod.
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jeremiah2360
Dodge Dakota
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1/20/2005
21:24:34
| RE: 180 thermostat
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Message:
http://easyperformance.com/
Click on TechInfo then Thermostat Test.
Notice they say most gains are from 2 degrees gained in timing. This would not work on a reg 4.7 because it has no knock sensor(s). They do advocate this mod to get as much edge as possible for racing.
Good info on CAI`s too.
03 qc 4.7 auto 4x4 46k
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BiergutRacing
Dodge Dakota
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1/21/2005
12:14:33
| RE: 180 thermostat
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Message:
Based on years of experience in racing and a BSME, a 180 degree thermostat is a good thing, but not a big performance benefit. 160 is better, but way to cold even for Texas winter and can cause problems because computer will still think you are warming up. 195 is good for break in and keeps customers happy because heater works good. 170 is about perfect for Texas, but usually only readily available for BMWs!
Advantages of 170-180 degree thermostat:
1) Reduces intake temperature. Maybe only 2-3 degress, but every little bit helps (which is why you should avoid CAI with pretty aluminum tube)>
2) Reduces underhood temperature 10-20 degrees. Everything that is not metal will last 1.5-3 times longer, especially electronics (rule of thumb is double life for every 10 degrees)
3) Allows additional timing advance which makes more power and about same combustion temperature. If you don't get more timing advance, can use cheaper gas!
4) Improves gas mileage (see my previous post on CAI)
Allan
Biergut Racing
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