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HIGHBERG, "A lot of people putting them in have also noticed mpg decreases."

TRUE. I worked for and designed c3-c4 and ODBII systems at GM for 17+ years. Many sensors and factors are involved. The high temps main purpose is lower more complete combustion, but then at these higher temps we get more NOX, aka we do EGR to reburn the fuel and lower the combustion temps. Which is diff than the water temps as you state.

The reason for the poor MPG is mostly related to the coolant temp sensor. When the temp is cooler the spray signal from the PC is wider, longer, fatter than at higher temps, since warmer temps will have a more complete combustion to a point. When real low temp are read the PC acts like a choke on a carberator engine. More IAC open and fat fuel for higher RPMs and richer fuel mixtures. Of course TPS, VSS, MAP, BARO all tie i nas well as do the primary and secondary O2 sensors, but here are also basic logic codes in the PC until the brain is in full CLOSED LOOP operation which is about at operationg temp and if enought time has passed and certain other conditions are met.

Now if you use say a predator to recalibrate the sensors and timings and can keep the engine a litle cooler you can help the heat soat issues, but I agree that more power is made at more heat all things relative to a point.

But then we also have to take alltitude, humidity, air temp air speed and many other factors into consideration.

Main thing is the fuel we are using too also reacts in this Stoichiometic equation right? And I recall in a lab in a perfect world I think it is 15.2 lbs of air to 1 lb of fuel. But most engines need 14.7 to be perfect and then bends in the intake, valves, ports bumps etc drop it from here. So mostn eed to run in the 13.8 - 14.4 range. Big power is made in the 9-11 ranges if you have what is needed to ignite the fuel.

Air-fuel ratio - Wikipedia, the free encyclopedia

Definition
Stoichiometry rests upon the law of conservation of mass, the law of definite proportions (i.e., the law of constant composition) and the law of multiple proportions. In general, chemical reactions combine in definite ratios of chemicals. Since chemical reactions can neither create nor destroy matter, nor transmute one element into another, the amount of each element must be the same throughout the overall reaction. For example, the amount of element X on the reactant side must equal the amount of element X on the product side.
Stoichiometry is often used to balance chemical equations. For example, the two diatomic gases, hydrogen and oxygen, can combine to form a liquid, water, in an exothermic reaction, as described by the following equation:

I love these threads :SM127: , you guys are right spot on top of it! Thanks:)

OH so this is why Nitrous makes a lot of power. Now, I have a great idea for power, we need to make O2 and put it into the engine in a very controlled manor with a timed chemical reaction. Oh and then better pistons etc.. you get the point..
 

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Definitely. Chemistry isn't my strong point. The air has a lighter viscousity than the liquid which causes this effect. My play here has been trial and error to get the right air fuel mixture. Spent a lot more time with carburation here.

The Nitrous does what it does as the engine is burning a fuel that it isn't really designed for. Higher, dryer and flashes faster to produce more energy but the engine can't sustain it for long. Simular to the diesel runaway you get when a natural gas leak is present.
 

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My mileage did decrease.. i'm about to yank this 180 thermostat.. I didn't drive too long with it, but I'd rather be on the safer end of the stick.. I want this car to last for a long time and I don't have the expertise to fix all the parameters in the ECU.

Does anyone have a dyno of only changing the 180 T-Stat?
 

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there in the mod face off on the LX forums, jason did just that. dyno before and after a thermostat change. where else can you gain more HP per dollar spent? this mod is by far the best bang for the buck. nothing even comes close.
 

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I'm looking for that mod face off now.. My only concern is I drive hundreds of miles at a time, and if my combustion is going to be off because of this(Fuel Mileage is a direct reflection of this).. is it going to wear my plugs out sooner, cats, etc? I can live without some HP if in my situation it will save me $$ down the line.

If I was only at the track and back all the time.. i wouldn't care. This mod is perfect for that.
 

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I haven't noticed a decrease in mileage on mine. I clicked off 27.4 mpg returning from a 320 mile trip staying at 65 mph. I can't imagine getting much better than this. Car has 9k miles on it.
 

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I for one am going toput in the thermostat as I have noticed a big drop off in power when the car gets really hot. I drove it around town for a few hours last weekend and with the temps up the car had no guts it seemed. Once the car cooled down the power was right back again.
 

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I for one am going toput in the thermostat as I have noticed a big drop off in power when the car gets really hot. I drove it around town for a few hours last weekend and with the temps up the car had no guts it seemed. Once the car cooled down the power was right back again.
Angelina fears Roxie! ;)
 

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There is no doubt about the power gains.. I'm more concerned with the long term effects on combustion as stated by the 17yr OBD II software engineer. If it is true that a different type of spray pattern is present at lower coolant temps, which will create a rich mixture.. then we will prematurely foul plugs($approx 700), Cat Converters(??200 each??)), in addition to whatever buildup may occur on the heads..

if the CMR tune can adjust these parameters, then I think all is good. I don't know enough about these tunes. All I have read is they create a WOT map that keeps optimum A/F, Knock, Etc.. when it's in that loop. I do not know if they mess with regular operating loops that the standard o2 sensor keeps track of. Cold Startup loops, etc..

In other words, there is not enough information on the EFI side to make me go 100,000 with a potentially over rich condition. If anyone has a wideband.. what is your A/F with the 180 deg at idle? and cruising? vs. 203deg? Is it exactly the same?

I need to get one of those next week and check it out.
 

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good stuff everyone! Very interesting. All I can add here is that it may be wise for everyone who does this to put original back in for their 5 year (Lifetime Powertrain Warranty) Inspections. This could be a definite reason for Chrysler to waive eligibility. That is if you are concerned about it.
 

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I did it again. LOL Hey I am new here... I'll get it right yet... Last forum was for my 88 t bird turbo... Had it 25 years... Miss it a little. bbmac
This site just recommends all kinds of odd old threads, it happens.
And I am familiar with those T-Birds. I had a 1987 Mark VII LSC "Hot Rod Lincoln" and seriously considered a manual swap from a T-Bird donor. That car was a powerhouse, and the AOD was nice, but man, 225hp, 300tq, would feel like boredom today.
 

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I agree with you about old school now but the 88 turbo style was way before its time. At that time I had cars in the 454 class... I'll admit the 88 wasn't a boss 302 but HP aint everything. That little (3200 plus ) would flip over before sliding side ways on a sharp turn... Garage kept for 20 years... Lost the garage to motor cycles. Hated to see it outside - sold it with 12K on it for 10K to a guy in Wyoming. Not that bad - paid 16K for it.... Just a memory now. bbmac
 
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