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Discussion Starter #1
Ok so ive been thinking about what the intercooler does. Has anyone taken the intercooler back off with a bigger turbo to see if you can gain efficiency without having to worry about egt's. The intercooler was first brought into use to help with emissions and it is a restriction. If we were able to eliminate that restriction would we see a gain in mpg's

I want to know if anyone has taken the intercooler back out of the equation for a daily driven application
 

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I had a temp probe on both sides of the cooler for awhile when experimenting with different intakes.
Considering that it most always lowered the intake temp from above 200F plus down to an average of 20° above outside temperature I don't think it would be wise to remove the cooler.
It does a lot more than reduce emissions, it also keeps your egts down.

Never tried a pressure gauge on both sides of the cooler but highly doubt it causes much restriction.
 

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Discussion Starter #3
i know now that it does help egt's but i would like to know how effective it is. was your cooler a stocker or was it aftermarket? Has anyone set up two pressure gauges to monitor the pressure drop across the cooler?
 

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RollinCoal on the forum here just finished up a set of non-intercooled twins for his VP truck so it is possible. He says his EGT's are sweet and under control. I think he was putting down decent numbers with it to so I might be inclined to believe him.
 

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Discussion Starter #5
yah i saw his posts and thats what got me thinking about doing the setup on a stock truck with a slightly bigger than stock turbo.
 

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on a stock truck I don't think you'd see enough gain to warrant it. Like you said it is a restriction, but that restriction is only a factor when you are trying to build massive HP. Stock truck, no need.
 

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Discussion Starter #7
im not looking for gain in hp or tq but mainly in mpg's
 

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the restriction of the IC isn't enough to warrant removing it considering the rise in EGT's and loss of efficiency because of higher air intake temps if you're going to mpg.
i would never run a turbo vehiclewithout an IC unless was using another method of intercooling like alcohol injection.
 

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Aren't engines more efficient when they're running hotter?


Doesn't hot air flow faster than cold air? Hence exhaust valves being smaller than intake valves?
 

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Aren't engines more efficient when they're running hotter?
Cummins says the for maximum efficiency ideal intake temperatures for the 5.9 are 50 - 90°F.
My 400hp rig is almost always in this range as measured at the airhorn.
In fact I have more trouble with the intake dropping below 50° in the winter than it getting above 90° except on the hottest days, steep hills and big loads.
 

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Aren't engines more efficient when they're running hotter?


Doesn't hot air flow faster than cold air? Hence exhaust valves being smaller than intake valves?
They run better when they run hotter Coolant temps not air intake temps. It is the delta between intake and exhaust temp that determines thermal efficiency. Exhaust valves are larger to reduce pumping losses from pushing the exhaust out of the engine.
 

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So what's a more efficient delta, an engine with IAT's at 300 degrees and EGT's at 1300 or an engine with IAT's at 100 and EGT's at 1100? The first one's going to have hotter coolant temps after a couple minutes.


You're saying our exhaust valves are larger than our intake valves? They're close, but our exhausts are smaller than our intakes, like the majority of engines out there.
 

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Let me rephrase my statement...Valve sizing is completed with pumping losses in mind on both the intake and exhaust stroke. On the intake side it is a pumping loss because the vacuum it is pulling in the cylinder, yes even with boost even if only for a half a millisecond when the valve opens. They try to find a happy medium between the two pumping loses and air requirements of the engine.

By a general rule of thumb higher temperatures hold higher energy content. That being said you are also losing oxygen density the higher the temp you get. So high EGT's are the best way to drive a turbo, but Cool IAT's are the best way to feed an engine if you want to put in a ton of fuel to burn.....
 

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So what's more efficient, an engine running at 100 degree IAT and 1100 EGT or 300 IAT and 1300 EGT?

Cruising temperatures. Those numbers aren't that far off for my non-intercooled truck.
 

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Discussion Starter #15
begle how much water meth are you using to keep your setup cool? do you have to use the water meth all the time or just when in higher boost/engine load situations ie towing.
also what are the highest egt's that you see since you dont have the intercooler. i realize that you are using the water/meth as a cooler
 

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I only use the water when I'm being irresponsible. I can cruise at 90-100 MPH at 1200 degrees EGT, which I've done for hours at a time through the desert.

With just the 150 PSI set-up, the EGT's are limited to around 1500. That's 40 GPH worth of diffuser nozzles, although I'm pretty sure that it's flowing less against boost due to the pump being over-whelmed. Without it, the pyro pegs.
 

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i'd rather see cooler intake air for the simple fact that cooler intake air contains more oxygen (density). the higher density makes it possible to burn the fuel more efficiently, which means better mpg.
 
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