06 cummins u7131 egt's

[gschwepp]

I have an 06 cummins with no modifications to the intake or exhaust. Im thinking of getting a egt gauge and then the u7131. My plan(good or bad im not sure) is to check the stock egt's before adding a mile tune. If the egt's get too high with a tune will adding an aftermarket MUFFLER...not whole exhaust remedy the situation? The dodge comes with a 4" exhaust so I cant see spending money on another 4" and I dont want to spend the $ on a 5" stainless(need a stainless...stuff rusts off in PA). As for the intake....will the stock one due? I prefer to keep it quiet in the cab so the less exhaust and intake noise the better. Any info would be helpful.
Thanks.

[mikel]

The muffler alone will not yield significant improvements in EGT reductions.
While the factory systems are called 4" systems, there are several areas where they neck down close to 3".
The aftermarket, mandrel bent setups maintain a true 4" throughout. This will show the best improvement in exhaust flow to help keep EGTs down.

Thanks

[gschwepp]

How much difference in cooling does the turbo back make over the cat back? What is the highest temp the egt should reach? Is an intake a must or will the stock work? Please forgive my questions...I had a tundra before the dodge.