My 2007 5.9 six speed has edge a/j with a 4" turbo back with a 5" tip. I just got the truck, and when hauling something or empty on a hill and getting on it the egts gauge says 1385 degrees and boost at 39 lbs. A friend of mine said not to go over 1200 degrees, he didnt know how much boost was to much. What i was wondering is this ok? Will a CAI lower the temps any? Will a after market high ram help? or hurt? Everything is stock with the exception of a heavy duty clutch. Thanks for the feedback.

 

First welcome to the forum! And congrats on your purchase.

OK, let talk temps. Your pistons are aluminum. Aluminum melts at a little over 1200*. That may be where your friend gets his number that he passed to you.

However, where are your temps measured at? That has a bearing on the answer given as the temps can vary greatly. After the turbo can be 200* or more lower than before the turbo. That can give a false sense of security. Most pyrometers are installed at the collector on the exhaust manifold right where the turbo bolts on. This will provide the highest temps as it collects gasses from all the cylinders. (well, on your truck, it will be the last two cylinders on one side of the divider and four on the other, but I digress) That said, it is not measuring what is going on inside the cylinder, but just providing a reference. Inside the cylinder can vary greatly. For instance, the stock cam has a profile that provides for in cylinder EGR (exhaust gas recirculation). This delays the opening of the exhaust valve for smog reasons. This also allows for a little higher in-cylinder temps. To combat this, Cummins designed "J-hook" piston cooling jets. This squirts oil for cooling purposes to the underside of the crown of the piston to help cool it. The oil is then run through a heat exchanger so your engine coolant then cools the oil.

So, in a more direct answer to the original question, the 1385* is normal with the EDGE and everything else stock. 1385* for a short few seconds will not hurt anything (that is not to be interpreted as an absolute statement-- some have melted pistons at lower temps and others have gone years with higher- but even a stock truck can see 1385*), but you don't want to be loaded climbing a long hill and keep it at that temp and expect the engine to not suffer damage. 39 lbs of boost is near the limit of the stock turbo, but ok. It is not "too much boost".

The CAI will not help your temps enough to matter. Neither will the High Ram. What they will do is remove some restriction and allow the engine to breathe easier and you can gain a few ponies that way.

To lower temps, here are your options:

1: lower the power level on the Edge.

2: Use a different programmer like smarty. Edge has always run hot. Smarty can give the same or higher levels of power at a lower egt. That is dyno proven time and again.

3: a better turbo. Notice I said "better" not necessarily bigger. A better turbo will provide more cooling air on the compressor side and has a larger turbine/housing on the exhaust side. The stock turbo is very restrictive and that back pressure elevates egts in the cylinder as exhaust struggles to get out.

4: a decent water injection system. Read the sticky on this subject in the high performance section of this forum.

Good luck!

 

The pyrometer is located on the exhaust manifold and in the back cylinders. How would the smarty lower temps and still make the same power? Thanks for the quick reply.

 

Two words, better programming. The smarty brand is the programmer of choice here for several reasons, they are a cummins only brand, that is all they work on and they have made vast improvements over stock programming. When you can spend months on a dyno again and again adjusting duration, rail pressure, timing and a bunch of other features you can do some amazing things.

Why did cummins not do these things? They have to abide by emissions laws. We do too, just we don't have to prove to the U.S. government that we still meet those emission laws.

 

Mine with a Bullydog on level 2 or 3 (crazy larry), empty will hit 32-33lbs and then settle in at 29-30lbs, 1200-1250, hammer down, up a mtn pass.
Pulling the boat, 6klbs, hammer down uphill, it will get a little over 1300deg same boost.
That in cyl EGR really hurts egts, IMO. Buddy with an 03, Edge JA, too big of injectors, consistently runs a couple hundred deg cooler egts in the same conditions..