I have 2002 7.3 towing a TT approx 8k. Just got my dp tuner with 80 tow. Hills i am doing 55-60 with egts at 1150. I was wondering if 4 inch exhaust will help lower the temps goin uphills. What do you guys think?

 

Where did you put the pyro? Before or after the turbo? If thats before, that is not bad on temps. But yes the 4" exhaust will help lower the egts. The tuning can help alot too.

 

Pyro is on the exhaust manifold. It feels like i still have more power but have to back off due to temps

 

Have you tried getting the revs significantly over 2000rpm, into the 25-2600 range? Not sure if you're getting the downshift out of OD, but lugging the turbo will spike EGT's.

Yes, a full 4" turbo back exhaust will help lower EGT's a good bit - although high EGT's for out of the box generic tunes seem to be a DP specialty.

 

Yes that is with OD off. Im not sure if i shouldve gotten 60 tow instead but i sure enjoy towing with 80tow. Looks like ill be looking at upgrading exhaust.

 

I've got A TS performance chip in mine, if I tow on 75 hp setting I can get EGTs to spike up to 1200-1300 if I don't downshift out of OD sometimes and that's with a 4 inch strait pipe. A lot of it has to do with who wrote the tune.

 

I could see where a larger exhaust will lower the measured EGT at the probe point if nothing else but due to the drop in pressure. But this would not be the same as the actual EGT temp at the cylinder dropping. And the ultimate point is to get an idea of what is happening inside the cylinder, not at some point in the exhaust system. Is there any data showing real reduction in combustion temperature due to a change in exhaust pipe diameter?

 

Oh, I suppose someone like Bank has the data your after...anything to sell a product. Im only giving info from my own observations from adding a larger exhaust to my trucks over the years. I think my tymar intake helped aswell. But again "think".... no data to analyze for proof.

 

If the prob is in the Manifold, it s as close to the cylinder as you can get, there's a ft or two of pipe from there to the turbo, than the exhaust pipe. so if we are seeing temp drops there, there has to be a temp drop in the cylinder itself too.

 

If the "cooling" is due to a pressure drop, then as long as the probe is outside of the cylinder then you are going to see a drop in temperature. How close it is to the cylinder isn't a material factor. The same effect on the observed temps could be accomplished with a cooling jacket around the exhaust but you still aren't affecting the temperatures inside the cylinder, which ultimately is what you care about.


Just how can an exhaust change magically lower the combustion temperature? Intake air pressure, yes. Fuel spray pattern and timing, yes. Exhausting everything afterwards? No. It really sounds as if all this does is lower the probe temperature, not the cylinder heat.

 

From how I see it (not an expert, just my understanding)

Theoretically a larger exhaust allows for more volume and the lower pressure area should result in a more efficient and faster transfer of combustion gasses as they evacuate from the piston forcing them out, along with the pressure differential afforded by the larger exhaust. So technically wouldn't the more rapidly exiting exhaust cause less heat soak from the gasses being in the cylinder? Lower leftover combustion gas levels should also help the residual chamber temperature stay lower. The manifold feeds the turbo itself, which in turn passively heat soaks the intake charge. Keeping things lower across the board results in lower, no matter how slight, intake charge temps which in turn help combustion and exhaust gas temperatures.

 

I think you shouldn't be towing an 8,000 trailer with an 80 hp tune, especially if it's DP tuner tunes.

If your truck is mostly stock as it is now and you're looking for a small bump in power, there are quite a few folks that can write you a mild tune.

If you were to tow in stock, you wouldn't have too much of an issue with egts. Given that you still have the stock exhaust, you have the best and most efficient setup to get and keep your turbo spooled, even with a mild tune.

If you open up the exhaust to a full 4 inches, yes, you're eliminating back pressure, but you're also eliminating the back pressure the turbo needs to spool properly and efficiently. You're also creating turbo lag for yourself as the truck now has to fill a 4 inch space with exhaust (takes more time to fill) as opposed to a 3 inch space with exhaust (takes way less time to fill). Unless you have considerably larger injectors, leave it alone.

As I was once told, unless you plan on racing your truck, leave the exhaust alone; give it more air to breathe, but leave the exhaust alone.

If you tow regularly two great mods for the transmission are the BTS valve body (personal preference over the John Woods and Factory tech) and the 6.0 trans cooler, these two mods help keep the trans together better and make it more efficient at what it does.

Moving on, there are plenty of more up to date tuners that can write you a good tow tune an economy tune when you're not towing while keeping egts more reasonably under control.

KEM Diesel
Gearhead Automotive Performance
Tony Wildman

 

So....dp is not protected on this board like most all of the others? Interesting... But then again they are a listed on 2 forums as a sponsor..

 

The 7.3 forum tends to get up in a row over words against DP, but not so much in here. I loathe DP Tuner, I bailed on them after months of crap service, idiotic tunes, and being told MY truck was the problem and not the tunes. Quite a few friends and FTE members alike have had similar experiences with them.

Since swapping to Gearhead: my rig runs better, idles better, towes better, shifts better, EVERYthing is better across the board.

High EGT's are just one of the DP-isms that exist. Try flooring it, then try going a little over 1/2 throttle on the next run. Zero difference. Yet another gripe I had with the tuning, dumping a ton of fuel to make it seem like there's a ton of power yet anything over 1/2 yields... nothing.