arninetyes What is the foam fender sleeve?

I guess I will start with running a friends smaller tires if that works it will at least tell m where to start without spending any money

Then I guess I will do gears, exhaust, then turbo

Sound good

 

Okay! I'll take that - and raise you this...

From discussions I've had with Dale and others, there is no significant dyno difference between 4-inch and 5-inch exhausts - though apparently, individual trucks can vary enough that one may work slightly better with one exhaust over the other.

Now, if you want to talk downpipes, there IS an appreciable difference. And the difference is - along with lowered EGT for the 4-inch (the subject of this thread ), the entire powerband moves upward in the RPM scale by a few hundred RPMs. So, if you like to lug your PSD (which you should NEVER do!), then a 3.5 inch DP is for you. (or, if you spend a lot of time at low speed and low throttle settings and want to maximize MPG for those conditions...)

Want lower EGT and don't mind losing some power in the 'lugging zone', then a 4-inch DP fits the bill.

Okay, now the OTHER issue - sound. I've listened to a 4-inch muffled - no comparison to a 5-inch muffled. I listened to a 4-inch straight piped, and it sounded just about as deep, and a bit meaner than my muffled 5-inch - and a LOT louder, especially at light throttle. But that is comparing apples to oranges, and I kind of like my truck quiet enough that I don't have to draw attention to myself - unless I want to.

What I have never heard, is a 5-inch straight piped.

Anyone heard a real-life, side-by-side comparison of 4-inch and 5-inch exhausts, both straight piped? Let us know!!

 

i think your egts would drop a lot if you re-geared with 4.56 37s are pretty tall and the engine is working a lot harder to turn them.

 

Check out <a href="http://www.blackclouddiesel.com/Tech/AIS%20foam%20install.htm"> here</a> and all will be clear.

 

Absolutely.

The big tires are a primary contributor of the high EGT's. I've done pretty much every air flow mod in the book, and when I switched from 33" to 35" tires the EGT's came up with them. Average cruise EGT's are up 50-100 degrees and 150+ when I pin the skinny pedal. I have no doubt that taking the load of pulling those tires off the engine with a gear change will help you....but still having stock gears I cannot prove it, and it's not my money you're spending.

 

cookie88 Thank you! Thank you! Thank you! That is what I had thought all along I dont want to put a bandaid on my problem. I want to find the cause and change it gearing has to be it. If you got say 150+ egt when pinned going from 33s to 35s

I have gone from 33s (stock?) to 37s this totally explains what is happening in my case though bigger exhaust is now on my list of things to buy as well as a turbo upgrade

Thanks to Everyone for the help and insite

 

Those 37's are not only affecting your drive ratio, but they are heavier and have more rolling resistance. I would compare the added load to having a small trailer always hooked to it.

Since they are an additional load the gear change will most likely not bring your EGT's all the way back to stock levels, but just putting the engne back into it's powerband will help it breath much easier. A good intake and exhaust system should soak up the rest of the difference easily.

Oh...and the stock tire (265x75R16) is a 31" tire, so the jump to 37's is a big one.

 

I'm a little late on this thread but I would like to clear up some misconception to the 35" tire's. Proper speedo calibration is very important because it is part of the PCM's adjustment equasion. I run 37's on my truck and there was a change when the tire's went on. I had my friendly Ford dealer recalibrate the speedo and they went back down. The idea that a 37" tire has more rolling resistance is nonsence. Diameter has nothing to do with it ,in fact a larger diameter tire roll's easier. Thats why bycycles have large wheels and allways have had. This is nothing new. Tread width and air pressure add resistance. With the stock tires and now the 37's i have seen little change in fuel economy which if there was an increase in load would be effected much more than the .2mpg decrease I have logged with my X. My Superduty is down 1.2mpg with 38.5" rubber that is 15.5" wide. The brakes work a little harder. I just recently finished my fuel air separator and testing has shown a 200+ degree drop accross the board and a wider, smoother power band.

 

Ramsmoker what gears are in your truck 3.73? Though no matter what a taller tire takes more energy or leverage to roll over. So what I have happening is my EGTs go through the roof much faster because it is like I am pulling a small trailer all the time. Not to mention the fact on long uphill pulls on a hot day I can sometimes watch my trans. temp go up as well when empty. I could care less about my speedo calibration just stick with traffic youll be fine. I feel my best bet is going to be smaller tires or new ring & pinions.

 

I have the 3.73 gears, 4" exhaust w/o muffler, Ramsmoker 4" ram air to the turbo. TS 6 position chip, HX w/aux oil pump, very high fuel pressure and a Hinton "Cyclone" fuel air seperator. And you are mistaken on the diameter of the the tire having more resistance. There are less rev's per mile and more leverage against obsticals. I have records for my truck fleet and noticed when I recycled my super single steer tires to replace duals, the trailers pulled easy and the fuel milage went up with the same surface size of contact. The difference was we went fron 38" tires to 44". I know you don't care about your speedo but your PCM does. If it is reading a faulse road speed your going to get a configuration of engine responce to what the PCM is seeing. Wrong numbers in, wrong numbers out. You can talk with Goodyear tech support on tires. There always willing to help. I used to run test tires here in the NW. They had no name or ratings on them, just a lab code. Let me know what changes you make and the results. My biggest bang for the buck has been the Hinton "Cyclone". My X droped over 200 degrees accross the whole rpm range