Starting to think about power - the big red tow truck weighs something in the ballpark of 12000lbs empty, and while sufficient acceleration, I'd like a bit more.
That said, I value reliability above all. There are tons of tuning/flashing options, what's safe? How can I make a bit more power without risking breakdowns?
Simple 5 position tuner.
downpipe makes a big difference but it's more involved. Both of those are very safe.
Motor will take lots. Transmission will take substantially less.
In reply to bearmtnmartin (Forum Supporter) :
It's a 6speed manual if it matters, new Luk clutch and single mass flywheel.
Not sure if the trans you have is the same as the one in the truck I drove for work. It was a F450 with a 5th wheel. It had the 6 speed and while it went through clutches it was also worked very hard. Like towing upwards of 25K lbs! And that's with a stock engine in stop-n-go traffic. I'd take a manual any day of the week over an auto trans.
The people at Riff Raff diesel were always honest and helpful. Maybe give them a call to learn about the various tuner options they have.
https://www.riffraffdiesel.com/
Also, look into Banks.
Do a chip or 5-pot tuner, but you need to so some supporting mods (which will further add power) This will depend on the year, also. The OBS doesn't have an intercooler, but the 99-03 does. This just means the later trucks have a bit more room to grow.
Downpipe and exhaust. Not letting exhaust flow freely can spike EGTs and cook a turbo.
EGT gauge
The factory air intake isn't bad, but it can reach a point of restriction past a certain point. Probably won't be an issue for you if you're just adding a bit.
If you notice that you're popping intake hoses, just get better clamps and/or silicone unions.
Chip, exhaust, and EGT gauge first. If you still need more, let us know.
Oh, you mention a 6 speed, so you're 99-03 right?
It would be a ZF6 transmission. Specifically S6-650. Its rated for 520 lb-ft, but I've seen trucks blow past that and not explode. As long as you're not hitching up 10k and flooring it with the knob turned up to 11 you should be fine.
Assuming my truck ever makes it out of the shop again, is a downpipe plus exhaust a safe mod without a tuner, or am I looking at adding a tuner at the same time?
My last 7.3 was pretty well done. Was a 2002 with a 6 speed so no transmission worries.
Ford AIS intake - may be stock on the big stuff, if not, its the best intake for the 7.3s. Everything else is a compromise in either filtering or flow.
Intercooler - if you dont have one, get one. You can get kits or retrofit later stuff
Intercooler boots - make sure they are tight and dont leak. Can do an air intake leak test and address them.
Up-Pipes and down pipes - Get the International up-pipes from the manifold to the turbo and then a 4" downpipe and 4 or 5" exhaust
Wicked Wheel compressor wheel upgrade - Nice lil mod, makes the turbo perform better at higher boost
EGT gauge - need to keep tabs on everything. I had an Edge CTS monitor and that was pretty slick.
Programming - 6 position flip-chips are the best, they are all about the same at this point, not a whole lot of innovation on the 7.3s. Pick one from the company that offers you the best service. I had a TS 6 position chip and it was fine.
High Pressure Oil Pump - HPOP - Eventually you will run out of oil for the injectors so you will need an HPOP uprade. Monitor the injection oil pressure with your Edge CTS and make sure it stays consistent. If it falls off at full load, then your HPOP is weak and you are not getting full fuel delivery.
Oil line upgrade - The oil lines in the HPOP system dead-head in the stock configuration. A looped oil line system ensures constant HPOP pressure. If you upgrade to a Diesel Site Adrenaline pump, this is part of the pump upgrade. I cant speak highly enough of the Diesel Site.
Fuel Line upgrade - Just like the oil lines, the fuel galleys are deadheadded. By adding a return regulator you can keep fuel pressure consistent at all the cylinders.
Injectors - Get a nice set of injectors in that 200-250cc range and get your programmer reflashed to reflect your new injectors and HPOP
Keep in mind the 2002 and up engines used powdered metal connecting rods that love to return to their original powdered state around 350-400HP, so dont go nutso if this is a later 7.3 and you need reliability. I had my 2002 about as spun up as is practical for something that just goes back and forth to church and the liquor store, never had problems other than an HPOP failure, fortunately that company is out of business now and the owner is in jail for being a POS. (Dyno Proven Diesel - you suck)
Thanks guys! A lot to digest, but it does sound like the basic power mods I was looking at are safe. This is all going on Cliford. He's a 2000 F-550 rollback. The last few posts in my build thread are about him.
He had a lower miles power train swapped in so I need to see what year it was our of, but it is intercooled, etc.
BoxheadTim said:Assuming my truck ever makes it out of the shop again, is a downpipe plus exhaust a safe mod without a tuner, or am I looking at adding a tuner at the same time?
Totally fine to add a better exit. The problem happens when you go too far with the entrance without upgrading the exit, so to speak. A better exhaust is often worth 20-30 hp on its own. Without the restriction it can sometimes let the turbo do spinny things better.
Diesels can't be thought of like gas engines. Since they lack a throttle, diesels are just a function of air and fuel. Less need to worry about cam and ignition timing (since there is no ignition). The intake is open to atmospheric air all the time. So you add more fuel, it adds more mass to the exhaust, which spins the turbo more (to an extent) which adds more air, which.... you get the idea. The ECM isn't controlling much. It doesn't adjust fuel trims or sense what the exhaust is doing and trim injection timing or shoot more or less fuel based on X parameters. It's not like with a gas engine where you may have to tune something to take advantage of a mod, like adding a bigger MAF, or bigger injectors. A diesel ECM (at least in the older stuff like we're discussing) is pretty dumb. It squirts fuel. If you add bigger injectors, it doesn't know that you've changed anything. It just keeps squirting fuel and has no idea that the bigger injectors are squirting more of it.
Having said that, you can also change the programming of the ECM to squirt more fuel within the limits of the injectors... or both programming AND injectors if you're going nuts.
Each diesel has known formulas for when you need to upgrade one thing or another, but it's always safe to add exits before adding more entrance.
Some general parameters:
Many of the inexpensive "tuner" plug ins you get on the market will do two primary things: Advance injector timing and add fuel. The 5-position chip in Dad's Duramax has Stock, Tow, Economy, Performance 1, Performance 2. Stock is just that (although he added 30% larger injectors, so the ECM is controlling what it THINKS are stock injectors, but even in that mode he's making more oomph). Tow adds mostly timing. It doesn't add fuel volume other than adding a little more duration. Increase in power, but the focus is on torque and MPG. Economy adds timing and keeps the injector duration closer to stock. When I towed an empty trailer down to the challenge last year with it, I got 24 mpg. Then Perf 1 and Perf 2 just add all the fuelz. As in 938 lb-ft to the rear wheels. Dear GOD that thing is quick.
In reply to Curtis73 (Forum Supporter) :
Thanks Curtis - the exhaust on my truck isn't in that great a shape, and I figured that if I ended up having to change the exhaust I might as well do the downpipe and give the turbo a bit more room to breathe easier that way.
Not planning to do anything silly with it anyway, but it might be a nice perk up for it if I can keep it out of the shop for longer than a few days. It's not the sprightliest of trucks anyway being a first year Powerstroke, but every little bit helps when towing.
Sounds like a plan. Expect the downpipe to be a b*tch to install, but worth it. 4" exhaust should be fine.
Curtis73 (Forum Supporter) said:Sounds like a plan. Expect the downpipe to be a b*tch to install, but worth it. 4" exhaust should be fine.
Oh, I know. That's why it doesn't have one already 
.
This is fantastic info, I'm not a diesel dude so this all kinda new. Nice how "simple" tuning these oldish trucks is. How big of PITA are we talking about for the downpipe? And the up pipes aren't worth it?
In reply to accordionfolder :
IIRC changing out just the downpipe is something like 5h book time, if not more.
In reply to BoxheadTim :
If I could do it in 1-2 days I'm not too worried, the problem with this truck is MAN IS IT TALL. Doing anything is such a pain, but it does feel like a bit like a dog compared to my other 7.3 - it's a steel bed truck so it's pretty dang heavy empty which I was assuming is part of it.
On our E450 7.3 we installed a simple Bullydog tuner and nothing else. This is a 12000lbs vehicle that we used to tow 5000lbs. On the mildest tune we felt a mild power bump going up hills(tested on the Saluda Grade in NC) and saw a 12% increase in fuel economy.
In reply to buzzboy :
I'm loving all these positive reviews on the tuners, I'll start there and continue as Curtis recommended me thinks.
The 95 OBS 4wd I had for a bit had the down pipe already done, thankfully. But t it was stock after that. I added 4" straight pipe after that, and saw a bit more gain, without a huge noise difference. I personally would not ad anything, before doing that exhaust.
I ordered a few things after that from Strictly Diesel , and even stopped by to chat when out in AZ. Dennis is a very good dude.
In reply to accordionfolder :
A heavy hammer and a toolbox full of four letter words should take care of it. I stared at the downpipe for a long time when I replaced the clutch in ours. I still can't believe it made it to production like that.
We went with a single mass flywheel as well, and that was a huge upgrade because my wife couldn't drive it with the OEM setup. She wasn't strong enough to hold the clutch pedal down very long with the dual mass flywheel.
In reply to bigeyedfish :
I've heard some folks just have to cuss a bit, and some need some "gentle mechanical persuasion" with a BFH to fit past the firewall.
I also heard that Ford did that smashed looking pipe, to be able to install the engine with the down pipe already in place. Has room for more after it's in, so I believe that one.
In reply to 03Panther :
One of my friends is a welder by trade, so he did his in about 3 hours by cutting out the trans tunnel and firewall and welding it back in. I thought he was nuts, but I guess you use the skills you have.
Damn. This is some good info. I've got a '97 7.3. The downpipe was already done when I got the truck, but I had to pull it when doing the trans swap. It was super easy. I presume previous owner massaged the firewall for me? There was enough room I added a second vband halfway up so I didn't have to remove it from the turbo to do trans work the next time.
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