I just got a 2001 7.3 F350 CCSB 4X4 auto with 198k miles. Transmission was replaced at 140k miles (saw paperwork).

The truck seems to have a little difficulty starting when hot. I'm in Phoenix and we just saw our first 100 degree day today. It still stats every time, but takes about 3 seconds maybe a tad longer to turn over and occasionally sounds off when firing over. I have a 97 F250 with a 7.3 and it has issues cold starting because I don't have a cold start tune, but when it's warm, it fires up immediatly.

First thing I noticed is both batteries have tags from 2015, and they are only 700 Cold cranking amps. I'm running dual interstate 850's in my 97. So I'm going to start with swapping the batteries, but if that doesn't do it, I figured I may be looking at new injectors soon.

I did stage 1's from rosewood and DP tunes on my 97 F250,.
My first question is, can I send OBS 7.3 single shots in to be rebuilt/upgraded, and throw them in my 2001? I know super duties got split shots and they can be converted, I just need to know if the single shots in the OBS would be a straight drop in on the super duty 7.3. I'm assuming they are, I just want to make sure. A buddy of mine has 2 full spare sets of OBS injectors so I can send one in and not have to have my truck down


My next question is, if I do that, what is my best option? I haven't torn into this truck too much, but as far as I know, it's mostly stock. It has MBRP 4" exhaust and still has the muffler on it. Stock air box, stock turbo(previous owner recently had all the gaskets replaced on the turbo, but it's pretty whining compared to my OBS with a 1.0 housing and my dad's 99 super duty, so I'm not sure why it sounds louder. It's not bad, just wondering why it would be louder. I don't think it's an aftermarket). Other than that, I haven't seen any non-stick parts. He has a super chips tuner for it which surprisingly works well. On the mileage setting, it seems pretty quick.
I haven't pulled the inspection port on the block yet to see if I have forged rods or PMR, but hopefully soon. But, I'd like to be in the neighborhood of 350 HP and remain reliable as it is my daily. I figured at that horsepower I'm over 600FT lbs and that's more than I will probably ever need.

Next is, tunes. I only have experience with DP tunes. They are great on my OBS. The only problem I have is now the gas pedal is way different. It used to be a smooth transition when stepping on the gas. But after the injectors/tune, you could step on the gas and it doesn't do anything and then it reacts and bucks. It sucks when rolling through a parking lot or a small side street. It has a ZF5 so I imagine I wouldn't have the issue with an auto.
I have also been reading a lot of things online that DP advance the timing a lot on their tunes and others don't. I'd like to have 3-6 tunes. I have 6 for my OBS and it's cool having a lot (although I don't have e fuel so my 2 highest settings kind of bog down and just create a black wall of smoke).

Is it any more difficult to change the injectors on a supder than an OBS? I think it took me and a buddy around 4-5 hours start to finish to do them on my OBS. I think we vacuumed the oil out instead of pulling the glowplugs when starting for the first time too.

Also, how good is the super duty HPOP? I know a lot of people to save money upgrade to it on the OBS, but how much is too much for the stock super duty HPOP?

That's all I can think of for now. As always, thanks for the advice.

 

The stock HPOP is just fine, until you see problems with it. 350 HP on the stock HPOP is not an issue.

OBS injectors are just fine - you can't see any difference externally. Send them in, tell the rebuilder they are for a SD, and let him do his thing.

Hydra is the flavor of the month - you can get a whole host of tuners that provide tunes on that platform... by email. No pulling the chip to send it in. Don't like your tune? Have the tuning specialist fix it, or go to somebody else.

It's easier to do injectors on the SD than the OBS... slightly. More room to work.

Stubborn to start when hot is all IPR coil. You can carry a can of air (like for cleaning computer keyboards). The next time you can't hot-start, invert the can and shoot the IPR coil (it's a freeze spray when applied upside-down). If that gets you going, replace coil.

 

I agree with Rich, hot start issues are typically due to the IPR.

OBS injectors have the same body as the SD injectors, so you can have them built to whatever CC/nozzle size you want. What I would suggest is decide who will be doing the tuning ahead of time, let them know what your plans/goals are, and have them recommend an injector builder that they know they can consistently tune for. It makes life much easier.

Tuning has come a long way since your OBS. Talk to several of the top 7.3L tuners and find out who you feel most comfortable going with. There really isn't a need for a ton of tunes these days. There's also no need for a cold-start tune.

If you're going with built single shot injectors, the properly sized injector combination for your target hp/torque goal should be easily accomplished with the stock HPOP. If you can't reach your hp/torque goal with your injectors on a stock HPOP, you built the wrong sized injector.

 

I will look into the IPR.

As far as everything see goes, I'm not sure when I will get around to doing the injectors. I have to start prepping my OBS to sell it. Then have a few things coming up followed by my summer vacation. So it may be a few months. But I'd rather do the homework now.

I'm familiar with tunes and injector work as I did them both with my OBS. The difference is night and day and that's on the stock HPOP and mechanical fuel pump. So since the super duty has e fuel and a better HPOP I'm sure it would be even better. I mainly want to stay around 350 maybe as high as 400 mainly because I am assuming at this point I have PMR instead of forged rods(but will check eventually).

I used Rosewood for my stage 1 injectors and DP tunes for the tunes. I have 6 different tunes. I did buy the F5 so if I want the tunes changed it does have to be sent back into them. Jody at DP did tell me that I should have a cold start setting. I was having issues with cold start despite new batteries, injectors, glow plugs, battery cables, and fuel pump.

 

Kinda off-topic..... You're in Phoenix, trucks here in Colorado and other colder areas don't even need cold start tunes (OBS and SD). Basically you have an issue with the OBS that has never been resolved, and a cold start tune is simply a band-aid. Just FYI.

Ok so back to topic...

PMR's are always a gamble, and special care must be taken with the tuning. The 02 I used to have put down those numbers in my sig on the original PMR motor (and stock HPOP). So your 350-400hp goal can easily be reached, and can be done relatively safely if it's done the right way. Again though, no guarantees that one day you couldn't have a hole in the block. Remember it's pay to play.

When looking at injectors you're going to be faced with some decisions. Going with single shots at your power goal is the obvious answer, but there's different options available. Your standard "Stage II" injector would be a single shot 180cc that would get you between 350-400hp, with the 400hp being a bit of a strain on the stock HPOP. Stepping up to hybrids, such as a 238cc (a "Stage III" injector), would be easier to hit 400hp given the lower oil volume needed for hybrid injectors, and can always be tuned down even to stock-level power and performance. All of this will depend on what your ultimate goals are and how much you want to spend.

Then you'll need to look at nozzle sizes. For a 350-400hp truck, 80% nozzles would work just fine. Over 400hp I wouldn't bother with 80% as the pulsewidth is just too long at that point to make over 400. Under 400, 80% is just right. They are easy to tune and have great street/towing manners. Some might suggest 100% nozzles, but I have found over the years that those can be hit or miss with regards to ease of tuning, idle quality, etc. Getting to a 100% nozzle adds an extra step in the process and sometimes the results are less than desirable.

So for your research, most likely a 180cc/80% injector or 238cc/80% hybrid would be among your top choices. Tuning... you'll have to decide who you want to go with, but I would again recommend talking to tuners and getting their input on who's injector builds they prefer to tune for.

Hope this helps, and good luck on your future build.

 

Another thing I forgot to include is I don't want it to be unbesrably noisy in the cab as well. My OBS is very loud and almost impossible to hold a conversation with somebody when it's running and sitting in it. I'm used to it, but it's pretty loud. I don't know if that's my exhaust setup and injectors, or something else. It definitely got noticeably louder after stage 1's as the injectors sounded like they were firing more aggressively. I have straight pipe all the way back on it from the downpipe. The 2001 I just got has a 4" MRBP exhaust but has the muffler still. It's very quiet compared to my OBS, and noticably quieter than my dad's 99 dually.

Thanks for the info though. I bought the 2001 because I wanted to have a truck to grow into. New trucks are too much money and working on them isn't something I enjoy. I'm familiar with the 7.3's by now as well. I wanted to get something that would be more than plenty to tow whatever I may end up with in the future, as well as have the interior room for whatever I may need in the future. So this truck has all that. I didn't want to have to run into a situation where I would have to sell it because it no longer works for my needs. Since I've been out of the military, I have had 4 different trucks and a few other cars/SUVs and really need to stop changing vehciles so freauently.

 

B-Rad88, you have been provided with some very sound advice, so I will not expand on that at all.

Although, I will say thank you for your service, I appreciate it everyday.

 

There is a discernible noise difference between single shots and splits, as splits will tend to idle a tiny bit quieter. However, if the idle is dialed in properly on single shots and the timing is correct, they shouldn't be much louder, just sound distinctly different to the trained ear. We're talking a few decibels difference here.

OBS trucks are particularly noisy in the cab, especially if you have a ZF-5 and/or manual t-case. Those are obnoxiously loud to me. There's really not much there around the firewall and trans tunnel to block the noise. With the Super Duty, there's more sound barrier and it's quieter in the cab, especially with an automatic. Still noisy compared to say a 6.7L, but a very big difference going from your OBS to the Super Duty.

Still there's the off chance you can get loud single shots in a Super Duty. Usually it's related to too much timing in the tunes, or poor build quality of the injectors themselves (bad injectors can make a racket). Really large injectors can get a bit noisy too since they need some timing at idle and at colder temps to keep from smoking, but you aren't going that big.

So the injectors shouldn't add too much noise, but there's other things you can do to keep from raising the decibel level too much in the cab. An open air intake will create more noise for you, where a shielded or boxed intake will keep things quiet. Also the exhaust, some kits can drone more than others. You can get free-flowing mufflers that help keep exhaust drone to a minimum. If noise is a concern, spend the extra coin on good quality intake and exhaust kits that will deliver the performance you need without making it unbearable in the cab.

If you're at 350-400hp, you will need to address the turbo too. Some turbos can add a little extra noise, so keep that in mind. Overall, when you're done it's probably going to be louder than the truck currently runs, but quieter than the OBS. Just trying to give full disclosure.

Some people have added dynomat or similar to the floor and firewall to offset the added noise.

 

"Again though, no guarantees that one day you couldn't have a hole in the block. Remember it's pay to play."

Couldn't the same thing be said about a 00 with forged rods ?

Or would that chance be all be removed with forged rods ?

Kyle

 

I see people go back and fourth on this. But the PMR's are supposed to be rated for around 400 HP before they have a higher probability of failing and the forged rods are at 500. But plenty of people exceed these numbers on both types of rods and never have issues. Over 400 HP on these trucks means you're either close to or over 700 foot pounds and that's a lot of power.

Everything I have found was all 7.3's got forged rods from 94.5 to 2000. They switched in 2001 and they did forged and PMR in 2001. In 2002 they were all PMR.

 

Sure there's always a risk when you modify anything above what the factory did. With PMR's, your chances of catastrophic failure rise significantly once you start making a certain amount of power. Mainly because PMR's don't bend, they break. Forged rods will usually bend first, often times saving you from having a hole in the block.

Tuning has come a long way since the days of popping PMR motors left and right. It's rare to see it happen these days. A lot of lessons learned.

One of those lessons is cylinder pressure. The old rule-of-thumb was 400hp on PMR's. However, injector/tuning combos at 400hp can vary greatly, and so could torque output. The more torque you have, the more cylinder pressures you create at any given RPM. Get the cylinder pressures up higher than the PMR's can withstand, and boom goes the dynamite. Same goes for forged rods, just their threshold is higher and they'll usually bend before they break. Torque is an excellent indicator of cylinder pressures, far superior than looking at horsepower as a guide in that aspect alone.

The best example I can give is when I did the dyno pull in my sig. It was a dealer event and quite a few Powerstroke's showed up. One truck had almost identical horsepower to mine, but well over 100 lb/ft torque more. In fact, he was teetering close to 1,000 lb/ft. So how is that possible? Increase the timing and fuel amount at lower RPM, create more cylinder pressures, and you increase the peak torque. He was running out of fuel at higher RPM so his peak HP equaled mine, but he was pushing a lot more fuel down low. Now if I ran that setup on my truck, I would have most likely popped the motor. His truck had forged rods, not PMR's.

The current rule-of-thumb (if there is any), is to keep PMR's below 900 lb/ft torque. Is this universally accepted? Not really, but neither was the 400hp threshold. It's just an indicator of when you might be in serious danger is all.

 

In a nutshell, the numbers you're talking about are not a threat to the engine - given what tuners have learned over the last 20 years since your OBS was last produced.

I have single-shots, and the truck is a bit louder than stock - but nowhere near as loud as with the previous tuner I once patronized. Tuners can make a definite difference with decibels.