Ok thought i might get some better input down here. Im planning an.. eventual build and right now im kind of stuck on turbo(s). Here are some numbers let me know if you guys need some more to help me out here.

7.3L idi engine
4500 rpm governed
300+cc inline pump
17 or 17.5:1 compression ratio
40-50lbs boost
500hp

From the get-go ive been thinking twins. The truck is going to be my "end all" DD. As in i want it to do whatever i want, driveable, towing, drag, maybe some sled pulling too. I thought twins because i want a system that is going to light fast and be fun to drive without choking down the top end. Im thinking im safe running 40-50lbs of boost as long as drive pressures are kept in check. Considering water-meth, but not sold on it unless it becomes necessary.

The engine will have all necessary supporting mods. Lighter / stronger custom pistons, balance / blueprint, port and polish, shot-peened rods, cryo'd rods wrist pins and crank (maybe block need to do more research), reground cam, matched springs, studded everything, main girdle or bed plate, one-off injectors / lines,etc.

Before it comes up, and its bound to... I know this is an IDI, i know a cummins is easier, i know alot of things are cheaper on other engines. Im aware of the supposed shortcomings of the IDI. I would like to keep this thread on track. I am looking for constructive opinions, and even some constructive criticism. Most of all i would like to know what options i have for chargers.

A few of us in the idi forum are discussing the pros and cons of a hx40/hx60 setup, i would like to know what else is out there. I would prefer to stay away from the more expensive chargers. So let me know what you guys think. Im interested in what works on the 7.3psd as thats about the closest thing to go on. Even supporting mods required for this kind of power on a psd.

Mike

 

My honest opinion, is that to do what your thinking, literally the only stock part in the engine bay will be the block.

Why not grab a 6.0 or a 6.4 engine, and then build it the way you want? Either of those engines will make the power your looking for with way less work. Then you can also easily run a transmission that will do what you want.

Are you trying to keep it all mechanical? Maybe a DT360 would be your cup of tea ?

I realise your stuck on the IDI 7.3, and heck i love that engine myself, but realistically, to push 500 HP, is there going to be a single stock part on it? Wouldn't it make more sense for such a drastic power jump to go into an engine configuration that will last longer and be more suited to dealing with that kind of power?

Didn't the 7.3 IDI already have borderline heat issues? Are you going to have one-off heads designed, cast, and machined ? My point is just that it seems like a lot of work and money.

Not saying it can't be done, just you also said you want it to be a daily driver as well, which really limits, IMHO being able to do this with mechanical injection, and have it run clean and streetable.


How much do you expect this to cost, from start to finish?

Even with the mods you listed, I'd think 300-350 HP would be much more realistic if you want this thing to last a while.

 

The only think the 7.3 IDI and the 7.3PSD have in common is the displacement, and manufacturer. Doesn't the 7.3IDI has thinner cylinder walls than the 6.9? If that's true, wouldn't you be better off building a 6.9? I have heard of some guys building some IDI engines and getting more power out of them, but I have never heard of 500hp from one.

 

Biggest reason for going IDI is that its already there, and its all mechanical. With the current fuel system, an inline pump conversion shouldnt be that difficult, another +

As far as parts, yes lots of stockers are stickin around for the fun, crank,rods,block, heads, intake (albiet modified) those are the big ones im thinking of right off the top of my head. I dont see any major reason the engine shouldnt have a normal lifespan running this kind of power. As long as its taken care of and not abused, which goes for any engine at any power level.

Now on to the one i really appreciate. Streetability. I do not know how much it will smoke or how squirly it will be. I realize a computer controlled system has alot more variables to keep it clean and making power. I think most of the excess smoke and radicalness can be tuned out of it, perhaps not on the first attempt. Im basing some of this off of a cummins as far as streetability. I know a few guys running 500 +/-hp on the street and they do pretty well. Biggest thing with my build is the biggest pump i can get is 90cc. So im stuck with 225rwhp, or inline conversion. So im opting inline. I dont necessarily want 500rwhp on the street, but i can have it if i want kind of deal. I plan on de-tuning if necessary, but i have the option for more kinda scenario, bump the wastegates / fuel plate and boom 100hp.

Most importantly, and not covered in your post, is how will these turbos perform on a 7.3? I have been assuming that since 5.9 guys run them in the 500-600hp area they should work well for me and light fast. Im going to rely on the twins alot to clean up the excess fuel.


On to CampSpring:

As stated in the OP, Im not looking for the difference between the 7.3IDI and 7.3psd, but how well the two turbos i listed should perform. I know the psd is alot more common platform to build, im looking to tap into some of that info concerning turbos.

The 7.3 does have thinner walls than the 6.9, but the turbo block has thicker walls at the deck and is in general "stronger", as in its got more meat where it counts. I also plan to sleeve the engine ( something i forgot to mention in the OP) so cylinder wall thickness should not be a concern.

I know of a few guys building IDI's, and some more than others. I dont know of any that have been aiming for 500hp, so it makes sense therefor that none have made 500hp. Basically it boils down to this. I want more than 225rwhp, therefore i have to go to a different injection system, EI: inline pump. If i put a p-pump on there, i might as well take advantage of the available fuel.

However, im not looking for what engine to use, how much power i should make, etc. Just some info / opinions on how well the turbos will perform. I appreciate your input, and hope i answered your questions. I hope you guys can try and help answer mine.

Mike

 

Have you posted up in the IDI forum? I know you're here in the competition forum, but I don't know how many IDI owners post up here. There used to be a guy from West Virginia that had a pretty hot IDI truck, but I don't think he's coming around here any more. Some of those guys would likely have some good advice on how to achieve your goal.

 

Ya I frequent thbe idi forums and have thread in there as well. However my build is above what most idis are doing and not many know much about a build of this magnatude. I was hoping to find some that have twins on a 7.3psd to tap into their experience and advice on what works and what doesn't as far as chargers go.

 

PSD advice isn't applicable to your engine though.

the 7.3 idi and 7.3 psd share very little.

I'm afraid since 7.3 idi build ups are rare, you will be challenged along the way if you decide to pursue this, you'r not gonna get much help, and it will be hard to borrow ideas from anywhere because of the rarity of this motor being built up as high as you plan.

 

They share almost nothing yes... fully aware as above noted. However a 7.3 is a 7.3 as far as displacement goes. All I'm asking for is some advice on turbos because I know there are 7.3psd with twins. Or at the very least some one in this forum that knows something about twins... that is all I'm asking for. Back to the cummins forums I guess.

 

Unfortunately, running twins, from what i understand, is or can be, a lot of trial and error. Also, someone opinion for example of what they consider streetable may greatly differ from yours.

I don't want to discourage you, but this is one hell of a major project you're proposing. If you are dead serious about this, I suggest you speak and consult with someone who does this for a living, and will understand what you expect from the system. Internet advice is great, but this will be an expensive project, and it's not like you're tuning a 5.9 cummins or chipping a 7.3 powerstroke, you've chosen a less walked path, and it may be challenging.

 

when you say "twins" do you mean twins or do you mean compounds? I have never been into the IDI scene, but i play with the 7.3 powerstroke a little bit. I have never seen actually twins on a PSD (not saying it hasn't been done), but there are several compound setups out there. WOP is running compounds on it's race truck. The only reason I bring up the PSD here is the packaging of twins/compounds in the engine bay

 

Just noticed the reply. Sorry i have gotten in the habit of saying twins when i do mean compounds. I honestly dont know much about the things, and not really interested in learning more than i have to in order to achieve the power level im going after. I have had a couple "fall in my lap" so to say so i guess the trial and error will start there. Theyre a HX35 with the small housing, and a non-gated HT60 with i believe a 24CM housing and something like a 73 / 107 comp wheel. and a 97mm turbine. Found some flow charts for Holsets and looks like the HT should deliver what i need, albeit almost tapped out in stock form. As for the compound, not sure if i would be better suited running an HX35/40 hybrid, or pickup a 16cm hot side HX40. I think the HX35 is a 12cm, and the consensus among the cummins guys is theyre only good to give or take 500hp on the hot side, which im assuming would be even less on a larger displacement engine. I would love to keep it spooling the way it does now for sure, but can give a little.

 

It will take a ton of fuel to satisfy a compound setup.

But for me if I was going to try to make power with a diesel it would be easier to do it with a in line pump.

I have a bud that is pulling a 640 inch Perkins in a super farm tractor with a 3 in and 3 out single turbo (rules dictated). He is running a in line P pump at about 400 cc of fuel and 75 lb of boost.

What we ran into was tuning, the John Deere and I.H. are the chevy small blocks of pulling.

Everybody knows what combination of parts will work to produce said hp.

We on the other hand had no one to get help from, so it's off to the dyno with it this November to maybe learn how to tune it.

Compounding is even harder to figure out. Your best bet maybe to talK to a turbo engineer to get in the ball park.

 

I would go with a h2e instead of a hx35 or a 40 the hx60 or a ht60.you will blow those 35 & 40 up with the 7.3

Dale

 

Ok, now thats more along the lines of what i was origionally asking. First off plans have changed somewhat. I will be running a 180cc Db4 hybrid. Still want something that will light fast and wont get things too hot.

So on that note, doesnt the 6.4 psd use something like a 52mm primary?

Been kinda thinking about using a VGT off a 6.7 or 6.0 or even a smaller vgt that will light fast but will open so theres not as much restriction as you would have on something like a hx35 with a 12cm housing.

On the stock engine im running at the moment, i have just a cranked IP and im running a hx35 i picked up cheap. Once it hits 1500 it really spools up. But anything 3000rpm + it really starts to sound like its about tapped out at only 15lbs. I dont have a drive pressure guage but i can venture a guess that its pretty restrictive. I can leave the wast gate open and unhooked and it will still hit 15lbs by redline going up any kind of hill.

So basically what im saying is, ya the hx35 is too small, but i want something that will spool at least that good. Kinda hard to judge how well all this is giong to work only running a stock IP, but i kinda figured i could go off of displacement and fuel to get a good idea of a turbo or turbos that will work.

 

How are you planning to get a VGT turbo to work on an IDI? Gonna swap the computer over from a newer truck?