I average about 11mpg with my cclb dually 4x4 with 4.11 stock tires, with my fully loaded camper on it, and I definitely drive it like and as*hole when merging on the freeway. Turbo is great for fuel economy, but again even as a farm rig that barely sees over 25mph, turbo still adds a lot of torque to pull all them stumps out.
If you wanted to rebuild a 7.3 idi, increase it's performance w/o a turbo, what would you do?
- Thread starter scsmith42
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scsmith42
Registered User
That's good advice. My compression and leak down testers are for gasoline engines/ what type of cylinder pressures should I expect to see on a 21:1 ratio diesel? I need to make sure that my equipment is suitable.
Thx.
Scott
scsmith42
Registered User
. We currently have a 2017 F450 with 6.7, a 2017 diesel GMC Canyon, a Sterling with a 12.7 Detroit, and a dump truck with a CAT. Previously had two '03 6.0's, an '05 6.0, an '08 6.4, a 98 Chevy with the older GM turbo diesel, '05 and 06 5500's with Duramax's, and 2017 and 2018 Freight liners with the Cummins. To say the least, I've got a pretty good idea about proper expectations from a non-turbo motor. The truck as it sits is pretty anemic in terms of power. How much of this is due to the wear on the engine at 186K miles versus just the non turbo engine remains to be seen, but I'm pretty sure that it left the factory with more HP/torque than it currently has.
If/when I do a rebuild I want to keep it in NA configuration, if for nothing else to keep things simple as a straightforward rebuild instead of a significant modification. My engine background is in the gasoline world though, where there are lots of options to increase engine performance w/o a turbo, or in the electronic diesel world where lots can be accomplished with tuners and injector / turbo mods. What I'm finding is that there does not seem to be many choices for the 7.3 idi though in terms of optional parts for increased power, as compared with newer and more modern engines.
If I remember correctly, 500psi is a new engine. Service specs are in the mid 400's as long as they are within 10% of each other.
IDIBRONCO
IDIBRONCO
There isn't because the newer, more modern diesels already have turbos. You can't get much more power without getting more air into the engine. I don't know what you think that you have to modify in order to run a turbo. All aftermarket turbo kits were designed to go on stock N/A engines and most were probably installed with head bolts and not studs.
recognize the truck for what it can do, not what it cannot. Let the unloaded 150’s fly by and smugly know you have way more truck. ‘91, 7.3 5 speed, 4x4, snow plow, Dump bed equipped, over 350 k miles, former well drillers truck. hard life. Farm truck now 20 years of hauling everything from rock, pond muck, trees. Don’t need the turbo added maintenance or noise. Relax, it will get the job done.
scsmith42
Registered User
Thx. Decades ago I owned a machine shop that specialized in racing engines (gasoline), and we did custom turbo work, so I'm familiar with the pro's and con's.
In the gasoline world, there are lots of options to increase power and torque w/o a turbo. Towing camshafts, advanced cam timing, low restriction headers and exhaust systems, carbs that are lower CFM providing better bottom end torque, different intake manifolds tuned to different torque bands, increased spark ignition systems, balance tubes in exhaust, inversion plates going between heads and exhaust, etc.
Different mods can help - or hinder bottom end torque or top end power.
What I'm wondering if similar options exist for NA 7.3 idi diesels. Other than the logger cam, for a 7.3 idi I'm not finding much information about anything other than adding a turbo, hence my inquiries.
I sincerely appreciate the time that everybody has taken to share advice; I'm not trying to be obtuse - just trying to learn.
IDIBRONCO
IDIBRONCO
The answer is no. You can't do much besides the cam and headers without a turbo. These are interference engines. They have VERY little valve to piston clearances. Gas engines can't hold up to the 20:1 and higher compression ratios that these engines have. Even the Power Strokes, Cummins, Duramaxs, etc. don't have compression ratios this high. What works for a gas engine, doesn't usually work for these engines. When these engines were in production, there wasn't the demand for more power like there is today. There wasn't as much research done as there is today.
It seems like justin @ r&d is pushing the front edge of the prototyping of the idi.
Others have advertised engine work also, so you might be able to get something from that...
Fwiw
Once upon a time here, there was a new guy that said he was going to make a dependable 400 hp daily driver that got way higher mpg than we see claimed on the 3-4 propper websites that cater to the idi.
This was before Justin dyno'd his mule.
He got buthurt when he got called on it and left.
You could look up the dyno days at the idi get 2 gethers that used to happen, here onsite...
Also follow
Agnem
here, that's mel of connestoga.
Others have advertised engine work also, so you might be able to get something from that...
Fwiw
Once upon a time here, there was a new guy that said he was going to make a dependable 400 hp daily driver that got way higher mpg than we see claimed on the 3-4 propper websites that cater to the idi.
This was before Justin dyno'd his mule.
He got buthurt when he got called on it and left.
You could look up the dyno days at the idi get 2 gethers that used to happen, here onsite...
Also follow
Agnem
here, that's mel of connestoga.
Last edited:
scsmith42
Registered User
Thanks guys - that helps me to better understand the "what" and "why".
For what it's worth, my all time favorite diesel engine that I both loved and hated was the 6.4 in my '8 450. I loved it due to the power that the sequential turbo system made after reprogramming. It would literally outpull the 12.7 Detroit in my '06 Sterling with only 1/2 of the displacement.
But I hated the darn thing because the heads were flawed and would crack - even before tuning. Aftermarket heads that I tried were also problematic.
If I were to build a diesel race engine, it would be a 6.4 with compound turbo's.
For what it's worth, my all time favorite diesel engine that I both loved and hated was the 6.4 in my '8 450. I loved it due to the power that the sequential turbo system made after reprogramming. It would literally outpull the 12.7 Detroit in my '06 Sterling with only 1/2 of the displacement.
But I hated the darn thing because the heads were flawed and would crack - even before tuning. Aftermarket heads that I tried were also problematic.
If I were to build a diesel race engine, it would be a 6.4 with compound turbo's.
A stock turbo or up to a t3 t40 super, will work on a stock na 7.3 and this person was happy with the latter recommendation. I have twin under size hx35 non gated turbos on a na bottom end, with the only mod being a glow plug deletion to drop compression and I have put a lot of miles on this engine with no issue. Na will have it braking a sweet to move weight, and the turbos make it effortless to move 2ton+ and I have not messed with the injection pump.
03wr250f
Full Access Member
a 6.4 is a hand grenade, fun while it lasts but eventaully go boom. way too much money for me, but man they are fast.
anyways back on topic
the 6.9/7.3 idi was developed in a time in which n/a diesels and 55mph speed limits were the norm. The were also diseigned to keep up with the turnocharged 12v of the time in stock form. In order to to this, large valves and high va to get air moved in and out of the cylinders, large long runner intake manifolds with large openings that were gasket matched essentialy from the factory. good flowing exhaust manifolds and high compresssion to burn the fuel efficently while making decent power.
Yes basic engine theory still applies to them, same as with gassers, air in, air out is how you make it make power efficently
a typ4 camshaft that is slightly more low end focused than the stock camshaft, custom headers, and r&d or otherwise custom intake manifold that just has a large cone air filter on it will likely be about as much as you can do without adding a turbo.
You could also look for a banks powerpak or raywell air cleaner for the stock intake manifold, they work well but filters for them are getting harder to find. then a 4'' exhaust off a powerstroke with a custom wye pipe that flows better than the stock one.
justin at r&d did all of this on a engine, with a 110cc stage 1 injectors and electric lift pump. He made "a very smokey 200whp that any bolt on used turbo kit would make just as much power for about $3-4000 less"
a used turbo kit will still add power and torque even at low rpm range or low speed. It will further multiply the power it can make if you have a load on it like a dump bed to make the turbo create boost.
a used turbo kit can be had for $500-1000 usually also you dont even have to mess with your current ip in order to turbo it. I made 226/501 on a stock turbo cal ip, 7 psi boost, 3'' downpipe, factory/ats093 turbo kit and a intercooler
if you are rebuilding it and want to keep it n/a get a typ4 camshaft, r&d idiperformance.com or deeringdiesel.com stock injectors, total seal rings and probably call it a day.
anyways back on topic
the 6.9/7.3 idi was developed in a time in which n/a diesels and 55mph speed limits were the norm. The were also diseigned to keep up with the turnocharged 12v of the time in stock form. In order to to this, large valves and high va to get air moved in and out of the cylinders, large long runner intake manifolds with large openings that were gasket matched essentialy from the factory. good flowing exhaust manifolds and high compresssion to burn the fuel efficently while making decent power.
Yes basic engine theory still applies to them, same as with gassers, air in, air out is how you make it make power efficently
a typ4 camshaft that is slightly more low end focused than the stock camshaft, custom headers, and r&d or otherwise custom intake manifold that just has a large cone air filter on it will likely be about as much as you can do without adding a turbo.
You could also look for a banks powerpak or raywell air cleaner for the stock intake manifold, they work well but filters for them are getting harder to find. then a 4'' exhaust off a powerstroke with a custom wye pipe that flows better than the stock one.
justin at r&d did all of this on a engine, with a 110cc stage 1 injectors and electric lift pump. He made "a very smokey 200whp that any bolt on used turbo kit would make just as much power for about $3-4000 less"
a used turbo kit will still add power and torque even at low rpm range or low speed. It will further multiply the power it can make if you have a load on it like a dump bed to make the turbo create boost.
a used turbo kit can be had for $500-1000 usually also you dont even have to mess with your current ip in order to turbo it. I made 226/501 on a stock turbo cal ip, 7 psi boost, 3'' downpipe, factory/ats093 turbo kit and a intercooler
if you are rebuilding it and want to keep it n/a get a typ4 camshaft, r&d idiperformance.com or deeringdiesel.com stock injectors, total seal rings and probably call it a day.
Curious, and for the search engine....
Did someone pick up on the cam grind Russ ( type4 cam ) was having made?
Aka
Are they still available new?
Did someone pick up on the cam grind Russ ( type4 cam ) was having made?
Aka
Are they still available new?
scsmith42
Registered User
Great feedback, thanks much.
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