"Ultimate" IDI
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"Ultimate" IDI
Well gentlemen, I want your thoughts on building the 6.9 of your dreams. I'm just a backyard grease monkey, and I know there are plenty of others just like me out there. I know Dave S has built a sweet 6.9 but I'm just wondering if what if any suggestions you gentlemen might have and to make this a little more realistic lets put a cap of $8000.00 CDN or $6500.00 US. These are my thoughts...turbo. 4inch exhaust, propane injection, water injection, reinforced heads, ceramic coated pistons...the milling of the pistons and the right IP and the heads I'm leaving up to your advice??
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
To start magnaflux everything to make sure you have good parts to work with.
Check all your surfaces for height and true.
Head studs from ARP.
DPS pump and injectors
ATS turbo
3" minimum exhaust
1" body lift to make room for the downpipe
Hypereutectic pistons milled about .040 will drop the compression to 20.25 to 1 which will let you run more boost but not introduce cold start issues.
More boost is about 25 PSI with head studs.
Do a minimum bore, just enough to get good clean surfaces on all the cylinders, I think 20 over is where you will have to start at for piston size.
Replace the 6.9 rockers with 7.3 rockers.
Balancing the engine will make it run smoother, but you could skip this if money is tight.
Surface the flywheel and replace the clutch while in there, no sense in pulling the clutch in 6 months to replace it.
Use quality components for all the other internal parts and you will be happy.
That will probably be about your dollar cap on the rebuild.
Check all your surfaces for height and true.
Head studs from ARP.
DPS pump and injectors
ATS turbo
3" minimum exhaust
1" body lift to make room for the downpipe
Hypereutectic pistons milled about .040 will drop the compression to 20.25 to 1 which will let you run more boost but not introduce cold start issues.
More boost is about 25 PSI with head studs.
Do a minimum bore, just enough to get good clean surfaces on all the cylinders, I think 20 over is where you will have to start at for piston size.
Replace the 6.9 rockers with 7.3 rockers.
Balancing the engine will make it run smoother, but you could skip this if money is tight.
Surface the flywheel and replace the clutch while in there, no sense in pulling the clutch in 6 months to replace it.
Use quality components for all the other internal parts and you will be happy.
That will probably be about your dollar cap on the rebuild.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
Big exhaust, large ATS turbo flange, no muffler, advanced timing, more fuel and adjust the wastegate.
With what I use mine for, I am happy with 10 or 12 MPG, would you be happy at that fuel mileage?
In fact when I am loaded heavy for most of a tank of fuel I have seen it go down to about 9 MPG, but you also have to remember heavy for me is over 20,000 gross and I do live in the mountains. The closest flat stretch of road I know of is over 100 miles from me.
With what I use mine for, I am happy with 10 or 12 MPG, would you be happy at that fuel mileage?
In fact when I am loaded heavy for most of a tank of fuel I have seen it go down to about 9 MPG, but you also have to remember heavy for me is over 20,000 gross and I do live in the mountains. The closest flat stretch of road I know of is over 100 miles from me.
Posting Guru
Joined: Aug 2006
Posts: 2,175
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From: Kent WA
Originally Posted by Dave Sponaugle
.....Replace the 6.9 rockers with 7.3 rockers.....
Better ratio (more lift)? Stronger? Rollers? What?
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
7.3 Rockers
The design of the 7.3 rockers is better and stronger than the 6.9 rockers are.
Other than the pivots and mounting hardware they are the same.
Body lift
I bought mine at a local off road shop, I did a two inch but it was more than I needed for downpipe clearance.
I also had to do a little work on the transfer case shifter linkage and parking brake cable that I might not have had to do with a 1" lift.
You will need to modify the fan shroud with any body lift.
You will also need to modify shift linkage on an automatic tranny.
The design of the 7.3 rockers is better and stronger than the 6.9 rockers are.
Other than the pivots and mounting hardware they are the same.
Body lift
I bought mine at a local off road shop, I did a two inch but it was more than I needed for downpipe clearance.
I also had to do a little work on the transfer case shifter linkage and parking brake cable that I might not have had to do with a 1" lift.
You will need to modify the fan shroud with any body lift.
You will also need to modify shift linkage on an automatic tranny.
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Posting Guru
Joined: Jan 2005
Posts: 1,051
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From: Douglas, Georgia
10-12mpg, sure.... considering I use my truck for pretty much the exact things you use yours for. I get 13-15mpg due to living on flat ground tho, the c6 no doubt eats a lil economy.
For the year 2005, I figured that I made $1000 for every $72.50 worth of fuel my truck consumed....
Considering in 2006 I'm mostly burning veg oil, milage isn't worth decreasing the fun factor.
For the year 2005, I figured that I made $1000 for every $72.50 worth of fuel my truck consumed....
Considering in 2006 I'm mostly burning veg oil, milage isn't worth decreasing the fun factor.
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Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
Not sure what you could get out of it running veggie oil.
The BTU content of the fuel after it is converted to heat is what spins the turbo.
Do you have hard numbers on the BTU content of veggie compared to diesel?
To much extra required equipment and to many other possible issues from veggie conversion that I have no desire to try it even with the possible cost savings.
The BTU content of the fuel after it is converted to heat is what spins the turbo.
Do you have hard numbers on the BTU content of veggie compared to diesel?
To much extra required equipment and to many other possible issues from veggie conversion that I have no desire to try it even with the possible cost savings.
Last edited by Dave Sponaugle; Sep 23, 2006 at 02:55 PM.
Posting Guru
Joined: Jan 2005
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From: Douglas, Georgia
btu content is lower.
I can't give any hard numbers due to the wide variety of feedstocks.
I will say that egts are a lil lower, but due to that and the lack of black smoke, I tend to put a lil more foot into it.... so probably making the same power, just burning a lil more fuel.
I can only use veggie effectively because most jobsites are 40miles or so from where I live, 40 miles of flat/straight/no stops.
I can't give any hard numbers due to the wide variety of feedstocks.
I will say that egts are a lil lower, but due to that and the lack of black smoke, I tend to put a lil more foot into it.... so probably making the same power, just burning a lil more fuel.
I can only use veggie effectively because most jobsites are 40miles or so from where I live, 40 miles of flat/straight/no stops.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 15
From: Nutter Fort, WV
Lower heat means lower boost is possible.
I have actually used header wrap on my crossover pipe, up pipe and part of the manifolds to keep as much heat as possible in my exhaust.
More heat = more volume of gasses = faster exhaust speed = more boost
I forgot to add that to the list above.
I am going to have to start watching, you guys are going to wind up getting all my tricks out of me.
I just hope you don't dump me in the ditch in some remote area after that.
I have actually used header wrap on my crossover pipe, up pipe and part of the manifolds to keep as much heat as possible in my exhaust.
More heat = more volume of gasses = faster exhaust speed = more boost
I forgot to add that to the list above.
I am going to have to start watching, you guys are going to wind up getting all my tricks out of me.
I just hope you don't dump me in the ditch in some remote area after that.
Last edited by Dave Sponaugle; Sep 24, 2006 at 01:42 PM.
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i never heard of a supercharger on one of thse engines yet. Also Dave do you have ceramic pistons or anything on your truck? What are your EGT's when you start to let off?
thanks,
jimmy
PS Also how much did you advance the timing? Do you hear that powerstroke nock out of it? Also i heard its hard on the motor to have it adanced.
thanks,
jimmy
PS Also how much did you advance the timing? Do you hear that powerstroke nock out of it? Also i heard its hard on the motor to have it adanced.
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Joined: May 2001
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From: Cabot, Arkansas
Originally Posted by Dave Sponaugle
Hypereutectic pistons milled about .040 will drop the compression to 20.25 to 1