Idi performance???
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New User
Joined: Sep 2007
Posts: 21
Likes: 0
rcrawler you sum it it up perfect. I dont want a dragster or a trans am or even a common rail. In glad some of you are being open minded in that a truck can be more than a boring workhorse. Its gonna be my daily driver and outside of the loads it will haul 2 trailers it will pull 3 days a week and numerous Chevys it will unstuck, I wAnt some fun. And yeah it translates to help with my work. So again thanks for the helpful help.
And dAve can I assume by those figures you posted that you believe your truck to be near 350 hp? North of 300 at least? And if thats the case than I can assume that 4500 is a good baseline? Or was that all for the sake of the discussion?
And dAve can I assume by those figures you posted that you believe your truck to be near 350 hp? North of 300 at least? And if thats the case than I can assume that 4500 is a good baseline? Or was that all for the sake of the discussion?
Junior User
Joined: Jul 2007
Posts: 70
Likes: 0
From: NW Ohio
My truck has run 17.9 in the 1/4. I was runnin the same times or faster than a 4.0l ranger with 3X the truck weight. That time was also with a lot of fuel, toolbox full of stuff 5th wheel hitch, car seat, and a cooler in the bed! Probibly could cut 500-700lbs off it which should net at least .5 quicker times.
Elder User
Joined: Dec 2006
Posts: 559
Likes: 4
From: On a farm.
What did Dirty Harry say? "A man's got to know his limitations." The same hold true for truck owners and their trucks.
As much as I love 'em, the 6.9/7.3Ls are old, outdated tech with very limited performance potential compared to modern trucks. There, I said it! And I'm a 22 year owner of one of these trucks. I love mine but am realistic. They make good workhorse trucks that can be very economical and long lived but their reliable, bilt-to-the-max upper power limit starts where many of the newest DI, common rails trucks start in stock trim. I've seen countless daily driven late model diesel trucks of all makes that can deliver 600 hp TO THE REAR WHEELS and turn 12-13 second 1/4 miles. I've also seen 800 and 1000 RWHP trucks too that were capable of being daily driven.
You don't expect Model-Ts to keep up with 2009 cars. Neither should you expect 30 year old diesel technology to be able to keep up with the newest stuff. The 6.9L IDIs were the big dogs in the past but accept the fact that you will never be running with the current big dogs. A few sensible mods make sense (there's no excuse for a naturally aspirated diesel) but just learn smile and wave when the new trucks blast by.
As much as I love 'em, the 6.9/7.3Ls are old, outdated tech with very limited performance potential compared to modern trucks. There, I said it! And I'm a 22 year owner of one of these trucks. I love mine but am realistic. They make good workhorse trucks that can be very economical and long lived but their reliable, bilt-to-the-max upper power limit starts where many of the newest DI, common rails trucks start in stock trim. I've seen countless daily driven late model diesel trucks of all makes that can deliver 600 hp TO THE REAR WHEELS and turn 12-13 second 1/4 miles. I've also seen 800 and 1000 RWHP trucks too that were capable of being daily driven.
You don't expect Model-Ts to keep up with 2009 cars. Neither should you expect 30 year old diesel technology to be able to keep up with the newest stuff. The 6.9L IDIs were the big dogs in the past but accept the fact that you will never be running with the current big dogs. A few sensible mods make sense (there's no excuse for a naturally aspirated diesel) but just learn smile and wave when the new trucks blast by.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
I just guesatimated a number for HP.
All I know is it runs way better than it did stock, it also runs way better that the reman 7.3 turbos I had tried.
If you want to be quick in the quarter mile, better go with a C6 tranny.
Course I drive mine like a truck, slow shifts, so the U joints stay in it for a while.
My goal was pulling loads, not drag racing when I built mine.
Start with a late 85, 86 or 87 6.9 engine.
Magnaflux everything, then mic everything to make sure it is worth building.
Milled pistons, head studs, intake studs, exhaust manifold studs, modified turbo IP, big exhaust, ram air cold air intake, intercooler, balanced rotating assembly, 7.3 valves, 7.3 rockers and I think 350 is very possible.
I am running an aftermarket ATS turbo on mine and at speed on the highway I hit mid 20's for boost.
I also am not running an intercooler, so that would be on top of the 4500 I have in the engine and I did already have the turbo so that is not in their either.
But most people have a hard time dumping that much money in a 23 year old engine.
All I know is it runs way better than it did stock, it also runs way better that the reman 7.3 turbos I had tried.
If you want to be quick in the quarter mile, better go with a C6 tranny.
Course I drive mine like a truck, slow shifts, so the U joints stay in it for a while.
My goal was pulling loads, not drag racing when I built mine.
Start with a late 85, 86 or 87 6.9 engine.
Magnaflux everything, then mic everything to make sure it is worth building.
Milled pistons, head studs, intake studs, exhaust manifold studs, modified turbo IP, big exhaust, ram air cold air intake, intercooler, balanced rotating assembly, 7.3 valves, 7.3 rockers and I think 350 is very possible.
I am running an aftermarket ATS turbo on mine and at speed on the highway I hit mid 20's for boost.
I also am not running an intercooler, so that would be on top of the 4500 I have in the engine and I did already have the turbo so that is not in their either.
But most people have a hard time dumping that much money in a 23 year old engine.
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Postmaster
Joined: Dec 2002
Posts: 3,594
Likes: 2
From: Southern Oregon USA
I just guesatimated a number for HP.
All I know is it runs way better than it did stock, it also runs way better that the reman 7.3 turbos I had tried.
If you want to be quick in the quarter mile, better go with a C6 tranny.
Course I drive mine like a truck, slow shifts, so the U joints stay in it for a while.
My goal was pulling loads, not drag racing when I built mine.
All I know is it runs way better than it did stock, it also runs way better that the reman 7.3 turbos I had tried.
If you want to be quick in the quarter mile, better go with a C6 tranny.
Course I drive mine like a truck, slow shifts, so the U joints stay in it for a while.
My goal was pulling loads, not drag racing when I built mine.
Very good points Jim. I think Dave's 6.9 may be near the ledge of what can be done with the IDI, and still be able to call it an IDI. Maybe the next step would be eliminating the pre chambers altogether and getting rid of the DB2 pump for an inline pump similar to the P7100. I've seen a couple of 7.3 PSD pull trucks converted to P pumps, but you would be in no man's land on the IDI. You can then take advantage of the DI design and give it a clean shot of fuel. Definetely going to need a charge cooler now. Add a larger, sequential or even a 2nd turbo to match the fuel you're giving it. I think you would be near the design limits of the IH block if you got crazy with it.
It would all be custom, not something you could rely on as a daily driver, though. But I think it could be done.
Jason
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
Since the pre cups cross the fire ring in the head gasket, just taking them out would not be an option.
And several people I have talked to say cutting them to large, kinda ruins the low RPM manners.
Much more than 30 PSI boost, unless you cut the pistons way down the next thing you will be looking for is O rings for the heads.
Dollars start adding up fast when you go that route.
I have a second turbo, and I have considered installing it with the one I have now to see if I could get another 5 PSI on top end and a little more pressure down lower in the RPM range.
I am far from maxed out on the IP I have now, and she still rolls the black at 25 PSI when I set my 13 on the floor.
The problem with big power from an IDI, getting enough air in the engine and keeping the head gaskets where they belong.
With what I have cut my pistons down, my base compression ratio is now 20.25 to 1.
At 25 PSI my effective compression ratio is just a tad higher than a Power Stroke running 30 PSI.
And several people I have talked to say cutting them to large, kinda ruins the low RPM manners.
Much more than 30 PSI boost, unless you cut the pistons way down the next thing you will be looking for is O rings for the heads.
Dollars start adding up fast when you go that route.
I have a second turbo, and I have considered installing it with the one I have now to see if I could get another 5 PSI on top end and a little more pressure down lower in the RPM range.
I am far from maxed out on the IP I have now, and she still rolls the black at 25 PSI when I set my 13 on the floor.
The problem with big power from an IDI, getting enough air in the engine and keeping the head gaskets where they belong.
With what I have cut my pistons down, my base compression ratio is now 20.25 to 1.
At 25 PSI my effective compression ratio is just a tad higher than a Power Stroke running 30 PSI.
Elder User
Joined: Dec 2006
Posts: 559
Likes: 4
From: On a farm.
Dang! Busted. I mean, no, it's a completely different truck.
Senior User
Joined: Jun 2004
Posts: 477
Likes: 1
From: florida
off topic, but has anyone seen the movie "The Words Fastest Indian" Its a true story about a KIWI by the name od Bert Monroe who bought a 1920 indian new. He modified it and raced it and in 1968 set a land speed record at Bonneville. This Motorcycle was designed to go 57 mph and he drove it 201 mph. The record still stands (I guess because they closed the class the day he set the record) and is available for anyone to see. I guess anything is possible, if someone is willing to do the work.