6.9 IDI performance help needed!
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6.9 IDI performance help needed!
Okays guys I'm in need of some help on the 6.9 IDI performance upgrades. I have a 85 f250 6.9 idi. Engine was leaking in every place there is a gasket. After reading many forums that there are many performance upgrades available for the 6.9 idi. I found one forum that said if you want to install a turbo on a n/a 6.9 that you would have to use beefed up connecting rods. My plan for my truck is to use a beefed up injector pump, injectors, ceramic coated pistons. Better camshaft. But my main concern is that the connecting rods won't handle the power. If anybody can jelp me out I would greatly appreciate it.
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Joined: Nov 2003
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From: Saint Maries Idaho
To be honest there are many myths surrounding the 6.9 and 7.3 motors. For example if you give one over 12 psi boost it will immediately grenade. Most of these myths are just that. The bottom end on these engines is VERY tough There are guys that have run 40psi boost 400+ hp with 900+ ftlb torque on mostly stock engines with no ill effects.. The only issue I have ever heard of a block being windowed on these engines is where a guy had a rod knocking and kept running the engine until it blew up (a couple of months later). If you are interested in building a performance IDI engine I highly recommend reading This thread.
It is a lot of pages but there is some valuable information in it. I have been following it for over a year getting an idea of what works for when I build my engine. You will need head studs as that is one of the weak points of our engines, but otherwise you can pull a lot of power out of a stock motor with no issues.. unlike the Chevy 6.5 which comes with a factory 2 piece separated crank.
Keep a build thread
It is a lot of pages but there is some valuable information in it. I have been following it for over a year getting an idea of what works for when I build my engine. You will need head studs as that is one of the weak points of our engines, but otherwise you can pull a lot of power out of a stock motor with no issues.. unlike the Chevy 6.5 which comes with a factory 2 piece separated crank.
Keep a build thread
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From: Kodiak, Alaska
Ok, so the connecting rods are pretty tough I wouldn't worry to much about them. If you were trying to push 400+HP and were really concerned you could find a set of IDIT rods with the bigger wrist pins and have some custom work done to your pistons so that they would fit. But that said the bottom end of these engines is very robust and can handle a lot. Head studs will be a must if you plan to run over 20 psi. RacinNdrummin is probably one of your best resources for Performance upgrades on the IDI engine. He has a website R&D IDI Performance
Posting Guru
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You are on the right track with what you want to do to your engine. Also a really good upgrade is a turbo that can push more boost than the turbos that are available for these engines. Check out idiperformance.com. They have all the parts you would ever need for a performance idi.
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I greatly appreciate all the info, definitely learned a lot just reading the replays here. I greatly appreciate it. Is there a turbo manufacturer that is better than the other? Or is the turbo on R&D IDI performance?
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Also how do control the psi a turbo is putting out? Or is there different turbos with different psi? Also how would you measure the psi? Is there a pressure test, or a gauge? Sorry for all the questions I'm okay with diesels but when it comes to adding turbos I get confused.
Thanks, Ryan
Thanks, Ryan
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One more question about 6.9IDI internals. I took apart my engine, and wasn't thinking clearly. But now my connecting rods and rod caps are all mixed up, how much of a problem will this be? Does it matter what cap goes to what rod,and vise versa?
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From: Kodiak, Alaska
By rod caps do you mean wrist pins or crankshaft bearings? A good practice is to keep everything together on trays with everything labeled (and don't trip on extension cords when you are carrying the tray) I also bag all of my hardware for each component and zip tie the bag to the part so that you do not have to dig through a bucket of hardware and figure out what is what upon reassembly. I would not recommend reusing any bearings that you have mixed up I would have the crankshaft turned .010 and buy new +.010 bearings. So to make a long answer short, yes, it matters.
Elder User
Joined: Dec 2011
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From: Kodiak, Alaska
Take lots of pictures for your build thread.
The 6.5s are known for breaking cranks.
Post Fiend
Joined: Nov 2005
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From: Charles Town, W bygod Va
Yes, it matters. The caps are bolted to the rods, then the hole is bored, so if you swap them or put them in backwards it won't work.