Looking for recommendations to upgrade my 6.9L to a turbo 6.9L

Its currently an auto C6.  I have a manual trans I could swap in.  Any significant advantage to the manual trans?  I am looking for more towing power.  Currently it ok for the most part but hills are horrible and getting up to speed is slow and limited top end.

Plan to rebuild motor and transmission and add turbo.  I am in Canada and hope to locate parts here due to poor exchange rates and shipping/duties.  Looking for the most economical options to make this happen.  

Any recommendations would be appreciated.  

Sorry I cant help on what you need to do to get what you want but if done right you will love it.

I had a 86 GM 6.2 diesel 4x4 auto that I did a Gale Banks turbo kit on, truck already had 4.11 gears.
Turned it in to a BB gas motor truck and was fun to drive.
I did the kit with 100K on it and at 230K sold the truck as the body was starting to need some love and I just did not want to deal with it.

Keep us posted on the project
Dave ----

The C6 is strong, but a gas and power hog.  Unlike later model auto transmissions the torque converter is always slipping, which loses power and causes heat.

If you go with a manual and want to drive on the highway I'd highly recommend going with the ZF5 manual.  That gives you overdrive and reduces the losses significantly.  And I believe it is the only one available for your engine with OD.

Hello, I am not sure where your experience level is with the 6.9 so my apologies if I repeat things that you already know…

1. Almost all IDI’s are running on worn out fuel system parts and are “dogs” because of it. As the rotor head wears in the IP, the timing shifts and throws off the injection timing. The springs in the injectors fatigue resulting in a lower pop pressure which further shifts the injection timing. The springs fatigue unevenly, so the timing for each cylinder is different. The injector seats wear and deform, causing some to drip and piss fuel into the pre-cups, further distorting the time of the actual ignition event and burn efficiency. The IDI is extremely forgiving, and it can sound great and run just fine in spite of all of this. That’s one reason I like it, but fixing this will make it a whole different truck. In stock form the early IDI’s actually put out more power without a turbo than the first Cummins did with a turbo because of the bigger displacement. Fixing the fuel system is pricey. Count on over a grand. The parts house injection pumps are more often than not just someone else’s problem glass beaded and shipped to you in a box. Get one from a reputable pump builder. I recommend R&D IDI performance. Stanadyne has begun making injectors again, and I would get a new set of those. You also need a timing light. Decide where to set it by butt dyno, but get in the ballpark with a meter and keep track of your adjustments to find where it runs best for you. DTI timing meters are on eBay for about $200 and you don’t need a light.

2. A mild turbo kit on a 6.9 is a great upgrade, but slapping one on to compensate for a worn out fuel system is just like it sounds. The results may be underwhelming. If you are buying a used kit, keep in mind that early Banks kits pipes are specific for automatic vs manual transmission clearances, so ask what it came off of before buying. Late model ATS and banks kits with a wastegated exhaust housing are better, but hard to find and usually a lot more expensive. A non gated kit will still help out a lot particularly while towing. Don’t turn up the fuel or upgrade to a higher flowing injection pump without a pyrometer and boost gauge. Head studs are a good idea, and 6.9 studs are a lot more affordable than 7.3’s. They can even be installed one at a time if you are not in a position to pull the heads.

3. Rebuilding… check the block serial number first. If it does not have bolt in position oilers I would find a block that does and build that. Also, keep in mind that many IDI internal parts may still be in good shape and actually better than the cheap-o replacements. Oil pumps and valve lifters are notorious for being inferior and the originals may still be serviceable. If you are thinking of rebuilding because it is down on power, make sure it isn’t just the fuel system (see above). If it’s puking oil, try new seals and make sure it isn’t just a clogged CDR. IDI’s have huge second ring gaps and a lot of blow by right from the factory. They also operate on low oil pressure but high oil flow rate. Blow by and low-ish oil pressure is normal and your engine may not be as tired as you think.

4. Manual transmission is my preference… but may not help your towing power. Is your manual that you have available a close ratio gear set? If not I would skip it. Wide ratio 4 speeds have some pretty big gear jumps and are not great with a low revving IDI. If doing a manual conversion I second the nod to seek out something with overdrive.

Thanks for the replies.  The engine I put in was rebuilt at some point in its life (so I  was told).  I believe the IP was done as well (it still has a sticker on it from the rebuild shop).  I have adjusted the timing slightly off of the factory mark.  My timing light doesn't register at the required RPM for setting though (a couple hundred rpm short). I bought different brand but haven't tried it out yet. The truck immediately starts and no smoke under normal acceleration (only when its right to the floor).  Injectors have been checked, new fuel pump and filter, return hoses replaced.  For the most part, the truck runs very well, just lacking on the hills and running at the speed limit.  

Was going to rebuild as good measure due to adding more power.  CDR has been replaced with a new one.

Not sure what "available a close ratio gear set" is?  I haven't had a look at the gear ratio yet on the donor manual truck.  Currently have 3.55 gears and I believe changing it to a 4.11 will help towing but engine will rev more.

I will have to look into the block numbers as you have mentioned, will also look into what oilers are.  I have an 83 and 85 engine to use.  

Close or wide gears refers to the transmission you have, your rear end only has one set of gears.  The same transmission can have different ratios depending where it came from, and you didn't mention which transmission it is anyways.  Some t18's have a 6.3:1 first, some have 4.3, with different second and thirds as well.  T19's can have even more of a spread.

The close ratio T19 has a 4.02 synchronized  first gear and drives like an actual 4 speed, not 3 speed plus a crawl gear. More importantly the jumps between gears are small which helps a lot to pull a load with an engine that does not like to rev.

It sounds like your fuel system may be recent. Any idea how many miles/years since service? Pulse method timing is accurate but not precise. The proxy is upstream of the injector and does not factor pop pressure, fuel cetane, air density etc., so it’s just a number. If you are a couple hundred off on your rpm don’t sweat it as long as you are consistent. The main thing is to be in the ballpark and be able to measure and track your adjustments. The factory marks are not close enough. They should get it close enough to start and run but that’s about it. A couple other tidbits: fuel pressure affects IP timing, both inlet pressure and return line back pressure. One common mistake is to run a 7.3L IP (which has larger plungers) with the smaller diameter 6.9L return lines. The resulting back pressure retards the timing and varies with rpm. Injection/ignition timing affects your exhaust temperature and pressure. If you turbo your engine, running less advance will typically help spool the turbo. The amount will depend on your turbo size, fueling etc., but playing with the timing will generally help you get more out of your turbo.

If you have a rebuilt engine, definitely check the block s/n. My truck is a 1986 but had an early ‘83 reman block in it 😖. Bolt in oilers were introduced mid-year 1985. The piston oilers cool and lubricate the pistons from underneath, and must be removed for any service that requires taking out a piston. Early design was an interference press fit and required new oilers plus an alignment tool and installation tool that are impossible to get. The oilers are obsolete and run $45-50 if you find the NOS. If you are extremely careful when removing them and re aligning them you can put them back with red loc tite. However if one falls out you will loose oil pressure and destroy your rebuild. Not worth it in my opinion. Bolt in oilers can be removed and replaced easily, but don’t loose the bolts. They are special and can’t be replaced with hardware store ones.