Best Upgrade for 6.5 turbo diesel

[Truckie117]

Hi
I would like to know what people think is the best upgrade to improve preformance and fuel mileage.
Thanks

[ercaduceus]

Intake and exhaust.

[JetBoater]

I agree...
Pull out the rubber snorkel found within the inner fender for unobstructed air flow into the engine.

Get rid of the stock down pipe and replace with a 3" unit and free flowing exhaust... go with minimum 3" diameter pipe and muffler.

Get rid of all extra weight and keep your tires inflated properly.

Almost everything else you do from here may gain performance but not necessarily increase mileage. An intercooler would be next, along with higher boost and more fuel. Extra HP is inversely proportional to your fuel bill ;).

[DennisG01]

What kind of milege are you currently getting? And, have you checked accurately over the course of a few fill-ups (not just over a 100 or 200 miles)? I'm curious!:)

Typically, our Suburbans will get a bit worse than a SRW pick-up because of the extra weight.

[JetBoater]

My mileage will take time to evaluate...and improve. I have approximately 3000 km (1900 miles) on the new engine. The oil just started turning black 500 km ago.

Currently my K3500 4x4 gets a poor 500 km(310 miles) per 100 liter(25 Gal) tank. The driving has been primarily through the city.
;)

[Truckie117]

I have consistantly been getting 17mpg city or hwy. But when i kick in my veggie I get 65mpg of diesel. but I would like to do better than 17mpg on straight diesel.
I have stock everything.

[damork]

I sold my 95 Yukon with over 250k miles last year but the engine head and pan had never been removed and the transmission was still original.

1. Best thing ever was the timing gears I bought from Kennedy - ran better from 160 k onward than before that.

1a. Performance chip - mine was the hottest available from BD but used it for the improvements to timing and shifting. Nice to know more was there, but never pushed it.

2. PMD cooler relocated to front of Driver side battery.

3. HO water pump and dual thermostats (factory equipped on newer models)

4. New downpipe to replace the smashed OEM unit. Came from Jardine (Dubois WY).

5. Re-wire grounds everywhere on truck to ensure you have bulletproof connections.

Beyond that, I tried a larger exhaust but not a huge gain. I believe Kennedy graphs showed maybe 10-15 HP at higher than highway RPMs. Slightly improved exhaust temps at cruising speed, but no gain in economy. Again - I never pushed it, was looking for steady state economy and usually got 19 mpg.

[More Power]

Hi
I would like to know what people think is the best upgrade to improve preformance and fuel mileage.
Thanks

For a mechanically injected 6.5, have the injection timing checked and/or set to 4 degrees BTDC at 700-rpm on a warm engine. I have the most experience with the Stanadyne Time-Trac timing meter. Snap-On also produces a timing meter, but the timing spec is a little different. If the injection pump hasn't been retimed for a long time, timing chain slack will slowly retard timing over time.

Injectors slowly lose their ability to properly atomize fuel as the miles accumulate, and should be replaced every 100K or thereabouts, or whenever your fuel economy tracking begins to indicate a slow decline.

Jim

[ad2]

I gutted out my intake the stock ducting, maf airflow sensor, and blow by line and made a strait caller mount for my air filter so it mounts on the turbo intake. It increased my power and my mileage quite a bit I am now getting 25 MPG on the highway and 20 in town the only problem with my 97 Chevy now is keeping if from speeding.

[Renntag]

Wow, this is an old thread.

For those that find this again, there are many many threads on what to do to a 6.5 to improve efficiency. Follow the suggestions above.

Water injection is a great upgrade as it's difficult to fit in an Air to Air intercooler. A Heath turbo master is a cheap upgrade and with more boost, the motor will be more efficient.

Our '99 burb would regularly get 18-19mpg on the highway. I'd love to see 20-21, not sure what else to do to achieve that.

Best of luck.

[Gmc65turbo]

I gutted out my intake the stock ducting, maf airflow sensor, and blow by line and made a strait caller mount for my air filter so it mounts on the turbo intake. It increased my power and my mileage quite a bit I am now getting 25 MPG on the highway and 20 in town the only problem with my 97 Chevy now is keeping if from speeding.

I have a 96 GMC with a 6.5 turbo all stock. What should be my first step in getting more pulling power and speed out of this truck. Especially going up hills?

[jrsavoie]

I have a 96 GMC with a 6.5 turbo all stock. What should be my first step in getting more pulling power and speed out of this truck. Especially going up hills?

4" exhaust, Feed the beast, K47 air box - the OEM air box off of a 97 or newer 6.5, Synthetic oils all around, Amsoil or FS2500 bypass filter.

New injectors if they are close to 100,000 miles.

Duramax fan upgrade, Engine oil cooler lines if they look suspect. If they are original change them

[AKMark]

The 6.5 I had with 4.10 gears and 285/75R16's pulled great. Much better than the one with 3.42 gears and 245/75R16's.

It'll never pull like a Duramax, Cummins, or Powerstroke without extensive modification, and even then probably not.

[CONGA1991]

I gutted out my intake the stock ducting, maf airflow sensor, and blow by line and made a strait caller mount for my air filter so it mounts on the turbo intake. It increased my power and my mileage quite a bit I am now getting 25 MPG on the highway and 20 in town the only problem with my 97 Chevy now is keeping if from speeding.


Would you be able to post a picture of your set-up? I'm very curious.

Sorry, I didn't realize how old this thread was.