Today in Shawn's Garage HX35 Turbo Upgrade on a GM 6.5 Diesel

[@jamesbeasley4132]

Keep the 6.5 videos coming!!

[@shawnsgarage]

Will do will have a new one likely next weekend.

[@stevebuttrum]

Got a 93 6.5 5 speed with 340k and gets 26mpg best truck ever

[@THUGLIFEhks]

Did you ad the hx35?

[@oliverhall4714]

Nice video, thanks for sharing. I'm in the process of doing the same thing on my 6.5l. I have all the parts and tune. I just need the time to install 😂. Looking forward to the next video.

[@deltafreshrelics1660]

I got a 95 burban with 4.10 gears. I put a 16cm non gated hx35 with 54 mm comp wheel on it. Rather than tune it, I put the stock MAP sensor where the atmospheric sensor was and installed a 3 BAR MAP from a 60 series Detroit and put a #9 resistor in the PMD. It’s got a Jasper engine that’s a Navistar block. TTY head bolts. Cruises at about 3-4 psi and will hit about 18psi under WOT. Think it’ll hold together? Lol. I papa the thing around and have only mashed it for testing. It doesn’t roll coal but it has a light haze to it under full throttle.

[@xxxxxxxxxx6903]

On OEM/Felpro TTY Bolts, 18PSI (might) be ok if your vehicle is lightly used only as a commuter. But if you try to tow heavy, you'll eventually lift a head due to bolt stretch. This takes out the head gasket(s)! W/O an intercooler, I would recommend limiting boost (at sea level) to 12-14PSI max! If you live at an altitude above 4000Ft, you can crank it up a bit. But if longevity is your goal, ARP head Studs or equivalent are the way to go! Just got to really seal the bottom threads, as they are in the water jackets of the block! Interesting what you did with the 2-Bar MAP sensor, and the Barometric sensor. I believe the Baro is "absolute" pressure, to read atmospheric. And the MAP is "gauge" pressure. Sticking the 2-Bar MAP in the Baro sensor location must be fooling the ECM/PCM into thinking it's cruising at 50,000Ft like Boeing 747 all the time! I'm rather surprised it hasn't thrown a code for a Baro circuit/sensor malfunction? Do you ever visit the online 6.5L forums? Truck stop.us, Diesel place forums are a treasure trove of knowledge on these antiques. Plus many there might be very interested in hearing the outcome of your sensor swap experiments! 👍

[@THUGLIFEhks]

How’s that turbo ? Good quality?

[@shawnsgarage]

The turbo has been excellent. No issues and fast boost generation.

[@a.lumberjack4456]

How are you controlling boost pressure?

[@shawnsgarage]

Using a turbo smart waste gate with a 15lb spring.

[@Scano41]

Omg 6.5 how fast will that go

[@shawnsgarage]

Not built for speed. Built to tow.

[@Barry11997]

What did you end up at for boost

[@shawnsgarage]

I have not pushed the truck yet as I am still breaking in the motor. It can get up to 12 pounds real quick. I am limiting it with a turbo smart 15lb waste gate

[@xxxxxxxxxx6903]

​@@shawnsgarage- The stock program in the ECM/PCM will detect the over-boost condition and throw a code, and/or enter limp mode and de-fuel on you. The guy further up this post string is experimenting with pressure sensors. Which is a way to fool the stock program into operating way above the OEM 11PSI boost limit!

[@xxxxxxxxxx6903]

Of course, getting an aftermarket Eprom/Flash can modify the stock boost limits. Probably in a more precise manner than fooling the puter with non-stock scaled boost sensors.

[@THUGLIFEhks]

@@xxxxxxxxxx6903what if it’s a mechanical 6.5?

[@xxxxxxxxxx6903]

@@THUGLIFEhks - I believe the 1993 with the DB2 injection pump still utilizes a vacuum controlled waste gate on the turbo? Many with the mech injected 6.5 went with the BoostMaster type (spring loaded waste gate controller). I'm not sure about utilizing a Three Bar MAP sensor to fool those setups? But if you're running a stock "GM" turbo, you really want to limit boost to 12psi anyway. After that you're hp/Tq gains plateau or drop due to really heating the air charge!