Turbo sizing guys, how about a Holset from a Cummins engine?
 

Hi Guys,

I've been turbocharging cars off and on for few years, all home built set ups with "junk yard" turbos and always have had great luck. I'm now looking at doing a custom turbo set up on my 03 Silverado 5.3L using an 01 Dodge Ram Cummins Holset turbo. Just curious if you all think that turbo is roughly a good match for this 5.3L gas motor. I see a lot of references on here to different commonly used turbos for these trucks but don't have a clue how to compare them to this Holset.

Thanks!

I've heard anything between a PT76-88 is the way to go.

For a 5.3??? Who told you that?? :confused: A T70 is a MUCH better fit for a 5.3. A 76-88 will take for ever to spool on a 5.3

I don't remember what the those Holsets are, but I know they are small, like 60ish mm. Might make 400ish power and it will be done.

agreed, the cummins motor only revs to what, 3500, 4000? That's why they don't use big turboes.

I would stick to the T70 realm, decent spool, could push a stock motor to the limits I would guess....

Yeah I think the stock holset turbos on a Cummins have a 54mm compressor inducer on a T3... Even if you ran like 30+psi to get high into the map, you're still only gonna have MAYBE 350hp of airflow available. I know the 12 valves only rev to 2500 from the factory, so they don't require a whole lot of air. Just a shitload of air density at low RPM, which is why those turbos are so small. You'd choke that turbo before the engine even reached an amount of power that an NA 5.3 could do alone. Would be fun up to like 3000rpm though! :lol:

I think the holset turbos are worth looking into. I actually work at the cummins power generation plant. We have many different engines for many different sized units. Anywhere from a 2.3L 4cyl ford gas motor all the way to a 78 liter quad turbo 10,000 ft lbs tq diesel. We have turbo 8.1L chev big blocks, turbo v10 fords, and many diesels in between. All have their own dedicated turbo(s). I can do some research if you are interested.

That 78 liter diesel idles at 10,000 ft lbs, right?

Well I went ahead and picked up a Holset today, a different one than the one I originally found but better. Its an HE351 from an 04 Dodge Ram with the HO engine. From what I can tell it appears to have a 60mm compressor inducer.

I have a hard time believing that this turbo would choke up on this engine but I could be wrong, I'm no expert on turbo sizing. Doesn't the fact that I'm probably only going to be running half or less the boost of a 5.9L diesel factor into the air flow equations?

Joey, if you can get any info I'd love to hear!

Thank,
Fred

Lol, you'd think. Its the same engine they use in the largest off road mining dump trucks, 3500hp, 10,000 ft lbs. Intercooler is just under 13ft tall and about 6ft wide. I wish I could have some of the parts here to use at my convenience.

If its a 60mm inducer, it will flow a good bit more than the 54mm version. As with all turbo compressor maps though, it will flow more as pressure rises. Since you'll run way less boost on a gas engine, the flow limitation is set lower. You might get 450hp out of that turbo before it starts choking. Would spool quick as shit though.