Holset Turbos, PART 4

[dsm-onster]

Google "super 40" and "7 blade" and holset. According to my research at TDR Roundtable, best diesel forum and pile of diesel info anywhere, the 7 blade has the same inducer. The 6 blade and 7 blade have about the same flow but the 7blade is more efficent, the 6-blade peaks out a little higher in flow. There's a super 40 and a redesigned super 40. For a while I was confused on what holset built. . .

Flow and efficiency are not interchangeable. The more blades the more efficienct and the fatter the efficiency islands become on a map. The extra blades prevents the air molecules from bumbling around as much adding to friction and adiabatic temperature rise. However there's a pocket of dead space that develops which trails every blade at high compressor rpm. Ths is called cavitation. The more blades the more volume of the wheel is taken by cavitation. This reduces peak flow.

[Slippi84]

Originally Posted by dsm-onster

The LARGE 7blade htturbo and other diesel shops have been talking about have an inducer more than 3mm larger than the 6-blade 60mm. Flow and efficiency are not interchangeable. The more blades the more efficienct and the fatter the efficiency islands become on a map. The extra blades prevents the air molecules from bumbling around as much adding to friction and adabiatic temperature rise. However there's a pocket of dead space that develops which trails every blade at high compressor rpm. Ths is called cavitation. The more blades the more volume of the wheel is taken by cavitation. This reduces peak flow.

Understood. But then why is it not a factor at lower rpms? Even though the blades may be spinning slower if its' still blocking some of the air it should still be less effeicent not more I guess the real question is ehat makes the 7 blade more efficent than the 6 blade now that you have stated what makes the 6 blade have a greater peak flow than the 7 blade.

[propeine]

The 7 blade can "grab" more air at lower RPMs. Its a fluid dynamics problem. Cavitation occurs when the pressure differential across the turbine is higher than the flow can support. When you pinch a garden hose and hear bubbles in the hose after the pinch, its not from air in the hose already. Its because the local pressure drops so much after the pinch (technical term would be a throttling valve) that the water boils. This is exactly how an AC system works. Aerodynamics of propellers for airplanes is the same principle. More blades = more thrust at lower speeds. After a certain either propeller speed or aircraft speed they are no longer efficient. Attack angle of the blades has a big effect too.

Anyone feel free to correct any part of this thats wrong. Been a while since I took aerodynamics or fluid dynamics.

[Slippi84]

At what point does the ability to grab more air assosiated with more blades equal or become less than the ability for more air being able to flow past less blades? Is it a amount of air flow thing a blade speed factor or a pressure factor? Or all of the above as of course they're all related?

[propeine]

Originally Posted by Slippi84

At what point does the ability to grab more air assosiated with more blades equal or become less than the ability for more air being able to flow past less blades? Is it a amount of air flow thing a blade speed factor or a pressure factor? Or all of the above as of course they're all related?

Its both a blade speed factor and a pressure/flow factor. There is a point where the extra blades just get in the way basically. Depends on angle of attack of the blades too. I'm trying to think of a way to watch it happen without using Fluent or another CFD program I don't have access to any more. There is a program thats free out there somewhere I can't remember the name of that could show the effects in a table but I can't think of what its called for the life of me.

Observation Of Collapsing Root-Cavitation Using a High-Speed Video Camera

A decent video page showing the effects of cavitation in water. Not exactly the same but similar principle.

[dsm-onster]

Good explanation! Either way. There's no different super 40 maps. The 7 blade is a revision. And part of the revision was to cure an infrequent failure in the hx40 shaft. Some hx40s exhibited this failure while SO many others under the same conditions were fine. The number of blades sets up a harmonic vibration in the charger. . . the odd number of blades could have been used to solve for possible damaging harmonic issues. Who knows.

Like I said, though, there's no differing super 40 maps though the 6-blade super 40 wheel was revised. So there's likely very little difference in performance between the 2. Don't worry slippy you have a 60mm 66lb/min compressor

Originally Posted by Slippi84

At what point does the ability to grab more air assosiated with more blades equal or become less than the ability for more air being able to flow past less blades? Is it a amount of air flow thing a blade speed factor or a pressure factor? Or all of the above as of course they're all related?

Simply, the lower the rpm the less likely you'll reach cavitation that will cause a loss in flow. But the catch is there usually needed a higher rpm from the compressor to sustain a higher flow.

[Slippi84]

Originally Posted by dsm-onster

Good explanation! Either way. There's no different super 40 maps. The 7 blade is a revision. And part of the revision was to cure an infrequent failure in the hx40 shaft. Some hx40s exhibited this failure while SO many others under the same conditions were fine. The number of blades sets up a harmonic vibration in the charger. . . the odd number of blades could have been used to solve for possible damaging harmonic issues. Who knows.

Like I said, though, there's no differing super 40 maps though the 6-blade super 40 wheel was revised. So there's likely very little difference in performance between the 2. Don't worry slippy you have a 60mm 66lb/min compressor

Lol yeah I wasn't worried just curious. This thing makes my old SBR GT14 look like a 14b even though that was SUPOSEDLY a 65lb/min turbo lol.

[dsm-onster]

This is over a year old. But I'm just linking this to here, so that the holset information can be a little more compiled. . .

New times on the Holset HX-35. He would have definately bumped into a 10sec ET if he could achieve a 1.6-1.7sec 60Ft. if he were running 30si and a better lauch, that would have sealed the deal for 10sec. 11.29sec @ 126.12MPH

272s, stock intake manifold, stock transmission (no high rpm shifting), stock 2.0L block, bolton BEP housing with evo3 exhaust manifold, GM MAFT and DSMLink. 500whp trap speed (126.12) with a stock 1g awd weight at 1600feet altitude with 225 50 series street radials.

. . . Faster than any fpgreen powered car within 200lbs of full weight listed in dsmtimes.org.

[propeine]

Originally Posted by dsm-onster

This is over a year old. But I'm just linking this to here, so that the holset information can be a little more compiled. . .

New times on the Holset HX-35. He would have definately bumped into a 10sec ET if he could achieve a 1.6-1.7sec 60Ft. if he were running 30si and a better lauch, that would have sealed the deal for 10sec. 11.29sec @ 126.12MPH

272s, stock intake manifold, stock transmission (no high rpm shifting), stock 2.0L block, bolton BEP housing with evo3 exhaust manifold, GM MAFT and DSMLink. 500whp trap speed (126.12) with a stock 1g awd weight at 1600feet altitude with 225 50 series street radials.

. . . Faster than any fpgreen powered car within 200lbs of full weight listed in dsmtimes.org.

That thread has given me such high hopes. 300 miles of clutch break-in and we'll see how I can do in a 2g with meth. Hoping for some track times in two sundays. Pray to the DSM gods I don't frag my bottom end.

[dsm-onster]

You have a 7-bolt. I will pray for you. They are GREAT blocks. The only more durable factory 4cylinder block is the 6-bolt. Or the 2.3 Lima turboford.

Tim (TimG). I don't think the compressor is too small or inefficient to run low 11s high 10s. You have a larger a/r housing since you're running a stock hx35 housing on a non-divided manifold. You should do way better with a better transmission. But, it loks like the stock hx35 turbine housing wasn't maxed out with your setup??? This guy has a stock intake manifold and was running 28psi with an evo3 exhaust manifold and the same cams.

I got my crank back. The DSMgods will smite my car. I had the crank cut .01" over . So now add that to the list of bad dsm kharma: my lsd insert, pushing a fwd to more than 300whp, a 6 puck clutch for the street, a cheap holset from ebay, an ebay FMIC, ebay wastegate, homemade crap every where including the suspension, both balance shafts, and solid welded motormounts. . . Now add a cut crank.

[Ghost1984]

Nice turbo. Looks like it's gonna be a lot of fun. But, on a more important note. DSM-onster, Can I have those top ramen noodles? Srsly, they OWN. lol

[dsm-onster]

HAHA! funny guy here Meanwhile I.

Don't ask for the Ramen. It's all I have!. . . Look! my babies' and my baby mama gotsa eat too!

[jkimes]

These holset turbos look really impressive. I probably would have purchased one already but i'm having trouble finding an HX40 with a 60mm inducer and 6 or 7 blades on ebay or the diesel forums. The only issue I can see so far that makes it seem like a BW 366 turbo might be a better choice over a holset hx-40 is the incredibly high amount of boost badman had to use to make his 600+whp run. It seems like a 4088 or an s366 would have made that power with much less boost, or was this simply due to the restrictive turbine housing badman was using? Also, how much power/boost are most hx40's able to make on pump gas without knock?

[ceedawg]

Originally Posted by jkimes

These holset turbos look really impressive. I probably would have purchased one already but i'm having trouble finding an HX40 with a 60mm inducer and 6 or 7 blades on ebay or the diesel forums. The only issue I can see so far that makes it seem like a BW 366 turbo might be a better choice over a holset hx-40 is the incredibly high amount of boost badman had to use to make his 600+whp run. It seems like a 4088 or an s366 would have made that power with much less boost, or was this simply due to the restrictive turbine housing badman was using? Also, how much power/boost are most hx40's able to make on pump gas without knock?

I think you answered your question right there(small exh housing).

The pump gas knock question would also depend on your whole setup overall(intercooler,whole exh system,inj,tune) etc.

[dsm-onster]

Originally Posted by jkimes

These holset turbos look really impressive. I probably would have purchased one already but i'm having trouble finding an HX40 with a 60mm inducer and 6 or 7 blades on ebay or the diesel forums. The only issue I can see so far that makes it seem like a BW 366 turbo might be a better choice over a holset hx-40 is the incredibly high amount of boost badman had to use to make his 600+whp run. It seems like a 4088 or an s366 would have made that power with much less boost, or was this simply due to the restrictive turbine housing badman was using? Also, how much power/boost are most hx40's able to make on pump gas without knock?

I don't know anyone who runs less than 38-40 psi and makes 650+ whp for a turbo as small as a 4088r or hx40 6-blade.

If you're looking for that kind of power, you're going to run a great exhaust manifold. Like a divided runner t4. Which the stock hx40 housing bolts up to. You can have any holset you buy used fitted and balanced with the 6blade wheel. The hx turbo wheels are individually balanced from the factory. . . But I would call HTturbo or similar and talk to them.

[Slippi84]

Originally Posted by dsm-onster

I don't know anyone who runs less than 38-40 psi and makes 650+ whp for a turbo as small as a 4088r or hx40 6-blade.

If you're looking for that kind of power, you're going to run a great exhaust manifold. Like a divided runner t4. Which the stock hx40 housing bolts up to. You can have any holset you buy used fitted and balanced with the 6blade wheel. The hx turbo wheels are individually balanced from the factory. . . But I would call HTturbo or similar and talk to them.

Or, a punishment racing divided T3 manifold and 45 psi

[90laserRSfwd]

So this would be a good one to get then... ?

eBay Motors: HOT ROD TURBO DODGE CUMMINS HOLSET HX40 PULLER RACE NR (item 320290512378 end time Sep-01-08 18:30:00 PDT)

[Slippi84]

Originally Posted by 90laserRSfwd

So this would be a good one to get then... ?

eBay Motors: HOT ROD TURBO DODGE CUMMINS HOLSET HX40 PULLER RACE NR (item 320290512378 end time Sep-01-08 18:30:00 PDT)

85mm COmpressor wheel

I don't think he's talking about the right wheel. Maybe turbine wheel but not compressor. Hx40's have a 56-60mm compressor wheel. I think there is a super hx40 that has a slightly bigger wheel but a 85mm wheel sounds like the hx52 wheel. Other than that looks like a good deal.