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HX-35 holset

IIRC, if you run an HX35 it is recommended that you run some sort of intercooler.
 
I know there are a few guys here that are running them. Id be concerned with boost numbers if you are running a stock compression motor. You are going to want to have a wastgate to keep your numbers around 10-12psi with stock compression. Your other option would be an 18:1 compression ratio which would allow for the higher boost numbers that the holset is capable of producing.
 
How is the spool up on these???

I have an 18:1 built 6.2L. I will be running a banks kit right now, but want to go for more boost. I want good throttle response and little lag.
 
I loosely considered it for my 6.2 but I'm stock compression. I'm probably going to just go with a standard 6.5TD setup but I hvae heard of guys running the Holsets. ON a Cummins they can produce well over 50 psi. so Highseirra is right , must be wastegated. My Cummins runs about 25-30 psi stock.
 
Samyguy said:
My kid is running these things on his cars, here's a link to some of their stuff.

http://www.dsmtuners.com/forums/turbo-system-tech/353498-holset-turbos-part-7-a.html

Alot of info there on Holset turbos
Click to expand...

It can work well on a 6.5. As mentioned earlier, you'll need to keep boost controlled to levels lower than the HX-35 was originally setup to maintain. Most folks w/ a stock compression 6.5 suggest 15 psi as the peak/limit. Go over & damage is the common result.

Most any turbo setup running > 8-10 psi boost can benefit from a well designed IC, or other method of charge cooling.

Holset used a number of different setpoint wastegate actuators on HX-35's, many of which are set to start cracking open the wastegate at 18-20 psi. On most boost referenced wastegates, the actuator opening point, sets the minimum boost the turbo can be controlled down to - at high loads/throttle positions - when there is sufficient exhaust energy to drive the wastegated turbo faster/more boost, than you want.

So you get an actuator that can be adjusted/or already works, to open at the lower boost pressure point. Then use one of the various boost control methods (Hallman valve, Electronic eg. Greddy Profec, etc) that bleed (a portion of the boost signal) away before the actuator "see's" it, delaying the 'gate opening & allowing boost to climb to the higher level you choose to limit it at.

Boost creep, what can cause it on a wastegated setup, & what to do to correct it, is something one should have some depth of understanding in, to make this project work successfully. As you probably noticed, if you took some time looking over the DSMTuner's site, they've got member's w/ significant knowledge on boost control systems. The info is there to study & learn, but it does take some effort/time.
 
Here's a link to a couple pics of the Holset HE351cw wastegated turbo that came on the 325 hp rated 5.9 Dodge/Cummins around '04 -> '06.

http://turbobyholset.com/forum/he351cw/hatchbox90's-holset-he351cw/

I top pic shows an example of an electronic bleed valve type boost control system. Holset called it "Command Valve" I believe. It works similar to aftermarket electronic boost controllers.

The solenoid/valve you see screwed directly into the comp housing, is controlled via PWM/duty cycle by the truck's PCM.

Say the wastegate actuator itself, cracks open the 'gate at 18 psi. So everytime the turbo has made boost up to 18 psi, the 'gate starts bypassing exhaust & boost can go no higher.

With this setup, when the PCM wants boost higher than 18 psi, it starts cycling that "Command Valve" which bleeds away a portion of the boost signal, so the actuator doesn't "see" 18 psi & doesn't open the wastegate yet. When the PCM sees boost pressures have gotten as high as it commanded, it cycles the Command Valve less, & allows the actuator to see enough boost signal to open the wastegate & boost stops climbing.

The PCM simply varies how much boost signal that command valve bleeds away. The PCM watches boost pressure via MAP sensor input & changes the PWM/duty cycle % the Command Valve gets, to control boost to the level the PCM wants.
 
Personaly I would not spend the money on a holset, don't get me wrong they are a good turbo but the A-team turbo is really what the 6.5 needs.
 
I have not, there are a few guys here that have and do. I was just letting you know my opinion on it. I know it can be done and is done, but the way I understand the 6.5's need volume of air not PSI.
 
Perhaps a better way to understand a diesel engine's mass airflow requirements is that, while diesels run under a wide variety of A/F ratio's, there's still a pretty solid relationship btwn how much mass airflow it takes to support making X hp.

There are a lot of 5.9 Cummins running around making 300 hp w/ their stock HX-35W. Pushing the mass of air needed to support 300 hp, through 5.9 liters requires a higher boost pressure, than the boost pressure required to push 300 hp worth of air mass through a 6.5L.

For the sake of an example, assume 300 hp takes roughly 50 lb/min of air. Admittedly, this is beyond the HX-35's best efficiency - but the 300 hp 5.9's out there are too numerous to refute the HX-35 isn't capable of supporting 300 hp.

300 hp means pushing the same 50 lbs/min in either the 5.9 or 6.5. On the 6.5 making 300 hp, you're pushing the same mass of air, throught a larger displacement (& at higher rpm) than the 5.9, so at a mass airflow rate of 50 lbs/min, the boost pressure of the 6.5 will be lower. The point here, is: x boost pressure & 50 lbs/min mass airflow is a function of the engine, somewhat independent of what turbo is providing the 50 lbs/min. (it is relevant to consider how the turbo's turbine section impacts exhaust restriction - eg. ATT showing lower T-drive pressure @ highway cruise & demonstrating improved fuel economy)

Really my point here, is I keep seeing folks repeating turbo A is better than turbo B without direct experience w/ both turbo's. Unfortunately, the list of 6.5'rs that have run more than 2 non-stock turbo's is VERY short.

I'm not at all trying to inhibit anyone from sharing their opinion. I simply know from 15+ year's experience on a bunch of different turbo/engine enthusiasts forums, that opinions w/o data/experience to support them, perpetuates statements that don't explain/promote a solid understanding of the subject - eg. "more flow, with less boost".

Turbo engineers talk in units of mass per unit time - lbs/min, rather than CFM for good reason.
 
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SmithvilleD said:
Really my point here, is I keep seeing folks repeating turbo A is better than turbo B without direct experience w/ both turbo's. Unfortunately, the list of 6.5'rs that have run more than 2 non-stock turbo's is VERY short.
Click to expand...

:iagree: This is why I follow the VGT Turbo threads with great interest even though I already have an ATT and am very happy with it.
 
I have run the gm1 on my 6.5 and a wh1c ,welded wastegate on both, max boost with the stock turbo was about 28psi, the wh1c was around 38 psi with the same amount of fuel it ran better with the h1c.When i replaced the 6.5 with the 6.2 I was having some serius issues it had no power with the wh1c so put I the stock stock turbo back on try to get a base line it still ran like crap, I thought 6.2 and 6.5 turbo injector nozzles were the same they are not, after putting in the turbo injectors in the differance was amazing, but still lacking, I then reinstalled the wh1c there was a lot more power and it spooled faster than the stock turbo, I got 60 psi with that turbo ,the hx35 is better with out over fueling they are ok. I had lots of fuel. I was pretty happy with it but never checked drive pressure Im shure it was very high. In a mild aplication the hx35 should work fine with a spring loaded wastegate that regulates your drive pressure ,I now have a pro 52 on it ,it made 50 psi , it lags alot.
 
That report would seem to agree well, both with the HX-35's compressor map, & Holset's output range rating going up to about 280 hp.

If you will actually be achieving a goal of 300 flywheel hp w/ a 6.5, no question the HX-35 is a little small. By comparison, the GM-x series was quite a bit small.

The stock 6.5 turbo engine ratings were 190 - 215 hp. Certainly w/ additional fuel & other mods, 300 flywheel hp is doable & has been done.

Another practical factor to consider, is how much fuel your setup can truly provide. If you've got 275 hp of fueling & a turbo capable of supporting 350 hp - the last 75 hp of top-end turbo mass airflow potential can't be utilized.

As my point isn't to be argumentative, but to encourage studying this stuff a little, here's a link to a simulator program. I believe the conditions assumptions to be reasonable, but regardless, check out the numbers. Play w/ changing one factor at a time & see how things interact.

http://www.not2fast.com/turbo/gloss...mp=21&SFC=0.40&AFR=23&maxInjectorDutyCycle=85

It should come up at 3400 rpm, 80 degrees F amb air temp, 85 inlet temp, etc.

Would like to hear from anyone that has seen actual 6.5 engine dyno data on brake specific fuel consumption & what A/F ratios actually were.
 
28, 32, 50 psi? On a GM 6.x block?

Now there's a real buildup story I'd be interested in hearing the fabrication of... care to share the details?
 
JiFaire said:
28, 32, 50 psi? On a GM 6.x block?

Now there's a real buildup story I'd be interested in hearing the fabrication of... care to share the details?
Click to expand...

x2. Particularly on any block/foundation mods/enhancements - HardBlok, girdle, etc.

Guess such details should prolly go in your thread in the performance section though. I must apologize for hijacking Samyguy's thread a bit.
 
SmithvilleD,
Since you are running 18:1 what is the boost level you are running now? And since you dropped your static compression, how much boost do you think your engine would handle?
 
The most important thing to do if you are going to switch to an hx-35 is to do the little things to so your engine will safely handle the boost. Such as an intercooler, a good cleaning of the radiator, and maybe some arp headstuds or a rebuild to lower compression. If not you run the risk of blowing a head gasket like I did. I wil say I am prolly gonna miss the whistle of that turbo now that i've got an att but I feel this will be a safer set up since I dont have the money to go to the lower compression. I might have been able to get by with adding an intercooler but I wanna be on the safe side this time.
 
GJF said:
SmithvilleD,
Since you are running 18:1 what is the boost level you are running now? And since you dropped your static compression, how much boost do you think your engine would handle?
Click to expand...

My engine should actually be close to 19:1 as I used the Mahle 18:1 marine pistons, and the block took a 0.010" to get things straight & square.

For now, I'm just running my stock GM-4, and my Kennedy chip/stock PCM/vac pump/solenoid will maintain up to 15 psi, or a bit more. I haven't put an IC on yet, & I tend toward the conservative side, when considering how hard to push an engine design w/ less than stellar track record.

You only really know where the limit of an engine is, when that limit's been found by a failure. I mostly do this mechanical work/hobby because I enjoy it - parts breakage & the associated expense can really take a good deal of enjoyment out of the experience.

My plan, when I'm ready to mount my Holset HE351ve (VGT turbo) & IC, is to measure lots of parameters & gradually increase how far I'll dare push it. I'm rather cash strapped until I've secured new employment, so I'm spending more of the commodity I have now (time) in planning, than $ to push forward quickly.

Maybe get near/up to 20 psi, but I'm not certain. Depends. Want to see how things interact as I approach the fueling limits of my stock DS4 pump & Kennedy chip fueling tables. I have no need to pull 18K lbs at 70 mph up a 6% grade & after having built a few pretty fast cars, trying to hustle too much in my 6600 lb clumsy 4x4 just feels silly.

While I spent $ perhaps beyond practical rewards, my goal was to build an engine that should comfortably outlast the truck - unless I get too enthusiastic & break it by pushing too hard. I just don't see the 6.5 as a logical foundation to go for big power with. I'm all for those that want to push the 6.5 envelope, but have little interest in doing so w/ my own $ & time.
 
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