HX-35 holset

[Michaeljp86]

How high psi will a 6.2 or 6.5 hold up to? I thought 40 would blow a head off. I also though 18:1 pistons was the lowest you can get unless you have pistons machined. Seems like if you lowered the compression to much you would have starting problems.

 

[6.2 turbo]

Your heads wont blow off, but you will blow the head gaskets if they don't have a solid core. This is an experimental motor. A hx35 with a waste gate like the gm1 would be near perfect as it is very large and operated by back pressure . My pistons are custom ground.

 

[Samyguy]

could'nt you port out the waste gate hole, or some thing like that?
To control super boost

 

[Acesneights1]

25 is probably max safe boost,60 was maxing the turbo ,all turbos will peak at a certain psi when over fueled, I estimate my compression at 16 -1. Boost is also directly related to fueling you need lots of fuel for boost that high.

Yeah that would be my question. How are you getting that much fuel to a 6.2. Short of a Mythical coveted DB4 I would wonder can a DB2 or DS4 put out enough fuel ? I had a long talk with Peninsualr Diesel about using a DB4 on a truck engine. They did not recommend it for non marine applications.

 

[HighSierra86]

Yes, on the manual tranny trucks (especially), you can physically feel things "tighten" up as the comp & turbine approach their limits/choke points.

Vibration builds above 2500 rpm, almost seems as if you can feel the cylinder exh puffs struggling to escape the cylinder :smile5:

I'm in no way saying the HX-35 is ideal for a 6.5 if you goals go beyond say ~ 275 hp. Because at that point, you're heading beyond what it can do well. But practically speaking, what % of 6.5 enthusiasts actually intend to go past 275 hp? And it looks to traverse nicely across the meat of it's comp efficiency (bit below it's ideal PR (boost) efficiency) where a lot of 6.5's will be doing a big chunk of their work.

Certainly some go past 275 hp. Lots don't.

For the more conservative goals, the HX-35's low cost availability & T3/easy adaptability to fit to the 6.5, make it worthy of consideration.

Regardless of what turbo, I think there might well be turbine flow/efficiency gains if we could do a more reasonable bend from where the stock 6.5 turbo location puts the turbine outlet.

I've gotten pictures from a few forum go-ers w/ body lifts to see what impact that might have on turbine outlet routing options.

X2 on the manual tranny trucks. You can deff notice a difference at higher RPMS. There is almost no point in even going past say 2300RPMS. And thats with a 4inch exhaust. Now my 1500 with the auto trans is a totally different story. Higher RPM's seem to be smoother and more productive in producing additional power.

And your mention of the average 6.5 user, this is why the ATT works so well for the majority of users with stock compression ratios.

Now im gonna be going the 18:1 route on my rebuild, so im curious to see what the advantages to running a holset is going to give me. The low cost is deff an advantage from the start. Now looking at the holset exhaust outlet/housing........does it set the downpipe closer to the cab than a stock GM-X turbo??

 

[Michaeljp86]

Yeah that would be my question. How are you getting that much fuel to a 6.2. Short of a Mythical coveted DB4 I would wonder can a DB2 or DS4 put out enough fuel ? I had a long talk with Peninsualr Diesel about using a DB4 on a truck engine. They did not recommend it for non marine applications.

That one guy in the netherlands has that pulling tractor with a 6.5 in it and has 2 injection pumps. I would think getting more fuel wouldnt be a big problem but keeping it cool would. You would probably want a radiator out of a 3500hd but then you would have to figure out how to make room for it.

 

[SmithvilleD]

Chicago TDP's album has some good pics of the downpipe he fab'd.

For the HX-35W's, a common approach is to buy one of the endplates sold on ebay made to easily allow welding in a 3" pipe.

http://cgi.ebay.com/ebaymotors/Hols...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

The degree of bend necessary on the turbine exit is similarly harsh to the factory turbo's as they're in pretty much the same location. That location & plumbing routing makes for some compromises w/ factory & alternate turbo exit plumbing.

My VGT project turbo has a 3.5" outlet which makes the routing even more challenging. As that turbo comes mounted on the side of the I6 6.7 Cummins, they use a beatifully smooth tapered diffuser/adaptor/gradual bend btwn the turbine outlet, out to the 4" exh size. Can't see a way to use that adaptor on my 6.5 fitment, but it's such a nicely designed part, I put a pic of it in my album along w/ the other turbo pics.

 

[6.2 turbo]

Wonder what the ATT would do with extreme fuel. A db4 on a 6.2 or 6.5 truck shouldn't be a myth.

 

[Michaeljp86]

Wonder what the ATT would do with extreme fuel. A db4 on a 6.2 or 6.5 truck shouldn't be a myth.

I thought the ATT would put out about 15psi max and it doesnt have a waste gate. It seems like the only way to get more pressure would be more fuel.

Isnt there one or 2 guys on here with a db4 pump on there truck? Maybe it was at the place.

 

[6.2 turbo]

Im planning on building my own db4 ,I will put updates in my thread and maybe some pics. You could port the waste gate a little on the hx 35, but the flapper is also small, you could try a 14 or 16 cm housing but you probably would hate the lag, a hx 40 exhaust turbine with matching 14cm waste gate housing might work, I dont know . I takes money to experiment with turbos , although you can by cheap ones on ebay, the last one I took the gamble on a rebuildable hx 40, and the shaft was snapped, so be careful.

 

[Michaeljp86]

Im planning on building my own db4 ,I will put updates in my thread and maybe some pics.

Dont injection pumps need to be calibrated? I know Ive heard of tractor puller guys building their own pumps.

 

[6.2 turbo]

My pumps are beyond the calibrations, a pump shop would calibrate a rebuilt pump on a pump stand to what ever fuel is required.

 

[Acesneights1]

The way it was explained to me was the DB4 was a marine appliaction IP and it was too touchy on throttle respone and advance for a driver. It was made more for steady throttle not driving. They didn't say it couldn't be done , just that drivablity might not be what I'd want for a daily driver.

 

[Slim Shady]

I thought the ATT would put out about 15psi max and it doesnt have a waste gate. It seems like the only way to get more pressure would be more fuel.

Isnt there one or 2 guys on here with a db4 pump on there truck? Maybe it was at the place.

I have had 19 psi runs under a load with my ATT. I know with more fuel you can make more boost how high we won't know unless 635 tells us how it boosted with propane.

 

[NVW]

I've seen 18 psi unloaded in OD with the conv. locked. I backed off as soon as I saw that, I think it was still climbing.

 

[635]

Just got my propane system back from the shop today. Had to make sure it was calibrated correctly, which it wasn't, it was set with way to much propane. Now it will start drawing at 1 pound of boost, but with just a whif of propane. At 2 pounds of boost the amount of propane is .5 CFM and then on up to 2CFM at 20 pounds of boost. Give me a few days to get this done. It is now monsoon season here and the dry spells are very far and few.

The Heath/Snow WMI boost gauge, today, showed 18.6 pounds of boost. It is cold here with great racing air! My 'A' pillar gauge only goes to 15.

Jamie, at Diesel Depot, says my engine will take 23 pounds of boost easily, if not more! So we will see!

 

[Slim Shady]

I've seen 18 psi unloaded in OD with the conv. locked. I backed off as soon as I saw that, I think it was still climbing.

Most people won't be at those levels for long you will be going way to fast,you also won't have excessive drive pressure on the turbine section. Ther drive pressures will be lower than the gm turbo.

 

[Slim Shady]

Just got my propane system back from the shop today. Had to make sure it was calibrated correctly, which it wasn't, it was set with way to much propane. Now it will start drawing at 1 pound of boost, but with just a whif of propane. At 2 pounds of boost the amount of propane is .5 CFM and then on up to 2CFM at 20 pounds of boost. Give me a few days to get this done. It is now monsoon season here and the dry spells are very far and few.

The Heath/Snow WMI boost gauge, today, showed 18.6 pounds of boost. It is cold here with great racing air! My 'A' pillar gauge only goes to 15.

Jamie, at Diesel Depot, says my engine will take 23 pounds of boost easily, if not more! So we will see!

I knew we would be getting into some interesting territory with turbos and more fuel. Going to be a good year for the 6.2 / 6.5

 

[SmithvilleD]

Im planning on building my own db4 ,I will put updates in my thread and maybe some pics. You could port the waste gate a little on the hx 35, but the flapper is also small, you could try a 14 or 16 cm housing but you probably would hate the lag, a hx 40 exhaust turbine with matching 14cm waste gate housing might work, I dont know . I takes money to experiment with turbos , although you can by cheap ones on ebay, the last one I took the gamble on a rebuildable hx 40, and the shaft was snapped, so be careful.

There are a number of the various internal 'gated & non-wastegated turbine housing options shown in the Gillette Diesel link earlier in this thread.

The wider mass airflow (hp) range you try to cover, to more compromises you'll make regarding turbine sizing & drive pressure.

Sized to peak mass airflow, an idealized non-wastegated turbo will typically be most efficient at that point; its compromise will be below peak mass airflow.

As a generality, any wastegated turbo designed to operate up to the same peak mass airflow as above, will have a somewhat smaller turbine section, so it will spool earlier. This design's compromise is, even w/ the same compressor section (sized for the same peak mass airflow), drive pressure will typically be higher in proportion to the difference in turbine sizing.

Neither 'gated or non-'gated design is fundamentally superior. But they can (& often are) tailored for somewhat different performance goals.

Modern materials & computational fluid dynamics modeling keeps improving blade/wheel aerodynamics/efficiency, which continues to improve turbo's.

This can result in a better turbo for a specific application. And in some cases, a given turbo works OK for a broader range of applications than before, so they may now sell 3 turbos to cover a mass airflow range where they formerly needed 4 different turbos.

 

[SmithvilleD]

Just got my propane system back from the shop today. Had to make sure it was calibrated correctly, which it wasn't, it was set with way to much propane. Now it will start drawing at 1 pound of boost, but with just a whif of propane. At 2 pounds of boost the amount of propane is .5 CFM and then on up to 2CFM at 20 pounds of boost. Give me a few days to get this done. It is now monsoon season here and the dry spells are very far and few.

The Heath/Snow WMI boost gauge, today, showed 18.6 pounds of boost. It is cold here with great racing air! My 'A' pillar gauge only goes to 15.

Jamie, at Diesel Depot, says my engine will take 23 pounds of boost easily, if not more! So we will see!

Did you end up putting an external wastegate in?