Hx40 weak link.

[RonA]

It seems that most people like their Hx40 size turbos. But the possibility of a shaft failure hangs over it. Has anyone looked into having a better shaft made for it. The next step up in a turbo costs $600 more. I've only seem pictures of them but as a machinist it did not look like something that would be impossible to have duplicated. Has the company that makes the turbo done any upgrading on the shaft design in the last 15 years. If not it may be that there are now better materials for this part. Just thought I'd ask.

RonA

 

[Jdimig]

from what i understand, the non modified hx40 turbos are not very reliable since they use the hx35 shaft with a larger compressor wheel. because of this, when you let off the accelerator pedal at high boost, all that boost wants to spin the turbo backwards, and because the hx40 has the same shaft size, but lager wheel, when this condition known as turbo bark, it creates alot more stress on the shaft and eventually breaks that shaft. now alot of companies modify this turbo, most noitably piers diesel, does extensive modificatons. i don't know if the shaft is altered when the modifcations happen, but from what ive read, pdr hx40 turbos are alot more reliable than just a stock hx40 turbo. vist piers website, they have a complete line of turbos and list what they do to the turbos as far as modificatons

 

[Forrest Nearing]

the shaft is not altered... if you don't abuse them, they'll hold up...



I've got a stock 60mm 6 blade HX40-16w... 370's and #6 forward. 42psi. I don't abuse it, but I see no reason why it won't last a long time.



I do let off at max boost every now and again, but I try to ease out of the throttle and not send all that boost back through the compressor.



after selling my stock turbo, I've got ~$250 in it. I'm happy.



Forrest

 

[Bob Wagner]

most hx40's are being wastegated in the 20's from the various vendors

 

[Bob4x4]

Originally posted by Bob Wagner

most hx40's are being wastegated in the 20's from the various vendors

Who is marketing an HX-40 in the 20's?



Bob

 

[Bob Wagner]

you are a tech so you should know, and its not marketing ... .

 

[Diesel Freak]

Bob, I am assuming that is initial opening of the wastgate? This does not mean the turbo is wastgated to 20 PSI.



Mine is set MUCH lower than when I bought it. The Valve is nothing but a flapper now... still hitting over 40 psi

 

[Diesel Freak]

As previously stated HX35, and HX40 shafts are the exact same material and size. The Cartriges are even the same. If you want to make a HX40 live at over 450 HP, roll into and out of the fuel. If you zing it from 0 to 45 psi and back you are asking for trouble.



The majority of all "modified" HX40s out there really are not modified much. They have a been ballanced to a tighter degree, and the bearings allow more oil to flow past them. That is about it. Some have the housings ported for faster spool also.

 

[RonA]

I just wonder if any of the places that work on turbos have looked into a possible shaft upgrade. May not be possible. But if it was there are alot of people who would benefit from it.

RonA

 

[BPINE]

I think the problem is that the turbine wheel is part of the shaft so I don't think it is all that easy. I'm not sure how you would get the wheel off the old shaft and on the new one .

 

[CATCRACKER]

this thread makes me question the massive $$$ a modded hx40 costs. if it spools just a little faster to me who is not racing just wants a powerful truck for as cheap as i can this may be the route like forrest find a parts bin 40

 

[BPonci]

The shaft to turbine wheel is fusion welded. If you can figure out how to seperate and reweld them (to make it last) you will have something there.

 

[RHARVEY]

Piers says to set the gate somewhere around 38lbs. Not sure where or who says set them in the 20s. I wonder if the 40 would flow more air than my PDR HX35/16??? Piers told me once that it might drop my egts 75-100*, but he also said timing would help and the right foot can do the trick also:{ :{ :{





Rick

 

[RonA]

I wonder if it would be possible to purchase a shaft with the wheel attached. By fusion weld do you mean fusion with a tig welder and no filler rod or do you mean a beam process where the entire contact surface of the two parts is fused together? Sorry for all the questions but I don't know squat about diesel stuff.



RonA

 

[Forrest Nearing]

the problem with going with a larger shaft size is that it generally requires a different center section, and all of a sudden, you're no longer dealing with an HX40! and, in-turn, affordability starts to fly out the window...



I like my HX40 fine, and at the time I was pretty close to flat broke, so it worked out for me, but originally I had set out to build a hybrid using a 16w turbine housing... well, we didn't have an HX35 turbine housing, but we DID have a 16w HX40 turbine housing... so I said screw it and grabbed an HX40 turbine wheel off the shelf, and ended up just building an HX40. I wanted the hybrid, and if I would have had the money, I would have just thrown down on a dodgezilla hybrid. a wastegated 16cm HX35 turbine housing will flow a decent amount of power and you don't have to worry as much about the turbine shaft.



like I said, I'm happy w/ my HX40 for the amount I've got wrapped up in it, but when I use it as a top turbo for my twins, it's getting an HX35 hot side for strength/reliability issues.



Forrest

 

[bgilbert]

Anyone know what size exhaust housing came factory with the hx40 on the C-series Cummins? I have a very big tractor trailer junk yard in town, and wondered if it would be worth buying one off a wrecked truck that had the C-series. Used how much anyone know? Thanks.

 

[BPonci]

Beam style process.