Mountaineer

Just like the title, mainly would like to find out how you killed it and if its death was do to boost pressures being in excess of 40+ psi.

HOHN

I've never had one, but a Cheyenne CTD guy lost TWO 40s-- even a modified one.(PDR). He's running a hybrid S300 now with no problems.

His boost levels were over 40. (12v)

You'd think with the B-W turbos all but taking over the CTD market, that a real bargain could be had on a Super 40 or something.

JH

Mountaineer

Justin, the reason I ask is because I rode in in a 12v over the weekend that was running one and the guy has made just under 500 with it and has had great success with it while keeping it gated under 40lbs. He was hammering it, burnouts and stuff and the truck ran great. He thinks most of them die due to over boosting, which I don't doubt.

schoust

Hmm I bet I know who that was,wouldn't happen to be Mcmopar would it? I'm not to sure what breaks them but I know this I did not like them at all! Some do,but there are much better alternitives out there.......

Mountaineer

What are you a psychic or something?

HOHN

I think it's not only over boosting, but also the violent changes in shaft speed associated with hard shifts or barking the turbo.

Now the guy I know who grenaded these 40s was a 5 speed 12V truck, but he was running a pretty good bit of fuel-- 530+hp at the local dyno events if I remember right.

I know that a 40 can make 500-- it's been done many times. But to live, I think it should be limited to 450-475 max. IMO, if you can find a way to increase the engine breathing (cam, ported head, etc), then a 40 can live well at much higher power levels.

The problem is that the turbos are designed for more flow at lowish boost levels. They are NOT capable of handling the stresses of elevated boost levels. It takes a lot less boost (at the same flow) to burn fuel on a C series 8.3 than a 5.9 B engine. With 29% less displacment, it takes MORE than 30% more pressure to get the same airflow into the smaller 5.9L engine.

Now in a twin turbo application where the turbo doesn't have to deal with high pressure ratios, I'd expect an HX40 to live almost forever. Indeed, we RARELY hear about 40 failures when used on top in twin sets. This is because 1) the operating PR is much lower, and 2) any changes in shaft speed happen much more slowly, and hence the turbos have less shaft stress.

Justin

cumminsdriver635

I think ill try an HX40 whenever i can get my hands on one. I personally think all the $1400-$1800 Schwitzers are overpriced pretty good. Im sure they spool a little better, and will handle a little more boost, but I think a hx40 gated at 38psi couldnt be too bad. Its funny the 40's use to be all the rage.

Eric

HOHN

So did Diesel Dynamics........

can i get a "touché"?



JH

smokin06

the HX40's are pretty good turbos ran one with a 18 housing it grenaded at about 62psi of boost, it totally disentigrated it, but i ran it for over a year at 52 to 55psi, no problems. I have a s300 and love it really strong turbo

1320

Its not the boost pressure. These things are made to compress air. The material is fully capable of 10 times the pressure. The thing that kills turbos, is
1. to much wheel speed (over speeding) ussually the compressor wheel comes apart.
2. bad balance
3. bad oil delivery.

Mountaineer

Well the above cases seem to prove the theory. Either excess psi, or overspeeding.

To much wheel speed. Isn't there some correlation with boost pressure.
I kind of figured that its hard to build 62 pounds out of that single with out over speeding it.

smokin06

yeah boost is overspeeding, thats why if you dont wastegate an s300 to 50psi when you slam the nitrous to it and it jumsp your boost pressure to 80psi it will overspeed it, i feel really safe with a 40 at 55psi should handle that pretty easy.

pmtg

wheel speed and boost correlate but other factors play into it...such as air density...and PR covers that.

Cheyenne, Wyoming is ~ 6000ft ASL...

Pomeroy, Ohio is ~570 feet ASL...
+40psi at 6000 feet is going to have lots of wheel speed.
62psi at 570 feet is going to have lots of wheel speed.

***of course, this is assuming these boost readings where taken in the area i associated the thread with***

i couldnt tell you which is more severe...just something to remember to think about...

schoust

Ok Cummins Driver go ahead and try one but if you like the way your stocker runs your gona hate the way a 40 lights. In my opinion they are for the Big cam Cummins and not our engines. They can be decent from what I have heard when modified by the likes of Piers. S300 or some derivitive of IMHO............

cumminsdriver635

For $450 or so for a used one how can you go wrong? My cousin ran a Sled Puller 68 charger on his pulling truck for a while. It spooled good, and ran pretty good down the track in 2nd gear. We put an HX55 he picked up on it just to try it out, and it spools a little slower, but the truck will now run 3rd gear down the track where the sp68 would kill out. Both running 50psi.

I personally dont have $1600 to blow on a charger at the time. I have never seen any 62mm schwitzer make much at all over 500hp on the dyno on a 12 valve. An hx40 will do that too.

Im not saying a 40 is the best charger and for everyone to go and buy one, but I think for the money you wont find anything better if you dont abuse it.

Eric