TST and turbo

[LThurman]

Loving the CR but need to keep the turbo going.



With the stock waste-gate I can hit 31 lbs on 4/4 in just a few seconds. As i understand it, letting off the go pedal with that much boost is bad for the stock turbo. As I understand it there is back pressure(sorry if wrong term) that works against the compressor side that slows the shaft too rapidly thus causing bad things. Can someone explain how this happens or why? Also wondering if the back pressure will be higher that the boost made? If it is could a pop off valve help the issue to bleed off that pressure and keep it from building against the turbo's compressor side thus reducing the stress on the shaft.





Thanx



Great site and Great people!

 

[jwilliams3]

31psi of boost will not hurt anything.

Your other question:

Basically when you create boost with your turbo that is air pressure that is not yet consumed by your engine.

When you are under boost you are usually consuming the boost with a constant or increasing rate of RPM.

When you are making say 31psi@2500rpm and then suddenly let off to say 1300rpm. Your compressor is no longer being driven as hard as when it created that boost. The pressure becomes greater on the cold side causing a rapid slow down of the impeller shaft.

Sometimes you hear a bark, sometimes it just breaks.

Most of the time everything is OK though...



--Justin

 

[SRadke]

At one time I saw a blow off valve made by BD for just that purpose. You may find it with a search of the archives. It was designed around high HP single turbo guys running over 40 psi boost. 31 psi should be fine with your stock turbo.



-Scott

 

[Pirate4x4]

Im really suprised there aren't more pop off valve options for us diesel guys. Seems like it would be soooo much easier on the turbos (from a guy who's fragged his stock turbo).

 

[LThurman]

Thanx for the feed back. I currently am runing the stock boost elbow to keep things in check for now. So will see how it goes. Me and a buddy and are thinking about make a BOV of some type. Would putting in the intake horn do an good or would it need to be closer to the turbo?

 

[JPitha]

the boost elbow that tst sends you is adjustable. I've run 24 up to 44 lbs of boost at 4/4. right now, I've got it set to run about 32lbs at WOT. No problems so far, Just let the boost go down a Little before you shift and you won't get the bark or the broken shaft. JP

 

[Wyatt 1]

Guys I am new to the diesel speed, power kinda stuff, what is 4/4?

 

[bpenrod]

The HP/TQ setting on the TST box they are running.

 

[Wyatt 1]

makes sense, thanks

 

[Big MAK]

An option to not abuse the stock turbo as much is to run a lower torque number. The boost doesn't come on as fast but will still build up really nice if you keep your foot in it. I have new turbos (twins!) coming so I've been pushing the envelope with the stock turbo to see what would happen. I've been running 5/3 a couple weeks and it runs great. Running 5/5 it was just spooling too fast for my tastes -- worrying about the turbo -- I'd rather it didn't blow up since I still need to run it a couple months and don't want to cancel my vacation coming up (need the truck to tow the camper).



Mark Chapple says it in the paperwork and it's true; that lower number is the one that's harder on stuff. It's great for the low end take-off torque but you still get a great power experience running a lower torque number then HP number and will barely notice the difference running empty.

 

[mattymac]

Originally posted by Big MAK





Mark Chapple says it in the paperwork and it's true; that lower number is the one that's harder on stuff. It's great for the low end take-off torque but you still get a great power experience running a lower torque number then HP number and will barely notice the difference running empty.

When I run mine on 5/9 it smokes and comes on about the same as 9/5. 9/9 is the whoa setting, If I only had a clutch and a turbo I bet it would be a diffrent machine! Soon, Very very soon!

 

[OT-OF-HERE!!]

Ok, I'll say it,...You lost me with that last paragraph

Originally posted by Big MAK

An option to not abuse the stock turbo as much is to run a lower torque number. The boost doesn't come on as fast but will still build up really nice if you keep your foot in it. I have new turbos (twins!) coming so I've been pushing the envelope with the stock turbo to see what would happen. I've been running 5/3 a couple weeks and it runs great. Running 5/5 it was just spooling too fast for my tastes -- worrying about the turbo -- I'd rather it didn't blow up since I still need to run it a couple months and don't want to cancel my vacation coming up (need the truck to tow the camper).



Mark Chapple says it in the paperwork and it's true; that lower number is the one that's harder on stuff. It's great for the low end take-off torque but you still get a great power experience running a lower torque number then HP number and will barely notice the difference running empty.

No comprehendo. Starting with "it's true;... ... . " That lower number is the one that's harder on stuff???? Pls explain. Do you mean that a lower dialup number 1, 2, etc is harder than 6,7 etc. That doesn't make sense to me if that is what you were saying. Help.

 

[GWoody]

I think what they are talking about is on the tst units display the top number is the timing, horsepower, and the bottom one, the lower one on the display, is the duration also refered to as the torque setting.

 

[OT-OF-HERE!!]

That makes sense,.....

if that's what he's saying. Appreciate the clarification.

 

[ThomasLawrence]

Yes - the torque enhancement number is the "parts-killer". That controls how much additional fueling is delivered in the lower RPM ranges, specifically between 1200 and 1600RPM. The additional fueling from the TE setting starts adding more fuel at 800RPM, reaching it's peak fueling at 1200RPM, maintaining this peak fueling to 1600RPM, then tapering off down to 0 additional fuel at 2900RPM.



Contrast this with the power number, which begins additional fueling at 1200RPM, increasing up to it's peak value at 2900RPM.



You can see from this that with a TE setting of 9, you're fueling very hard at 1200RPM, and EXTREMELY hard at 1600RPM (because here you're getting additional fuel from both the TE and power fuel curves).



As far as the "timing/duration"... no, the power level is not exclusively timing, and the torque is not exclusively duration. With the power setting on '1', yes, you get only advanced timing and no additional fuel. However, on any other setting, timing and duration are altered to deliver the desired amount of fuel, which is determined by the combination of the two additional fuel curves described above.



Hope that clarifies things...



-Tom

 

[desertbull]

Pop Off Valves... Jenna Jameson?? Does she have pop-off valves on her turbo?



Ahhhhhhhhhhhh...



Next time you see Tom Geviss... Nelson's spotter... . he'll build you a turbo w/ pop off valves... Geviss owns a company that builds turbos... mostly to big rigs and comp rigs. . but he'll build ya' something cool.



DB:--)

 

[Pirate4x4]

Originally posted by desertbull

Pop Off Valves... Jenna Jameson?? Does she have pop-off valves on her turbo?

Don't you have a satellite to play with or something?

 

[mberry]

Originally posted by Pirate4x4

Don't you have a satellite to play with or something?

Is that what the kids are calling it these days?