[Gregs DMAX1320]

Ok we have been having tuner wars over Quad, Diablo,TST, PPE, TTS, Van Akken, and Edge. Enough if were gonna make more power IMHO we need a different charger set up. Comming from Experience DO NOT DISCONNECT THE WASTEGATE HOSE!!! I have blown 2 turbo's trying to run the VA 225 Box nothing against Van Akken the power is Awesome! Just i have heard alot of mixxed things about the charger set up on the Dmax. I have heard 40PSI is max amount of boost you want to run I also heard from a well known Dmax Source 30PSI is pushing the outer limits. I know this much both of my chargers basically shattered the shaft in the turbo. My Dealership who very graciously warrantied my stuff both times said that the force applied to that shaft shoved the compressor wheel into the housing so hard it disentigrated sending the parts into the intercooler. Now I didnt take anything apart nor did I verify this with my own eyes. I know a few people are wanting to build Hybrids and so forth well lets get er DONE! I saw ATS's compound twin set up I dont care much for it because of having to run a separate oil pump for the charger and the fact the stock charger is still used. I think a big single would be ideal. a much larger exhaust housing and center shaft would be ideal ball bearing would be sweet but adds a little to the price. Th compound charger idea is great. Use a larger turbo than stock then feed a HT3B or H2 hell the cummins guys use it we can too gotta be creative as far as mounting goes underneath is ok but what if your truck isnt lifted. Better yet mine is 4X4 and is actually lowered 3 turns on the torsion bars to help with the dreaded 4X4 bounce. no tierods to date and helped my Buds 8100 powered HD with 200HP shot of Nitrous to keep from snaping the tierods like twigs. Let get the discussion going and get some chargers built and fabbed winter is upon us drag racing and pulling seasons are almost done time to think about winter projects.





Greg

 

[heartbeatcanada]

You da man. Took my thoughts right out of my light bulb going off over my head. 2 more pulls for me and then 8 months before play time again. Thats alot of time to get some shiznaz done. Later Jeremy

 

[Micheal Tomac]

lowering the t-bars gave me a 1/10 second better 60' time


I know of a couple companies working on a bigger turbo for the Duramax but nothing has been released yet...Edited by: mtomac

 

[Quadzilla]

Hopefully we will be testing our Beta version in about 2wks. It is not the garrett BB turbo either. We are waiting for a new version of the charger and new piece to make it a bolt on application. I think we wil be able to run 50+lbs through the charger we are going to use, and I will test it good before it is released. I am not sure that the head gaskets will hold? I know at 46lbs the valve cover start to seep a bit, but nothing major.


More than likely (not always) you are barking your turbo or it is "back slapping" itself. In otherwords you hammer it, it makes boost like mad and then you need to shut down, this puts a tremendous load on the turbo shaft. I have heard that people have broke them on acceleration, but that is rare from what we have seen. If you make a lot of boost ease out of the throttle and let the turbo spool down slowly, or as slow as you can. We have beat on ours pretty hard and run a lot of heat through it and so far it hasn't broke....knock on wood. I can't believe with our boost numbers that is hasn't imploded, but every now and then someone smiles upon you!

Our kist will come with a cast mount and a 4" downpipe when and if we release one. It looks like everything will come together, but I don't dare shoot my mouth off at this point.


I believe that this turbo will support over 700rwhp. All we can do is wait for parts and see hwo it comes together. As soon as I have a better feel I will release more info.





Just to answer some questions...


The turbo that we are going to use is being built. There are similar turbos on the market, but this one will be unique for the Dmax.


Yes I will have compressor maps available if we do this. I will also release drive pressure numbers, max boost numbers, and egt drop.


I have no idea what it is going to cost. It wil be less than ta twin turbo set up and more than a stock turbo...


If I missed anything let me know.





Quad

 

[RATDOC]

QUAD:


What about replacing the pathetic stock exhaust tubes that go from each head to the turbo????.........Those accordian bends can be restrictive due to the turbulence that they cause.


Tom

 

[Quadzilla]

I guess if you have the cash to do it, then go for it. I don't worry as much about exhaust turbulence with an aftermarket turbo. Generally the turbo causes a restriction which causes to much backpressure. With an aftermarket turbo this is greatly reduced. I suppose if you go that far you might as well hog the head out, if you do that you need bigger valves.....this list goes on and on, and you are right it might help, but is it realistic? I know some other people have tried it with other makes and the results have been minimal.


I think if you went bigger you might have a heat problem with the firewall. Also even if you go bigger you are still going to have some nasty bends to get it to fit. You could re-route it, but what a nightmare.


You make some, I'll buy them and test them!

Quad

 

[gsxr1216]

What about adding a decent blow off valve so when you cut the throttle it can dump out the blow off valve instead?

 

[Diesel Tech]

What about adding a decent blow off valve so when you cut the throttle it can dump out the blow off valve instead?

These are not typically needed on a diesel because you have no throttle plate to back the boost pressure up. When you release the throttle all you are doing is cutting back the fuel delivery and timing. This lowers the heat energy developed by the motor and the turbine slows on it's own.

 

[FirstDiesel]

If you don't need a blow off valve due to no throttle plate then why would the turbo be exploding when you let off the throttle hard??


I agree with your thinking but want to know why someone thinks the turbo has broken from letting off under boost??

 

[Diesel Tech]

FirstDiesel


Some people must be thinking of what happens in a gasoline vehicle

The only thing to slow down the turbine is the exhaust backpressure and that will not hurt it. Most if not all turbo failures are due to overspeed. If one looks at a compressor map there will be a line that starts at the bottom of the graph and extends upward and to the right. All the islands are drawen from this line to the right nothing to the left. This is known as the surge line. When you cross this line the compressor tries to reverse itself. When this happens a couple times to many it breaks the turbine shaft and the compressor wheel explodes when it hits the housing, or it will cause the nut holding the wheel inplace to come loose and again the compressor wheel explodes against the housing. All in all not a good thing to do. When the design was done on these engines the engineers make sure to leave some range away from the surge line. When raiseing the boost you push it closer and over in some cases. This is why we donot recommend running over 30 psi with a stock turbo, sure you can do it............. for awhile

 

[Quadzilla]

So making 30psi of boost and jumping off the throttle is fine right?

 

[FirstDiesel]

Well what happens if you let off at 30 psi?? The turbo starts to slow down, right??? No backpressure so how would it do any harm??


Now if you had an exhaust brake??

 

[Quadzilla]

FirstDiesel,





Try it and and see how many pieces you can come up with.


No backpressure? What do you think was driving 30psi? You ever heard the chugging sound coming out of your intake on deceleration? The is your trubo backslapping itself.








Quad

 

[FirstDiesel]

How, give me the explaination. All you keep sayiung is it's happening. I have a turbocharged sportscar. I intalled the kit myself. I understand the basics of turbo systems. In a gasser you slam the throttle shut the turbo gets hit with a pressure wave of pressurized air that reverses direction when it hits the closed throttle plate. This is why a gas system has a blowoff valve, to vent tthis wave.





There is no throttle plate in a diesel so where is this inverted pressure wave being created???

 

[Gregs DMAX1320]

the first turbo i nuked was on acceleration. the second was because of rapid deceleration. I was just I ha no back pressure due to the muffler was deleted and the airbox was cut out.





Quad keep us informed on the beta testing I am highly interested in buying a kit or developing my own turbo set up. I know this much a big selling point is ease of install and providing a down pipe for the allison trucks I have seen CPMAC's downpipe for the 6 speed trucks but I think a down pipe for the allison would be nice just have to reroute the dipstick tube for the trans.





Greg

 

[FirstDiesel]

Greg


Both situations could have been overspeed conditions caused by excessive boost, right??


Obviously the first one was not caused by backpressure, and with no muffler or throttle plate it is highly unlikely the 2nd was either.

 

[Quadzilla]

When you jump off the throttle is instantly releases the pressure on the exhaust side of the turbo. The intake side is designed to suck air. When you just release the throttle after making a lot of boost is causes the wheels to become unbalanced. It doesn't take much to warp a shaft. This very thing is one of the reasons the Dodge boys quit playing with the HX40. Yes you can overspeed a turbo, but it is much more common to see a turbo that has barked.


As far as you gasser. Typically they are much much smaller and have less pressure on them because they need a smaller valoume of air and you are feeding them a smaller amount of fuel. UNless of course you have like a T6 or something?


One of the things that will be important in an aftermarket turbo will be longevity. It is one thing to make boost and reduce egt's, but to make them tough is why it is hard.

 

[FirstDiesel]

A diesel is just a big air pump, right? That's why to develop any real grade braking you need to have an exhaust brake to shut off the air flow. So if you flow air all the time how do you reduce the pressure on the exhaust side? You stop adding fuel the engine slows down and the turbo spins down. Nothing happens like a immediate snap shut of a throttle plate.

 

[a64pilot]

Quad,


This backslapping your talking about is it compressor stall? I understand what your saying about unbalancing the wheels, the instant after the fuel is cut off temps drop and exh. pressure drops so the driving force is cut off from the hot end of the turbo, but inertia continues to keep boost up for an instant or so.


The only thing I can come up with on what could cause the turbo to bark is compressor stall and the associated air flow reversal from a stall. Does boost spike for just a second after letting off from a hard pull?

 

[CPMac]

A64pilot boost doesn't spike after you let off. I can drive around and pull around 40psi then let off and clutch it at the same time. It will (bark) because the engine rpm slows down fast enough that it won't take the volume of air the turbo is flowing so therefore it has to reverse some of the air.