Which is better-diabled wastegate or boost elbow

[Jetpilot]

Which is better-disabled wastegate or boost elbow

Ok here is a question. Which would be better disabling the wastegate (turnbuckle method) or using a boost elbow (like supplied with an EZ)?



It appears to me you would get more boost with the turnbuckle method. But, could it be too much boost? What would be the advantages and disadvantages to both methods? I would be doing this to a HX35 turbo.



Thanks for your replies... .



Doug S.

 

[Bob Wagner]

HX 35 I would use the supplied boost elbow (rubber tube)



HY35 you have no other easy choice but to disable the wastegate

(hardlined)



The debate goes on... ... ... .

 

[High Voltage]

I would use the boost elbow with the hx,as for myself i have the hy(for now)and that little guy sure does spin(30+psi)with the turnbuckle on Time will tell.

Hutch... .

 

[tom sweeney]

i have the HX35 with boost elbow... boost is 30-31 lbs... tom

 

[Jetpilot]

I see from the above posts that the boost elbow seems to be the prefered choice with the HX35. Now my question is why? Right now I am getting 40+ PSI boost with an HY35 until above 2800 RPM, then it drops down to 32-35 PSI. With our diesels isn't more boost = to less EGT's? If this is true then using the turnbuckle would ensure max boost from a wastegated turbo.



I suppose there is a point that you could create too much boost, but I am doubtful this would happen with an HX35. Maybe I am wrong, and that is the reason for the post. Please those of you with more knowledge than I please explain what I am missing . If we can create 40 PSI with the smaller turbos why are people opting for an HX40 and setting the wastgate for 40 PSI? Or am I incorrect in thinking we can make 40 PSI to max RPM with the HX35



Thanks,



Doug S.

 

[Guest00]

Unless you can massage the hose and oem clamp off the old elbow you will be waving a red flag in front of every DC mechanic that is getting bonus point toward the Hawaii vacation give away for voiding warranty's.

 

[CCahill]

Jetpilot,

The thing with the HY is this... . the tiny little 9cm can provide a lot of pressure but no volumn... so when you are seeing 40# of boost, you are really not moving that much air. Thats why the heavy fuelers go to the bigger turbos. They give more air at the same pressure..... The little HY is not efficient past about 25#... My $. 02



Colin

 

[JR2]

I was told that the Hy is out of its range at 32 psi... ... . I can get mine to hit 40 also, but my egt still go throught the roof. I am looking for a new turbo... either an HX40 or some hybrid HX35.

 

[Jetpilot]

Now I am really confused... . How can one turbo put out 40 PSI of boost but a smaller volume of air? I can see where a larger turbo would move a larger volume of air at a lower turbo RPM, but 40 PSI boost through the same plumbing should be the same volume .



As for efficeincy, I assume (correct me if I am wrong) that the smaller turbo starts creating more heat than cooling at some point? If this is correct I can see why a larger turbo would cool better on the top end... . As with any volume of air it will get hotter when it is compressed. So everything else equal I really don't see the difference except for the efficeincy and I am still not sure I have this correct.



So guys, please chime in and help me to understand the mysteries of our turbos .



Thanks,



Doug S.

 

[CCahill]

jetpilot,

Take a 1/4 in. pipe and force liquid or air thru it at 40 psi, lets say... ... ... ... ... you can only get so much volumn of product comin' out... ... now take a 1 in. pipe or orifice and pass the same 40 psi thru it and now you have much more volumn comin' thru... . In the case of water, it s hard to measure the temp diff , but the smaller pipe fluid is warmer..... Same thing with your turbo... you can only get so much air out of it . . no matter how much pressure you get... ... ... .





Colin

 

[Jetpilot]

CCahill,



You are correct with your explanation but..... The pipes where the pressure is taken are the same size. The housing is smaller but the rest of the system is the same (from turbo to intake). The boost pressure reading is coming from the intake not inside the turbo. This being the case I don't see the advantage.



I am not saying you are incorrect, just stating based on this I don't see a volume difference .



Doug S.

 

[Jeepthing]

I will have to agree with Jet

 

[Bad340fish]

I kind of ran into the same misunderstanding when I uprgraded to a larger turbo on my 87 Conquest. With the larger turbo I was able to run 4psi(4psi makes ALOT more difference on 2. 6 gasser motor than on our cummins) less and get much better performance. I really couldn't understand how two different turbos can flow more or less air at the same PSI. In fact I still don't understand it lol. Didn't really bother me though. . the rear tires new the difference

 

[B. Gill]

jet pilot, i think this is what is happening,lets take a volume figure for example that is the max the turbo can put out,say 100 cu. in. at 2000 rpm for example the maximum the engine can let pass thru is 75 cu. in, so as a result there is a higher pressure built up, when engine runs at high RPM it lets more air pass thru it which in your case could be close to or equal to the max that turbo can produce,thus that pressure drops. i could be wrong and if so please do correct me.

my 2 cents

bob

 

[Jetpilot]

Bob,



The way you are looking at this is the same as me... . I can see why a larger turbo would be better if one could not maintain max boost, but if someone can maintain max boost what would be the advantage of the larger turbo? Seems like you would be trading the dreaded turbo lag for nothing.



As for the original question on disabling the wastegate. The guys at Poweredge said to disable the wastgate unless boost goes above 40 PSI, and in this case go with the elbow. So this is what I did when I swapped my HY35 for a HX35 today. Max boost is around 38-40 PSI and I can hold it till a higher RPM. Sure do love the DD2's with the PE-Comp .



Doug S.

 

[JR2]

Jetpilot - what is the max egt you get with your new turbo. I have (or will have) almost the exact setup as you and wonder what to expect.

I am currently debating the HX35 vs HX40 question in my mind.

 

[Jetpilot]

JR2,



As far as my setup and egt's let me first say that I love it so far ! Now as for the egt's, on level 1 I don't have any problems with egt's. The highest I have seen so far is around 900 going uphill with my foot in it for quite a while... . But, on level 5 you better watch out egt's approach 1200 REAL FAST .



As for going with a HX40, I don't think I am..... I can go as fast as I want with the HX35. I suppose the HX40 would help for really long periods of WOT but I don't keep my foot on the accelerator for any longer than the HX35 can keep me cool.



If you have any other questions please let me know. If you want a second opinion ask viperacer, he was over this week and took my truck for a spin ..... Now he has ordered almost the same setup



Doug S.

 

[ReggieRam]

a lesson in aerodynamics

Just some thoughts on why your turbo may be able to pass more air at 32# boost than it can at 40#, thereby being more efficient: I'm going to base my info on hydraulics, which I know a little something about, but I'd imagine that it would translate to aerodynamics fairly well. When you create too much pressure through a hose, you create a couple of problems: 1) friction is created, which equals heat. If EGT's are a problem, that kind of friction certainly won't help the problem, but exacerbate it. If you ever get a chance, walk up and touch a firehose that has been flowing a high pressure of water through it for a long time. You'd be surprised at how hot it will be! 2) friction causes a Correolis Effect, meaning that the air will not flow in a straight line, but rather circle around causing an eddy effect along the sides of the hose it flows through, greatly reducing the amount of air flowing through it at high pressure. There are ways to reduce this problem involving various pipes to straighten the airflow, but I doubt if anyone makes them for this application (do I smell a business opportunity here?). Put those two things together, and it seems to me that running too much boost through your turbo may be a bad idea.



Every cylinder has a maximum pressure and volume that can easily pass through them before these problems arise. That is why the guys running the turbos with bigger inlets get more bang at lower boost. The problem here is that it takes a while for them to build up boost (read dreaded turbo lag). I guess that the only way to have it all is to run really freaking huge injectors, a 1/2" fuel line, two turbos in sequence, and maybe some propane thrown in for good measure. Just don't forget to shell out the extra cash to get some really cool flames painted on the side of your truck!



I hope this info is not only correct, but helps. Like I said, my knowledge comes from a rudimentary knowledge of hydraulics. Maybe we can get a phycisist in here to give us a hand.

 

[JR2]

ReggieRam -

I think that is the problem I have now. I can hit 1500 at WOT with all the boxes maxed out. I see others on here say they can not get to 1200 with the same set up. I am trying to figure out how to adjust the opening pressure of my HY turbo to limit it to about 30lbs of boost and see if that makes any difference. Then I am going to install a new turbo (HX40 or Piers or ??) so that I can add the DD2's.

 

[Lug-nut]

While you can get similar boost pressures from both turbos, you must realize that the smaller turbo is turning much faster to achieve these boost levels. This in turn creates more heat. As I understand it, the HY35 is getting well beyond its design curve when running over 30psi on these engines. The larger turbo turns at a more leisurely pace to achieve similar boost levels, and thus creates less heat in the process (it is operating within its design parameters). I am not an expert on these things so don't take my word as gospel. Ted J. posted a good explanation of this either here or in the products forum under the heading of "tell me why I need a wastegate. https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=19216 The gist if it is that you DO need a wastegate, and pushing the smaller turbo too hard WILL create high air temps (read excessive EGT).



One further note of caution:



While I have not heard of it happening here, turning a turbo well beyond its design limits CAN CAUSE A CATASTROPHIC FAILURE (COMPRESSOR EXPLOSION). I have witnessed this on maxed out gassers, and it is something to behold. There is much more potential energy in one of those little compressor wheels than you would believe, and when it lets go you do not want to be around. The damage caused is impressive. You do not want to experience this on your beloved Ram.