Wastegate size??

[Diesel Freak]

Hey im still in high school! I haven't even learned these yet but the year just began and you can bet that im in physics.

Sorry, that was not directed at you dude. It was directed at the peanut gallery.

 

[Diesel Freak]

Is this 60 psi actually measured in the cold pipe (maybe not so cold lol) or are you just assuming it's there because the wastegate is set at 20 and you've got 80 psi total?



-Scott

Scott, good question!!!!!!! The answer could clear up a lot of speculation!!!! Then something good could come of this thread.



hmmm talk about a Hijack!!!!



It was initially started asking about what size a wastgate should be!!!

 

[Diesel Freak]

Diesel Freak, thanks for replying to my questions... remember that report you did for some college class about compounding turbo's and posted on the tdr for the members to read? I still have and read that from time to time.

No problem!!!





Yep, I remember that paper. All 18 pages of it :{



Had a few Engineers and a couple Grad Students look it over before I turned it in for a grade.



I got an "A" on it!!!!!

 

[Devan Manis]

Sorry, that was not directed at you dude. It was directed at the peanut gallery.

yeah i know it wasn't, i was just trying to make a little point.

 

[RonA]

On page 2 Jim Fulmer said that he didn't see how 60psi from the primary feeding a secondary wastegated at 20 could net 80 at the secondary outlet. That seems right to me. Could someone post the correct number for this scenario. I seem to be doing the math wrong. (I got 81)

 

[Bpostel]

He is measuring the boost in the cold pipe.

 

[Diesel Freak]

as previously stated..... TOASTY, and not the Quiznos kind either!!!

 

[RonA]

I was talking about the math. You will find that back east some of the trucks with hp tend to push the bottom charger rather hard. The 60 figure is not exclusive to JR. Maybe you can take your college degree and go back to Ohio and show those guys how to make "west coast power" I'm sure they will be impressed.

 

[Diesel Freak]

I was talking about the math. You will find that back east some of the trucks with hp tend to push the bottom charger rather hard. The 60 figure is not exclusive to JR. Maybe you can take your college degree and go back to Ohio and show those guys how to make "west coast power" I'm sure they will be impressed.

That would be overkill. Kinda like using a . 460 Weatherby Magnum to hunt Prairy Rats.



Bottom line, it is possible to get more air into the engine by lowering the pressure on the primary and cranking up the secondary. That is all I have been saying.

 

[Diesel Freak]

for the math impaired.

Both turbos running at the same pressure ratio.

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Why density ratio is important.

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[mrsmith]

On page 2 Jim Fulmer said that he didn't see how 60psi from the primary feeding a secondary wastegated at 20 could net 80 at the secondary outlet. That seems right to me. Could someone post the correct number for this scenario. I seem to be doing the math wrong. (I got 81)

sorry for not posting this sooner. overall boost at the manifold is 80psi,the boost reading at the cold pipe is 60psi. Thats whats making me say the 4C is making 60 and the lil 55 is making 20. I'm no math wizard or physics geek but I've been involved in tractor/truck pulling for over 24 years and I know what the math says isn't always what works best going down the pulling track. The point I was trying to get across was for all out performance a J. R. lil 55 is a good upgrade from a HX40 and it'll bolt in place of an HX40. You can tell the 55 isn't as restrictive at higher rpm's. I've tried both and I know which performs better and clearly(IN MY APPLICATION) the 55 is better on the top end.

 

[Bpostel]

West coast have power :-laf Everyone knows the East coast is where the power is. DF, give it up, until you see this combo you can't say it doesn't work.

 

[Diesel Freak]

heh heh



go read my previous posts... . I just said it could work better if you knew what you were doing. This system is not taking full advantage of what a compound set of chargers can really do.



If you ballanced the pressure ratios at peak boost, you will move more air into the engine AT THE SAME PEAK BOOST PRESSURE AS BEFORE!!!

 

[mrsmith]

heh heh



go read my previous posts... . I just said it could work better if you knew what you were doing. This system is not taking full advantage of what a compound set of chargers can really do.



If you ballanced the pressure ratios at peak boost, you will move more air into the engine AT THE SAME PEAK BOOST PRESSURE AS BEFORE!!!

HX40's don't like a lot of boost getting pumped though them,20 psi is a really safe number,If I had my top wastegate set for 40 psi the 40's life span would be much shorter then running it at 20. HT4C's will live a long life making 60,but since you have vast twin building knowledge you probably already know that.

 

[Diesel Freak]

your kidding Right?



A little HX40 is barely running at a 2. 5 pressure ratio.



It is the rapid acceleration of the turbine shaft that causes them to break. Not the peak boost obtained. But that is a complete different topic, and I do not think you can understand the torsional loading on a shaft... . when you obviously cant comprehend the simple arithmetic posted elsewhere in this thread.



Like I have said, prove me wrong. Nothing has been presented to the contrary. I have presented enough info here for anyone to spec a compressor(s), therefore due to the lack of verifiable information, I am correct... . neener neener neener



Time to put this puppy to bed. The ignorance in this thread has exhausted me.

 

[Cummins4Life]

Time to put this puppy to bed. The ignorance in this thread has exhausted me.

ahhh man you're gettin soft in your old age. :-laf

 

[Diesel Freak]

heh heh I would rather get the bike ready for this weekends race.

 

[Diesel Freak]

Just a couple last thoughts.



There are a number of reference books available to the public that can illustrate the concepts I have presented in better detail. The best one IMO is "Maximum Boost" By Corky Bell. IMO, this is required reading for anyone selling or developing a turbo system.



If your turbo vendor/system designer either does not have any such reference material, or worse yet can not comprehend the concepts presented inside it..... RUN AWAY!!!!!!



You can find it at your local Barnes and Noble. It costs a measly $34. 95



Have a great day!!

 

[SRadke]

Did we ever reach a conclusion as to which wastegate is the proper size? I got confused somewhere in there around page 4.

 

[Diesel Freak]

I read somewhere, that the proper wastegate size is



"bout ta size o tums cap or maybee use a can o t'bacco. That's 'bout right I reckon"