Wastegate size??

[Jim Fulmer]

60 psi on the bottom charger? and your peak boost is what



60 psi means it's out of it's map, my B/B only makes 35-38 and kenny said it would be over 40.



Jim

 

[Diesel Freak]

heh he ya think?

 

[mrsmith]

60 psi on the bottom charger? and your peak boost is what



60 psi means it's out of it's map, my B/B only makes 35-38 and kenny said it would be over 40.



Jim

The 55 is making 20 lbs and the 4C is making 60. What the map is on my 4C is I have no idea,but what Brent said is correct at 80lbs of boost backpressure is 60 psi. When I had the HX40 on top at 80lbs of boost backpressure was 85psi. I have the external wastegate set at 80,if I told you all what I've seen for overall boost while adjusting the wastegate none of you would believe me.

Performance wise there is a little more lag with the 55 on top, but with either on top I can make boost before I leave the line.

When I get this thing to the dyno the numbers are going to be really impressive.

I'm having some non-turbo issues right now but when I get those bugs out it'll do O. K. in some up coming street twin classes :-laf

 

[mrsmith]

I forgot to ad next week I'm going to try a Pro 52 on top for entertainment.

 

[Diesel Freak]

Ah I see... . HX55 feeding a HT4C?



if so, I stand corrected.

 

[Jim Fulmer]

It's not that I doubt the 80 psi..... it should be good for say 100-110 as a guess looking at that drive pressure, I just can't see how 60 feeding 20 makes 80, guess I'm lost and will just crawl back in my hole ... ... ... BOTW my combo also nets 85 drive at 80 psi.



Jim

 

[Bpostel]

So Diesel Freak, it sounds like you didn't believe me with Mike's setup. What do think now? Thanks Mike for posting and shutting up these non believers. Next time maybe they'll stick there foot in there mouth before they open it.

 

[Jim Fulmer]

I forgot to ad next week I'm going to try a Pro 52 on top for entertainment.

Cool with an external gate driving the big turbo..... sweet, been looking for someone to try that to... ... reports are in order here!



Jim

 

[Diesel Freak]

Bpostel your initial post was missleading.



The way I initially understood it as you wrote it the Bottom turbo was making 60 PSI. If so, then it is way out of its efficiency range.



If the bottom turbo is making 20, and the top is then taking that 20 and then making 60, there is not an issue.

 

[J.R. Adkins]

Hey DF you gotta map on my HT4c??





J. R.

 

[Bpostel]

Not sure what was misleading. The low pressure charger (HT4C) is making 60psi of boost. The tractor guys are running a similar charger and I'm sure there making at least 60psi if not more. I don't think there out of there map. I think it's hard for people to believe we can drive these big turbo's that hard, thats the advantage of the big external wastegate.

 

[Diesel Freak]

hmm so basicly you are pushing a turbo at a Pressure ratio of over 5:1



must be some real toasty air comming out of it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!



back to my original statement... .



Give me a break!!!

 

[Diesel Freak]

Hey DF you gotta map on my HT4c??

J. R.

nope, but why not post it so we all can learn something :-laf

 

[Diesel Freak]

hmmm this got me thinking. (fyi, the following example is a pipe dream on a B series Cummins!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!)



a HX55 is basicly done at a mass flow rate of 99 LBM/min (look it up).



so to really feed this, you need a turbo that can move more air than that... . right? So if someone were to really take advantage of turbo compounding, a turbo with a mass flow rate of say 180 LBM/min would be used... ..... a T100 comes to mind!! Do you know how hot the air would be from running a T100 at over a 5:1 pressure ratio? Ouch!!!!!!



It has been said that the low pressure (bottom/primary) turbo is making 60 PSI of boost, and the high pressure turbo is only adding another 20 to that... correct?



hmm is this system really compounded? or is is some hilljack frankenstein creation That is for competition and the only boost cooling is by injection huge ammounts of water?



If the system were truly taking advantage of compound turbos, boost would be in the range of 300 PSI.



If would definately work better if Primary boost was lowered to 25-30 psi, and then seccondary boost was raised to 95-100 psi



next question... .

How much air is actually going into the engine? I'll give you a hint. Start with a Density ratio of 1:1 and a VE of basicly . 92..... do the math.



Is a primary turbo with a flow rate of over 130 LBM/Min necessary!!!! Why yes, if 800+ non continuously supportable HP is the goal!!

 

[Jim Fulmer]

Do you know how hot the air would be from running a T100 at over a 5:1 pressure ratio? Ouch!!!!!!



I've got a little bit of an idea... ... HOT! Now to the B/B as it comparable in size to a HT4C... ... . at 38 psi it's a 400 degrees in the cold pipe..... if you want to call it that!



I do know that the Gasser single guys push that turbo(or a 106) to close to 50 psi in to a 400 ci small block!



Jim

 

[Diesel Freak]

to attach a number.....



569F!!!!!!!!!!!!!!!!!!!!!!!!!!



and then it is run through another compressor adding 20 more PSI.



hmmmm assuming the HX50 is running in a decent place... . oh say 70%



temp then climbs to a freakish 906F



This is just stupid!!!!!!!!!!!!!!!!!

 

[Diesel Freak]

I guess I need to finish this up.



Continuing with the above scenario, we end up with a Density ratio of 1. 56 prior to intercooling. After intercooling density ratio rises to a whopping 2. 81. This is why boost pressure alone is MEANINGLESS!!!



Since we are dealing with a 24 valve engine, this gives us mass flow rates @ 3000 RPM of 67 LBM/Min woo hoo we are cooking!!!! :-laf



However since this engine may or may not have a P-Pump, mass flow rate at 4500 RPM is 100 LBM/Min.



If this was still a VP44 engine, you would be better off with one of the current crop of 66mm Schweitzer derivatives!!!! YES, A SINGLE TURBO!!!!



If a P7100 engine, you could do MUCH better with a set of properly balanced and tuned (smaller) twinset!!!

 

[mrsmith]

DF,Were not dealing with a 24V its a 12V. if you bothered looking at my signiture before you started babling LBM/Min, Density ratios you'd saved yourself some math that doesn't apply to my truck. . I don't have to shoot any water to it the exhuast temp doesn't get high enough to need it although it is plumbed for water/meth.

If your ever in northwest Ohio I'd gladly take you for a ride and then you could tell me how unbalanced and over sized my twins are!

 

[Diesel Freak]

it is really not a huge issue. It takes more work to get air through a 12 valve head... i. e. porting, cam... etc... etc



The number of valves is not really an issue since 24 valve heads flow better when stock, and 12 valve heads can be made to flow the more than a 24 valve head when modified. Assuming you have a healthy bumpstick, VE for your engine is prolly closser to 1. 00 than the ISB . 92. I would assume about . 95 to . 98.



Post some documented information... . turbo compressor maps, turbine trim... etc, and we can really discuss this. Your flow rates are not much more than 6% higher.



With the boost pressure already posted, it does not take much to see that you could do much better with a different set of turbos. You are relying on low drive pressure to keep EGT low. You would be ahead of the game if you resized them, raised the aftercooled density ratio, and kept drive pressure at sane levels.

 

[Morse]

I didn't understand most of that conversation. . With the sledpuller, big brother, and 44 mm tial wastegate is it gonna work correctly without having really high EGT's?