Can we talk about triples?

Big Blue24 said:
For the record, two hx35's flow more like one S475 or 98-100 lbs per minute.
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Everything I have seen to this point says they are about a 55lbs/min charger strung out, though I am just adding them straight together, there maybe an efficiency loss that I am not taking into account here.

If that is the case that they are closer to 98lbs/min together it makes me happy, as that is far closer to what I need.
 
How many lbs/min is needed for 1000hp with a normal engine efficiency.
 
roachie said:
How many lbs/min is needed for 1000hp with a normal engine efficiency.
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~120lbs/min.

Gasser world rule of thumb is 10hp per lbs/min, Diesels are a little less efficient, so somewhere around 120lbs/min should be close. This is fuel only obviously.
 
dvst8r said:
~120lbs/min.

Gasser world rule of thumb is 10hp per lbs/min, Diesels are a little less efficient, so somewhere around 120lbs/min should be close. This is fuel only obviously.
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diesel are more effcient with fuel then air compared to gassers. diesel usualing 20-30% more air then gassers... mainly cause the run leaner.

deffently ager 120lbmin should put you 1000-1100hp. pendign the rest of your setup and tuning
 
138.8 lbs/min @200F IAT is what we are after.

The only thing on turbo flow I could find is a thread listing the CFM of each charger but it didnt list MAPs or anything.

Even if I did how would you go about adding the maps up. You would effectivly have a set of parrallel charger getting compounded by another.

Any ideas?
 
roachie said:
138.8 lbs/min @200F IAT is what we are after.

The only thing on turbo flow I could find is a thread listing the CFM of each charger but it didnt list MAPs or anything.

Even if I did how would you go about adding the maps up. You would effectivly have a set of parrallel charger getting compounded by another.

Any ideas?
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100lbmin / .061= 1639cfm

theres you conversion form LB/min to CFM
 
I thought you had to have the air temp that the cfm was taken at to properly convert it?

Now, compounding parrallels math anyone?
 
roachie said:
I thought you had to have the air temp that the cfm was taken at to properly convert it?

Now, compounding parrallels math anyone?
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You do need to take air temp into account to go to CFM. IIRC, a twins setup will only flow the lbs/min of the atmosphere charger. The math for compounding was posted somewhere here before. I think it was in a Banks math thread? NWBombers has some good archived info too.
 
Since this is 2 atmosphere chargers do we add their flow rates together?

Hoping its that simple


I did find this;

Diesel Freak said:
There is some debate as to where the turbos "should" be.

Most street twins (my setup included) have a primary that is actually too small to run the system 100% compounded.

In a setup similar to the one described, total boost is 60-70 with 30 comming from the primary.

On a truely compound set, you would square the pressure ratio across the primary.

Mathematically: Total boost (gauge presure) = (((PR1)^2)x14.7)-14.7)

if the Pressure ratio across the primary is 3:1 (essentially 30 psig in the cold pipe) then total boost would be ~118 psig

if the top turbo has a wheel that is ~60mm, then the bottom would be close to 85mm (not counting the hub diameter)
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WTF does that mean in english?
 
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roachie said:
Since this is 2 atmosphere chargers do we add their flow rates together?

Hoping its that simple


I did find this;



WTF does that mean in english?
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I don't know if merging the outlets will reduce the overall airflow, but I would think a rough estimate of adding the two flow rates together would be close enough for the atmosphere estimate.

In english that means the setups we run have the bottom turbo too tight, but it's ideal for driving and obtaining a good result across a wider power band.
 
Must find that formula for compound flow rates.....

Does it multiply X3?
 
Bottom turbo(s) (atmosphere) = twin turbo flow rate minus the lost efficiency from running air through the top charger that adds more heat to the system.

In other words, if you could spool an S480 and run it as a single, you would get more airflow than running an S480 as the bottom (atmosphere) turbo in a twin compound setup.

More airflow does not necessarily mean more power because your motor can swallow a lot more mass of air at 60psi than it can at 25psi due to the intake restrictions like the cast iron head.
 
keep this one going guys ive wanted to do this for a while and its getting me thinking again
 
Ok, so our theorectical engine at 1000hp will need 138.8 lbs/min @200F IAT.

From what I read this would require 2 chargers (primaries) that could flow 75-80 lbs/min (accounting for loss though the secondary and head). Going on the high side with 80 would yield 160 lbs/min.

Going on the 60% of the primaries combined total the seconday would need to flow 96 lbs/min.

That sound about right?

If it is then how would the exhaust housings need to be sized? 16's (0.9 A/R)on the primaries and a 14 or 16 secondary with an external gate to bypass it?
 
The 138.8 takes into account the head inefficiency. Find a turbo with a 70 lb/min map and double it up. Since your exhaust wheel is half the size as well, you can get away with a tight housing that's wastegated. I think you'll be around a triplet of 64mm turbos when it's all done.
 
WUnderwood said:
I've posted this before, here it is again...

DSC07166.jpg
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HELL YEAH!!!!!!!!!!!!! now get it to fit:hehe:
 
Say we use 2 S465's (I have no idea what they flow), then wouldnt the secondary need to be a 71mm or larger so it isnt being over worked trying to compound 140 lb/min of air?

Here is a real fancy artists conception of the plumbing of triples to those that are wondering:

triples.jpg
[/IMG]

LOL
 
roachie said:
Say we use 2 S465's (I have no idea what they flow), then wouldnt the secondary need to be a 71mm or larger so it isnt being over worked trying to compound 140 lb/min of air?

Here is a real fancy artists conception of the plumbing of triples to those that are wondering:

triples.jpg
[/IMG]

LOL
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a 2.8 charger shouldnt have a problem swalloing 150lbmin

what the flow rate on the 71mm? 90lbmin?

example take a 62-64mm wheel is roughly 50lbmin and most twin that with a 75-90mm or 80-100lbmin atmo charger with little problems of the small charge coocking the air flow.
 
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