I can't stop reading about the difference between a K24 and a K24/18 ... some says that the difference can be calculated in 60 HP, some others talk about 100 HP !
Why ? Is there any reason which can lead me to believe that this is true ?
If a K24/18 is able to produce 40 lbs/min ... means that can produce 18.14 kg/min (excuse me but i prefer to work with kg. but nothing changes at the end)
So, 18.14 kg/min is 0.3023 kg/sec. and can be converted in a max power of 329,65 HP each turbocharger ... without dispersions meaning that this power will not be possible in the real world (but just something less).
Now some say that a K24 produces 30 lbs/min ... 13,61 kg/min ... 0.2268 kg/sec. and a max power of 247.32 HP, but the problem is that a K24 produces a lot more then 30 lbs/min !
Borg Warner which produces this turbocharger, and is supposed to know better then any other the K24, says that this turbochargers have a max flow rate of 0.30 kg/sec ... 327.14 HP.
That's the point:
K24/18 max flow rate 0.3023 kg/sec and 329.65 HP
K24 max flow rate 0.3000 kg/sec and 327.14 HP
Where is the difference ?

As a reference point, how would a K16 turbo rate in your calculations?

are you using fuel and temp as a constant in your calculations?

Here is a before and after dyno plot of my car with K24s (chipped - unsure which chip since i bought the car used and the owner told meit was stock) vs. K24/18g with an EPL tune:



Obviously, the red lines are the K24/18g turbos. We are not talking about more HP at a particular point. Look at how much HP and torque these things make throughout the power band!

If you race two exact same cars with only difference the k24 Vs k24/18g turbos(and of course the corresponding ECU tuning) from rolling 2nd to 250km/h the difference is about 3 to 4 car lenghts...
On the other hand when K24/18g turbos are used you can raise up the boost and put in good racing fuel as well as bigger injectors...Then you will see great difference...

A K16 has a max flow rate of 0.26 kg/sec ... 283,52 HP which means 560 HP in a 996 TT clearly not possible because this is the power that K16 can produce but not the power the engine will produce but we all know that a well remapped 996 TT with oem K16 can easily achieve 490-500 HP

Yes, temp 293 K press 981 mb and fuel not important for me in this calculation

Yes i can see but here's the point ... are you sure were you getting the max power from the K24 or just the power the tuner wants to give you ?
Numbers are numbers and don't lie ... Borg Warner doesn't make mistakes about the calculations on the turbos is producing !
If K24/18 produces a max air flow of 40 lbs/min this means only one thing ... is equal to a K24 ... other endings are not possible !

interesting...

k24 and 18g compressor map for reference.

I can run 1.25-1.30 bar at max rpm power with a K24 ... which boost do you think you can get from a K24/18 ?
Numbers doesn't confirm what you say ... if we make work the K24 as it can work and not as some tuner say !
K24/18 40 lbs/min
K24 39.6 lbs/min
Until these numbers are correct they are equal !

to be honest with you i did not had a great look over the numbers...However during past time i had my car at k16,k16/24,k24 and k24/18g setups...So...max boost sustained with k24 was 1,2 to 1,25 while k24/18g can very easy get to 1,4 bar...These turbos are not equal...They have a very noticeable difference especialy as revs go up...

Here is 2 dynos to compare. K24/18G vs K24 Stage 2 -

Is this with stock fueling system or a 5 bar FPR on 24/18g?

All K24/18G kits should be run with the 5bar FPR only unless you have something different and creative for the motor.