You're generally going to need more boost if you want more hp. Regardless of turbo size, xx psi boost will give you xxx hp, with all other things being equal.

Sent from my F8332 using Tapatalk

 

You're generally going to need more boost if you want more hp. Regardless of turbo size, xx psi boost will give you xxx hp, with all other things being equal.

Sent from my F8332 using Tapatalk

Well, 18 to 19 lbs of boost im fine with. Anything above that I don't want.

Sent from my SM-G928V using Tapatalk

 

No need to upgrade your turbo then, stock can handle that no problem. That's only a 3psi increase over stock. Hilton stage 1 might even be higher (is it is, you can tell him to limit it to whatever you want).

For more power, you me then need to focus on increasing your engines breathing, and other NA power increase tricks.

Sent from my F8332 using Tapatalk

 

No need to upgrade your turbo then, stock can handle that no problem. That's only a 3psi increase over stock. Hilton stage 1 might even be higher (is it is, you can tell him to limit it to whatever you want).

For more power, you me then need to focus on increasing your engines breathing, and other NA power increase tricks.

Sent from my F8332 using Tapatalk

Well I want 400hp. I dont need 500 or anything like that. 400hp at the crank is fine with me. I notice the ipd 4t4 turbo gets 410 415hp with 17lb of boost. Just wanted a boost range of what people are getting with the k24 hybrid.

Sent from my SM-G928V using Tapatalk

 

To answer your question, my Hybrid 7+7 is running 25psi of boost
I do not really understand your boost limitation though, whats the reasoning behind that?



If your goal is +/-400 hp at +/-18 PSI, get a real turbo and forget the Hybrid K24

Go at least something like BW EFR 6758 or Garrett GTX 2867, at least, you might consider even bigger for your goals, but bigger means you will sacrifice spool.....

Your goals are unrealistic with a hybrid, don't waste your time on that, redefine your goal and then decide what to change.

 

To answer your question, my Hybrid 7+7 is running 25psi of boost
I do not really understand your boost limitation though, whats the reasoning behind that?

If your goal is +/-400 hp at +/-18 PSI, get a real turbo and forget the Hybrid K24

Go at least something like BW EFR 6758 or Garrett GTX 2867, at least, you might consider even bigger for your goals, but bigger means you will sacrifice spool.....

Your goals are unrealistic with a hybrid, don't waste your time on that, redefine your goal and then decide what to change.

The reason is I want it to be somewhat reliable. My other R has everything but a bigger turbo. It runs 18lbs of boost with a stg 2 tune. This R has low miles, 6speed and it's my weekend car. Thank you for the advice!!

Sent from my SM-G928V using Tapatalk

 

Hows the top end with that 7+7? Does it hold 25 to redline? I have a turbo at the shop for a hybrid rebuild and I'm trying to choose compressor wheel and whether to clip the exhaust. With the stock K24 stage 2.5 boost drops from 23 to about 16 psi by redline. I'd gladly trade some boost down low for some more top end. Stock k24 doesn't seem to be capable of flowing more than stock boost up top.

 

Not saying you shouldnt opt for a hybrid, just that high hp with a modified K24 will require higher boost than 18 psi

The K24 is fine for quick spool, a hybrid will give you higher hp at the cost of higher psi/boost.
Depending on the compressor wheel it will hold that boost also in higher rpm, the 11 blade hybrid theoretically should give you the best results in higher rpm.
But be aware, the hybrid has a bigger compressorwheel but still the same and relative small turbinewheel and housing, that will always be its culprit.


Clipping the turbinewheel might help that but at the cost of spool and your EGT's will always be higher when raising boost in a situation like this.
You can get more in, but you also have to be able to get all out ;-)

Its all about efficiency...

If you want 400 hp AND low psi, study efficiency ranges and pick a turbo which has potential for lets say +/-500hp and run it with fairly low boost.
Or run a hybrid and accept that you have to run higher boost.

 

Not saying you shouldnt opt for a hybrid, just that high hp with a modified K24 will require higher boost than 18 psi

The K24 is fine for quick spool, a hybrid will give you higher hp at the cost of higher psi/boost.
Depending on the compressor wheel it will hold that boost also in higher rpm, the 11 blade hybrid theoretically should give you the best results in higher rpm.
But be aware, the hybrid has a bigger compressorwheel but still the same and relative small turbinewheel and housing, that will always be its culprit.

Clipping the turbinewheel might help that but at the cost of spool and your EGT's will always be higher when raising boost in a situation like this.
You can get more in, but you also have to be able to get all out ;-)

Its all about efficiency...

If you want 400 hp AND low psi, study efficiency ranges and pick a turbo which has potential for lets say +/-500hp and run it with fairly low boost.
Or run a hybrid and accept that you have to run higher boost.

Orrrr just orrr pay my life savings for an ipd 4t4.
[emoji41]
Definitley something to think about.

Sent from my SM-G928V using Tapatalk

 

Oh and if I remember correct my Hybrid 7+7 starts building boost around 2200rpm, then holds 25 psi from 3200 to 5800 and then tapers to 23/22

 

That T4T is crazy expensive, only advantage would be it's plug-and-play.
But to be honest, never saw any reals and/or spectacular results from those

 

You're not kidding when it comes to expensive.
But hey to each their own. Thanks for the advice.
Much appreciated!

Sent from my SM-G928V using Tapatalk

 

No thanks, hardly advice, more of a personal experience ;-)

 

Maybe it's just me, but I don't see how 18psi, from different turbos, can create that large of a power difference. Resistance at the exducer is directly related to resistance/air force into the engine at the inducer, so aside from docent power curves, how would one torii at 18psi create more power than another?

Sent from my F8332 using Tapatalk

 

Maybe it's just me, but I don't see how 18psi, from different turbos, can create that large of a power difference. Resistance at the exducer is directly related to resistance/air force into the engine at the inducer, so aside from docent power curves, how would one torii at 18psi create more power than another?

Sent from my F8332 using Tapatalk

Wow ok.

Stock K24 at 22psi will do lets say 350hp. My wifes brother who has a huge Borg Warner on his BMW makes 700hp with 22psi.
Boost is only a restriction.

 

A bigger turbo/compressor will move more air at lower boost levels. More air = more power, doesn't matter if it's from higher boost levels, or a more efficient compressor.

 

More Massflow = More Power

In order of increasing mass flow capability...

OEM Turbo
Hybrid Turbo
IPD Turbo
Larger custom turbo (EFR, Garrett, etc)

As mentioned above, boost is just a how hard you are stuffing the cylinders but now how much you are stuffing in. If you can stuff more in more softly than that's more efficient and will equal more power.

Of course you can't ignore the drawback that a larger turbo will take longer to spool and generally give up some low end punch.

I have run a Hybrid and Cavalli turbo. The latter is no longer available on the market and mine self destructed after about 30k or so miles of use, but it was the biggest bolt on turbo available. Despite being a ball bearing (vs journal bearing like OEM or Hybrid) I lost some low end punch vs the OEM turbo. The Hybrid turbo with a 7+7 comp wheel that I'm currently running gained back nearly all the low end punch I had with the OEM turbo and flows more. It makes around 23-24 psi max on my car and does taper out a bit. I love the low end power for around town but miss the top end of the Cavalli. We're talking maybe 1100kg/hr peak flow with the Cavalli vs 1400 kg/hr or so with the Cavalli at around the same 23-24 psi.

If you have to stick with a bolt on solution, the Hybrid with a 7+7 wheel is your best option.

If you are willing to go custom and want to keep the low end punch but add more top end, there are others on the forum with great results using the EFR 6758. You're going to get significantly more top end out of this turbo (I recall seeing something around 1500 or so kg/hr from Austin's setup).

If you're dead set on the Hybrid and can wait until Spring time, I plan to upgrade to an EFR (leaning toward the slightly larger EFR 7163) and will be selling the Hybrid.

 

So the really interesting thing if KG/hour of air. That's how you know how much HP your engine is producing.

My hybrid K24 (built by my company) is pushing about 1500kg/h air ---> Contrast says he's never seen any other producing such numbers consistently

 

Hybrid K24 != Hybrid K24 ;-)

 

Can you share some more details of yours?

Anything specific done when machining the compressor housing?
Is the turbine side/wheel also modified?
What (360) bearings were used?
And were axles modified or upgraded?

Could be interesting for people about to jump the fence.


Unlike what we want to believe, each Hybrid is different, they are not 100% comparable, a lot of people don't realize that.
If you research the available wheels, its dazzling, for example 7+7 and 11 blade compressorwheels come in about 10 different flavors and dimensions.
Besides that, some companies swear by also machine the snail, some clip the turbine wheel, others don't

My point is that Hybrids cant be really compared since they all are custommade and different, makes defining or anticipating an outcome on forehand rather difficult.
It's not like some factory turbo from a series which are built to the same tolerances.

 

AFAIK, 1 unit volume of air at 24psi has more air molecules than 1 unit volume of air at 15psi. So the only factor I can see that's different is exhaust restriction causing hp numbers to differ between two different turbos pushing the same psi.

Bb, clipped turbine, larger turbine, all reduce exhaust restriction, so this must be where the difference in power levels at the same psi comes from... Right?

Anyways, not all hybrid are built the same.

F it, just add NOS! lol

Sent from my F8332 using Tapatalk

 

AFAIK, 1 unit volume of air at 24psi has more air molecules than 1 unit volume of air at 15psi. So the only factor I can see that's different is exhaust restriction causing hp numbers to differ between two different turbos pushing the same psi.

Bb, clipped turbine, larger turbine, all reduce exhaust restriction, so this must be where the difference in power levels at the same psi comes from... Right?

Anyways, not all hybrid are built the same.

F it, just add NOS! lol

Sent from my F8332 using Tapatalk

What you said is true, but it isn't the whole story. For any given orifice, there is only so much air that can pass though. Basically, the air going through the orifice speeds up more and more until it gets to a point (that can be determined through a bunch of annoying fluid dynamics equations) where a bigger pressure delta doesn't increase the flow. This is known as choked flow. The pressure and flow rate at which choked flow is reached differs from turbo to turbo.

Horsepower is directly correlated to the mass of air that can enter the engine, not the pressure. So, if you think of a very small turbo as a straw and a big turbo as a pipe, clearly the pipe can flow more despite the fact that both can be pressurized to the same level. So, a bigger turbo at the same pressure makes more power...but if it is bigger by enough margin, it can make more power at a LOWER pressure.

 

I have the pure turbos K24 hybrid which is a 6+6 billet compressor wheel that has 51mm inducer x 62mm exducer diameters. Not as big as most other hybrids, only a bit bigger than stock.

With a Hilton stage 3 It makes 20 psi by 3500 RPM, hits 26.5 psi at 4000, and is still holding 24 psi at 6000. Pulls hard all the way to redline, makes me not want to shift. It's pulling just under 1300 kg/hr at its max.

Keep in mind these are gauge pressures at 5600 ft elevation. They're about 2.5 psi lower at sea level.

 

The reason different sized turbos create vastly different power outputs at the same psi is similar to the reason a car at elevation will have less power at the same psi. Psi is a measurement of pressure, not air mass.
Pressure is directly proportional to temperature. A smaller turbo at a high boost level will be creating much hotter air than a large turbo at the same boost level. The small turbo will be working hard because its at the top of its efficiency range. At higher boost levels, a large turbo will move the same amount of air with less effort, creating less heat, therefore producing less pressure. For a fixed volume, hot air at 20 psi will hold significantly less air molecules than cold air at 20psi.
Mass air flow is a great way to predict power output, psi alone is not.

To make this relevant to the op's question, the larger compressor wheel on the hybrid would shift the efficiency range of the turbo upwards, it would create more power than the stock k24 at 18 or 19 psi... not quite 400 like the 4t4 though.
If you don't want high boost because you don't want to, say, crack a sleeve, you might think about water/meth. As long as the injection is properly working you can safely increase boost a bit more without worrying about detonation, it'd be comparable to running a larger turbo at lower boost. Water/meth will also allow you to recoup some of the lost efficiency from running a smaller turbo to its limit. You can put in a good system with a failsafe, for me that's reliable enough. I'll be running water meth with a hybrid hoping for 420+, with 23-25 peak psi. I don't think 400hp can be done 100% safely on the stock block regardless of turbo though.... FWIW I've done 10k miles on 23 psi with water/meth so far without breaking anything.... I have a spare block ready to be shimmed when the time comes.

 

I'm way past 400hp with stock (shimmed) block and a K24 hybrid

Again it's producing around 1500kg/h of air at 25psi.

I also have water injection btw

 

I understand stock blocks have held up well to a lot of power most importantly with a good tune and set up, I just mean from what I've heard reliable is a difficult term to use when you add horsepower to a stock and not shimmed R motor, if you're using the car as a daily driver or not willing to swap out the engine at some point.
My hybrid is arriving later this week, so I'm glad to hear the inspiration. What kind of specs on the hybrid? Have you dyno'd your car?