Sierra 2014 lt1 416 Twin turbo supercharged

[jarrah]

What u guys think I am building my truck now, its a 2014 sierra 5.3 swapped the engine with lt1 416 forged to take boost I am trying something different this time twin turbo and supercharged.

any ideas

[PST]

My opinion is that with the twin turbos, the supercharger is just a heat pumping parasite in the combination. But it sure looks cool! Good luck tuning/fueling that thing.

[doc350]

What kind of power are you looking to make that can't be achieved with just one or the other? Or are you just doing it to do something different? Either way, it looks wicked! Keep us posted.

[Ranger6202]

my good friend had me tune his c6 with a newly installed e-force on it last summer. He just recently came to me and said he wants to pull the supercharger and go twin turbo. I've been trying to talk him into feeding the supercharger with just a single big turbo. So i'm definitely intrigued with your build!

[Montecarlodrag]

This thread reminds me of the Twin-Turbo-Supercharged-Nitrous 69 Camaro.
A correctly sized single turbo can give you enough power to make this engine grow a few legs.

[cesar]

im guessing its a truck located in the valley? lol.

Pointless to have a whipple and twin turbo.

[Ben Charles]

The idea of it is cool, but that's about it. Compound boost is kind of ignorant due to one of the Power adders being the hindrance of flow. I would remove the whipple and just power it with turbos. Be less boost and more power and cooler IATS I bet.

That a 2.9 whipple from the looks of it and I am very familiar with what that blower is capable of and with the pulley you have on it (4.5?) its not doing much anyways.

[Montecarlodrag]

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[LT1Z]

Looks cool but ditch the whipple and run twins with an LT1 manifold.

[GHuggins]

Definately looks interresting. But I'm curious. Why the big blower and bigger turbos? If I were looking for a torque monster, which I assume you might be here, I would run a smaller 1.9ish blower with pulleys (so it builds a little quicker and will blend better when the turbos come into play), then have the turbos kicking in good around 3500 to 4000 rpms. SC will be gasping around what 53 to 5500, while the turbos keep feeding? I know that would be one heck of a torque demon... Of course you could very easily use two smaller turbos, run boost around 11 to 12 psi, tune it right and still have more than enough torque down low and all the way up top.

I just always thought the point of this was for one to come into play when the other started "dyeing" out or that was atleast it's original purpose for the OE diesels. Don't see much point in a whole ton of boost coming in at once... BUT that whipple with it's config does only do about 9psi, so I guess it depends on when those turbos come into play? The whipple will be more iat friendly due to it's screw design. Then there's the whole efficient issue. Your costing power with SC whereas turbos are pretty much the most efficient there is...

Don't know - I only see this config being used as a torque beast, so I would go the smaller SC setup with pulleys, TB and ported snout to combine with the bigger turbos.

Guess I just added more confussion? Sorry, but like I said - interresting....

Please let us know how this turns out.

[edgZ06]

I don't think you guys realize the benefits of compound boost.
Bigger blower and spun slower keeps the IATs down, but provides initial boost/torque and increases exhaust gases to spool the turbos quicker which then add the real boost that is compounded ie. multiplied when it exits the blower.

Ex. Blower pushes 5 psi on its own, turbos spool up another 5 psi, which enters the blower and is multiplied by 5 equaling roughly 25 psi with no lag (5 psi ramps up to 25 psi) and none of the compressors are working hard.

[GHuggins]

Was just curious if you were ever able to go through with this and what numbers it wound up putting down?

We were recently considering the "sameish" combo setup, but were explicitly told that right around 900 to the rear wheels the supercharger is nothing more than an airflow renderer or rather an expensive choke point. Abosolutely wouldn't allow air to flow through it anymore. I personally think you could get more than that out of it, but who knows for sure? I guess you could run a 4 or 4.5 liter blower, but what would the point be then? Much less the cost.

I'm really hoping you had very good fortune doing this and can disprove what I was told

Anyway, just curious...

Thanks

[TurboCobalt]

edgz06 i don't think that's how compound forced induction works.
You make it sound like turbo 5 psi in series with supercharger 5 psi gives you 25 psi? that's not how it works
First of all lets work in kPa like a real calibrator / scientist / engineer / STANDARD units?
5psi is: 5psi/14.7 psi * 101kPa = 34 kPa
the pressure ratio of the turbo would be (101+34) kPa / 101 kPa = 1.34 pressure ratio. (Pressure_out / Pressure_in)
lets assume that the supercharger would also generate 5psi above atmosphere by itself, therefore also a 1.34 pressure ratio.
if put in series, now multiply the pressure ratios 1.34 * 1.34 = 1.8 total pressure ratio (unitless)
Assuming the input is an ideal 101 kPa (atmosphere) then the output of the series turbo-super-charger is 101 * 1.8 = 181.8 kPa (absolute pressure)
in the ever popular "boost pressure in psi" units that's : (181.8 kPa - 101 kPa) / 101 kPa * 14.7 psi = 11.76 psi (above atmosphere) "boost" in Psi
nowhere near 25 psi.
Compounding FI could have it's advantages and disadvantages but that's a much more complicated discussion, difficult to have without knowing the end goal of the OP.
Someone please correct me if my math and/or formulas are wrong.

EDIT: i just realized, someone let that math error slide for 3 months on a tuning community forum?

[GHuggins]

edgz06 i don't think that's how compound forced induction works.
You make it sound like turbo 5 psi in series with supercharger 5 psi gives you 25 psi? that's not how it works
First of all lets work in kPa like a real calibrator / scientist / engineer / STANDARD units?
5psi is: 5psi/14.7 psi * 101kPa = 34 kPa
the pressure ratio of the turbo would be (101+34) kPa / 101 kPa = 1.34 pressure ratio. (Pressure_out / Pressure_in)
lets assume that the supercharger would also generate 5psi above atmosphere by itself, therefore also a 1.34 pressure ratio.
if put in series, now multiply the pressure ratios 1.34 * 1.34 = 1.8 total pressure ratio (unitless)
Assuming the input is an ideal 101 kPa (atmosphere) then the output of the series turbo-super-charger is 101 * 1.8 = 181.8 kPa (absolute pressure)
in the ever popular "boost pressure in psi" units that's : (181.8 kPa - 101 kPa) / 101 kPa * 14.7 psi = 11.76 psi (above atmosphere) "boost" in Psi
nowhere near 25 psi.
Compounding FI could have it's advantages and disadvantages but that's a much more complicated discussion, difficult to have without knowing the end goal of the OP.
Someone please correct me if my math and/or formulas are wrong.

EDIT: i just realized, someone let that math error slide for 3 months on a tuning community forum?

This is why in my earlier post on the subject I said it would make one heck of a torque beast. Not much load on the motor with lower supercharger pressure so your still getting instant torque from blower with minor added boost of turbo, but then when you brought in and really compounded the two later = much more hp... Thought the 5*5 logic was off, but didn't know enough about it to comment on the subject. But from what I'm told by people attempting this on the bigger builds, it doesn't work due to the airflow limitations of the supercharger.

This is why I was curious as to how it turned out...

[edgZ06]

edgz06 i don't think that's how compound forced induction works.
You make it sound like turbo 5 psi in series with supercharger 5 psi gives you 25 psi? that's not how it works
First of all lets work in kPa like a real calibrator / scientist / engineer / STANDARD units?
5psi is: 5psi/14.7 psi * 101kPa = 34 kPa
the pressure ratio of the turbo would be (101+34) kPa / 101 kPa = 1.34 pressure ratio. (Pressure_out / Pressure_in)
lets assume that the supercharger would also generate 5psi above atmosphere by itself, therefore also a 1.34 pressure ratio.
if put in series, now multiply the pressure ratios 1.34 * 1.34 = 1.8 total pressure ratio (unitless)
Assuming the input is an ideal 101 kPa (atmosphere) then the output of the series turbo-super-charger is 101 * 1.8 = 181.8 kPa (absolute pressure)
in the ever popular "boost pressure in psi" units that's : (181.8 kPa - 101 kPa) / 101 kPa * 14.7 psi = 11.76 psi (above atmosphere) "boost" in Psi
nowhere near 25 psi.
Compounding FI could have it's advantages and disadvantages but that's a much more complicated discussion, difficult to have without knowing the end goal of the OP.
Someone please correct me if my math and/or formulas are wrong.

EDIT: i just realized, someone let that math error slide for 3 months on a tuning community forum?

It doesn't matter if you are using PSI or KPA, they are both just units of measurement for pressure.

Your math is wrong, but it sounded good!

[TurboCobalt]

It doesn't matter if you are using PSI or KPA, they are both just units of measurement for pressure.

Your math is wrong, but it sounded good!

I agree that units are irrelevant, works out to same answer in psi.
If my math is wrong, please correct me.

[PST]

The blower being fed positive pressure does increase its output... but it's not a straight multiplication of original boost pressure times incoming boost pressure.

Back in the day, I tuned a built SBC with Accel DFI, it had a maggy making 10psi. The owner later added a single turbo setup with the wastegate spring set for 5psi. The resultant manifold pressure did not increase and the wastegate was wide open before the turbo could spool. We swapped to a 10 psi spring, manifold pressure stayed the same, but the waste gate wasn't open as much.

We then tried swapping the WG from a manifold sourced boost signal to turbo sourced signal (so the waste gate saw the pressure produced by the turbo alone). Boost went up to 15 psi (10psi pulley + 10psi WG spring.

Out of curiosity, we went back to the 5psi spring. Boost dropped to 12psi with the WG referencing pressure between the blower and turbo.

Still wanting a total of 20psi, we then swapped to a 15psi spring.. we got 18ish psi and iat's through the roof.

The owner eventually removed the blower, adjusted the WG to get 18psi, and was rewarded with lower iat's, more power through the curve, and just slightly later torque peak.

After typing all that, I don't have the patience to spell out the math. But you can see that imperical data completely disproves the multiplication math spelled out by edgz06.

[GHuggins]

Good to hear from you on this PST... Kinda just confirmed what I thought and what we were told on the bigger builds too. Thanks... So straight twins running 20 or so with a 427 for the next camaro build I think the camaro photo'ed above put down rather low numbers from what little I've seen of it on youtube even with it's giagantic blower, but could be completely wrong on that as I've only been able to find peoples disapointing reactions after it's dyno debut... They never actually said what the numbers were, just "that's it?"...

[Ranger6202]

The owner eventually removed the blower, adjusted the WG to get 18psi, and was rewarded with lower iat's, more power through the curve, and just slightly later torque peak.

I can see being able to keep the same boost with either setup, but i'm with Huggins on this, where you get the benefit from the instant boost form the SC and then the turbo comes and carries the pressure compound upward. So when your friend pulled his blower off, even though he was able to maintain the 18#'s with the Turbo, didn't he also receive boost lag with absence of the blower? Higher iat's would be a guarantee with a setup like that, so a turbo and SC inter cooler upgrade and/or meth injection would be mandatory.

[edgZ06]

The blower being fed positive pressure does increase its output... but it's not a straight multiplication of original boost pressure times incoming boost pressure.

Back in the day, I tuned a built SBC with Accel DFI, it had a maggy making 10psi. The owner later added a single turbo setup with the wastegate spring set for 5psi. The resultant manifold pressure did not increase and the wastegate was wide open before the turbo could spool. We swapped to a 10 psi spring, manifold pressure stayed the same, but the waste gate wasn't open as much.

We then tried swapping the WG from a manifold sourced boost signal to turbo sourced signal (so the waste gate saw the pressure produced by the turbo alone). Boost went up to 15 psi (10psi pulley + 10psi WG spring.

Out of curiosity, we went back to the 5psi spring. Boost dropped to 12psi with the WG referencing pressure between the blower and turbo.

Still wanting a total of 20psi, we then swapped to a 15psi spring.. we got 18ish psi and iat's through the roof.

The owner eventually removed the blower, adjusted the WG to get 18psi, and was rewarded with lower iat's, more power through the curve, and just slightly later torque peak.

After typing all that, I don't have the patience to spell out the math. But you can see that imperical data completely disproves the multiplication math spelled out by edgz06.

You are siting one specific build with many variables. What types of heat exchangers were being used? What were they iats pre Maggy and post Maggy? What size turbo? Cam specs, Etc.

Maggy's tend to shoot iats up considerably at higher boost levels and personally, I would have run the Maggy at a lower psi, with more psi from the turbo and I also would have made sure that iats were kept in check before the Maggy.

Sizing between the two (or more) compressors is critical as well.

At the end of the day, a compressor does not know the density of the air entering it, it will compress the air just the same and if the iats entering it are higher going in, they will be even higher coming out.

There are way to many variables with each build to say that there is a simple exact multiplier, but a compound boost build could be done right and it could be done wrong.

Oh, thanks for trying to prove me wrong, but just because you tuned one failed combo doesnt prove or disprove anything other than that combo missed the mark.
This discussion shouldn't be about who's right or wrong, it should be about keeping an open mind, learning and sharing data.