Supercharger vs. Turbo (or simply NA advice..)

[mFei]

Before I begin, let me state that for all intensive purposes I am a gearhead-in-training. I have very little (see: < 1 year) hands on experience working with automotive parts, and the majority of my terminology is from what I have picked up in the process. I have no formal education or even second-hand education, and my interest in auto repair came purely by accident when I decided to pick up a Chilton's manual for an '96 Stealth and figure out how to solve an electrical misfire problem.

On that note, I've evolved into various things from motorcycles (helping rebuild a CX600 from a box of parts, and partially rebuilding a '85 Nighthawk 750S) and now to trucks.

Most of the time I don't really know what I'm getting myself into, both monetary wise and and time/labor wise. I have a mentor of sorts who's way of teaching usually involves handing me a powertool I don't even know the name for and then laughing at me when I ask stupid questions in regards to generic tools. I have a great desire to learn, however, and that sort of falls into play with wanting to take things apart and get dirty.

Now we come to our current project. I have an 07 GMC Sierra SLT, pretty much fully loaded with touch-screen nav, leather, and the Yukon/Denali suspension package. Weigning in at almost 6,000 lbs with the 6.0 V-Max package, my current goal is to turn this into a bit of a hobbyist truck - but for the most part I honestly don't know where to begin.

What I HAVE done:
6" BDS + Wheel/Tire replacement.
K&N Intake + Custom Flowmaster 3" in dual 2.5" out.
Motive re-gearing from 3.73 to 4.56 (amazingly actually increased gas mileage by almost 2MPG, hah)
HyperTech Power Programmer III

I've been struggling with the Turbo vs. Supercharger debate with various people, but I'm honestly pretty weary of putting something like that onto the truck that with my own inexperience has the heavy potential to cause extreme engine damage to the vehicle.

So, I'd like to start with a general inquiry. If this was YOUR truck (and for the sake of GMC/Chevy haters, Dodge/Ford fanboys, what have you - just pretend for the sake of argument I bought what you would have bought with a similar engine =P ) what would you change/upgrade? Steer me in the right direction so to speak with advice; anything from electrical, suspension, porting the engine, cams, headers, you name it.

If my objective is to naturally tune for more HP/Torque and avoid a blower, where do I begin?

Edit: Changed '06 to '96 to accurately reflect the real year of previous vehicle before people started yelling at me about no Dodge Stealth being made since '97!

 

[Arkaign]

Supercharger is always best for 8 cylinder vehicles. I'd have to recommend it over any more complicated idea of taking the engine apart to take it out of spec.

Whipple does SC right. Kit it and hit it!

 

[mFei]

Originally posted by: Arkaign
Supercharger is always best for 8 cylinder vehicles. I'd have to recommend it over any more complicated idea of taking the engine apart to take it out of spec.

Whipple does SC right. Kit it and hit it!

Nobody has really been able to explain to me in lamens terms why a Supercharger is superior to a custom Turbo setup for my engine. Can you possibly help me out there? I understand the physics behind both types of forced air and pully vs. exhaust driven, but not really how the smaller curve helps since it (appears) to limit the topend torque.

I've been debating Vortec vs. Whipple. The people I have spoken with all recommend Vortec (The V3 kits specifically because they are self-contained and you don't have to punch a hole in the oil pan) but I honestly like the idea behind the Whipple FAR more due to the fact that the boost rev's up around 1800 RPM, and for the low revving 6.0 in my truck that seems like it would give me the most benefit.

Additionally, I don't even know where to begin if I was going to piece out a kit from parts. Blower, intercooler (usually sold separate from what I've seen) ect. Hard as hell to find a DIY Supercharger walkthrough when there is so much money to be made for installers it appears.

Disclaimer: I know so little about most of what I said, please excuse any odd statements and/or bad termnilogy.

 

[Demon-Xanth]

I'd go for the supercharger. Cost and complexity wise it's a lot easier and cheaper to install. As well as availability. Also, unlike a custom turbo kit, you're likely to be able to find a supercharger kit with a warrenty, CARB EO number, and everything needed to put it in proper tune. Turbos can make more power, but they take a more work to get right.

As far as where you can begin for naturally aspirated power. Things like an exhaust, chipping it, and an intake can wake the engine up considerably and are easily installed. I'm not sure what all is out there for the 6.0, but I'm sure an intake manifold, throttle body, and cams are likely to be around. It's a matter of how much money you want to spend and how much work you want to do.

 

[The Boston Dangler]

big v8's can easily overcome the sc drag (10 or so HP) and it response is instant. small and medium size engines see more benefit from a turbo, as it recycles wasted energy. the downside is turbo lag and a narrow power band.

to squeeze out more oomph from any motor, look into extrude honed parts. http://www.extrudehone.com/auto/auto-performance.php

as always, if you want to go faster, add lightness.

 

[mFei]

The biggest issue so far with a Supercharger is that there are no kits for the 07-08 trucks. Which means unless I intend to wait half a year+, the only thing I can do now is custom fab a kit or make a custom Turbo. Given my general lack of knowledge this all equates into paying someone else extremely large amounts of money to do it for me - which kind of defeats the purpose of learning, heh.

 

[Dman877]

Are you doing this because you want your 6000 lb vehicle to be a sleeper and hit 60 in 7 seconds instead of 8? Or do you really just want the experience? If you just want to learn, get a late 90's wrangler or something cheap and go to town. No sense learning on a brand new 40k vehicle...

 

[mFei]

Originally posted by: Dman877
Are you doing this because you want your 6000 lb vehicle to be a sleeper and hit 60 in 7 seconds instead of 8? Or do you really just want the experience? If you just want to learn, get a late 90's wrangler or something cheap and go to town. No sense learning on a brand new 40k vehicle...

A combination of all of the above. I love the experience, but have no desire to do anything on an older truck. I like mine, and it's the only truck I could actually get into enough to buy - so the idea of toying with something I DON'T like isn't super appealing to me.

Basically I want to have the sleeper truck that makes people feel downright bad that the 6,000lb pickup DID just leave their WRX's turbo chirping in the dust behind me.. on the track, of course.

 

[DivideBYZero]

"Intents"

 

[mFei]

Originally posted by: DivideBYZero
"Intents"

Out of the many responses I expected from this type of a question, I honestly figured someone would resurrect the "I hate lifted trucks" thread WAY before someone decided to be a grammar nazi.

DBZ, you sir are my hero. And I genuinely didn't know I was mistyping.

 

[DivideBYZero]

Originally posted by: mFei

Originally posted by: DivideBYZero
"Intents"

Out of the many responses I expected from this type of a question, I honestly figured someone would resurrect the "I hate lifted trucks" thread WAY before someone decided to be a grammar nazi.

DBZ, you sir are my hero. And I genuinely didn't know I was mistyping.

PS: Lifted trucks are teh debil.

 

[Zenmervolt]

Originally posted by: Demon-Xanth
I'd go for the supercharger. Cost and complexity wise it's a lot easier and cheaper to install. As well as availability. Also, unlike a custom turbo kit, you're likely to be able to find a supercharger kit with a warrenty, CARB EO number, and everything needed to put it in proper tune. Turbos can make more power, but they take a more work to get right.

As far as where you can begin for naturally aspirated power. Things like an exhaust, chipping it, and an intake can wake the engine up considerably and are easily installed. I'm not sure what all is out there for the 6.0, but I'm sure an intake manifold, throttle body, and cams are likely to be around. It's a matter of how much money you want to spend and how much work you want to do.

This post FTW.

You can almost always get more power ultimately from turbos. However, that brings with it additional complexity and cost as well as a large amount of custom fabrication. The other downside of custom work is that it seriously reduces the resale value of the vehicle and makes it much more difficult to find a mechanic for. Since I'm sure someone will come after me for both of those statements, I will explain.

Yes, if you find another person who wants a custom truck you can sometimes get a small portion of your money back when you sell the vehicle. However, the pool of people who want a truck with a fully-custom setup is much smaller and the average person will look at it and say, "Well, that's neat and all, but a mechanic won't want to work on it and if something breaks I can't get parts for it.". Ultimately, custom work makes a vehicle more difficult to sell. That may not be a consideration, but it sometimes is.

As far as the mechanic comment, very few mechanics I know like working on custom cars professionally. It's harder to diagnose them and parts are more difficult to find. That doesn't mean you cannot find a mechanic, rather that you'll need to find a specialist. There are fewer specialists around, they can be harder to find, and they certainly will charge more.

If you never plan to sell it and never plan to have anyone but you work on it, go for it. But otherwise, just wait for a good aftermarket supercharger kit to come available.

ZV

 

[mFei]

Originally posted by: Zenmervolt
This post FTW.

You can almost always get more power ultimately from turbos. However, that brings with it additional complexity and cost as well as a large amount of custom fabrication. The other downside of custom work is that it seriously reduces the resale value of the vehicle and makes it much more difficult to find a mechanic for. Since I'm sure someone will come after me for both of those statements, I will explain.

Yes, if you find another person who wants a custom truck you can sometimes get a small portion of your money back when you sell the vehicle. However, the pool of people who want a truck with a fully-custom setup is much smaller and the average person will look at it and say, "Well, that's neat and all, but a mechanic won't want to work on it and if something breaks I can't get parts for it.". Ultimately, custom work makes a vehicle more difficult to sell. That may not be a consideration, but it sometimes is.

As far as the mechanic comment, very few mechanics I know like working on custom cars professionally. It's harder to diagnose them and parts are more difficult to find. That doesn't mean you cannot find a mechanic, rather that you'll need to find a specialist. There are fewer specialists around, they can be harder to find, and they certainly will charge more.

If you never plan to sell it and never plan to have anyone but you work on it, go for it. But otherwise, just wait for a good aftermarket supercharger kit to come available.

ZV

I paid 3/4th of the truck cash upon purchase, and brought my own financing for the remaining PURELY to use SOME part of the transaction to benefit my credit score. The 2.3% APR for the life of the loan probably helped that decision making process along, too.

I don't intend to sell this Truck and it will probably be my primary vehicle for a very long time unless I move to a city that is unfriendly towards vehicles of this size. Even in the future if I decide do so something else I will keep this truck for what it is intended to be - a monster powerhouse capable of hauling, mudding, rockclimbing, and burning rubber on pavement.

With that said, I care extremely little about resale value and am more concerned with what will help the truck stay mechanically sound longer - and from what I gather, a Turbo is a lot more stressful on the engine than a SC (please correct if wrong).

From the advice so far on my primary question it appears the best thing to do to appeal to my interests is to aim for the SC kit when Whipple or Vortec actually releases one for my vehicle.

Now - outside from this, what else should I really investigate? Even petty things like plugs or suspension mods would be appreciated suggestions.

 

[Zenmervolt]

Originally posted by: mFei
I paid 3/4th of the truck cash upon purchase, and brought my own financing for the remaining PURELY to use SOME part of the transaction to benefit my credit score. The 2.3% APR for the life of the loan probably helped that decision making process along, too.

I don't intend to sell this Truck and it will probably be my primary vehicle for a very long time unless I move to a city that is unfriendly towards vehicles of this size. Even in the future if I decide do so something else I will keep this truck for what it is intended to be - a monster powerhouse capable of hauling, mudding, rockclimbing, and burning rubber on pavement.

With that said, I care extremely little about resale value and am more concerned with what will help the truck stay mechanically sound longer - and from what I gather, a Turbo is a lot more stressful on the engine than a SC (please correct if wrong).

From the advice so far on my primary question it appears the best thing to do to appeal to my interests is to aim for the SC kit when Whipple or Vortec actually releases one for my vehicle.

Now - outside from this, what else should I really investigate? Even petty things like plugs or suspension mods would be appreciated suggestions.

Cool. I just wanted to put that information out there.

Done properly, a turbo setup is, IMO, less stressful on an engine because with a positive-displacement supercharger like a Whipple or an Eaton the S/C is always producing boost, even at idle. With a turbo setup, you're off boost a lot of the time and the engine only sees boost stress when you're on the throttle hard. It does take more care to set up a turbo well though. You need to run coolant lines to the turbos and oil lines as well (I am a big proponent of water-cooled turbos as it makes them essentially maintenance-free and vastly reduces the chances of coking), and you need to be sure to insulate the rest of the engine bay from the heat generated by the turbo.

On the other hand, there's not enough difference for it to really come into play. And having boost all the time is a good thing for a truck that wants to have low-RPM torque. I think you have the right track by looking at superchargers. I personally really like Eaton's offerings, so look at them as well as Whipple.

As for what else, exhaust, intake, and a chip will give you the most bang for your buck. You can also look into new cams if they are available for your engine, but that's more spendy.

ZV

 

[thomsbrain]

Originally posted by: Arkaign
Supercharger is always best for 8 cylinder vehicles.

Tell that to Lotus, Saleen, and Ferrari, to say nothing of the countless turbocharged V8 diesels out there.

 

[Arkaign]

Originally posted by: thomsbrain

Originally posted by: Arkaign
Supercharger is always best for 8 cylinder vehicles.

Tell that to Lotus, Saleen, and Ferrari, to say nothing of the countless turbocharged V8 diesels out there.

Yeah, I guess I should qualify the statement somewhat.

Supercharger is best for 8 cylinder vehicles, except for really expensive sports cars and diesels

 

[SnipeMasterJ13]

My vote is just do both! I've actually seen a few setups like that, and they are monsters!

If you have to pick just one, I'd go with the supercharger for all the reasons listed already.

 

[exdeath]

Turbo always has the potential for more power. You also have the luxury of trade off with turbo design to decide what you want. You can get bottom end torque on par with supercharging with properly sized turbos but limit top end potential, or you can go with over sized turbos and have max power up top but with a weak bottom end and narrow peaky power band.

Superchargers, especially twin screws positive displacement types (always pump the same amount of air per revolution, independent of RPM) like the Whipple, basically make your engine feel like it has twice the displacement; instant boost at all RPMs with a flat torque curve. Typically can be faster than a comparable car with turbo due to area under curve (ie: not just peak horsepower), but doesn't feel as fast due to the lack of a sudden surge of boost.

Turbos may run hotter under the hood but the outlet air is cooler and denser due to efficiency, which is why turbos in the long run can have more power potential. Superchargers don't get as hot as the exhaust driven turbos on the outside, but the air intake temps to the engine are much hotter, which limits maximum boost attainable compared to turbo. However the direct drive nature of the supercharger makes it's power response immediate, even compared to the most lag free turbo setup.

If you staying with the stock high compression engine, I would say go with the Vortec. The boost builds much more gradually with the centrifugal type blowers, and will be less stressful on the engine, and with the stock compression ratio you won't be suffering on bottom end torque like you would on a low compression blower motor with a centrifugal.

I'd go with whatever is cheaper. Without a forged motor and lowered compression ratio you won't be seeing much boost, and therefore the costs vs. benefit will quickly reach diminishing returns. It wouldn't make much sense for example, to spend $8000 on a custom turbo setup (that could run 30 psi on a built motor) to run 9 psi and have lets say 550 HP when you could spend $3000 on the supercharger (that could run 24 psi on a built motor) that you could install yourself in a day and also run the same 9 psi and see 515 HP.

Bolt on centrifugal supercharger kit is your best bet on a stock high compression N/A engine.

As always make sure that the computer and air metering system (MAF) are capable of measuring the increased airflow without "pegging", and that the fuel system is capable of compensating with an additional proportion of fuel to go with it.

 

[fbrdphreak]

It looks like this is the motor in that truck:

LQ9

The Vortec HO 6000 or VortecMAX, technically the LQ9, is a special high-output version of the Vortec 6000 V8 truck engine originally designed for Cadillac. This engine was introduced in other truck lines as VortecMAX for 2006. It features high-compression (10:1) flat-top pistons for an extra 10 hp and 10 ft·lb, bringing output to 345 hp (257 kW) and 380 ft·lb (515 N·m). LQ9s are built only in Romulus, Michigan.

LQ9 Applications:

* 2002-2006 Cadillac Escalade
* 2002-2006 Cadillac Escalade EXT
* 2003-2006 Cadillac Escalade ESV
* 2003-2007 Chevrolet Silverado SS
* 2004-2005 Chevrolet Silverado and GMC Sierra Vortec HO Edition Only [Badging on truck]
* 2006-2007 Chevrolet Silverado and GMC Sierra VortecMAX Option

This motor should have 317 heads, which flow pretty well and given the lower compression ratio when used with stock pistons, work well for a forced induction setup. If you're going to run NA and want more power, you will want to increase the CR with different pistons and depending on the stock valve size, perhaps upgrade those a bit. If you dig into the motor, hardened pushrods & aftermarket rockers are a no-brainer while you're in there. You should be able to use most of the numerous LS-motor aftermarket camshafts to add a nice 50+ RWHP.

I would vote for the bolt-on SC kit personally. Some of them are CARB-certified, reduce any driveability/tuning issues you might have with more wild heads/cam combo's, and your mileage shouldn't change much.

Whatever you do - make sure you invest in the fuel system as well. The stock injectors are likely already at their ideal duty cycle and even doing a cam-only upgrade will draw more from them. If you get into more aggressive cams or upgrading the heads, not to mention an FI setup, you will want to throw in bigger injectors (60lb flow-rate seem to be the best value, the 42lb-ers aren't much cheaper) and to be on the safe side, an upgrade fuel pump. Last thing you want is the motor to lean out and blow up on you.

You should visit http://www.ls1tech.com - huge resource there

 

[ElFenix]

how much different can a belt driven centrifugal compressor be from an exhaust driven centrifugal compressor in terms of power output?

 

[Zenmervolt]

Originally posted by: ElFenix
how much different can a belt driven centrifugal compressor be from an exhaust driven centrifugal compressor in terms of power output?

There's a small percentage of parasitic drag from the drive belt, but the compressor mechanism is essentially identically efficient.

ZV

 

[SJP0tato]

If this is your only car and is your daily driver, I'd recommend not doing anything beyond simple bolt-ons. Reason being, way too many times I have seen people install turbo/supercharger kits, have something go wrong (sometimes something as simple as a $0.25 piece of rubber tubing burn/rub through), and trash their only means of transportation.

It almost always works out better if it's a second car, where being out of commission for a few days/weeks won't hurt anything.

 

[Dman877]

Originally posted by: ElFenix
how much different can a belt driven centrifugal compressor be from an exhaust driven centrifugal compressor in terms of power output?

Superchargers normally spin up to a peak of 25k - 30k rpm. Turbo's will do 70k - 100k+. Higher rpm = more boost. Additionally, because a supercharger is connected to the crank, it's boost increases linearly with engine speed. A turbo can be tuned to achieve it's peak boost at any point in the rev range (after which the waste gate opens to prevent it from spinning faster).

That's how I understand it anyway. Might be wrong though.

 

[shabby]

First you need to figure out if you have enough space under the hood for either a pair of turbo's or a supercharger. If memory serves me right that engine compartment is pretty tight, so a pair of turbo's is out of the question. So that leaves you with a supercharger, either a roots type of centrifugal supercharger. For a roots type will need a custom low profile intake manifold, this will cost you a pretty penny since no one is making these so far. So that leaves you with a centrifugal supercharger.
Odds are it'll fit in the engine bay but you'll need a bracket to hold it and a longer belt to drive it, but thats the easy part. The hard part is making the ecm take advantage of the extra air that's being forced into the engine, and that certainly isnt easy especially when going from naturally aspirated to forced induction. Imo i wouldnt touch this with a 10 foot pole unless you know what you're doing.
Honestly i would wait until a s/c kit comes out for your truck.

 

[ElFenix]

Originally posted by: Zenmervolt

Originally posted by: ElFenix
how much different can a belt driven centrifugal compressor be from an exhaust driven centrifugal compressor in terms of power output?

There's a small percentage of parasitic drag from the drive belt, but the compressor mechanism is essentially identically efficient.

ZV

doesn't the increased exhaust pressure from the impeller do something?