0APS

I'd take a guess and say around 26 hours for a competent shop to install an APS twin turbo system on the C6 and possibly quicker one the shop had a few TT installs under their belts.
I am asking what the other shops charged their other customers. I'd estimate around $2k for an install though obviously this will vary across the country due to higher business costs in some regions.
I hope that my post adds value for the guys.

Peter

Swave Dave

REPLY: The Magnuson website says that the MagnaCharger consumes "1/3 h.p." if i read it correctly. Further, dyno sheet on an 06/LS2 has the Maggie at 560 rwhp/ 500 rwtq ; this is 160 h.p and 100 tq over stock .... absolutely more than enough for the street (and strip imho).

TTRotary

That's when free-spinning, off boost. They have to list this, because there is no way to de-clutch the blower. Positive displacement blowers consume A LOT of power under boost. For example, the Ford GT's Eaton blower consumes 90HP under boost.

Swave Dave

REPLY: Considering the dyno of 560 rwhp and 500 rwtq..regardless of what it consumes, its plenty of power for the street. ANd, its well engineering for the LS2 and is proving reliable. If it were a Strip Car, then squeezing every little bit from a SC would be important. THis seems to be the consensus on this thread.

Swave Dave

REPLY: Heres what the Magnuson Website says on the consumption ; note that they say this is at '60 mph'.

TTRotary

Yes, that's off-boost, just like I already said, so you have an idea of highway mileage impact.

My point about turbos was that they put less stress on the engine for a given power level than a S/C does. That's extremely important when adding boost to a high compression engine that is susceptible to detonation.

Also, the higher efficieciency translates into more max. power if that is what you are after. Turbos are capable of producing boost levels that are far beyond what any engine can take and are far in excess of what an S/C can produce. Either way, they are the technically superior solution in a street/strip car. Neither is inherently more or less reliable than the other, and both use wastegates. A crappy install and incorrect tuning will blow your motor either way.

promod69camaro

My diesel truck has a turbo charger on it. Not a supercharger. The turbo is more efficient. Have you ever watched the drag races on TV. Those blower belts don't just break because they are built poorly. They cost about $275 each and can handle around 800 HP before coming apart. Why do they use such large belts? It takes that much power to turn that blower moving the volume of air it does. Why do the belts break? The forces on the blower exceed the capacity of the belt and something has to give. Better the belt than the crank.
You do not get anything for free. With a turbo, you get increased back pressure. That makes your exhaust stroke not function as efficiently as free flowing exhaust. So you are burning a little exhaust that has already been burned and just could not get out because of back pressure. But you are not taking power from the crank.
I like turbo chargers. I think that blowers are easier to control.
Just my thoughts.

0APS

Why do you think blowers are easier to control? I reckon that turbochargers are far easier to control (I assume you mean controlling boost pressure) in terms of boost pressure and with computer technology available today the boost pressure of the turbocharger can be mapped across the entire rpm range for optimum torque and power.

Peter

promod69camaro

You are very correct in the statement that torque and power can be optimumized over the entire RPM range. But I do not think it is easier to control. Now with full service companies tunning cars like you guys do, it makes it much easier for me to purchase a kit and have a successful install.
With a supercharger, I have a map of volumectric flow verses rotor/compressor RPM. So at a given RPM, I know how much air and how much fuel is necessary for efficient combustion. The only changing variables are temperature, barametric pressure, and humidity. That is why a low pressure kit can be successful with ignition retard and adjustable fuel pressure regulator calibrated to the intake manifold pressure. With those kits, you just run rich enough to cover all situations. If you do creep into pre-ignition, hopefully your knock sensors will be to your aid.
I do believe in turbo systems. And I look forward to having one. I am glad companies like yours are out there making it easier for enthusist like us.
When you map the fuel and ignition curves for the car, does the map adjust for altitude? I like to travel to Colorado frequently and have been wondering if the system will be as accurate at altitude as it is here in Dallas where it will be tuned.
I really like your work.

TTRotary

To maintain boost pressure at altitude, you need an absolute pressure transducer aka absolute MAP sensor. Most factory pressurized engines use this system, and GM does therefore make such a sensor. Whether the Corvette's ECU can read this or not is the question. I know all Ford ECUs have that capability built-in.

You will reach your set boost level at altitude with this system, but your lag increases as it takes the compressor longer to pressurize the intake in thin air. On the plus side, you get better turbine efficiency becuse of the greater pressure drop across the rotor.

ronsc1985

This is not generally true if you are running in the high efficiency island of the turbo map to begin with.
If you require the pressure ratio to increase to achieve the same absolute pressure at higher altitude you will most likely shift to a lower efficiency island in the map.

With respect to compressor efficiency of a turbo vs SC it depends what type of SC you are talking about. A Procharger for instance is a centrifugal compressor just like any turbo and it's compressor efficiency is the same for a similar size turbo.

Don't anyone compare what goes on in TF or FFC classes in the NHRA or IHRA. Comparing these nitro motors to anything that will ever be seen on a Corvette is like comparing your local little league baseball team to the New York Yankees. BTW the belts usually break because of an internal blower failure which locks up the blower internals in these engines. These SC setups inject fuel right into the blower. Any valve hang then usually does in the blower internals plus assorted other damage. When a belt breaks usually a lot of other things need to be replaced before the next pass in addition to the belt. These blowers use about 150 hp which is well within the design limit for the belts unless something tries to seize up. They also are run at something like 50% overdrive which adds up to the blower spinning somewhere north of 11,500 rpm's.

TTRotary

What is not true? I agree with you that you shift to less efficiency, but that corroborates my statement about increased lag.

I never stated the compressor efficiency was different. I was referring to the compressor drive system: One (the S/C) draws crank power, while the other draws nearly "free" exhaust energy. The efficiency is obviously higher for the turbo.

No sure why some of you are not getting this...

promod69camaro

He is right in what he has said. Crank power or exhaust, the power has to come from somewhere.

I am not compairing a corvette motor to a top fuel motor. I am making the point that it takes energy from the crank to move the air. In the case of top fuel, a lot of energy and its easy to see because the belt can break. We all have see top fuel belts break and it just kind of leaves an impression in our mind. I am making the point that blower power is not free. Please do not say I am compairing a procharger system to a top fuel system. I am saying they are the same in that they are crank shaft driven.

Blower belts break for a lot of reasons. Most of the time its not the blower failing causing the problem. The blower has a lot of rotating mass. I have a lot of expertise in racing blower motors. I have a race car with a top alcohol blower motor in it. We use a cam driven fuel pump and try to match the fuel curve to the blower curve. Its not easy because the curves are not the same. But that is a discussion all its own.

My racing blower has about 30 lbs of rotating mass inside the case. The edges of the blades are said to rotate at near the speed of sound. So imagine a 30 lb blender spinning at the speed of sound and you get the image of the energy it takes to spin a blower. A street blower may have 5 lbs and rotate 1/2 the speed of sound. You can see this in your mind. It takes more power than you first think.

When we break a belt, its usually because of the tune up. If the detnation is bad enough, the motor will stop instantly. The blower has a whole bunch of rotating mass depending on the RPM at detnation. Something has to give, and thank goodness its usually the belt.

But back to my point, it takes power from the crank to turn the blower. And we can predict the amount of airflow at a given RPM for any blower. We take temperature, RH, and altitude in calculate and adjusted altitude for the blower performance. Then we set up a tune up to try and run the predicted conditions.

It was hard to do that in the past with a turbo motor because boost has a lot to do with launch and is not RPM dependent. If you spool up the turbo real good then launch, you will have a different pressure than if you spool it up little, drop the clutch and then floor it. There were just to many variable to keep up with, so a blower was the preferred system because you have a given volume of air with every rotation of the blower.

Modern turbo systems do not suffer from the problems I just stated above because of the electronics function so quickly that they track and match the performance of the turbo system. I am very glad the electronic systems are available and they work very well.

I know I am getting long winded, but I want to excite a few people out there to look into modern turbo technology. My engine is almost twice the size of a turbo motor making the same power. It does take hundreds of horse power to drive a large race blower. Other wise, my motor would not have to be 200 CID larger to make the same power.

If you guys get the chance, go to a local promod or outlaw back half event and look at the turbo engines starting to show up on the scenes. Not the foreign cars, but the quick 8 and promod cars. There are cars out three capable of running the 1/8th mile at 4.0 seconds and quicker with under 400 CID and a big hair dryer.

I hope everyone enjoys this. It has taken almost an hour to type, but I am passonate about power and have enjoyed this time with the key board.

Mr.Big

I have, and have had many turbo and S/C "street" cars and bikes, busa 500+rhwp, Supra 900+rwhp, Viper 700+rwhp, Corvette 620+rwhp to name a few... I like superchargers on street cars, and turbos on bikes...just my opinion after several hundred thousand invested in my rwhp
"Habit"
Jeremy

promod69camaro

I have heard Supra stories but have never seen one run. I hear its not that hard to make them really fast. I would like to drive one some day. I noticed that you live in the Dallas area also. Do you ever go to the Texas King of the Hill Outlaw Backhalf Races. We run at Denton, Redline, Kennedale, and a few tracks in the Houston area. I have a KOTH car, but have not been able to drive it. I was hurt two years ago (non racing) and just can't seem to recover well enough to drive. One of these days, I will figure out how to shrink one of my car pictures to I can put it on my advar.

Is you C6 an auto or stick? If its a stick, does your leg get tired in heavy traffic? If its an auto, did you have to modify it to handle the extra power you are making?

Thanks,
Shawn

ronsc1985

Compressor efficiency refers to the increase over theoretical of the temperature rise in the compressed air. This is the standard definition of the term and is what is represented by the islands on a compressor map. The way it usually goes in engineering is you don't get to make up your own definitions unless you are the inventor.

Don't confuse this with the overall compressor system efficiency. There is no debate about whether a turbo system is usually more efficient but for comparison purposes with a supercharger system this is only part of the equation. Each has it's place and price point.