Which supercharger is better? Why? :confused: :confused:

 

well there two different types. The ati will increase boost in a non linear relationship with rpm. The Magnason will increase boost in a linear relationship. The ATI will have more boost at high rpm. The magnason will have more boost at low rpm. The ATI wont require a new hood. The magnason will. The Magnason will probably be simpler and more reliable (no intercooler, many used OEM in other cars).

 

I believe the Magnuson puts out a hotter charge since it isn't intercooled also, so you'll want a forged bottom end for sure for significant boost as well as pulling more timing.

 

I called Lingenfelter to get a copy of the dyno run made on the Magnuson car in Car and Driver. Apparently they are not allowed to release any graph or charts at this time. I haven't found anyone with a Magnuson yet that can supply some feedback. It would be really nice to compare a dyno table for both to help in making a determination as to which I perfer. Someone posted an ATI table a little while back, most of the power is at the top end.

 

I believe your infromation is incorrect. The ATI will increase boost linear with RPM and make significantly more top end power. The Magnuson power and torque curve is not linear. Quicker bottom end response and torque but less top end power. I would be very suprised if the ATI did not out MPH the Magnuson in the quarter mile. Et's should be close with possibly a slight edge to the Magnuson at comparable boost levels. However, if both cars are launched equally, although at differnt RPM due to differing torque curves, the ATI will win hands down.

 

True and this is the 1/4 mile.

Rolling on the street or highway the ATI should really be in it's sweet spot!!

 

Turbos rule.....put that exhaust heat to work. Supercharger is one more parasite on the belt.

 

Let me make this simpler. linear = strait line, in this case with a slope = 0 so you will see constant boost but more boost at low rpm relative to the ATI.
exponential = f(x) = a^x So you will see more boost at higher rpm with the ATI, and it will be a curve. Why? because it is a fan and the output of a fan is not 2X at twice the speed, it is >2X.


[Modified by 1990bevile, 3:49 PM 4/15/2002]

 

also turbos are cool but they put the exaust heat to bad work also. They heat up the air ont the intake side, also were do u think all the power in the exaust gas is coming from? Thats right on the exaust stroke the piston has to push exaust gases out which are even harder to push with a turbo in the way, so turbo's arent compleatly unparasitic. Right?

 

The Magnuson is a Positive Displacement (PD) supercharger. The ATI (along with other centrifugals, Vortech, Powerdyne and including turbos) is a Dynamic Compressor (DC) supercharger.

PD's move more or less the same volume of air per rotation. This produces a fairly flat boost line from off idle to redline. An 8-psi setup would make close to 8 from say 2000-6000rpm.

DC's actually compress air internally and must spin relatively fast to make any boost. Once making boost the boost climbs faster than rpm creating a "growing" boost line starting from around 2500rpm (varies by application) with 1-psi to redline making the rated 8-psi.

Performance is completely dependant on how the vehicle is geared and driven. The midrange power of the PD will outpower the DC. Usually (not always) the top end power of the DC will be greater at a given boost level.

A turbo does use exhaust energy to power the compressor but the heat of the boost coming out of the compressor (ANY compressor) is almost completely due to the adiabatic efficiency of the compressor and not the fact that exhaust is flowing through the turbine side. DCs usually are more efficient than PDs so the boost temperature will be lower at any given boost. Turbos can have lower compressor outlet temps at a given boost level than DC superchargers. DC superchargers can have lower boost temps than PD blowers but NOT always! Many variables are at play.

If you noticed how often I said "usually" you can get a guess as to how critical total system efficiency is. Intercooling is after the supercharger and before the intake and has NOTHING to do with compressor efficiency. Intercooler efficiency is another subject completely. PD setups are often the most simple and make very good power. Turbos are usually the most powerful but also the most complex.

Years ago I tested the highly efficient lysolm type PSI supercharger on Offshore powerboats 572cid engines. It was replacing the theoretically lousy GMC 8-71 type roots blower. Although physically bigger the PSI displaced closer to a 6-71. The result was LESS power at a given boost level. BIG surprise! I look forward to seeing the Magnuson setup and anticipate BETTER performance than some are guessing. The Eaton M112 is a highly refined roots type blower with surprising efficiency in the rated range.

 

Withya on everything, but with the ATI DC's, aren't the intercoolers between the SC and the Intake?

I haven't heard anything about Magnusons and intercooler setups yet.

 

I agree !!!!!
Show me the DYNO !!!
Only then can we make a choice.

Anyone know if the Magnuson will require the KEYED HUB

 

The 490hp(flywheel) as tested in C&D will set you back about $11300 it include intake & exhaust mods. For that much $$ I'd rather do an all bore. There 's no question as to the drivability & reliability of the unit, the question you should be asking yourself is whether you're willing to spend the xtra $$. I spent $6400 for the ATI 7lbs installed. W/ just the SC my completely stock 99 FRC(down to the mufflers) makes 476rwhp & 417rwtq & yes useful boost doesn't come on until about 3000rpm(just over 2lbs). Then again remember you're driving a 5.7L high performance V8 not some dinky little 4 or 6 cyl for that matter which bottom end power may be an issue. As it is, it's hard to keep the car hook up. W/ street tires the 7lbs ATI setup should at the very least match the magnuson 5lbs kit...W/ a lot less $$. :cheers:
Keep in mind gobs of tq down low may be good for you but NOT for your drivetrain. :D


[Modified by boblackhardtop, 2:57 AM 4/16/2002]

 

MellowYellow, yes, the intercooler is between the outlet of the compressor and the intake. The C5 Magnuson does not appear to have intercooling as an option. However, the Ford Lightning uses this supercharger (Eaton M112) and has an air-to-water intercooler sandwiched between it and the intake. With a tall enough hood bulge one might be able to use this type of intercooling. The 89+ Ford Supercoupe used an Eaton M90 in which the outlet pointed up and ducted to a front mount air-to-air intercooler and then to the intake under the supercharger. That design was complex and limited the intake to little more than a plenum.

 

It doesnt matter how good the mag. kit is right now, its not available. Lingenfelter said TODAY end of July-June at the earliest, they had 27 people with 50% deposits. RK sports and TByrnemotorsports, said a couple weeks. But werent sure, and I think they know its going to be a good bit longer. I really want a supercharger, and guess I will just go with the ATI and deal with the tuning involved.

 

Of course if you read other posts some people dont even gety there ATI's for months and months so maybe u should wait.

 

In reply to the original question, a couple more thoughts, the ATI will have more max power potential and is intercooled. The Magnusen will make more mid range torque (for a given max boost level) and is considerably quieter at idle and cruise. DC use step up internal gears. Some, like the Vortech quiet series head units have helical cut gears that are not as loud but the others use straight cut gears that make what many consider unwelcome noises at idle. Try to find a car already equiped and listen to it to determine if it will be acceptable for your car and attitude.

 

I know.... I know.... I want to see the dyno :cry I want to see the dyno :cry I want to see the dyno :cry

 

I would love to see a dyno too. :yesnod:

 

I believe the Magnuson might give the ATI quite a run in the 1/4. The overdriven roots blowers in the funny cars are pulling 50lbs or so......and I believe they tried turbos, similar to centrif blowers, but that tiny lag was enough to make the roots the blower of choice. Detonation might be handled with methanol/water injectionfor a little extra punch. If centrifugal sc was the fastest, then that's what would be used. I think I'm right but feel free to correct me.
All we need is more room under the hood.....then all kinds of wild plumbing could be done....personally I like the looks of the ARE twin turbo setup under developement.