MRAMG1

This statement by itself is not true my friend.

Just because the supercharger can supply more airflow does NOT by itself imply more horsepower.

Now if you are talking about the entire engine, aka heads, valves, cams, intake and exhaust system, then YES I agree whole hardly

Sometimes bigger is NOT better in the realm of engines.

Just ask the guys in old small blocks that put in a BIG cams and see what that did for their performance

Or stuffing on a HUGE throttle body and leaving the rest of engine stock

Edit: Please also do not forget to upgrade the fuel system as well to satisfy that addtional airflow, aka larger injectors, fuel pump, and fuel lines.

Ask me how I know, ha, ha

Biscuit

Now here is something worth discussing in this thread. With all the experience floating around in here why don't we try to come up with a supporting mod list required for the larger supercharger? Then try to start attaching some prices to those mods. At least this way even if nothing ever comes of it the next time this topic comes up, because we all know it will, we just point people to this thread with a "Here is what to expect.".

msheredy

Thank you! Couldn't have said it better myself, (and I tried )


When we have conversations such as this I feel that's it's implied that we're talking best case scenarios here (real world upgrades with appropriate supporting mods). Nobody's saying to go out and install a 14-71 blower on a C32 to get the most HP.

-Matt

c32AMG-DTM

Interesting that you say that - this conversation started out discussing removal of the OEM S/C and installing a larger-displacement Kenne Bell unit in its place, but otherwise keeping the rest of the engine stock (surge tanks/plenum, cyl heads, bottom-end, etc.). And that the Kenne Bell S/C would make significant power at only 10 PSI of positive boost pressure through an otherwise stock C32 motor.

Here's a data point for you guys, maybe this will help the discussion:

Thanks to mustang281man for initiating the S/C CFM example. I'll expand on it a bit, if that's alright. We're assuming a 100% stock C32 motor @ 6K rpm.

OEM S/C, OEM pullies
CFM = 712, resulting in recorded boost = 14.5 PSI (which we know, per AMG, as well as datalogging)

OEM S/C, 178 pullies
CFM = 815, resulting in recorded boost = 18.5 PSI (from many owners' datalogging)

OEM S/C, 185 pullies
CFM = 847, resulting in recorded boost = 22+ PSI (from many owners' datalogging)

So, a 14% increase in CFM results in a 28% increase in PSI from stock.
And, a 19% increase in CFM results in a 52% increase in PSI from stock.
Perhaps even more telling, is the increase from 178 to 185. A measly 4% increase in CFM causes a 19% increase in PSI.

What do you think the boost pressure will rise to if you start pushing 979 or 1165 CFM of airflow through an otherwise stock motor? 28 PSI? 30+?

MRAMG1

Well with out getting into it, I do not imply anything as it only makes for bad scenarios IMHO. I would not expect anyone was looking into a 14-71, glad to know you are informed. However, you are taking it to the extremes my friend.

I am stating with good knowledge that simply putting a LARGER Lysholm screw blower on a stock C32 motor is NOT going to do you any good. UNLESS, as I have stated, you up the boost, and the corresponding MANDATED equipment.

Please prove me wrong

msheredy

Well this just turned out to be one of those overly drawing out arguments where no one can agree or come to a consensus . No sense turning blue over this one

-Matt

TemjinX2

agreed.

mustang281man

Yep I agree, we put the data out there for people to use if they want to. Would it be cool to put a kenne bell on a c32? Yes. Would it be worth the money? No probably not. I would say just step up to an e55, or a c6zo6 which is what I'm in the process of getting. I also have some c32 performance parts for sale, if anyone is interested pm me. Brett

MRAMG1

Guys, I am ALL for it in a MAXED out style

I am just trying to save you some money, as it really isn't going to do a thing on a stock engine. Sorry for the reality of it all. But physics work, whether you like them or not.

Sorry to break the bad news as I am NOT busting anyone's ***** here. At least that wasn't my intention.

And if you are willing to do ALL of the leg work, it could turn out to be a FREAK. Just expect to buy into it north of 10K to see any real return. AKA heads, cams, injectors, fuel pumps, ECU or stand alone, etc, etc.

c32AMG-DTM

+1

I thought it was a good discussion, but I guess others just see it as an argument. I agree with you, I'd love to see someone attempt it, but they should know that simply switching twin-screw blowers isn't going to yield any significant improvements, especially if running the system at low boost (e.g. max of 10 PSI @ 6k engine rpm) on an otherwise stock C32 engine. That approach would actually result in a lower-than-stock level of output. Doesn't make sense to do that, and IMHO shows a fundamental misunderstanding of how the system works.

However, if one were to P&P the heads, build the bottom end, increase the capability of the fueling system, address any IC system inadequacies, and crank up the boost to 20+ PSI with that shiny new 2.6L blower... now we're talking serious gains. Would be expensive though.

msheredy

LOL! I like how you 2 think you are right and the 3 of us are wrong

MRAMG1

As you obviously have all the answers and no one else could possibly know anything better than yourself. And since the laws of physics do not work in your universe.

Just please go ahead and do it.

Good luck, good reddens, audios amigo.

c32AMG-DTM

It isn't just two of us.

If you don't change the volume of the intake tract, don't increase the flow capability of the heads, don't change the CR of the pistons, etc. etc. - you can't run a larger blower that pushes more CFM than the stock one at a given engine rpm, without causing a corresponding increase in boost recorded at that same engine rpm. You might think that's just "my opinion" - I believe it to be the physical reality of how the system has to operate.

Conversely, let's say you back into it with a specific boost target for the larger blower (say 10 PSI max @ 6k engine rpm). You'd have to slow the bigger blower's rpm way down with your pulley ratio (and with a corresponding decrease in CFM level) to make sure you don't exceed the targeted max boost threshold.

You guys seem to suggest that changing one variable (larger 2.6L blower), but keeping everything else constant, blower-supplied CFM goes up proportionally at all engine rpm's, but somehow boost goes down at the same time? Think about that.

dlwiser

Hi fellas! TemjinX2, you sir are exactly right! I am living proof of your thoughts. I when I upgraded my S/C I made MORE hp at a mere 16psi than I did with my OE charger. I had upper and lower pulleys installed on both systems.

splinter

Is this one of your posts?
It's all good,dlwiser. :y

Seems Kenne Bell’s superchargers don’t mind being overdriven a bit.
Witnessed this gent laying down solid 10-second/130+ mph passes in his Featherlite-transported Lightning..

Biscuit

Just going to throw out one small idea here... Everyone on this chain is correct. Just look at a couple small facts here:

1.) If a small blower were to generate 15psi at 500cfm then a larger blower is still going to generate 15psi at 500cfm. You can't get around that. It has nothing to do with the blower itself but rather anything the air traverses beyond the blower. This would be the case if you did a flat out blower swap with no supporting mods at all.

2.) A larger blower could still be capable of generating more horsepower at the exact same rating of 15psi at 500cfm if it has a higher adiabatic efficiency than the smaller blower. Less heat = colder air = more oxygen per CF of air. If the efficiency difference were large enough then it could theoretically be possible for the larger blower to generate more horsepower at a lower PSI.

That's the way I've always understood this to work. To me it seems like everyone is right and nobody is looking at the whole picture.

TemjinX2

A twin screw compresses air, the roots sc does not and is a straight blower. Hence the slang term people came up with as "blower".

So yes, a larger blower that can compress the air more efficiently can provide more cfm because the air molecules are compressed to a smaller size to increase the volume of air.

Here's a article I found the different types of superchargers. The efficiency arguments makes more sense on the roots type blowers.

The Roots Supercharger
The roots supercharger was originally designed as an air moving device for industrial buildings. The roots supercharger features two counter-rotating lobes that trap air from the intake side of the supercharger (normally at the back of the supercharger), move it around the outside casing of the lobes, and out the bottom of the supercharger through an outlet / discharge port.

First, the roots supercharger does not compress air - it only moves from the intake port to the discharge port (i.e. it is the only supercharger design with no internal compression ratio).

The Twin Screw Supercharger

At the heart of the twin-screw supercharger are two rotors, or "screws" that rotate towards each other. The rotors mesh together and draw air from the back of the supercharger. The twisting rotors move the air to the front of the supercharger, while compressing the air before discharging through a port at or near the front of the supercharger.

Because the compression is done inside the supercharger, this design produces less heat than a roots supercharger - in fact, it is almost as thermally efficient as a centrifugal design.

One disadvantage of the twin screw design is that, because it has an internal compression ratio, the twin screw is compressing air even when it is not sending boost to the engine
(i.e. under cruising or deceleration).

The Centrifugal Supercharger
The centrifugal supercharger essentially operates like a high speed fan propeller / impeller, sucking air into the center of the supercharger and pushing it to the outside of the rapidly spinning (40,000 + rpm) impeller blades. The air naturally travels to the outside of the blades because of its centrifugal force created by its rotating inertia. At the outside of the blades, a "scroll" is waiting to catch the air molecules. Just before entering the scroll, the air molecules are forced to travel through a venturi, which creates the internal compression.

http://www.superchargersonline.com/content.asp?ID=76

here's a better description of how the twin screw compresses the air.

http://www.kennebell.net/techinfo/ge...romcatalog.pdf

Biscuit

Yep, I'm aware of the different types of superchargers. Just faster to type blower. I was making no inference as to the actual type of supercharger.

TemjinX2

what supercharger did you use? What are you running 1000cc injectors?

Were you able to reuse the oem intercooler and throttle body?

msheredy

LOL! At least I know how to spell! Here's a little advice for you, If you're gonna try to make me (or anyone else in the future) look bad please do yourself a favor and run spell check. You do know how to do that right? Do you need me to tell you how that works too

Newzchspy

Picts, video, time slips or dynos of this SC you put on your C32????

MRAMG1

Ah I have just been mortally wounded. You really are a peach my friend.

Stop de railing this thread and PM me, as I won't waste band width on you anymore

TemjinX2

i'm hoping dlwiser can clarify what he did. I'm started this thread, because I wanted to see how viable it would be to reuse the oem parts to keep the engine bay oem looking.

Otherwise, going turbo or a centrifugal sc would be more of a cost effective way of making power.

gt4awd

To sum it up bigger isn't always better. (Johnson Thread) Yes, mine is bigger though...

I really think our best option would be forced induction via turbocharger. We can run the same boost with more potential output due to the belt driven losses of a supercharger being eliminated. Wouldn't it be in the range of 80HP gain just by running 22PSI boost off a turbo? Internals could be left alone. More cost efficient.

betrezra

Turbo does not have the parasitic drag of a blower; however, more complex:
Heat, must run oil in/out cooling lines, and must run exhaust lines, and custom cold side lines...... and you now have to plumb an intercooler.

The eaton supercharger with heatexchanger is really a fabulous tidy/powerful package, with off idle tq to make some big blocks jealous.