more supercharger talk

[tindias]

just imagine how much power it takes to pump out 22psi? LOTS! a turbo makin 22 psi will take right about 9 horsepower to build the boost.

A Lysholm will not use any more than 9 hp to make 22psi.

Brendan

i call extreme bull***... theres no way you can compress 22 psi of air with a roots supercharger powered by 9 hp. roots/twin scroll, what ever, it takes more than 9 hp. a eaton M90 takes almost 40 horsepower to make 15 pounds of boost...

lysholm superchargers do not work with voodoo and black magic.. the laws of physics still apply to them too.

Someone's been drinking Hater-ade this morning.  First off, root and Lysholm are two different things.  THe Twin screw has over 80% efficiency on the adiabatic scale.  Most root style chargers are closer to 60%.  Now once again, there reason for this project for me was to do something no one had done before.  I started this project in the early summer, to find something to do with my caddy. I also have a 2002 golf TDI and enjoy the turbo.  I am not saying one is better then the other, I just want both.  If you are going to be a hater then go find another topic.

[Turbinepowered]

Hey guys, we can have a calm discussion about this...

Just popping off PSI numbers for superchargers without talking about how much air they're moving while making that boost is rather meaningless. It takes a lot less power to push a liter of air at 15psi gauge pressure every minute than it does to push a thousand liters of air at 15 psi gauge pressure every minute.

I'd like to see a source other than the manufacturer's for that 80% efficiency for a lysholm. I've heard 60-70% for twin screw superchargers, with rootes blowers being more in the 25-40% efficiency. A centrifugal supercharger tends to have turbo-like efficiencies, in the 60-70% band, but the big advantage I see being hawked of a twin screw is that it's the "instant boost" throughout the RPM range, unlike a centrifugal.

[tindias]

Caddy is running, just needs to be fine tuned a bit.  Still needs some exhaust work done and I should be able to post a few pictures.

[macka]

A lysholm charger and a roots charger have twin screws, thats where the similarities end. A Lysholm has steeply tapered screws whereas a standard roots charger has a gentle taper. This steep taper keeps the charge cooler from what I understand, which is what we want, a cooler denser O2 level in a cooler charge. PSI means something, but if you are pushing hotter air, other factors come into play such as PING and combustion efficiency. They may be in the same zone for charge volume, but the cooler charge is going to win as it has more usable oxygen.

[Rabbit on Roids]

im not trying to be a dick or start stuff, it just pisses me off when people think that something is way better just because they have one. lysholm chargers are good, sure, but they are not magic. i bet a g60 charger is more efficient than a lysholm.
and saying that a lysholm takes less than 9 hp to make 22 psi, yea, maybe if its moving a small amount of air at 22 psi. but a diesel engine takes significantly more air than that... i think its awesome that people are putting chargers on their diesels. i wanted to do it so bad, but i just dont have the means to do it right now.

[tindias]

The reason I went with the lysholm is because it is more efficent then the G60.  I researched this for a long time before I purchased the charger and started the project.  The main reason I suggested it to truckinwagen is because we are both working on a similar project.  The G60 is bulky, is known for failures and appears to be a pain to mount.  The lysholm is half the size and much easier to mount considering you have to work around the IP. 

[truckinwagen]

I may be totally wrong here, but I had always understood that scroll superchargers were the most efficient positive displacement supercharger(better than twin screw, but not as good as centrifugal)

the G60 is the only really available scroll supercharger, it really is not that big(the lysholm is just flatter and narrower)

the cheapness and efficiency are what drew me to the G60(that and they are fairly quiet)

I think I am going to initially build the motor with an N/A injection pump, the supercharger will make boost based on throttle position, not engine load, so I think it will work well, and will be easier to tune.

I will introduce the Cummins pump eventually, but as the project has been put on the fast track, I will wait on it.

[Turbinepowered]

Both the Lysholm and the G60 (scroll) are internal compression superchargers, which is part of what makes them more efficient. All of the compression takes place within the body of the supercharger itself, in a relatively gradual manner. They make boost pressure through finesse rather than the Rootes blower's brute force, shove-more-air-than-the-engine-can-swallow approach.

The slower, more gradual compression over the body of the 'charger means that the air is cooler when it comes out, yes, so you get more actual air mass making the pressure versus heat applied to a smaller mass to produce pressure.

[macka]

im not trying to be a dick or start stuff, it just pisses me off when people think that something is way better just because they have one. lysholm chargers are good, sure, but they are not magic. i bet a g60 charger is more efficient than a lysholm.
and saying that a lysholm takes less than 9 hp to make 22 psi, yea, maybe if its moving a small amount of air at 22 psi. but a diesel engine takes significantly more air than that... i think its awesome that people are putting chargers on their diesels. i wanted to do it so bad, but i just dont have the means to do it right now.

no the exchange of info is what keeps us up to speed. When name calling occurs because someone can't discuss something because they really don't know. Its good to be able to argue and discuss the pros and cons of these situations. Hell it may bring a point up that the builder missed, even if it is a wild hair but can cause a major problem for the build.

[truckinwagen]

well, I spent a couple hours on the motor, and I have the webbing welded to the supercharger bracket spacer, which is about an inch shorter.

the supercharger is now as close as it can get without interfering with the injection pump itself.

I had to clearance the injection pump bracket, and the supercharger mount a bit, but I don't think I hurt the structure of either.

I will be spending some more time on monday, and will hopefully have the pan and head on by the end of monday night.

[gtidiesel1.6]

Sounds like an interesting project, i have a blown g60 engine in the garage with charger and all accessories and bits but not the encouragement to throw it on a diesel. If there's any g60 parts/info you need let me know.

[truckinwagen]

well, I bought a headgasket for $65.

all the cheap stores only had three notch ones, and as I needed a one notch I was forced to go to FATS, possibly the most expensive place in the world to buy car parts.

as for G60 parts, I need the little link that goes between the back of the throttle shaft to the boost return on the G60 throttle body.

if you could spare one that would be great!

-Owen

[gtidiesel1.6]

well, I bought a headgasket for $65.

all the cheap stores only had three notch ones, and as I needed a one notch I was forced to go to FATS, possibly the most expensive place in the world to buy car parts.

as for G60 parts, I need the little link that goes between the back of the throttle shaft to the boost return on the G60 throttle body.

if you could spare one that would be great!

-Owen

thats probably the only thing i dont have, sorry.

[truckinwagen]

thats cool, I was planning on making a new one with a pair of hiem joints and some allthread.

I got the head on, supercharger on, bottom end torqued, camshaft in, valves adjusted, pulleys on(the VR6 water pump pulley works perfectly), and the boost tubing on.

all I have to do now is throw the oil pan/valve cover on, install the injectors and pump and time it!

should be firing up next weekend!

[Smokey Eddy]

thats cool, I was planning on making a new one with a pair of hiem joints and some allthread.

I got the head on, supercharger on, bottom end torqued, camshaft in, valves adjusted, pulleys on(the VR6 water pump pulley works perfectly), and the boost tubing on.

all I have to do now is throw the oil pan/valve cover on, install the injectors and pump and time it!

should be firing up next weekend!

Video... please...