Any Comment About RMS supercharger

[Carzzi]

Originally posted by Rich 328
I doubt a Pos. Displacement SC will see the light of day. its the holy grail of 6 cylinder BMW's. I think if it was possible it would have already been seen on the E36's; downing atlanta has a 4-cyl model, I am sure there is a reason why they didnt tap the 6 cyl market.

Hiop racetec (www.hioprace-tec.com) makes a lysholm/autorotor for the M52 single VANOS. Dunno whether they make one for the newer sixes tho'. They advertised in either Bimmer/Roundel or summin'likezat. They had an intro price of around $5-6K. Call them if it's not listed on their website.

[wontonjon]

figured it out...

so there are basically three types of blowers on the market

1. centrifugal blowers (everyone's heard of vortech)
2. screw-type blowers
3. positive displacement ...otherwise known as roots blower

just an fyi

...waiting patiently for blower...and money...
-----------------------------------------------------
and btw, did any of u guys check out one of the ebay auctions...bout to end but i thought it was a pretty good deal...item:600015061

evidently...the divorce is forcing the sale of below vehicle...

http://cgi.ebay.com/ebaymotors/aw-cg...item=600015061

[RichP]

Originally posted by Carzzi


Hiop racetec (www.hioprace-tec.com) makes a lysholm/autorotor for the M52 single VANOS. Dunno whether they make one for the newer sixes tho'. They advertised in either Bimmer/Roundel or summin'likezat. They had an intro price of around $5-6K. Call them if it's not listed on their website.

Carzzi, this company has been touting this thing for years now, and I still havent seen anything become of it. When I designed my kit, I came to the conclusion that it may be nearly impossible to do a roots blower without major modifications to the car.

[wontonjon]

hey rich 328,

what kinds of "major modifications" would we be talking about...and why would it take all that...if you don't mind delving into that conversation a bit...

furthermore, what type of SC are you running and would you recommend it to others??? im assuming centrifugal?

thanks

[Keith 95 M3]

Originally posted by wontonjon
figured it out...

so there are basically three types of blowers on the market

1. centrifugal blowers (everyone's heard of vortech)
2. screw-type blowers
3. positive displacement ...otherwise known as roots blower

just an fyi

Sorry, but not exactly.

1. Exhaust-driven superchargers (ever heard of turbos? )
2. Centrifugal superchargers (crank-driven turbo)
3. Positive-displacement superchargers

#3 covers Lysholm / screw-type as well as straight-rotor roots-type. Positive-displacement means that it's always in a greater than 1:1 (more than atmospheric could drive in).

And Am1r, get a clue. If positive displacement blowers were so superior, then WHY do they generate so much heat, why do they (especially roots) suffer drastic pumping losses, and why do you see so few of them? Do you know much about forced induction in general?

Maybe the boost not comming on until 3k is an advantage? (One might not *always* want to be in the boost (traffic? idling?)) And screw-type superchargers are more efficient than straight-rotor or even twisted rotor, but there is still the issue of heat. The action of compressing air, even with a 100% efficient compressor, STILL generates significant heat. ALL superchargers, regardless of drive, will be better with an intercooler.

The best method for supercharging intake air is turbocharging. PD and centrifugals both take power off the crankshaft, which is power that would have otherwise gone to the tires. If the crank-driven blower makes 150hp extra and takes 50hp to drive, then you only get 100hp to the tires, while the engine gets 150hp worth of stress (efficiency here hypothetical for discussion). Turbos get their drive energy off exhaust gasses, most of which is waste energy which would have otherwise been bled off as heat into the exhaust system. However, since the turbo is basically a restriction in the exhaust path, you do lose *some* power from that. But when others have taken the 3 methods and driven them with an external input to the engine, the turbo is shown take the least amount of overhead to compress air. The downside is the high complexity of a turbo system, and an air-to-air (or whatever) intercooler is a small price to pay for the efficiency returned.

Even positive displacement and centrifugal superchargers gain much when intercooled (aftercooler is what Vortech calls it, it's still an intercooler).

I run a centrifugal supercharger, but I *still* would advocate a turbo system over either of the other two types, given the lesser horsepower loss and what you can do with them, when going for the most amount of power. There are only a few times when I wouldn't - if you want to keep it simple, if you want to improve the overall powerband and are willing to sacrifice making alot more power up top, or if it just suits you.

What I'm curious about - isn't the compression on the E46s and ESPECIALLY the M3 (11.x:1?) far too high to run any worthwile amount of boost? I'd like to know because although I have an E36 M3, the dad unit just got an E46 330i.
-keith

[wontonjon]

thanks for the info!

[RichP]

Wonton,
Ill talk E36, but it would be the same for the E46. I have only seen one installed, on an Aussie car that must have cost a fortune (a lot of custom parts).

First, a custom manifold is needed, that somehow can fit the large blower. Then the piping is an issue. The intake on the SC is on the back, which means you then have to mount the throttle body (and move it significantly) to the intake of the SC,and, if you arent already hitting the firewall, then pipe it back toward the front of the car. The brake booster then gets in the way, and perhaps the strut tower, as well as all the other things hidden under the manifold.

It may be able to be done, but I feel there is a reason why Downing Atlanta does not have one, nor did Dinan chose this route. The units are just to big overall.

I use a Vortech blower. Yes, there is little difference down low, however, the car has a very wild top end and pulls nicely. If I disconnect it, immediately you can tell the car is lacking. The power comes on seemlessly, and overall, the unit is very quiet.

[wontonjon]

when does the vortech "kick in" in your 328...in that cobra that i was riding it...it started to pull hard around 3500 rpms or so and on up to redline...

and also, which company did you go with and why?

thanks

[Samir]

#3 covers Lysholm / screw-type as well as straight-rotor roots-type.

This is a very generalized statement and is not necessarily true...the consensus among tuners views the screwtype as just that, a screwtype. Positive is usually reserved for roots type blowers. It's the ignorant that cannot distinguish between the Lysholm design and the roots design.

The reason for distinguishing between the two is this:
-A roots type positive blower compresses the air inside the intake manifold, not the blower itself. The screwtype does the opposite and compresses most of the air inside the unit (like a centrifugal).
-The internal workings of the roots are completely different than the screwtype. While both display twin helical blades, a Lysholm screwtype's rotors are more twisted with conical tapering, making them more efficient, and are arranged in an intermeshed female/male fashion.

Positive-displacement means that it's always in a greater than 1:1 (more than atmospheric could drive in).

Uhhh...that doesn't make any sense? You lost me there. Positive displacement simply means that for every revolution of the rotors, a given "positive" amount of air is displaced into the engine.

And Am1r, get a clue. If positive displacement blowers were so superior, then WHY do they generate so much heat, why do they (especially roots) suffer drastic pumping losses, and why do you see so few of them? Do you know much about forced induction in general?

Perhaps you're the one that needs to get a clue. Again, you are displaying your lack of knowledge about the Lysholm screwtype. The new units from IHI which are currently being used by AMG and other car makers are internally intercooled thereby eliminating any excess heat from the intake charge. This cannot be said for centrifugal/roots setups which do not include any type of heat exchange methods. In addition, the adiabatic efficiency of a screwtype is right around 80%...much higher than a roots. This can equate to roughly a 100 degree drop in intake charge temp vs. a centrifugal/roots @ 9+ psi.

The best method for supercharging intake air is turbocharging.

Yeah...perhaps for racing purposes where boost pressures of 30PSI are needed. For low boost street applications, a screwtype can offer the same type of performance as a turbo, for less cost and maintenance.

PD and centrifugals both take power off the crankshaft, which is power that would have otherwise gone to the tires. If the crank-driven blower makes 150hp extra and takes 50hp to drive, then you only get 100hp to the tires, while the engine gets 150hp worth of stress (efficiency here hypothetical for discussion). Turbos get their drive energy off exhaust gasses, most of which is waste energy which would have otherwise been bled off as heat into the exhaust system.

Yawn...that's everyone's defense of the turbo. So you're saying that Saleen, AMG, etc. are all wrong?

What I'm curious about - isn't the compression on the E46s and ESPECIALLY the M3 (11.x:1?) far too high to run any worthwile amount of boost? I'd like to know because although I have an E36 M3, the dad unit just got an E46 330i.

The M54 3.0 in the 330 has a CR of 10.2:1...which is safe for about 6-9psi of intercooled boost

[ernie]

Techna330,

This is Ta right? I saw an article about your crew in some import magazine a while ago, congrats

Samir,

I heard that you posted something on e46fanatics about the advantages of the lysholm blower, are you considering making a kit?

Ernie

[Gibba]

So is it worth the money or not to supercharge a 330? You people are saying that the ESS/ERT superchargers dont produce any power down low right? So if the power only comes on at 4k RPMs, what is the point? You will be near redline soon enough anyway.

So I am guessing the acceleration; 0-60 and 1/4 mile are not really improved much on a 330 with a supercharger? Anyone clarify that?

What would be a rough estimate of the 0-60 of a Step 330 with a supercharger producing 340 hp(as advertised by ESS)?

[techna330]

ERNIE

Yes...it's meeh TA...i don't if i met u before ....but i got to say rite now is your car looks so dope with that custom exhurst....right now i'm running RMS supercharger kit on my car(330i). it's really good.....if u are interest let meeh know...caz i work for RMS. i'll hook u up.

[K-DOG]

Gibba, probably around 5.5 for step, probably 4.8-5.0 on stick.

[ernie]

Ta,

thanks for the compliments man! it means a lot coming from someone who is experienced in modding. I have yet to meet you but the guys all have nice things to say, so hopefully i will sometime soon. thanks for the offer regarding the supercharger, i really appreciate it. im kind of low on money right now but if i do start thinking about a supercharger you will be the first to know. thanks again!

Ernie

[techna330]

ERNIE
i wonder that .....where did u get your rollbar at....it's look really nice....when i saw it in the bimmerfest picture....i do want it for my car also.