boost on twin screw chargers

[oldcorollas]

ahh, thanks for that agreed on the sales pitch thing for sure..

AS RMS said, it depends where you wan to rev to.
millenia SC on a 2J would be like putting an SC12/14 on a 1UZ?
perhaps it can be overdriven, but... they are not a big flowing SC (iirc)
however, apparently they are very long! but perhaps that is not so much a packaging issue with a 6

use it as a low rpm part of twincharging?

hmm, it might good for a 4AG... how cheap can they be gotten?

[oldcorollas]

more tidbits

http://forums.mazdaworld.org/lofiver...php?t8526.html

Ok, this information I'm supplying is not exactly the same as the SC found in the milly, but according to lysholm (yes, lysholm is a company all of its own):


QUOTE
The Compressor used in the Mazda was to some extent designed
at our sister company SRM. The compressor is a screw compressor
"Lysholm" type. The compressor received its final designed by
IHI in Japan, an is as efficient as any other screw compressor.
If you look at www.lysholm.se you can find information about
the efficiency of a normal generic lysholm compressor. The size
nearest to the compressor size in the Mazda is the LYS 1200.



So, these are specs for the LYS 1200 (alot of these were metric or other measures which I have converted to more familiar measures):

maximum screw speed: 15,000 rpm
maximum operating pressure ratio: 2.2 (this equates to 32.34 psi, or about 17.6 psi "boost" pressure)
displacement: 1.2 L/rev
maximum operating flow: approx. 600cfm at full pressure

For those of you who know about adiabatic and volumetric efficiency, or better yet want to read the compressor flow map for yourself, here it is:
http://www.lysholm.se/PDF/diagram_lys1200ax.pdf

the 1200 is 4SG sized.. not 2JZ

[fixeruperer]

jag have 2 differant s/c setups one is from a xj40 (xjr) its a supercharged 4.0 liter, side mount similar to toyota and they have the xjr, xkr and s-typeR 4.0 4.2 liter v8 supercharged top mount similer to holdens eaton style with the topmount they come with 2 w2a intercoolers either side of the supercharger.

[mrshin]

Several years ago I looked at using the Mazda blower on a 4AG, but gave up on it due to having trouble getting one at the time, any that anybody did have seemed to be completely knackered, and they wanted too much for them.

[5000gt]

ahhh... there goes the idea....

US ebay sees them go for around 100-200usd mark quite regularly.

EDIT: anyone know how much air a 2jz ingests across rev range....in standard form.

[Norbie]

Given 7000rpm and 90% VE (numbers I pulled out of my ass), airflow should be approx 330 CFM according to this calculator:
http://www.4secondsflat.com/Carb_CFM_Calculator.html

If the specs Stu posted are accurate, a 600 CFM blower will give a very useful boost in power!

[5000gt]

I thought as much.... so it's still a viable option (cheap if diy) for supercharging a 2jzge... seeing 250kw should be possible in terms of airflow???

[Norbie]

Rough calcs suggest 600cfm should be good for 280kw, assuming ideal conditions - so in real world conditions 250kw is probably about spot on.

[oldcorollas]

http://www.opcon.se/www/files/lyshol..._lys1200ax.pdf
that 600cfm is getting up there, and a bit out of efficiency.. then again, it doesn't seem to drop off that quickly tho...
600cfm on 330cfm is 1.8 pressure ratio
32kw to drive it (belt size/strength?), 110deg outlet temp,
hmm....

[5000gt]

is that hmm a bad thing or what? haha... gotta be a little more transparent here... i'm keen on using this thing on something or another and the 2jzge just happens to be what i can get my hands on for next to nothing atm.... that and 4age in sprinter... but im not gonna play with the sprinter for awhile.

EDIT: how does the toyota sc12 and sc14's compare?? Looking at the numbers and the mess of a graph, i don't think the mc charger performs too badly....especially with a 2.2 atmo ratio...

[oldcorollas]

"hmm, i wonder"

IF the matsuda charger is same in spec to the 1200, then it would be a good thing..
it is different in packaging size tho.. i thought the rotors were a fair bit longer..
i haven't seen one yet tho.. so i should look around, but none at wreckers locally, and rarely come up on yahoo...

main issue with 2.2 is the discharge temp is ablistering 130-140deg.

also.. 2.2 would be 730cfm, which the charger cannot do.
if you want 1.2bar boost, you will need to reduce max revs to... 5800 or a bit less... hardly exciting

with 0.8bar boost, you can go to 7000rpm.

ass-u-ming it is similar to the 1200, it looks to be a good thing.

SC12 and 14.. at 0.8 bar boost they are probably not getting too hot yet, but efficiency is worse. if VE of the SC14 was 95%, (and it could spin at 12000), it would match the matsuda one for airflow.. but it probably won't... will also take more power to drive it


edit: buy me one and i will play with it ... 1-1.2bar boost on 4A would be good,

[5000gt]

really got me thinking now... my brother lives in the states and is able to send me smallish things like this with no real hassle.... like was said, they do come up on US ebay quite often (just checked, nothing cheap atm) and they go for as little as $100usd... fully rebuilt ones can be had for like 1200 or 1300.... still not a bad price for a "new" twin screw charger!!

at what drive ratio (engine to charger) are you working out 5800rpm for 1.2 bar of boost? I was looking for 1 bar MAX on a GE with thicker gasket (povo spec decomp)... I'd do this for fun and abit more poke, not trying to outdo turbo's or anything.... just torque off the line for a GE in a heavier car...

[oldcorollas]

not on drive ratio.. just max rpm for SC, to get max airflow of 600cfm and then work backwards and see what 600cfm means as a boost ratio for 2J (from 330cfm for NA) = 1.8 ratio max.
for 1.2bar boost is same. 2.2 ratio = 600cfm.. but 2J uses 600cfm @ 1.2bar boost at only 5800rpm

hmm... as long as the $100USD ones are not fubar....
if some can be found in good condition.. it's worth having a go for sure! if not for the 2J, then for the 4A..

it also depends on the internal compression. but even without, it still uses less power to drive than a roots

[5000gt]

sounds good... i'll be checking US ebay regularly then....

[5000gt]

After a little more digging, this is what i found. Model and actual flow according to "potatonet" on VWvortex forums who is using a lysholm ihi charger also.

mazda S76 charger 1.65L/rev

Either way, it's better than first thought.... will really keep an eye out for these things now!