Good magazine article comparing roots and twin- screw chargers

Re: Good magazine article comparing roots and twin- screw chargers (Mark Morris)

So for those of us that dont have the magazine.. Witch one was better..? And why?


[Modified by dontouch, 3:13 PM 2-12-2002]

Re: Good magazine article comparing roots and twin- screw chargers (dontouch)


good ?

Re: Good magazine article comparing roots and twin- screw chargers (joeZX6)

I'll post the details of the article this weekend, when I'll have some time to sit down and type them up. To give you the easy answer, the Llysholm was the winner-- but the really interesting stuff is all the comparison data collected from the different tests.
The mag is easy to find and well worth a few minutes of reading time.

Re: Good magazine article comparing roots and twin- screw chargers (Mark Morris)

test car: 2000 Saleen S281 with 4.6 2- valve GT engine, automatic transmission, Bassani X- pipe & exhaust (no cats), boost- a- pump, 42 lb/ hr injectors, and custom chip.
Car comes stock with Eaton M90 supercharger and air/ water intercooler.
Test monitered oil and water temps, air/ fuel ratio, ambient air temp, engine speed, boost pressure before and after intercooler, air temp before and after intercooler, water temp through intercooler core, mass air voltage, timing curve, knock sensor, and inlet vacuum before the supercharger.
Used 100- octane race unleaded fuel.
Test compared the Eaton M90 and Autorotor 3150 (both 1.5 liter).
Adapter plate was used to switch between Eaton and Autorotor.
All tests done on a Dynojet.
Eaton M90
pulley//max boost//inlet air//intercooler inlet/intercooler outlet//rotor rpm//peak hp
2.75"---7.7 psi------77 F------185 F-------------162 F---------------14,180-----287
2.40"---9.3psi-------81F-------235F--------------185F---------------16,249-----308
2.20"---10.4psi-----77F--------265F--------------205F---------------17,727-----314
1.975"--12.6psi-----76F--------304F-------------233F----------------19,746-----318
Autorotor 3150
3.125"-8.3psi------77F--------166F--------------129F---------------12,480rpm--311 hp
2.75"--10.0psi-----75F--------190F--------------140F---------------14,180rpm--331 hp
2.40"--11.9psi-----73F--------201F--------------148F---------------16,249rpm--347 hp
2.20 13.7psi-----71F--------226F--------------157F---------------17,727rpm--359 hp
1.975 15.7psi-----74F--------260F--------------173F---------------19,746rpm--388hp
1.975 18psi-----------------------------------------------------------19,746rpm--419hp*
*This last run was made with a larger throttle body, mass air meter, and a recalibrated chip-- (these mods made no difference with the Eaton). Boost increase is due to the changes in airflow afforded by these mods.
Just as telling as the peak numbers, in all the different dyno graphs the Autorotor had more area under it's power curve [throughout the range of engine speeds (2000 rpm- 6500 rpm)-- at all the different boost levels].



[Modified by Mark Morris, 4:42 AM 2-19-2002]

Re: Good magazine article comparing roots and twin- screw chargers (Mark Morris)

Got it fixed now-- enjoy.