4AGE info, where to find?

[oldcorollas]

i didn't see any mention of a 3 speed gearbox for the centrifugal blower on their site.

ahh, i was lookign at wrong number re the impeller size
the input pulley needs to be turning max of 12000rpm for the bigger one, and 16000 for the smaller one (before the drive ratio multiplication)

unless you do use a gearbox (which has it's own problems), then your boost output will be linear at BEST, but the inefficiency of the impeller type blower make it's output at lower rpm much worse. centrifugal doesn't have the range that a PD does.

look at a turbo shaft speed vs efficiency.

i know in jet turbines, the efficiency range is rather small.... ie.. you can't get similar efficiency from 10,000rpm to 70,000rpm.

as they said
"What is needed is a multi-speed supercharger drive delivering optimum boost conditions on demand."
but such a system is not available yet. there is a 2 speed one in the media somewhere.. but..

what happens when you change speeds? unless it is a CVT, designed to keep the impeller spinning fast (which creates extra losses if engine speed is low, due to the higher gearing neeeded), then you will have steps in the boost curve....

a turbo works as it can maintain a high impeller speed, without having to rely on mechanical link with engine at low speeds.. and it's max speed is limited by wastegate....

anyway, they look like an interesting version of the vortech.. but they are not more than that

they say "Efficiency up to 98 percent" but what they really mean is the gearbox unit at the front.. not the impeller
if you have a look at the tech data sheets for the impellors... then compare to turbo.. then remember that turbo is spinning a lot faster

for example.. the C30 range. the graphs start at 45000 and go to 120000 max.
drive ratio of 9.5, gives minimum Sc speed of 4750 to even be on the graph. assuming you will be revving to 8500 (drive ratio 1.5), that means that you don't even get on the graph until 3200engine rpm...

anyway.. they are still centrifugal compressor... and until you can get a vey small CVT gearbox that can transmit 30+kw to be able to keep the impeller in correct speed range.. they will still be the worst of both worlds..

edit: and why have they corrected 15degC and 101.3kpa, when standard temp and pressure is 20C and 101.3kpa...

[oldeskewltoy]

It would require a different thread.... (temporary thread jack) but I'm mostly happy with my 4AGE... My thoughts would be to add a bit of low end... and a bit more on top... my thoughts went to the C15-60.
It has an hp peak of 200hp, but that is 30-50 more than I need (yeah I know the "drug" of power.... been there - Shelby Mustangs, Mach1 big block, late 60s GTO, I've owned a few powerful cars....)
I was thinking of running the small rotrex instead of a small turbo on a mostly stock (mechanicals) 4AGE, with proper management. I'm looking for 130ish#-ft with a hp of about 160. Something ubber reliable, that works as a daily and works on the track(grip) At first what comes to mind is an SC12... or a T25. The SC12 is TOOO heavy, turbos causes too much heat(LHD so turbo can cook brake master). The Rotrex fits on the right side so its minimal mass will add to passenger side.... albeit up front. I can get a bit better response with less heat and less mass than the other options. It isn't perfect, but I don/t know a perfect answer to my particular equasion