Active Autowerke Turbos, part 2

[Jason Leung <bmwturbo@xxxxxxxxx>]

The exhaust manifold to mount the turbo
is made of cast iron, which I'd imagine is
horrendously expensive for them to produce.
A cast manifold is a hell of a lot more durable
than a stainless steel welded up manifold in
turbo applications.  

Anyways, so how does the car drive?

A primer on what I used to drive:

I used to have a 325i, 2.5L six, with a centrifugal
supercharger from ERT.  This was a very nice set
up, but low end torque was lacking.  Top end pull
was great, the thing would rev like crazy, but
since supercharger speed was limited by the speed
of the engine, I got maybe 1psi of boost at 3000 or
below, 3 psi of boost at 5000 or so, 5 psi
of boost at 6300 or so, and 6 psi if I revved the
car to 7000.  The car felt normally aspirated
until 4000 rpm.  And it felt like the supercharger
created a lot of parastic drag at low RPMs.
Dave Kelly, who is a local member of the CCA
in Chicago and has a 94 325i, swapped cars
with me before, and we both noted to my chagrin
how is normally aspirated car would accelerate
better than my supercharged car until 4000 rpm.
The ERT kit, however is a simpler kit than
a turbo kit, and is easier to uninstall.

Anyways, so how does the turbo car feel?
Part throttle driveability and in-traffic
driving....its all good.  Feels like stock.
8.8:1 compression doesn't seem to detriment
bottom end pull at all, it takes off from the
line like any 3.2L six from BMW.  Smooth,
torquey.  No hestitation, no pinging, no bucking,
temp needle didn't budge.

Now, pass 2000 rpm on the tach.  In the e36 cars,
with a stick shift, you're NEVER under 2000 rpm.

At 2000 rpm, the big stage 2+ turbo starts making
boost.  I'd imagine the smaller stage 1 starts making
boot even earlier, but if you're never under 2000 rpm
anyways, who cares?

So at 2000, you're making boost.  At 3000, you're making
6, 7 psi, which is what the supercharger made at 7k rpm!
>From 2000-3000, the car digs its rear wheels into the
ground and starts charging with earnest.  Its mad.
Its angry.  Its a bull, and it wants revenge.  It claws
at the pavement and launches you forward.  You're
hauling ass man!  And you're not even at 4000rpm yet!
The inivisible hand of God just yanked you forward.
By 4000 rpm, you're doing 12 - 15 psi of boost, whatever
you set the boost controller at.  Basically, this is 
where the car explodes forward.  You're being shot out of
a cannon!  BOOM!  Nothing will prepare you for the
violence of acceleration here.  Whaddya got underneath
the hood there, a firggin' JET?  4000-7000 rpm, Crimony,
its the friggin' Saturn V rocket strapped to your ass!
You better pray here cause if your foor is too the floor
and you're not pointed straight, then its not gonna
be pretty.  Think Explosive.  KER_BLAM!
Whatever your destination was, you just missed it.

(Forget first gear, its useless.  Used for making tire smoke)
So you're 2000rpm in second, hammer the gas.  Car
digs in, lays rubber all the way through second gear,
WHAP, hit the redline, shift, into third, tires scratching
the pavement again, pleading for mercy,  count...one-
one-thousand-two-WHAP, hit the redline, shift into fourth,
mash the gas, unnnnnhhh, unnnnnnh, you're breathing
heavy cause you're scared, count, one-one-thousand, two-one
thousand, three-- WHAP, hit the redline, alright,
120 mph is fast enough.  Brake it down.

Lemme tell you guys, Active's turbos are so 
powerful, its like a huge drug.  Its incredible.

Perhaps this statement tells it all....I rode a 757
yesterday to go back home.  Ya know how a
commercial jet feel when it takes off?  Its all
exciting and all from the endless massive
acceleration?

Well, on Sunday, the 757 felt postively
weak.  Unevenful, Boring.

your humble servant,

Jason Leung



_________________________________________________________
DO YOU YAHOO!?
Get your free @domain.elided address at http://mail.yahoo.com

------------------------------