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Date: Mon, 25 Jan 1999 08:20:20 -0800 (PST)
From: Jason Leung <>
Subject: Active Autowerke turbos <long>

I went to Miami this weekend for the purpose of driving my car and creating a final
punchlist of little things to be taken care of before Active Autowerke releases the car
back into my custody. One of these items on the punchlist was to replace a door panel!
It seems that my car lived in the Midwest without ever experiencing the dreaded door-panel-vinyl-bubbling syndrome, but during its stay in hot Miami, and managed to
bubble a door panel!

First things first, its really odd being in Miami for a Northerner like me. Its 20F at home,
but its 80F in Miami, and I couldn't sleep every night without having the a/c

Anyways, a short background on the car:

92 325i. 3.2 liter six, billet 4340 steel connecting rods, forged aluminum pistons, OBD1
computer, OBD1 intake runners, big Bosch HFM (different from the Euro HFM), AP four-pot, 8.8:1 compression, M50 non-vanos double-valve-spring head with M3 cams and
Vanos retrofitted to the head. Basically, a stage 3 turbo setup from Active with the
exception of the non-vanos, yes-vanos head. I used the older head for the double valve
springs. I didn't want the single conical valve springs of the M50TU, S50US, and S52US
engines. I figure this may give me just a tad more margin for error in the event of a real mild misshift. I've misshifted my motor before,
mildly, with no damage.

The installation the turbo system is very very sanitary. Spring loaded hose clamps
everywhere. All pipes that are pressurized have rolled lips to prevent the hoses from
blowing off. The turbo system is modular, and designed for easy servicing. The whole
entire wastegate assembly can be removed in 10 minutes for an average schmoe like
me. The beauty is in the details.

Details like the Euro Oil Cooler. Active gets these things imported, but throws away the
mounting brackets as supplied from BMW because Active feels that the brackets are too
flimsy. Active welds up their own steel brackets. Details like the ECU code. They
partner with Jim C to develop code for their turbo systems. Talk about going straight to
the source for the best....Active uses Jim's Motronic Editor on a daily basis.

Details like Raceware head studs, metal head gaskets, and o-ringed blocks. There is a
lot of thought that went into this system...its easy to tell because if its clamped, then its
clamped with marine heavy duty spring loaded clamps. If its bolted and it only needs 2 bolts, then they use 6 bolts to bolt it down. If there needs to be a bracket to hold
something in place, then they have TWO brackets holding it in place, and the steel for
the brackets is twice as thick as it needs to be.

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

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+ or 3 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
round 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 foot 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, 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. Uneventful, Boring.

Your humble servant,

Jason Leung

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