From bmw-digest.v4.n271 Wed Mar 6 14:11:52 1996
From: "Burr, Barry J BB" <BurrB_at_po7.bb.unisys.com>
Date: Wed, 06 Mar 96 11:54:00 PST
Subject: 318i tuning; beating the ticket; cel-phones; stickers
Enough people have asked for the following information that it seems like a
topic for general interest. Some of this carries over to many other BMW
318i-8 valve, 84-85, tuning, the (relatively) short version:
plugs - NGK BP6ET
wires - NGK RCH?? as listed for a Honda 1200 or 1500 civic
coil - Mallory Voltmaster
cap and rotor - as listed for 77-79 320i
timing - 38 to 42 degrees total advance at 4000 rpm, depending on engine
condition, gasoline available, how much shaved off the head, and how
stretched out the timing chain is.
Valve Adjustments (absolutely fully cold):
intake - six thousandths snug
exhaust - eight thousandths even
as old and stretched out as possible, with tight fresh timing gears.
torque head-bolts to 70 lbs-ft.
If head is removed for any reason, shave 15 thousandths off if you want to
stay SCCA stock legal, or 60 thousandths if you want to shave as much as
conservatively safe as possible. I did one motor with a stock cam at 80
thousandths with no clearance problems.
Air filter - Purolator as listed for a Chevy Sprint and Isuzu I-Mark
saw off the rounded upper bulge of the air filter housing,
then press fit the air filter onto the inlet ring of the air-flow-meter.
Perfect fit 8-)
Air-Flow-Meter - probably no change at the springwheel, possibly one tooth
leaner if your car has a lot of miles.
NEW TIP I HAVE NOT SEEN WRITTEN ABOUT ANYWHERE:
BEND THE BUMP STOP BACK so the pointer can more easily reach the upper end
of the carbon band. Ideal positioning is where the air flap just touches
full open as the bump stop just barely makes first contact with the pointer
Idle control system - REMOVED.
Also remove all idle control valve plumbing from the intake system.
Plug the feeder hole in the intake boot with the rear shock absorber upper
mounting nut cap that comes with Koni shocks. This is a perfect fit. A
little dab of silicone sealer makes the seal absolutely airtight.
Run a breather hose from the valve cover breather fitting straight out
the bottom of the car. I put a universal fit Purolator breather filter at
the end of the hose to prevent sludge buildup on the bottom of my car, and
needed to change it a couple of times a year.
To get a cold idle, turn up the screw a half a turn or so at the
throttle butterfly. The cold idle will just barely take when its very cold,
and the warm idle wil be around 1000 rpm if the engine is tuned well. I
never considered a cold idle too important, as long as the engine would warm
EITHER: Metric Mechanic ported exhaust manifold, or Stahl header, but NOT
THE STANDARD ONE. The standard Stahl header is a waste of money. The one you
want is a custom order, made to 1-3/8 primaries, with a 2-1/4 inch outlet,
including oxygen sensor fitting.
Then use 2-1/4 inch pipe, back to the free flowing muffler of your
choice. Make sure this muffler has 2-1/4 inch inlet and outlets. Standard
aftermarket exhausts should not be used. more noise, minimal, if any, power
increase. I used a Thrush California turbo, which Jere Stahl personally
reccomended. You can also use a Flowmaster or a Supertrap. Clamp a thick and
strong L shaped bracket to the pipe where it passes under the rear subframe.
This acts as a mount for the round rubber hanging ring that hangs down from
If you keep the catalytic converter, Weld the 2-1/4 pipe to the outlet
pipe from the cat. Get rid of the flange behind the cat. The pipe diameter
at the flange's weld bead is only 1-3/4 inches or less.
Mounted downstream, past the exhaust collector. Placing the single wire
sensor further downstream meters cooler exhaust gas than at the manifold.
This 'fakes out' the computer into running the engine a little richer than
stoichiometric under load.
///Mobil 1 or Redline oil in the engine, Redline MTL in the trans, Redline
Limited Slip Lube in the differential.
THESE SUGGESTIONS ARE MY OPINION ONLY. I HUMBLY YIELD TO ANY OTHER TUNINGS
THAT CAN PRODUCE THE SAME PERFORMANCE.
318ti Club Sport, Hoosier Autocross R(adials) on Revolution lightweight
wheels, tc kline KONIs, just counting the days until the first autocross.
If you want to go as fast as everyone else, first you have to do
what everyone else is doing.
But if you only do what everyone else is doing,
how could you go any faster????
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