No Subject

[Charles]

	Loyd (and others): Hope you don't mind my replying on the list,
but I figure this discussion might help somebody else...

>On the Turbo Regal list they talk about adjusting the regulator to the
>pressure you need under boost, disconnecting the return line, and adding=
 a
>line to a vessel with a known size. Then energise the pump and measure =
how long it takes to fill the vessel.

	Did this yesterday. With the engine off (so batt voltage is
somewhat lower, thus lower pump output), I got:

	at 43 psi, 1650 cc/ 30 sec.
	at 58 psi, 1300 cc/ 30 sec. (i.e. 15 psi boost level).

By my calculation at .5 lb/hp hr BSFC, this should support over 450
hp. Don't think I'm running THAT rich!
=20
>i'm assuming the regulator is like the on the Turbo Regal, that =
discharges
>a volume to the return line to maintain regulated pressure on the
>injectors.

	Correct. All the Bosch L-Jetronic (and I believe the Motronic)
has this setup.

>  There is are tricks you can do to a Bosch 233 regulator to make
>them adjustible.  In the tube where the air inlet hose attaches, thread =
add
>a roll pin and a allen head screw with small hole drilled through.=20

	I bought a 3.0 bar regulator (for a 728i) which screwed in place
directly of the 2.5 bar. Since I had increased my engine size from
3210 to 3453 cc, I needed 7.6% more fuel. It so happens that the
square root of 3/2.5 is 9.5% more. This and a little tweaking of the
AF meter spring put me in the ballpark.

>Sounds like you need to get a reading off the O2 sensor during a WOT =
blast.
> Need to have around .8 mv otherwise the engine will detonate.  Very =
tough
>on piston tops, head gaskets and the top rod bearing.  Hopefully you =
have
>instrumentation on fuel pressure, turbo boost pressure etc. if you are
>pushing this that hard.

	I do. Fuel pressure (and a pyrometer in the exhaust manifold).
It's interesting how much hotter the exhaust gets when you're getting
too lean!

>Finally the amount of spark advance should not be so aggresive with NOS,
>from my reading on various lists.

	True, but 50 hp of NOS/gasoline only requires about 1-1.5 degree
of extra retard. I have an MSD "Boost Timing Master" which I use
instead of the distributor diaphragm retard.

>  Is there a way to monitor the amount of retard the ECU performs after =
sensing a knock.

	Only my ears. The L-Jetronic '81 doesn't have provision for a
knock sensor.

>  the only tools you have left are an adjustible wastegate

	Got one of those too (modified it myself for a dashboard
"horsepower screw".

>Sounds like you should have licked the fuel problem, with a textbook
>solution of larger line, larger wire for higher current, etc.

	You're right! I'm beginning to wonder if it isn't electrical
after all...

> members have had problems with
>electrical gremblins.  Under high load the engine twists and the =
electrical
>connections may get stretched.  An engine tie down is recommended, with =
a
>check of all cables etc.

	Now _this_ hadn't occurred to me... I'll try it this weekend and
let you know!
Thanks to all who replied.
-Charles
'81 745i working most of the time ;)