RE: BMEP and ft/min and tt clarification

[Eaton Dave <dave.eaton@minedu.govt.nz>]

mmm, thanks chris, not sure i required a dissertation on bmep.  anyway...

my point is simply that audi has been in the game of high bmep and [what you
clearly think is] high stress engines for some time.  also i wouldn't use
your definition about 3,500 to 4,000 ft/min as f1 league.  surely a little
off n'est pas?

for instance, the i5 has higher piston speeds than the 1.8t.  the rr/aan/adu
turbo motors would be around 4k ft/min, with a higher static cr to boot.
don't forget that these motors will red-line at 7k, the adu @7,500.  mind
you, the adu certainly sounds better at 7k than the rr does....

so, i expect no more worries about the 1.8 than of any other audi motor.
they're not bmw's after all :-)

the haldex is basically a clutch.  coupled with an epicyclical diff (a la
vc), it could form a full-time awd system.  looking at the schematics, slip
fires the pump which activates the clutch.  so, it is 2wd with a progressive
awd being used when required.  as i said, just like a vc (without the
progressive, or computer-controlled bit).  the key control element is the
throttle (bleed) valve which the computer uses to control the feed-back
pressure to the clutch.

also, there is no "centre app" mode for this diff.  in the vw/audi scenario,
the diff is bolted onto the front of the rear diff, so the input shaft is
the output shaft from the front diff presumably via a take-off from the
gearbox output ring.  in this arrangement there clearly can be no more than
50% power to the rear axle which would seem to fly in the face of the
testers who expound the oversteer characteristics of the car (ttc)...

as i said, we currently don't know the details of the audi app of the haldex
lsc.  i'm working on it.  rumours of the s6tt 400hp v8 using 4 haldex
clutches (1 per axle 1/2 shaft) are also being substantiated.

dave
'95 rs2
'90 ur-q

> ------------------------------
> 
> Date: Wed, 7 Oct 1998 08:28:34 EDT
> From: CM1022@aol.com
> Subject: BMEP and ft/min and tt clarification
> 
> Sorry if I confused some people with witing about BMEP as if it were the
same
> thing as ft/min.  To clarifiy, BMEP stands for break mean effective
pressure
[snip]