[s-cars] RS2 MAF deliberations

Sat Apr 19 23:53:02 EDT 2003

So Scott..

Suppose I wanted to convert my ECU to a WBO2 SD system. How much would it
cost ?
Can I add bits later in the process, and with every change I have to get new
programming right ?
At what point does this SD system really become necessary, or more usable
than the standard mototronic.

And on a similar note, just how far can the I5 2.2 be taken before there is
major build requirements.
I guess really my questions is, it a streetable modified form is there any
call for this extreme SW mod ?
I am all for HP, give me more. But I am starting to get to point  where I am
sinking WAY too much into a 10 + year old car.
After the winters exorbitant use of sand / salt mixtures and my desire to
drive fast, my front end now looks like I drove thru an Iraqi sand storm !
I was out buffing today :( Baby needs a paint job.

Mark, selling what I can for paint, S
----- Original Message -----
From: <QSHIPQ at aol.com>
To: <mik at info.fundp.ac.be>; <rpastore at animalfeeds.com>;
<toddekramer at msn.com>; <s-car-list at audifans.com>
Sent: Saturday, April 19, 2003 10:27 PM
Subject: Re: [s-cars] RS2 MAF deliberations

> --
> [ Picked text/plain from multipart/alternative ]
> In a message dated 4/19/2003 4:07:00 PM Central Daylight Time,
> mik at info.fundp.ac.be writes:
>
> >>Totall agreed the RS2 is preferable from an "open mesh" point of view
but
> >>from a programming point of view, I prefer the stock unit. And I think
> >>several people over there have found out the RS2's screen only gives a
few
> >>more horses (with the right programming of course, there's no point in
> >>comparing 2 MAFs with the same SW when the SW doesn't take the MAF
>>values
> >>into account the same way), nothing really relevant actually... I can't
> >>explain why the RS2 used that MAF as at that time I was still playing
and
> >>repairing/upgrading guitars and amps, not cars, though...
>
> I'm an old fart...  No one (even Bosch) has given me the answer to that
> question either.  Porsche ego, or definitive advantage?  My bet is on the
> latter, but have seen plenty of the former....
>
> >Those asterisks are what keep me smiling Minhea.  I'll go back to a point
> >I made long ago.  That MAF - ANY MAF - in the I5 20vt is not necessary at
> >all.  ***  With proper tuning ***  it can be eliminated alltogether, in
> >which case:  up goes HP, torque, throttle response, preturbo inlet
> >pressures and temps lower.  Why not "properly tune" that pipe right out
of
> >the fuel equation?
>
> >>Well, at least me and the German engineer whom I've learnt Motronic
systems
> >>with don't think it's good to remove the MAF from the circuit *** in a
> >>Motronic I5 20vt ***, not even for 500 HP...
>
> Why?  Speed density systems are what Motronic systems default to anyway
(with
> absent or bad/maxed MAF).  I see the MAF as redundant and unnecessary to
any
> motronic system.  A velocity stack to the inlet of a turbo is the cats
meow.
> The "redundancy" of MAF is really to protect from air leaks in the system
> causing boom (we can also define "air leak" as too much HP bolted on).
SD,
> especially WR02 SD won't care if you have an "air leak".  Whatever's
> happening upstream of the combustion chamber results in a O2 reading which
> gets fuel.
>
> >>I don't want to enumerate the pro's and con's of alpha-n vs. MAF vs.
speed
> >>density systems but my point is that Bosch know their stuff better than
> >>anyone else and if they did and still do the Motronic with a MAF (as in
the
> >>S4tt's, 1.8T's, VR6's and so on), there is a reason to it.
>
> I think that may be an audi demand more than a Bosch requirement.  For
> redundancy purposes, the MAF can provide some failsafes that SD systems
> can't.  However, they can also be THE restriction to more HP.  Wide Range
02
> is going to make Bosch and audi look at that redundancy in terms of cost
vs
> benefit.
>
> >>The new systems
> >>are very complicated right now, i.e. they monitor EGT, use wide-band O2
> >>sensors, check for the feasibility of an actual particular injector
opening
> >>time and so on, but so far, they do still use MAFs, even on the RS6....
and
> >>this is because the MAF Mo(t)ronic system has proved that for everyday
> >>driving it is the best system around. Alpha-n and speed-density require
> >>reprogramming every time one changes a part that alters VE and can't
> >>compensate by themselves for an engine wearing out and loosing >>
> compression...
>
> I disagree with this conclusion of SD, in fact just the opposite is true.
SD
> doesn't care what you add to the engine, it will measure PT and TPS,
> corrected by O2.  Wide band O2 actually makes speed density an even better
> idea, since there is no need for any WOT "tabling".  O2 based systems are
> more accurate than MAF, there's no "estimation" only lean/stoich/rich.
>
> >>Then, if one removes the MAF and reprograms the chips accordingly, the
> >>system would only be an alpha-n system, and I think an SDS or similar
> >>system is cheaper than an alpha-n reprogrammed Motronic, right? The
> >>Motronic can't run as a speed-density system as the MAP or PT is only
used
> >>by the "boost control" part of the ECU, i.e. the bottom board. Then, the
> >>pressure drop across the MAF is only 0.05 Bar (measured by a friend of
> >>mine), which is minimal and I can't see why the intake temps will be
lower
> >>without a MAF rather than with a MAF... of course the argument can go on
> >>for days and months but I simply can't see why the MAF is such a big
> >>problem in here...
>
> Drive a SD system, there isn't a problem, only gains to be had.  All I can
> tell you Minhea is, that the MAF has been deleted, on a neu S4 with all
the
> extra goodies.  I haven't seen a higher HP table from a MAF equipped one.
> For SD, you already have ALL the components for it in the Motronic system.
> With proper tuning (-tm MC:) it can and should be taken out.  I look at
the
> monster MAF projects MLP/Hap/Jonsie have taken on, and think that's a lot
of
> money for something that's really not necessary.  Me, I'd be spending
those
> dollars deleting MAF and adding WBO2 into the software.
>
> >>Well, Scott, this is where and what my respect goes to you for! I've
tuned
> >>quite a few different 20vt engines, some of them with weird parts bolted
on
> >>(Garrett hybrids, unusual injectors and so on) but I haven't built an
> >>engine myself yet!!!! So, you're a tweeker but better than I am (though
I
> >>did my 20vt swap on my own from scratch and only with my wife's help).
So
> >>this is why I respect you and I don't want to argue with you on this
> >>subject for months.. :-)
>
> Good wife, keep her.
>
> >>WRT Hoppen and MTM programs, I can't really commit as I dunno what they
> >>really sell... I've received a supposedly Lehmann SW for RS2ed AANs
which
> >>is almost identical to a SW I got from MTM so I really dunno who or what
to
> >>believe except what I program myself and check for "proper" EGTs
myself...
>
> I think the bed has been shared so to speak on the urs programming.
Beyond
> 400hp is where the play is now.  What to do?  Those resultant SW changes
get
> bigger, and scrutiny of the HW changes should be made concurrently.  Since
> the variance of HW of these 400+ machines is going to get wider, why not
use
> SD and let "Hapersize Go Wild" (video soon to be released).
>
> >With regard to accepting/needing any MAF at all, I'll freely argue our
> >definition of ***properly tuned*** will always differ.  I know it can be
> >deleted, I saw it done on a S4tt.
>
> >>Of course it can be deleted, I just simply still think it's not so
> >>necessary to delete it, but maybe when I blow 2 or 3 per month (with
450+
> >>crank HP) I'll see the need to delete them :-)
>
> Others are already there and have BTDT Minhea.  At which point, this
> tweekster looks at the problem and says, hey, you don't NEED a maf.  The
best
> argument for that thinking is affordable WR02.
>
> >>Anyway, thanks for your thoughts again Scott!
> >>Mihnea
>
> Yours as well Minhea...  I gotta go talk to my wife now....
>
> SJ
>
>
>
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