[s-cars] EM type, chip upgrades and cracked heads

[Dave Forgie]

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Mihnea: The little old lady story sounds suspciously like the factory
either put exhaust valve springs in that were too stiff (from another
application) OR the exhaust cam, for some reason (it was a 7A cam??) had
too high a lift.  Either way, it would seem like the spring seats were
unduly but physically stressed by stiff or very compressed (and
therefore stiff) springs.

One reason that more data about cracks and burnt valves could be
available from "bone stock" (box stock?) (Botox stock (tm)?) is there
are more cars that have  lived most of their lives without mods.  Only
the loveable nut cases on this list modded their cars right out of the
showroom floor.  Its the second and third owners that are now the ones
that are modding what was a previously stock car (late in the car's life
for that matter).  Its these people that are the next but short-lived
market (probably four to five years max.) for chip upgrades. These are
the ones that need to know whether an upgraded EM is truely needed or
not.

As to never hearing about any burnt exhaust valves in an AAN engine,
that doesn't mean it didn't happen. Hap Maguire responded to me and Mike
Pederson on the issue on July 10th and said (sorry Hap, I need your
quote):

"Guys: I did run a larger T3/T4(RS2 equivalent) turbo with the stock EM
for about 4 years and 70,000 miles. I did end up with burnt valves at 1
& 3.  Hap. "

So, we could both be right.   The valves will eventually burn.  But
70,000 miles is a long time (e.g. 5 years at 14,000 miles per year,
seven years at 10,000 miles (16,000 km) per year).  Some people would
consider that to be a non-issue, i.e. people who keep their cars less
than 70,000 miles.  However,  I presume that the factory (Audi and
Porsche) figured that was a BIG deal and therefore, the RS2 EM manifold
was designed and/or developed - probably to meet the equivalent of
200,000 km or some big number without any problems.  Of course, at the
same time, they may have been able to extract a bit more HP (say, 5 HP)
with this new, better flowing, less heat risky EM.  It wasn't done just
so it would "cool" and all the kids would want to buy them (Hi,
Pizzoman).

As per someone else's post, it is amazing that nobody has done and/or
published any four wheel dyno testing on the S-car to show the various
HP and torque gains: OEM stock (baseline) stock with Stage 1 chip, stock
with Stage 1+ chip, stock with RS2 EM, Stage 1 with RS2 EM, Stage 1 +
with RS2 manifold, Stock EM but RS2 turbo and appropriate chip step, RS2
EM and turbo and appropriate chip set, full RS2 kit (MAF, injectors,
EM, turbo, RS2 chip set, etc).  Aren't there any "scientists"/automotive
engineers out there?  Scott J.? Scott M.?  Ned (Q)?  Dave Jones?  Joe
Hoppen?  Bueller?

Dave F.


Mihnea Cotet wrote:

> Dave,
>
>
> In all but one case, all the cracked heads I have seen before were on
> UNCHIPPED engines running bone stock turbos on bone stock EMs. The
> chipped engine was running a kind of "racing" chipset for which many
> things could be blamed but without a real in-depth analysis it would
> be quite hard to determine wether the chipset was responsible or not
> for the head damage.
>
> Most of the heads that were cracked had those cracks under the exhaust
> valve springs area as in this particular picture
> http://www.rs2-club.net/S2R/Images/Culasse3.jpg, one of them was
> cracked under all 10 valve springs and that was the one driven since
> new by a middle-aged woman, had 50K miles and had stock everything.
>
> So basically, you can draw the conclusion yourself, I for one wouldn't
> try to draw any yet.
>
>
> Cheers,
>
> Mihnea
>
> At 23:04 11/07/2003 -0700, Dave Forgie wrote:
>
>> Mihnea and others:  When these cracked heads show up, are  there any
>>
>> correlations between the EM type, the turbo, the chip set, etc.?
>> What I
>> was thinking when I asked the EM question a few days ago was, if you
>> go
>> to an upgraded turbo and/or a chip set that makes 300+ hp and you DO
>> NOT
>> upgrade the EM,  the probability of burning valves, e.g. 1, 3,
>> and/or 5,
>> AND/OR cracking the head (e.g. around the exhaust valves or exhaust
>> port
>> areas) increases dramatically.  I would like to do a litter
>> forensic-type "epidemiology" (sp?) on this data, if it is available.
>>
>> Dave F.
>>
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>
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