[s-cars] 1.8Tcoil pack symptoms

Javad Shadzi javad at 034motorsport.com
Thu Jun 1 23:57:06 EDT 2006

Yes, I understand, we run these coils with our 034EFI systems with over 4 MS
of dwell with no problem, the AAN does not run more than 3MS of dwell, I
can't imagine this is the problem, as well as we've not seen this on any
other AAN cars either.

Keep me posted, thanks.

Javad Shadzi
(408) 910-5289 - Cell
(510) 657-6707 - Shop

On 6/1/06 8:51 PM, "John Tilden" <j.n.tilden at comcast.net> wrote:

> I had it on initially, but have removed it since the first stalling issue.
> Have I over heated the coils and damaged them? My car runs pretty nominal
> with regard to Temperature, and Seattle is not a HOT place thermally!
> The point raised in the previous post was dwell time not voltage.
> But if the 1.8T has the same range of dwell time/angle as the AAN then there
> should be no issue. Has anyone compared the dwell time for the 1.8T to the
> AAN?
> I don't have the tools to do so, nor the specs for the coils or the output
> voltages for the coil drivers.
> Again it may be some other failure, just looking for alterantives. The
> failure is not throwing any codes however! Damnit!
> John
> ----- Original Message -----
> From: "Javad Shadzi" <javad at 034motorsport.com>
> To: "John Tilden" <j.n.tilden at comcast.net>
> Sent: Thursday, June 01, 2006 7:50 PM
> Subject: Re: [s-cars] 1.8Tcoil pack symptoms
>> John, are you running the stock coil cover?  We've only seen this when the
>> stock coil cover is installed.  Otherwise, we have cars with 10k miles
>> running our kit with no problems.  There is no "voltage" problem as has
> been
>> suggested, the 1.8t and AAN both use the same basic high side coil trigger
>> voltage.
>> Thanks,
>> -- 
>> Javad Shadzi
>> 034Motorsport
>> www.034motorsport.com
>> (408) 910-5289 - Cell
>> (510) 657-6707 - Shop
>> On 6/1/06 7:44 PM, "John Tilden" <j.n.tilden at comcast.net> wrote:
>>> Hi Paul,
>>> Well, that makes sense!
>>> So why me and not everyone else?
>>> I do have a chip in the car, but I doubt that the dwell time was changed
> any
>>> differently than anyone elses if at all.
>>> Timing yes, dwell why?
>>> But I appreciate your ideas especially since the coil/core is
> significantly
>>> different from the original.
>>> Hope you don't mind me forwarding your post to the list.
>>> Javad, Any comments or thoughts?
>>> How about a new chip to modify the dwell if required?
>>> My coils get very hot, but I thought it was from the proximity to the
> valve
>>> cover (like inside!).
>>> John
>>> John Tilden
>>> Tilden Consulting Services
>>> 2820 164th Ave N.E.
>>> Bellevue WA 98008
>>> (425) 881-2895 Office
>>> (206) 240-5318 Mobile
>>> j.n.tilden at comcast.net
>>> ----- Original Message -----
>>> From: "Paul Gailus" <gailus at mindspring.com>
>>> To: "John Tilden" <j.n.tilden at comcast.net>
>>> Sent: Thursday, June 01, 2006 6:37 PM
>>> Subject: Re: [s-cars] 1.8Tcoil pack symptoms
>>>> John,
>>>> I'm guessing that your coils could be getting hotter because
>>>> the drive signal from the AAN ECU probably has a higher
>>>> dwell time than the signal from a 1.8T ECU.
>>>> Most pencil coils like the 1.8T ones have a lower inductance than our
>>>> OEM coils which use the traditional E-I core lamination format.
>>>> So because V=LdI/dt, the dwell time needed for the 1.8T coils
>>>> to ramp up to full current is probably smaller.
>>>> I'm guessing that it's in the 1 to 2msec range vs. about 3msec for
>>>> our OEM coils. It would be interesting if someone could verify this
>>>> by measuring the drive signal from the ECU on a 1.8T car.
>>>> The 1.8T coils very likely go into current limit once the current
>>>> has ramped up to a preset value (probably about 10 amps or so).
>>>> To achieve this current limit, the voltage drop across the internal
> pass
>>>> transistor has to increase substantially in order to allow the voltage
> on
>>>> the coil primary to be correspondingly reduced.
>>>> This will increase the power dissipation on the transistor.
>>>> If someone could put a current probe & scope on the supply line to a
> 1.8T
>>>> coil conversion, it could be verified whether this behavior is
> happening.
>>>> I'm not sure if the dwell time on the AAN Motronic ECU can be adjusted
>>>> or not. I seem to remember someone mentioning that there may be a
>>>> custom timing chip on the board.
>>>> Alternatively, one could use a monostable circuit and some logic to
>>>> eliminate some of the beginning portion of the ECU pulse
>>>> while leaving the end time of the pulse essentially the same.
>>>> This would reduce the dwell without affecting the timing.
>>>> Running the 1.8T coils on something less than full battery voltage
>>>> could also help, but this would require a voltage regulator of some
> type
>>>> to do it properly.
>>>> Regards,
>>>> Paul
>>>> -----Original Message-----
>>>>> From: John Tilden <j.n.tilden at comcast.net>
>>>>> Sent: Jun 1, 2006 1:20 AM
>>>>> To: s-car-list at audifans.com
>>>>> Subject: [s-cars] 1.8Tcoil pack symptoms
>>>>> My car, after the 1.8 T coil conversion, has been dying after running
> on
>>>>> warm days,
>>>>> It starts to die at stop lights and as the car slows between shifts
> and
>>> then
>>>>> finally dies an refuses to start again until it has cooled off.
>>>>> It started doing this immediately after the update, I was/am convinced
> it
>>>>> has nothing to do with the coils, but my mechanic is convinced it is
> due
>>> to
>>>>> the coil swap.
>>>>> We replaced both the timing sensors at the flywheel and I got a good
> week
>>>>> plus out of it before it died again, of course today was the hottest
> day
>>> in
>>>>> a week in Seattle, you know, 75F!
>>>>> It appears to lose spark, fuel pressure is OK, but no spark until cool
>>> down.
>>>>> I haven't notice the cold start problem that others are reporting.
>>>>> I have removed the Coil cover.
>>>>> Any ideas?
>>>>> John
>>>>> John Tilden
>>>>> 1995.5 S6 Avant Europa Blue
>>>>> Bellevue WA
>>>>> j.tilden at verizon.net
>>>>> _______________________________________________
>>>>> S-CAR-List mailing list
>>>>> S-CAR-List at audifans.com
>>>>> http://www.audifans.com/mailman/listinfo/s-car-list

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