PorscheG96

My 968 still had an NA performance chip which doesn't work well with a turbocharged engine. I suspect that the dyno shop who performed the tuning advanced spark timing through the lower and mid-RPM ranges, and added fuel in the higher RPM's. The extra timing was really BAD so I didn't drive the car terribly hard and it's been impossible getting a nice fuel curve from a turbocharged engine using a normally aspirated chip...the air/fuel ratio is either too lean or right on in the mid-range while the top end is super-rich. So now I have a chip that delivers fuel like a turbo and mimics the 951 in retarding timing under boost. Somehow it receives a pressure signal now instead of a vacuum signal and pulls back timing when the boost hits. Pretty cool! Anyway, I took some pics of the procedure with steps that I'll share:

1. Remove battery cable from negative terminal of battery.

2. Pull back carpet on passenger side floor, remove floor board secured with 4 philips screws and washers.

3. Remove DME/Alarm bracket secured by two philips screws on bottom and two plastic flat-head fasteners on top.

4. Pull bracket out and remove the big plug [there's a metal clasp that you pull back and the connector kinda 'rolls' off the DME box].

5. The DME box is secured to the bracket with 2 8mm nuts, remove those. Take out DME.

6. Opening the DME box requires the removal of 4 small torx screws. There are also a series of tabs on the outside that must be pried back.

7. Pull the cover off...the DME chip is in the corner and you pry each side up just a little at a time with a flat-head screwdriver. Make sure you're not statically charged or damp.

Pics:

Pry up the tabs
<img src="http://www.imagestation.com/picture/sraid59/p8c0079f1120b066ad382e00f7f77ce8d/fc5e73d8.jpg" alt=" - " />

Here's the connector
<img src="http://www.imagestation.com/picture/sraid59/p11201fb6850b1f5693ee992c48c065bd/fc5e73d7.jpg" alt=" - " />

Case removed
<img src="http://www.imagestation.com/picture/sraid59/p266dfd6e657bd38ba504b590da999032/fc5e7443.jpg" alt=" - " />

Old dyno chip
<img src="http://www.imagestation.com/picture/sraid59/p05742e0be64ab060f80be7c516df6c2e/fc5e73da.jpg" alt=" - " />

New turbo chip
<img src="http://www.imagestation.com/picture/sraid59/p672a7676a5143e44dde98cee622952a1/fc5e73bc.jpg" alt=" - " />

Chip installed
<img src="http://www.imagestation.com/picture/sraid59/pa91c12c1649e0cb6124f8072bde4d6c5/fc5e7445.jpg" alt=" - " />

Look closely at the case next to the tabs...if you see little marks [from prying] then your DME has been opened before. If you don't see the marks, then there's no need to open the DME to check if you have aftermarket chips.
<img src="http://www.imagestation.com/picture/sraid59/p3570e223e86e00041fdf883c4dc355b9/fc5e73bf.jpg" alt=" - " />

Steve Lavigne

Looks good Trevor.

Your MAF sits on the vacuum side between your air filter and your turbo, right? I assume timing must be reduced when the DME reads high airflow signals from the MAF.

Just curious, were these chips from Guru, Powerhaus, Chen, or someone else?

PorscheG96

Thanks Steve.

Yes the MAF is located pre-turbo...just after the airbox. I'm not sure of specifics but the new chip might retard spark timing once a MAF voltage threshold is reached/exceeded.

I think it's a Powerhaus chip which I got from David Chen.

How are ya Steve, we miss you in the bay dude. Good luck with the new job!

85944na

Holy crap!! I've been on these boards and pelican for a long time, but I never realized your car was a turbo...damn, that thing is sweet!! ( I thought it was sweet before I found out it was a turbo)

Ahmet

That looks a whole lot more advanced than the stuff in our 944s! Technology I tell you... Ha!

I hope it works out for you, keep us updated.
Ahmet

adrial

G96, so...how does it drive???? When's the dyno tune?

It's a shame the car wont be at Hershey...

Porsche85944na, dont feel too bad, it hasn't been turbo for very long.

DangerIsland

Looks good Trev... nice fruit bowl.

Hey Steve, what are you doing up here in the rainy NW now? Where's the new job?

PorscheG96

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Porsche85944na:
<strong>Holy crap!! I've been on these boards and pelican for a long time, but I never realized your car was a turbo...damn, that thing is sweet!! ( I thought it was sweet before I found out it was a turbo)</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hahah, thanks I really appreciate the compliments. I bought the car on a whim a couple years ago and had NO idea that I'd be turbocharging it so soon. Never thought I could afford it but John Anderson gave me an opportunity I couldn't pass up! It's been turbocharged since last June but wasn't tuned until February-ish.
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Ahmet:
<strong>That looks a whole lot more advanced than the stuff in our 944s! Technology I tell you... Ha!

I hope it works out for you, keep us updated.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Thanks man. I haven't seen a 944 DME so I'll take your word that the 968 computer is more advanced. All I know is it controls one additional knock sensor and the Variocam...did I mention that I tried finding the Variocam brain but wasn't sure what the heck it would look like if I saw it. Would've been interesting to find, though. You bet I'll keep you guys updated. Don't I always??
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by adrial:
<strong>G96, so...how does it drive???? When's the dyno tune?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">It drives NIIICE! <img border="0" title="" alt="[Eek!]" src="eek.gif" /> I beat the **** out of the car as soon as I got the new chip installed. The transition from off-boost to on-boost is far more defined with the turbo chip. I attribute this to the timing...it was super-advanced before which made the off-boost performance great but on-boost performance lacking [knock sensors drew the timing back]. But now the knock sensors are happy, and it drives KILLER on pump gas. I don't have a dyno day planned yet but I'll definitely be doing one to see what the new fuel curve looks like. I also need to adjust the fuel pressure again.
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by DangerIsland:
<strong>Looks good Trev... nice fruit bowl.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Thanks Joe! Heh, it's fake fruit.

Bill

G,

I would be down for a dyno run, as long as it is not too soon. call me.