Engin

Have a great year everyone!

I have bought my 90 C4, with an FVD chip already installed (Part no. FVD 964 618 XX). Though the chip is correct for my car, the local octane rating is a questionable 95, whereas the chip requires min. 98. The previous owner was using octane boosters to overcome the problem.

I have the original chip and would like to replace it as I am not a big fan of octane boosters (any comments welcome on this issue).

I searched through Adrian's book and the forum but could not find any info on how to do the swap.

I am usually ready to do some minor surgery, but wanted to ask before opening up the brain!

Adrian

Dear Engin,
Go to this web site. http://www.sportwagen-club.de/index.htm
Scroll down the page until you see technik. Click on here. Then you will see a list of items. Motronic chip is the one you want. The instructions are in German but the pictures are very good.
The reason this is not in my book is because the procedure (I have it and I did have it installed) did not have any images to go with it and I could not get a good set made up. The procedure is quite tricky especially when you have to pull the circuit boards apart. I felt this needed really good and seriously close up images. Maybe next time.
Ciao,
Adrian
964C4

PS: I did not find this web site until my book was at the printers. Twas too late.

Engin

Dear Adrian,

Thanks for the quick reply. The German text is no problem as I can read German. I guess it will be a job for coming Saturday morning.

Best regards,

Lorenfb

You'll find a notch on the chip and on its socket on the circuit board.
The chip's notch is oriented to align with socket's notch.

Your decision to remove the chip is a wise one, especially on a 964 DME.
Check out this website (www.andial.com) on Question 2 for insights
about chips. Andial is Porsche's USA arm for racing. They know Porsches.
Also, check out this other website (www.systemsc.com) on the Problems
page on Performance Chips for additional info.

Good Luck
Loren
'88 3.2

jchaley

You might look here
http://members.rennlist.org/951_racerx/
then look under chip installation. The 944 turbo DME is very similar looking to the 964.

john

Doug H

Andial may have incentive to bash cheap mods if they are trying to sell expensive engine upgrades/rebuilds as a means to increase performance.

Doug H

Out of curiousity, why would any chip require 98 octane since compression is the same. Is this a timing advance issue. Is that 98 RON as whatever as opposed to actual octane. I can only get 93 around here and Octane boost is probably a bad idea. I have 4 different chips for the 964 and they all require or recommend 93 Octane for optimal performance.

Engin

Interesting reading on performance chips on Andial and systemsc sites and they seem to make a lot of sense.

Most chips today come with warnings to use minimum 98 RON.

There is info on fuel rating and octane boosters at the rennlist address given in John's message above. Although the octane boosters tested are mostly of Australian origin (at least the better ones), even those best ones cannot manage a complete 3 point increase in RON.

I am also worried about the temperature at which these additives are burning and their effects on pistons, what sort of deposits they are leaving in the engine, whether they are truly mixing homogeneously in the gas tank, whether they accumulate in the gas tank, in which case do they degrade over time, etc.

delhi

I believe 98RON ~ 93 AKI. Europe and Asia measure octane rating as RON while North America is AKI (Anti Knock Index).

Tom W

You need to be sure of what the chip requires unless you want to risk engine damage. US chips like those from GIAC or Rennsport Systems usually mean US octane rating ((RON+MON)/2) and not RON. Usually you would get the higher octane by mixing racing gas with pump gas, and not through use of questionable octane boosters.

I buy 100 octane at Union 76 or at the track. I can also get 104.5 octane unleaded from ERC fuels...

Engin

I have swapped the FVD chip with the original one. However, when I turned the ignition to ON mode (without starting the car) the idle speed control valve started to make rapid clicking sounds. When I tried to start the car, the engine was turning over strongly, but the car would not start.

I guess somewhere along the line one of a few things might have happened:
a) somebody tried to reprogram the original chip without much success,
b) the original chip was somehow damaged
c) something was altered along with the chip change, which is now incompatible with the original chip??
d) I should have done something else before(/after) trying to start the car??

Anyway, I have put the FVD chip back on, and the car runs fine again.

Any ideas on how to diagnose whether the problem is with the original chip or with some other component?

joey bagadonuts

I looked at the FVD-USA catalog and it apears their chips are sold with an entire Motronic unit, i.e. the chip, new circuit boards and housing. Engin, is there an FVD label on top of the housing?

Engin

Joey,

The Motronic unit appears to be original w/original stickers on it. The housing was obviously opened before. I also have a FVD box for the chip with the FVD stock number etc. I assume that the previous owner received just the chip and replaced it in the original unit.

Engin

PS: I just looked through the FVD catalogue as well. It seems that just the 993-996 & Boxster chips are sold with the Motronic in exchange.

joey bagadonuts

Last thought (for now). Is it possible you installed the stock chip incorrectly? On one of the short edges, there is a half moon cutout which acts as an installation guide; the FVD chip has a similar cutout.

I'm not sure if it CAN be installed incorrectly only that this cutout needs to be pointed in a certain direction to work properly.