The 28 Pin Eprom DME has a little better performance and
runs a little smoother than the early 24 Pin Eprom DMEs.

You may not notice a difference with the Pin 10 brown wire
disconnected. It probably only advances the ignition 2 -3 degrees.
You can check it with a timing light with the RPM constant at
2000 RPMs to get an idea.

Have Fun
Loren
'88 3.2

Movin, in 87, Porsche used a special 24 pin chip that was specific only to the early 87s. This was the transitional period when Porsche was going from the 24 to 28 pin DMEs in order to consolidate inventory because the 28 pin chips had a larger memory and therefor could contain the various maps for different countries. There are a couple of versions of the 24 pin program for 87 just and there were a couple of versions of the 28 pin programs for 87-89. Between the two versions for each year, one produces a little more power than the other. This means while one 89 could produce 217 hp, the other might only produce 207 hp. Probably you originally had the 217 hp chip in your 87 and the 28 pin DME you got had the 207 hp chip. No big deal though, because you can take the 24 pin chip out of your old DME and insert it into the 28 pin DME and have your old program back. If you install the 24 pin socket in the 28 pin socket, you need to insert the chip in the socket to the side of the socket away from the half moon notch.

Also, early 24 pin 84-86 DMEs can be easily modified to accept the 24 pin 87 chips, or late 28 pin eproms. It's just a matter of installing a larger 28 pin socket, and moving a jumper. The difference between the early 24 pin programs, and the later 28 pin programs is that while the 84-86 cars produced 207 hp, a large portion of the later cars had a 217 hp chip. Also, idle ignition timing is increased by about 5-6 degrees in the later cars for improved efficiency, and raised the idle speed from 800 to 880 rpm. However with a revised chip with all programming the same between the two, I've found no difference between a early 24 pin v.s. a 28 pin program.

What do I think of Steve W after reading his posts, meeting him in person, and installing one of his chips... Highly intelligent, unassuming, kind, personable, and VERY, Very, generous with his time and expertise!

Thank you Steve.

Sincerely,

Mike

Thanks Mike for the kind words, although you give me more credit than I deserve. I had a blast meeting you guys also! :)

Adam, in the U.K, your reply email address does not work. Tried to reply but got a bounceback. Could you shoot me another email again? Thanks.

Correction:

The early 3.2 DMEs ('84) used 16K EPROMs which could accept the 32K EPROM
WITHOUT any jumper changes. The later 64K EPROMs used in the '88 and '89
require a number of jumper changes to convert from the 16K/32K EPROMs in
the early DMEs.

Unless all the maps and all the additional data points are included in the 24 pin
EPROMs, the 28 Pin EPROMs (later DMEs) are still much better. That's why
Bosch went to a 64K EPROM, i.e. more map data which couldn't be placed
in the smaller 24 Pin (16K/32K) EPROM.

Porsche owners always notice an overall improvement when switching to
the later DME box on their 3.2s. The improvement is over the full RPM
range and not just at a few RPM points.

Have Fun
Loren
'88 3.2

so, I disconnected the little brown wire today..took the car for a drive. I really can't say I notice any difference. I'd like to think it's doing something to help..but who knows. I guess I may just hook it back up since I really can't prove a positive improvement.

Danmatar, the difference in power by disconnecting the pin 10 brown wires is minor with a stock chip, no where near what a remapped chip does. By connecting it, it essentially leans out the fuel mixture everywhere to reduce emissions on cars for California.

Once again for the third time:

1. The Pin 10 brown wire is connected for CA & Japan cars to retard the
timing for NOX reduction. It DOES NOT affect the fuel mixture. Once
disconnected, it will advance the timing a few degrees.

2. The Pin 28 brown wire bypasses the altitude correction sensor by shorting
Pin 28 to ground, which is what the sensor does at high atitudes, to lean
the mixture. With it connected, the mixture will be lean. You need to use
a CO machine to see its effect.

You guys need to determine which brown wire you're disconnecting.

Have Fun
Loren
'88 3.2

I'm just recounting my experience. BTW, I'm disconnecting the ONLY brown wire going into my ECU. Pin 10 or 28, I have no idea.

Then it's probably the Pin 10 brown wire. If the stock chip has been
replaced, then it's possible that the function has been disabled or
masked by the chip mod.

If you have the stock chip (xxxxx358), then you may have to use
a timing light to see the change. Also as I've said, the timing advance
is minor (2 -3 degrees) and may not be that noticeable.

Have Fun
Loren
'88 3.2

...troll...

You have to "love" those chip makers who CLAIM to make performance chips,
but lack the BASIC understanding of how the Porsche DME functions. Don't
you just wonder what you're getting, when you buy one of those chips?

As a result, you have to ask yourself what the long term effect is of running
such a chip.

Have Fun
Loren
'88 3.2

Perhaps you should pull out your gas analyzer, stick it up your tailpipe and take it for a drive and tell me it does not affect the fuel mixture. Either way, I am done discussing this issue with you because it is an irrevelent issue to anything. I am not interested in entering into a pissing contest, and if it makes you feel like you've got the bigger schlong, then so be it.

Wait a minute! Is this another E-ram thread?:D

Just kidding - take it easy guys!!! this is only a thread!!!

Loren - if steve rubs you the wrong way :mad: , then look the other way.
Steve - if loren rubs you the wrong way :mad: , then look the other way.

That way, people interested in Steve's Chips can chit chat in a civil manner. The ones who are not, can chit chat elsewhere.:D

Can't we all get along?SmileWavy

:D

Such prose...on so many different levels. :)

Boy, if you read the threads you'll find Steve's are informative and helpful regarding engine performance and DME workings.
If you read Loren's, you'd think he has a vendetta against Steve and anyone who tries to improve the Bosch computer, as if it was the motherland's gift to car creation. I'm amazed Steve keeps debating this. On the sheer fact alone that the software in the 84-86 chips is 20 years old now, its pretty obvious to me that improvements can be made in the timing setup by itself, since the old chip-ware is programmed for use with 87 Octane fuel. If all you had to do was fiddle with the sensors and their ancillary functions, you wouldn't need a FACTORY CHIP IN THE DME IN THE FIRST PLACE would you?
Nope. Guess not.SmileWavy

BGCarrera32

I'm with you on this one - although sometimes I think Loren might be Steve's alter ego - sort of like two face in the batman comics - one doesn't exist without the other.

No offense Steve -- Loren does a good job of bumping any thread associated with the evil computer hacker!!

Well Loren is right about the brown wires. My car runs like a charm, pulls more chicks than ever before too.

Why does everyone get so upset? The issue was what the brown wires do.
No one provided the correct answers. I've provided that info.

Also, if you don't like my asking questions which should be provided by
chip solicitors, then just ignore them. These are questions everyone
should be asking when no real data exists. I doubt that most of you
would replace the factory specified oil with some oil that an unknown
source just produced, because the claim was a performance increase.

The more information we all have, the better off we all are. That's the main
purpose of this forum, isn't it. When people solicit business on a public
forum, they should expect to be challenged.

Have Fun
Loren
'88 3.2