John Struthers

I recently aquired a gorgeous 89', auto, S4 allegedly equipped with GT cams.
Would it be a sound assumption to figure:
1. That a ECU configured for the GT cams was installed ?
2. That a GT equipped 89' auto, S4 would suffer without the GT ignition ECU?
3. How would a neophyte like my self identify if I had the GT cams installed without a top end teardown? Dyno?
4. Is there a way to identify the ignition ECU's from different 928 models by part number?
I'd hate to purchase a spare/trade-in rebuilt John Speake ECU only to find out that when needed it was not what the engine needed.
The GT info was provided by the sellers/mechanic, Randy Karr and he is gathering what build info he can from the Porsche Shop that did
the top end/GT Cam install /front end refresh - roughly only 500 miles since refresh-.
TIA

GregBBRD

The ECU's are all the same....the only difference being the eprom inside. They changed the decal on the cover to identify the internal eprom....but the decal won't really tell you what is inside, this many years down the road.

Open the ECU's and see what eproms are in them. There are people (on this Forum) that have master lists of what Bosch number came in what vehicle. There's a possibility that the internal eprom might not even be an original Bosch, but you will only know that once you open the boxes.

As far as tuning is concerned....GT cams obviously only came in a manual transmission vehicle....so any stock eprom you have or use will not be perfect....perhaps not even close.

Find someone who can Sharktune the vehicle, for you. This will give you a custom eprom for use in your automatic transmission vehicle, giving you optimum performance. The other benefit of Sharktuning is that you can change the programming as many times as you please, with the same internal chips, like when you get real serious and add a set of trick headers and a higher performance exhaust system.

GT cams, when installed in an automatic transmission vehicle really helps the performance, especially when installed with a transmission with a "shorter" ring and pinion, which your '89 should have. The next step of adding headers, an exhaust system, and retuning will turn this thing into a veritable rocket.

Sander_Baas

I have an GT engine in an 87 S4, and it used to have S4 eproms.
The biggest difference it made when I got GT eproms was, that with the wrong eproms you have lots of low torque but it’s all a bit slow on response. And then after 4000rpm it goes like hell.
Now with the right eproms it feels much much more linear. So maybe that helps you a bit?
(I do have a manual gearbox)

I got my Eproms from Theo jenniskens. Great guy, great knowledge, and perfect price!
He has all the different eproms and can just make you one, sending is not expensive since it fits in an envelope
http://jenniskens.livedsl.nl/

Theo is also here on Rennlist under the name TheoJ

John Struthers

Thanks much, to you two.
Ive learned a lot in you're few sentences.
I probably won't be looking at the eproms till after the 2nd week in August when I make my
final trip to Oil City, PA, even though the 89' and several other vehicles will be convoying
up there on the 19th of July.
Still hoping for any build information from Randall.
Rocket ... how much trouble can a old, fat man get into I wonder? :>}