[hernanca]

Happy New Year!

I posted this question on the other site too - see post 29 in this old thread of Louie's. Note that I could only get into the other site from my phone by using a DuckDuckGo browser:

https://rennlist.com/forums/928-forum/3 ... ion-2.html

So, in a discussion about tuning my motor, and specifically about individual cylinder knock sensing and corresponding ignition retard, I was once told that the best approach was to retrofit 87+ computers to my 86.5, retrofit both knock sensors (done), add a Hall sensor, change my flywheel, and do some rewiring in the CE panel. I prefer to avoid most of that if possible and see what I can do with my stock computers running the 6.5L Stroker motor.

I am willing to go through the pain of tuning my 86.5 (stroked) motor's stock computers (LH2.2 + EZ-F) using my sharktuner, but I would also like the safety of knock sensing and corresponding retard. In the above thread, Louie Ott recommended the J&S Safeguard Vampire model:

http://www.jandssafeguard.com/index.html

for the 928 which seems to be able to provide per cylinder knock detection and corresponding per cylinder ignition retard.

Has anyone installed this on an 85-86.5? How does it provide the per cylinder feature? It looks to me like it just counts ignition events and knows how many occur per 2 engine revolutions? Will this work without having a Hall sensor to track cam rotation (which is what I think the Hall sensor does)?

Thank you, in advance!

[Crumpler]

Following, but afraid I will only be moral support.
It looks like some big names are involved on the other channel, so hopefully they will be helpful.
You may want to PM DaveK9, he had alot of experience with the vampire system, and Sharktuning 85-86 performance mods.

I’m impressed you got a second knock sensor in there. I only have the forward position in use.

My first SC iteration was actually stock ECU’s, scary old FMU, and one of those self contained knock sensor lights in the cabin. Among other issues that light never really “self-calibrated” for ambient noise.
My current VEMS system has the ability to detect global knock based on adding threshold to ambient noise curve of rpm’s.

My two cents: aftermarket ECU conversion.
Not VEMS, something with more support.
By the time you retrofit those S4 components, actually I think you would have to change ISV as well, it’s going to be more work and expense potentially.
If you have a sharktuner already potentially not.
My full support either way.

[hernanca]

Thanks, man - I do appreciate the support! The intake was already off and, according to my mechanic, the only thing preventing the rear knock sensor from going in was a 3rd mounting tab on the maf/throttle body assembly. Not sure if it will cause me any problems down the road, but I told him to go ahead and file it off. He seemed to believe the two mounting tabs were sufficient for that assembly.

Yes, I will reach out to Davek9. I know he is interested in all this because of his 85/86 cars. He said on that thread that he is happy with his vampire on his supercharged car. I need to reach out to Hans also but I want to read up a bit on the system he linked to and refresh my knock sensor knowledge by re-reading that 944/951 guys articles.

Good point about all the work and expense involved in retrofitting S4+ bits to the 86.5. I prefer to keep things as stock as possible because I don't want to have to explain to whoever is working on the car what all the mods are. It is hard enough finding someone local to me that knows the 928 and unfortunately I don't do the motor work myself (no experience and no time (currently) to get that experience).

The shop I am using has experience with the Lynk/Link (sp?) system and I know they want me to switch to that. We'll see.

I do already have a Sharktuner. It is the upgraded non-PEM version that can tune some 84, the 85-86.5 LH 2.2 and EZ-F, AND 87+ LH 2.3 and EZ-K.

I certainly cannot complain about not having options at this point!!!