76FJ55

Yes, there in lies the challenge with the 85-86 cars. There is no knock sensor to feed knock count to the Shark Tuner for ignition tuning.

Jaguarpig

So in reality you can not fit any supercharger to 85-86 car.

Speedtoys

Not at all, just solve that problem..aftermarket ECU.

rag928s

I appreciate all the feedback any suggestions on aftermarket ECU. Thanks Rick

davek9

This is not exactly a true statement, If you read the "TwinScrew" thread, there are other option and I have successfully been using one of them for over 3 years now on the street.
Add a stock Bosch Knock sensor in the V where one of the stock S4's are mounted and connect it to a Vampire Ignition management system which will give you individual Cylinder Knock Control.
Tune the Stock ECU's with the Shark Tuner, burn the chips, this will take multiple runs and chip burns, as on the S3 the Fuel and Ignition ECU must be done individuality and changes to one will affect the other, so there is a back and forth tuning. Using the Vampire w/ Boost input, one can adjust the amount of spark retard and at what boost level and can dial in a safety factor.

Granted there are newer systems that make it much much simpler and easier to get the proper AFR and Timing retard under boost w/o as much work, but a total over haul of the stock ignition system is not required to Supercharge a 928 or any other older technology engine.

Here is my 86.5 with also with an NLA Andy Keel Kit that has been modified a bit to my liking, It uses a "Auto Rotor" (now Kenny Bell) 2.2ltr Twinscrew, witch I'm in the process of upgrading to a 2.4 and hopefully utilizing some of Han's newer designed parts to build a Hi-bred

Super Charging old cars as like any power adder is a slippery slope and not a plug and play thing that one installs and walks away from, custom parts require Custom work and that requires additional attention to the systems in-order to maintain decent reliability.
Note: The Best Plug and Play kit that I've installed on an S4 is the Murf kit, however you better have a well sorted engine with new Head gaskets before doing any type of Power adder.

hacker-pschorr

Anyone who says you need knock sensors to properly tune a car should step away from the laptop and hire a professional before they blow the engine.

Knock sensors are there to protect the engine in case something goes wrong. They are not a tuning device. The whole idea of tuning just shy of knock is very, very wrong.

Sure you can, Murf928 has a very well designed and tuned supercharger kit for the 85/86 cars. See this thread:
https://rennlist.com/forums/928-foru...s-new-car.html

I think you misunderstood the statement you responded to. What's wrong is running a car under boost with the stock ignition timing maps, which you are not doing.
The subject is the 928 Motorsports kits which retain the stock ignition timing for all of their supercharging kits, which is just stupid.

belgiumbarry

Speedtoys

Lots of things may not optimal from time to time and outside user control or knowledge..you saying you can tune an engine to peak timing HP without that additional feedback, and that you can go forth from there without knock input safely for any period of time?

Petza914

Guess I'm one of the stupid ones then, and happy to be as the car runs great and has since 2015. Though maybe you're referring to the kits for the 32v engines and not the 16v ones as there aren't really ignition maps, just distributor timing and I'm retardingmy timing under boost with pressure into the vacuum advance port. I have a knock sensor installed in my valley to notify me if there is any knock detected and have now set my timing so it never sees knock. My fueling via the AFR gauge is perfect and between 12-13 under boost, various loads and rpms, and 13.5-14 when idling along or coasting.

Darien

Not true… my 86.5 had a Twinscrew SC installed for 14 yrs and absolutely no issues once Sharktuned. There have been lots of 85-86 Sharks boosted!! The Murf kit is another SC kit that ran beautifully on Shane’s car and has been installed on others as well

I’m sure you have seen but lots of info here. https://rennlist.com/forums/928-foru...ew-thread.html

davek9

Before we had knock sensors we learned to read the spark plugs, looking for the heat band on the ground strap, the closer to the outer end (away from the threads) the more advanced the timing was, optimal was in the middle, at the end was too advanced. This method requires shutting down the engine and removing the plugs right after a hard pull, or at the least a slow drive back to the garage
The knock sensor gives one a level of automation and the ability to adjust on the fly and also to log the data,

rag928s

The amount of information in everyone's heads for these cars should pulled together to help current and future 928 owners upgrade and modify cars. I'm learning a lot and haven't scratched the surface. It would be amazing

Petza914

We have such a place, and you've found it - Rennlist

Speedtoys

It will be interesting to see how to improve the budget friendly challenges in the original kit he sold.

Dont get me wrong, IT WORKED, but...it was limited to very short bursts (temps), and had MAF turbulence issues with the intake design.

I had one, and enjoyed it.

I also think that the only way to relaunch this is with a standalone ECU.

Petza914

Using the windshield washer fluid as a cooling medium from the reservoir and pumping it through an intercooler and radiator has proven to be an easy and effective means of cooling. I also have mine plumped to the warming chamber of my Verus dual chamber AOS to heat the captured oil and condensate so it doesn't gum up the AOS.