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05-20-2002, 02:50 PM
I'm looking to retard the timing a bit on my supercharged 4 cylinder. M44 engine.

KC Ron Carter
05-20-2002, 06:21 PM
Hey WannaM,

My friend and yours Sweeney was just telling me about the APC system that can be adapted from Saab.

Let me do this cut and past.

Posted by: Sweeney NE 86 635Turbo on 2002-05-18 at 13:57:41
(posted from: Host: IP:


My solution for knock prevention is the installation of a Saab APC unit. This uses a knock sensor to listen for detonation and at it's onset opens the signal line tothe wastegate. The wastegate gets set to a low, 5psi setting, well below a point where detonation will occure. The APC blocks manifold pressure from openning the wastegate, allowing much higher boost, untill it begins to sense knock. My Saab SPG's gate was set to 5.5 psi base boost but the APC allowed 17psi without knock. The parts can be gotten in a salvage yard for under $150.00. There is no other boost controller on the market that does this. If you want more info, just ask.

KC Ron Carter
05-20-2002, 06:32 PM
the Monotronic spark control and you may be able to make a work around. But the knowledge will help to keep it tuned.

I know that most people can get a tune every 50k and be happy.
You will not be able to forget a turbo for 10k without paying.

The only sensor that affects the timing is the engine temperature sensor. You can either make it provide more advance or reduce the advance by varing the temperature sensor voltage back to the ECU.

I have made and installed variable resistors for Local Law enforcement and Hiway Patrol cars in the Kansas City area.

It is against the law to modify a customers passenger car but the Hiway patrol is excempt. Your liking this already.

More after I get to eat,
Ron Carter

KC Ron Carter
05-20-2002, 08:55 PM
Hey now,

I located a web site that explains the concept of measuring the sensor output. See below.

I will need to get the specs on what Multimeter is needed.
There is a gotcha, that I remember, but I will need to do research on what the meter spec needs to be.

Ron Carter

KC Ron Carter
05-20-2002, 10:35 PM
This is the APC site posted below.

Ron Carter

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Dan Pinder
05-22-2002, 03:50 AM
Yeah.. but what about the knock sensor?

The M20 doesn't have one that I know of.. can this be added?

KC Ron Carter
05-22-2002, 07:08 PM
Too many problems and I like to live dangerous anyway.

Ron Carter
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05-25-2002, 03:11 PM
I have been involved with and trained on Bosch injection since 1970 and GM since 1972 and can assure you I have spend more time bypassing knock sensors than any correction they have saved me from.

The aviation industry, my big money maker, has always avoided knock sensors since there are no credible information to back some of the manufactures claims.

Any system that will reduce horse power by 25% because it felt a vibration is a little overboard. And almost impossible to troubleshoot.

You may have notice I have a little bias against knock control but if you want it check out the ricer Greddy listed below.

Ron Carter
I really like Greddy especially the models.

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