MSD Knock Alert, any one use it?
 

Anyone using the MSD Knock Alert or other listening aid?

Here:Engine Knock Alert - 8964

For dyno tuning of as a safety?

Any thoughts.

http://forums.pelicanparts.com/uploa...1286933487.jpg

That looks suspiciously like the knock unit that I used with my MSII install. Below about 4000 rpm it was ok but over this it could not differentiate engine noise from knock. Basically it sets the noise threshold at only one spot in the rpm range rather than building a multi-point profile.

This is new to me.

So it is more just a volume of noise, not a frequency or sound profile of some type?

Knock sensors have been around for years in the older VW's... Customers would come in and complain that their cars had no power.... Come to find out that the knock sensors were picking up the "noise" of worn water pumps and alternators... Then they ran dual knock sensors and this seemed to fixed the issues.

Pay slightly more money and get a J&S Safeguard which provides boost retard (thereby letting you run more advance off-boost) and per-cylinder real-time adaptive retard on knock detection as well as a blinky light.

+1. Why bother with knock detection if it doesn't include an active ignition retard? There have been massive discussions on this topic - specifically on J&S Safeguard IIRC- and there still seems to be a divided acceptance on how well this works in aircooled engines.

Couldn't agree more. If it cost $30 and took 5 minutes, then a blinky light as a tuning aid/warning light? Sure, whatever.

As the Bosch sensor itself costs more than that - I think that once you invest the time to install and calibrate something you might as well have it actively protecting the motor in real-time.

I've yet to see anyone saying "brand X didn't work for me" - for any value of "brand X".

If my Safeguard did nothing more than save me from a tank of bad gas, it just paid for itself 10 times over - yet it does so much more.

I would have to go back and search as to specifically whose "brand" was being discussed. It was quite awhile ago.
I don't currently use a knock detector...rather, an active ignition retard via pre-set boost level(s). Still, the concept of a knock sensor seems very sound whether or not it can hear past all the background noise. As I recall, half the users swore by them, and the other half were on the fence. Hey, the worse thing it can do is cause premature retarding and a little power loss. Seems like a fair trade off I guess.

http://forums.pelicanparts.com/3904852-post7.html

I assume Les was talking about knock sensing on a TEC 3.

Safeguard has ignition retard at pre-set boost levels too, but knock retard is a separate feature that can provide additional retard as required (until it doesn't knock, up to 20 degrees extra).

I have the timing advanced over stock and use boost retard feature of the Safeguard to pull it back as manifold pressure increases to arrive stock timing at 12.5PSI. (Initial fairly conservative settings, need to sort out the top-end fueling).

No knock detected whatsoever under full power conditions on the dyno - but as soon as you lift from a full-power run, the Safeguard lights up with the extra motor noise for as long as it takes for manifold pressure to drop below the arm point - the Safeguard has a built-in MAP sensor). Which doesn't hurt power at all, as the throttle is already shut.

Mine seems to. You do need to calibrate the gain for your sensor/motor.

The only situation where I see any knock retard indication is lower (2600-3000) RPM when the Safeguard arms at 5hg/in due to load/throttle, and usually only climbing hills at a steady RPM and suddenly opening the throttle. I think at least part of this may be CIS going momentarily lean.

For me, the Safeguard pulls back 1-2 degrees of timing for a few seconds (it's always trying to advance each cylinder back to the full setting) in these conditions, although if I goose it harder it will pull back as much as 6-7 degrees of distributor curve before manifold pressure gets high enough that the boost retard starts to kick in as well, CIS catches up and delivers more fuel, or the revs rise - probably all 3 things are a factor, would be my guess.

This pretty much only happens when climbing hills and suddenly accelerating, haven't noticed any knock retard whatsoever doing the same thing on flat and level ground.

As far as power loss, I'd say the car is far more drivable off-boost, ignition advance is independently tunable on-boost, low to mid-range power and drivability vastly improved. It made quite healthy numbers on the dyno.

Full Boost: - stock timing, no false knock. No power loss.

Partial Boost: - Advanced timing, no false knock, better response & more power.

Off-Boost: Maximum timing advance. Much improved throttle response & pickup off the line.

I'm obviously biased, but only because I'm a satisfied customer. I read the thread John linked first time around and decided then to take a chance on the Safeguard.

Finally got around to it and got a professional to install it. (Who, by the way, would happily use MOTEC knock detection on your 930 if you stumped up the necessary megabucks to enable that feature).

I think it works, Guy that installed it agrees. Steve Weiner, Todd Knighton and Jake Raby all have testimonials on J&S's website. Turbocraft sell an ECU that has knock detection.

I don't understand - who exactly is saying "air-cooled motors are too noisy for knock detection"?

John is a great guy to deal with who makes a quality product. That product does just what it says on the tin, as far as I'm concerned - money well spent.

The "blinky light" MSD box is half the price of active per-cylinder knock control - with boost retard.

I think the Safeguard is a no-brainer choice - even if you install it on an otherwise stock motor just to guard against bad gas or other issues (like a detached waste gate hose).

Great writeup Spuggy. Lots of food for thought. I don't know either who's saying that air cooled engines are too noisy...I'm just repeating the sentiments of other people who may or may not have any first hand experience. That's where your comments hold their own weight.

I run a lot of advance (12 at idle and about 36 degrees total advance in the absence of boost). All that excess timing makes a real noticeable difference in the mid range power delivery, and the MSD Boost Retard shaves it all off progressively to where I'm back close to stock max timing (28 degrees) before full boost is reached. That's for detonation control, but individual cylinder knock control would be an added safety margin. That's just one more thing I have yet to play with. Good positive testimony is important.

You might consider taking a look at water/ meth injection, simple, cost effective, stops detonation, makes 109 octane race gas out of 93 octane using washer fluid, allows you to safely run more timing and 1.2 bar of boost, produces a 10-20% horsepower gain, and drops egt's by a couple hundred degrees. A lot of bang for the buck.

I owed you John !!!!


Cole

We have a verity of these devices, I mean knock sensor units.
MSD is just one of many available. It depends on if the unit is 911 specific and if
it needs to be configured.

You need to have a pretty good understanding of how and where to place the knock sensor and or sensors depending, along with the fact that as someone mentioned the 911 has a lot of mechanical noise however this is not to say that it's impossible to detect knocks etc.

Somethings to consider, it also depends of if you're management system if isolated or combined beyond that road conditions will always be different from a dyno. So you need to factor in these things, also note that suspension, chassis re-enforcements and other areas will effect a given set up. ie the road vibrations -

Good luck -

Thanks. I was intending to sort out CIS (my AFRs start to get a little worrying over 5,000) and get the Safeguard into more aggressive mode before writing it up, but the topic kept coming up... :)

There's the rub. There's a list of statements that basically seem to amount to "I heard" - with little or no attribution and no date. Those could relate back to attempts back in the day with stone-age electronics, for all we know. Or devices that just didn't work. Once you approach those statements with a desire for actual facts, they just kind of crumble away and you're left with nothing. IMO.

There are professional tuners, racers & individuals (some even on this forum) who tried this before me - on air-cooled motors yet - and had good results. I wasn't a trailblazer on this.

Heh. I'm running 34 degrees total advance @ 4,000 and pulling back to factory RoW timing (28 degrees) at full boost. I consider this quite conservative, as knock retard is almost never in the picture (just the very specific circumstances I've noted before). I figure the factory left some (if not quite a lot) on the table for safety - without knock sensing, that'd be appropriate for a production car. Agree that it makes a huge difference in the way the car drives, especially low-end throttle response and part boost.

Once I sort out the fueling, I'd like to make the Safeguard work a little harder for a living and see how much difference that makes to performance. I think it should be significant.

All good benefits - I don't see any reason why it need be either/or, I would just do both...

spuggy,

Absolutely no need to be either/or, both is fine. I was implying nothing other than another viable alternative. I looked at all the alternatives before I choose WMI. To this very day I do not believe knock sensing will work consistently and correctly on an air cooled 930. And so for the same price point, actually less, I went with the WMI and got the added benefits of no longer having to pay $4.00 to $6.00 a gallon for decent gas. Nothing other than another alternative.


Cole

Open and honest discussion....I love it!

I can just see myself - Mr. Gimp and his Gizzmos - hooking up all the latest doo-dads to a master control panel in the cockpit with multiple gauges, bar graphs, flashing LED's, knobs, switches, and buttons to support every add-on I can find. You know what they say, mo' is betta'...to a point anyway. So much for simplicity.

In 1 hour and 20 minutes from now this will be the farthest from my mind as I fire up my girl for the drive home from work. I plan to take the twisty way home (and I do mean twisty), on boost as much as I can and still be safe, and damn any detonation or knocks 'cause I can't hear them anyway.

And here is another option that looks promising:

KnockBlock — Link Engine Management Systems - plug-in & wire-in aftermarket ECU's