knock sensor
 

Does anyone make a knock sensor suitable for the 930?

The "safegaurd" by J and S electronics is off the market until they come out with their new and improved version. The new one retards spark for any cylinder that needs it. It has general retard controls and a host of other stuff. I told the dude who designs and owns the company that I don't know if I need all that stuff. He said "don't waste my time" and then hung up on me. :confused:

douchebag.

I just installed the MSD ignition with boost retard. I have advanced my timing a little bit, retarded boost, and want to use the knock sensor both for safety and tuning. BUT, if no one makes an accurate-n-reliable one, then I guess I'm just playing with a grenade.

been wondering the sme thing, I have seen sensors that bolt onto the block but I wonder if they will work the same way with separate cylinders.

Douche bag here. Sorry I lost my temper with you this afternoon but I couldn't take it.

I just wrapped up the new design this morning, then you call asking if my system can reliably detect knock in all cylinders on an aircooled engine.

I say I'm not really the guy to ask since it's my design, then explain an aircooled isn't as noisy as most think, and relate a story, etc, then I tell you about the features in my new design.

You say you just installed a boost retard and all you want is a simple system to say it's knocking. I make a very fine closed loop system for not much more than you paid for your boost retard ignition and you want a knock LED. Sorry, but I lost it.

As for whether it works or not, Steve at Rennsport posted this a while back:

So, I have no horse in this race (no knock control), but I can attest for the widespread respect that J&S has in the non-Porsche boost community. If I were looking for sensitive active control they would be a serious contender for me.

Wow John, that's some serious radar. Your apology is accepted. I am a bit of a newbie who has spent 3x the money I intended on my engine and 400x the amount of time intended. I know little about this subject, so I am sorry that I can't ask direct and intelligent questions on the topic.

As for your current creation, it sounds fantastic......yet, while you described it I felt another 1000-2000 bucks being sucked from my pocket (not that you told me the price). It sounds far more sophisticated thus I assume more expensive than your past knock sensor creations...just a guess.

Several people have mentioned that the general noise of an air cooled engine makes knock sensors inaccurate. I don't know your history, thus I could not know whether you spend most of your time working with liquid cooled engines.

I've also heard it said that knock at different RPM's creates ping in different sound frequencies. Perhaps some knock detectors only search for sounds at one end of that range. I wanted some details on if and how you address this. Just gathering info.

Pelicanheads,
Is a knock sensor a tried and true insurance policy on our expensive motors?

Doug: There are a few that have posted about the system. I'll dig up their posts after a bit.

Can't remember how I got this pic, but it must have been from an engine builder in Daytona Beach who installed several of our systems.

This was probably from '96 or so. I think the customer raced it in Panama.

http://forums.pelicanparts.com/uploa...1209002800.jpg

When I built my motor I asked about knock sensors from the Company selling me my ECU, harness etc. The knock sensors will sense knock in an air-cooled noisy Porsche engine. I was told that the issue is that they "falsely" sense knock when it is not there from the cacophony of noise in a Porsche engine. Basically a false Positive. So you are a retard much more than you would like. I wold love to have one that was accurate and sensed knock when it needed to and didn't sense it when it was no there.

:D

Do you mean "So you retard much more than you would like."? :)

993tt's have knock sensing right? If it can be done on the 993tt then it can be done on the 930. I've read that it's all about where they are positioned, not that it isn't possible

"Stupid is as Stupid does" -- F. Gump ca.1994

Here's my scenario, I asked a few companies who specialize in Porsche 930 tuning, and they say, sure they are available but...

I got 35K in Engine Parts, I would love to put one on mine if I was convinced it wouldn't "false" on piston slap, etc.

I've heard the 930 engine makes "too much noise" as well to use a knock sensor RELIABLY. Not sure if its the chain and ramps, etc that do it?

Hi,
No offense, but you SELL knock mitigation equipment. I read this thread you referenced. No proof of anything here. I'm sure your system can stop knock(well sorta sure), the question is does it stop performance? There are a lot of high end Porsche performance shops out there. Which one refuses to sell you a Hi Po engine without a knock sensor?

If I sold you a 65K motor and a knock sensor worked well on it, I would force you to buy it to protect your engine and my business.

Contrary to this, the Tuner shops I have spoken with have basically told me to forget it! It will kill performance. The fact that a guy tore his motor down and all his rings and lands look good doesn't really prove anything. Let's see his "Knock log" for the last 10,000 miles. Let's put his motor on a dyno and watch the knock sensor while he produces power, the engine is loaded and we mod the timing curve.

For the cost of a knock sensor, who wouldn't want one, comparatively speaking, they are DIRT CHEAP!! There's lots of modified cars here on this forum, the knock sensors are for all practical purposes ABSENT.

John,
You got a SIGNIFICANT amount of Porsche data and testimonials, and dyno time with 930's, I'd love to see it. i THINK WE ALL WOULD. Prove to me your system detects "positive's" properly and does not make "false" detections, and you've sold me one and most likely a lot of others. I basically would like to see the scientific method employed here, not sales brochures.

The first time I pulled my motor apart, every compression ring was broken into uncountable pieces, all twelve.

To coin a phrase...
Sho me sumpin' Mista!

Les:

The thread I linked to doesn't prove anything, but the post by 350HP930 should score us a few points.

http://forums.pelicanparts.com/showpost.php?p=1658863&postcount=72

I don't know him, so he probably bought it from the engine builder in Daytona we used to sell to.

I checked his profile, and he hasn't been on the forum in a couple of years.

John

Hmm...IMHO, the only bombproof way if detecting the knock w/o running into false positives is by using ion-sensing (thus measuring ionization current over plug gap after each combustion).

Those acoustic I came in contact with certainly work, but are often tuned to go "safe" as revs climb and pull timing/boost as they go deaf att higher revs. They usually do their stuff at middle revs where BMEP/torque is highest.

A knowledgeable and expirienced gentleman gave me a very usable hint when it comes to detecting knock on dyno (while mapping etc.) He used brake line tubing that he connected directly on the block on one side and to some sort of megaphone on the other. He claimed he could hear a single knock on this contraption. :)

Hi John,
I'm not making my point obviously. I have no doubt that "most" if not all these knock sensors suppress knock. The issue is that they suppress performance. The fact that everything was fine when he pulls his motor down means nothing other than anecdotal evidence. That is, his engine didn't blow up. Why??? Maybe he only ran 20 degrees of timing with 103 Race gas all the time?? Maybe he never drives above 4200 RPM? Kinda doubt that but who knows.

The issue with the knock sensors is not that they can't sense knock, it is that they sense it when it is not there, and pull timing(Performance) out.

From your response I can only conclude that there is no empirical evidence of the efficiency of your knock sensor in relation to Porsche 930 motors??

I also quoted Rennsport in post #3 above.

Ehhhhh? Whatdya say Sonny!!

MSD knock alert, look it up on the web. It's just an indicator tool, no integration ability or feedback.

Les:

I don't know if you have heard of a guy that goes by"Turbo Mike", from Hacienda Heights, CA.

He has installed several of my controllers, used in conjunction with a F.A.S.T. EFI.

Here is his car on the dyno with my system:
http://www.youtube.com/watch?v=Xhf8fUZJ6a4

The MSD knock alert is all analog. Not that there's anything wrong with that, but it doesn't even have a knock window, which is a form of noise blanking.

No one heard of Turbo Mike? I think he's Armenian, or has some accent like that.

Nope, never heard of him.....

Found a little more public information on him from GT Pro's site

John, you seem a nice guy and you have a nice product there. You seem to have developed it well and it is very up to date.

The problem is, with the 930 the timing chain ramps are very noisy and this is why your product is not as suitable for us as it is for other Porsche air cooled engines.
We're a very small market so it's not much of a loss to you.

Hi,
I'd love to have one as I'm sure we all would. The people with 930's that I have heard that have had them deployed, pulled them back off. I tried to get my ECU salesman to sell me one and he wouldn't.

Les

Les:

I don't know Porsches. How similar are the cam chains on a 911?

The 911 was our first test car in a magazine, must have been early '91. I rode along with an oscilloscope on my lap, since I had heard stories about how noisy these engines were. Not true at all. I was surprised at how quiet the engine was.

The owner was an engineer at CalComp, who had reverse engineered the Motronic chip. He had a version he used on the weekends with more timing and less fuel, and that's what we ran when we tested the unit. Can't remember his name, maybe I can get hold of James Sly. He probably knows. I think the guy that installed it was Greg Brown, a Porsche mechanic here in Orange County.

John

Nice thread. Porsche tuning community has largely made do with no form of knock control because SO FAR nobody has come forward with the right product. ALL knock sensing systems register false occasionally but what a good system can do is help you tune the car beyond what`s possible sans knock control. The DSM tuning community is well familiar with the bane of pulled timing from false positives on their knock sensors but the mega high power turbo motors need the knock control systems to attain those high power levels.Some early Fuel injection systems were pretty bad, maybe the time has finally come that someone has developed a system that does more good then harm? l for one am interested in the system and suggest that J&S get some units out for testing. l`ll take one at a good price and real world test it and pass it on to the next guy,etc. lets get this on :)

If these work, they'll sell like Hot Cakes, no doubt.

Kinda related but figured some yous might get a goof out of this one...

A bud of mine does alot of chip tuning in the Audi circles, been working closely with VEMS lately, etc.

He just rig'd up this neat little concoction as he too is skeptical of knock sensors and 'normal' engine 'noise'. He wired up an adapter harness to a factory audi knock sensor to a standard microphone jack. Plugged that into a laptop PC with a set of race style headphones plugged into the headphone jack.

Which allowed him to produce this on a stroker '95 //S6 pushing around 400allwhp:

http://www.theswansonfamily.us/modules/gallery2/d/57834-1/brian_s6_onramp.mp3

Pretty neat. He's a madman, gotta love it.

Interesting... Keep in mind that that has a crankcase and head come with water dampeners in it to quiet it down a ton. I think that it would not be hard to detect knock in that engine. There ain't no way a 930 engine sounds that tight with a microphone.

Oh I know (good points), but the timing on this thread and my bud doing that were uncanny so I thought I'd share as I found it kinda cool.

it sounded cool...

I didn't hear any knock....

Any of the SoCal guys know Rick Hearn? I had forgotten his name until I spoke with Greg Brown of Precision Motorworks in Anaheim today. He remembered doing the install of our system on Rick's 911 back in '91. This was our first magazine test, can't remember the issue.

Rick was an engineer at Calcomp and had reverse engineered the Motronic chip. He programmed one with more spark and less fuel and ran it when he went racing on the weekends.

If the unit was retarding inappropriately, it would have shown up in poor or inconsistent lap times.

James Sly was a technical writer for European Car at the time, and he told me Greg went through the engine three years later. Greg told him (paraphrasing) without the knock controller, there was no way the engine would have looked that good running Rick's chip.

John (J&S),
It sounds like you have a product that is "useable" and I commend your hanging in there with this post. Assuming someone was to install your system on a 3.2 911 engine, (non turbo 1984 through 1989) , where would you suggest the sensor be located or do you recall any customers who noted this?

I think Ivalt's installation used a single sensor. You might ask him if he's still using it and where it's mounted.

He posted in early April that he was going to the dyno, no forum activity since. As they say, no news is good news.

http://forums.pelicanparts.com/showpost.php?p=3864485&postcount=204


Turbo Mike used two sensors in his installations. I've been on a couple test rides with him, but never looked at where he mounted the sensors. He can be reached at innovativeprodesign.

First unit is up and running. I spent the last week "porting the code" to work on the new processor.

Ray Sedman at american-pi.com will be showing it next week at the Corvair convention in Ventura.

http://conventions.corvair.org/2008/

Over the years he has sold maybe a hundred of our earlier systems to his Corvair customers.

I posted pics last week in this thread:
http://forums.pelicanparts.com/showpost.php?p=3995878&postcount=6

neat stuff. l would really like to get one of these once you get the system dialed in for our cars.l have a 1984 3.2 Carrera with a turbo system, l`m running conservative boost and have a huge intercooler..