From knowing nothing to having a Thunderbird supercharger on an m20b27i

[The Dark Side of Will]

I do not have any knock detection anything, but cept for my ears. Let's take it there. How do I go about getting my ms2 to listen for knock?

I don't know about MS2 specifically, but I'm sure there's ample info out there on how to do it.

There are also dedicated external systems (like the J&S Safeguard I previously mentioned) which have a logic level output that can be used to trigger timing retard on an engine computer.

Knock detection will be CRITICAL to making this combo live, especially on 87 octane.

Meanwhile, I'll be getting my o2 sensor on Monday.

When it gets running, I know you guys are gonna want video. I have no idea how to put a video on the intertubes. Especially with this shit satellite internet. It really sucks so completely. But if you have an iPhone, I'll send you a vid that way I guess. I'm pretty technologically impaired.

YouTube account... Youtube videos can be embedded in some forums via specific tags.

[Ether-D]

I'm not dead set on using 87. I just thought that if it could be done, maybe I could try it. No biggie.

I guess I'll cross the youtube bridge when I get to it.

Also, Victell, taco, dark side, and FLG (and anyone else), what are your actual names? I'm Jacob. I'd just love to refer to yous by your actual names instead of your handles. I bet I can guess Darker side's name...

[Victell]

Preignition and detonation are very different things. Preignition is instant death to an engine (e.g. holing a piston). Detonation is survivable... for a while. How long depends on how much boost the engine is running.

The "corners" of the map, like the situations to which I alluded earlier in which the engine or intercooler might be heat soaked, or other combinations of operating parameters which are rarely experienced--and thus difficult or unlikely to be correctly tuned--are going to be risky.

High coolant temps are especially bad... He'll need to be very familiar with and have very conservative settings in the ignition advance vs. coolant temp and mixture vs. coolant temp tables to make sure he doesn't pop the engine on the first hot day he drives it hard.

Awesome. Thanks for the reply.

[Victell]

Also, Victell, taco, dark side, and FLG (and anyone else), what are your actual names? I'm Jacob. I'd just love to refer to yous by your actual names instead of your handles. I bet I can guess Darker side's name...

Victor

[ButtJuice]

We need lots and lots of videos.

[The Dark Side of Will]

I bet I can guess Darker side's name...

William ;)

You're Jacob, right?

[Ether-D]

Yes indeed. Glad to know you fellows!

I'm working on throttle linkage currently. I'll have a pic or two up of it tonight.

[Q5Quint]

I almost put knock sensors on my ms1 so I could run straight ethanol like the dukes of hazard. MS2 should be able to do that and take your girlfriend out to dinner at the same time.

Remember that the 3.8l pontiacs/buicks that your supercharger came from had knock sensors back in 2000. That way even though they 'require' 91, if you are an idiot and put in 87 they will keep themselves from exploding. How smart of them.

The knock setup usually works by putting the engine into a 'limp' mode, with drastically retarded timing and increased fuel, when a knock is detected. On my old jeep I would do this manually by unbolting and turning the distributor by hand until the knock went away. Bad/crappy gas on a summer day and you would hear the tinglelingdinkyding of knock, and you better pull over and turn that baby down. The knock sensor and fancy voodoo computer does that for you now.

Sure you can tune for 87 octane and have a supercharger, or turbo, or nitrous. Anyone that tells you different hasn't done it and doesn't have a clue what they are talking about. This is exactly why the chip on a stock e30 gives you +15 to 20hp or so, because the ignition tuning was assuming bad gas for safety. Good gas + advance timing usually = mo powa.

In fact, if you daily drive your car, I would RECOMMEND that you tune for worst case 87 octane to ensure you get no knock. That way when you run 93 every day like you should, you have a safety margin. If you tune for 93, and one day at the pump you arn't paying attention and pump in 87, SURPRISE, next time you punch it you just bent a rod from detonation because you wanted 20 extra hp, and you forgot to add a knock sensor.

The fun part about megasquirt is you can setup a button (or tune) to switch tables, so when you are at the track and you KNOW you have a good tank of 93 you can get that extra 20hp. Or, if you want to be a complete baller, add a knock sensor LIKE THE SUPERCHARGER HAD FROM THE FACTORY that will do this for you, and then you can sleep well and not worry as much about your mother-in-law cheaping out and exploding your car with 87 octane after all your internet friends told you to tune it for 93..

They are right though, you will get more power on 93, and more power than that on ethanol/methanol. The drawback is if you oops and forget your 93, moonshine, or forget to add water to your h20 injection system, do you have a knock sensor to retard your timing and keep the boom boom from happening? Or did you just boom?

Never used one of these, looks like you need a stock knock circuit but give it a look: http://www.summitracing.com/parts/cei-102003/overview/

If you have megasquirt try this to interface properly: http://www.viatrack.ca/

The knock sensor is tuned for the size of your cylinder, so it can correctly 'listen' to what a 'knock' sounds like. I guess it just gives off a signal like a o2 sensor does and lets a gauge or your computer know your mother in law is trying to break your car again.

Edit: Read backwards and wanted to repost what nando said:

you need to buy a copy of TunerstudioMS

you need a wideband

you need to setup a proper AFR target table. use VE analyze live to tune fuel (it's built into Tunerstudio). Tune ignition on the dyno.

the www.msextra.com site has a ton of valuable information (MS2extra manual, as well as the support forum). also there are a number of timing maps posted on e30tech which would get you started.

I suggest learning what each setting does. So many of the maps I've looked at over the years were just plain wrong, because people just copy things but don't understand them.

M20s are pretty simple to control and tune, so probably half of the features, or more, you don't even need to worry about..

I dont think you need a wideband if you are using another tune with the same size injectors, but if you actually do want your afr to be correct you will certainly want one. A narrowband tweaked a bit too rich will be just as safe, but you will have worse gas milage and change plugs more often because it is 'too rich' a lot of the time. I cheated and started with a ignition and fuel table tune I got from another member (maybe even nanda... how about that). Using your wideband you can zero your fuel table in, and using your knock sensor on a dyno you can tune your ignition table in. I feel like I went with a verified knock sensed 93 octane 14psi ignition table and then de-tuned it, ie retarded the timing a bit at the peaks, to run in my daily driver. Just in case somebody put that 87 in there.

[The Dark Side of Will]

I almost put knock sensors on my ms1 so I could run straight ethanol like the dukes of hazard. MS2 should be able to do that and take your girlfriend out to dinner at the same time.

Remember that the 3.8l pontiacs/buicks that your supercharger came from had knock sensors back in 2000. That way even though they 'require' 91, if you are an idiot and put in 87 they will keep themselves from exploding. How smart of them.

The knock setup usually works by putting the engine into a 'limp' mode, with drastically retarded timing and increased fuel, when a knock is detected.

The 3.8/3800 V6's had knock sensors LONG before that... since the '80's I think, as they were turbo back then. Heck, the Corvette V8's had dual knock sensors starting in '92.

Depends on how advanced the engine management is. Most OBDII apps can select from several timing tables. Each run cycle, the engine computer would test the fuel as I outlined previously, and then select the timing table that matched the octane number it measured. Seamless from the driver's point of view... 87 octane = less power, 93 octane = more power and really that simple.

However, I don't know if MS can do that... I'd be moderately surprised if it could. Owing to the nature of the user community, MS doesn't need many "idiot proofing" features. How many people who've spent thou$and$ on an engine or turbo system are really accidentally going to put 87 in the tank?

The typical way to react to a knock detection is to pull timing sharply and then add it back in slowly if no additional knock is detected. The sensitivity varies based on how recently knock was detected or whether knock is still detected after the initial sharp reduction of timing. The algorithms that do this are quite sophisticated, but tuned by OEM's to be very conservative. Again, I don't know how complex MS's knock detection and timing retard algorithm is. I would expect it to be fairly advanced, as handling knock is a key element in keeping a ragged-edge forced induction engine alive.

[Victell]

MS3 knock module http://msextra.com/doc/ms3/knock_module.html

[Ether-D]

Q5quint, good thoughts as well. And Victor, I just have the MS2 so that module won't jive with my squirt, and I believe it's overkill for this stage of the project anyway, but thanks for the link.

Here's my promised throttle linkage. I just welded some more angle iron on to the end of the top brace, did a little bending magic and, Bob's yer uncle.

[Ether-D]

One more.

[george graves]

Along with ignition retard, what about "colder" plugs? Spark plugs that is.

[Q5Quint]

Here is the knock circuit and settings for ms2 from the manual: http://msextra.com/doc/ms2extra/MS2-...ware.htm#knock

This signal is fed to the MS2-Extra ECU via either Pin 3,4,5 or 6 of the db37 connector (SPR1,2,3 and 4 respectively) and linking that pin to either JS4 or JS5. However you need to reduce the module signal voltage since it is too high for the processor port directly. You can use the proto area on the V3 main board, a 1K Ohm resistor (1/4 or 1/8 watt), and a 4.7 Volt Zener 1W diode (Digi-Key 1N4732ADICT-ND, 36¢) to do this, as shown below:

Colder plugs are so the spark doesnt blow out with the super boost swirl going on in there. They don't run as hot though, so they will foul out faster if you are running rich (I think thats how it works, or it did on my turbo ix).

I would try to find a boosted ignition map tuned on 87 if you are going to run that every day. If you are going to run 93 every day go ahead and tune for that, just dont forget that you must use 93 or boom. Granted, even tuned for 93 you might be able to run 87 with minimum detonation on a normal colder day, but on a hot day flogging it if there wasn't enough safety factor in there it could be bad.

If you already have megasquirt the hard work there has been done, and unless you are taking it to a dyno I wouldn't recommend borrowing an edgy tune especially with a custom intake/supercharger thing going on like you have. Nice work on the TB as well, that is one of my supercharger fears currently.

[Mr. Tasty]

this is rad, I really want to throw a SC on my vert.