WB + stock knock sensor enough for high boost?

[huguetpj]

Cotinuing with a previous discussion in some other thread....

I would have a knock setting simply retardy 8 degree's of timing. Pretty simple really, just like running N2O. Just a knock sensor triggering the timing retard rather then the On/Off N2O source. Have it trigger a light at the same time so you 're aware of whats happening.

WD

WD, would this be with the stock knock sensor or a "better" one? Cause I'm pretty sure I can do this with the Ultimate.... need to keep on researching.

Quote »With a high boost motor like yours is getting to be hugetpg, I would try to avoid tuning by listening to knock. Yes, of course you should watch out for it and listen for it, but once you start getting up in the higher boost I like to go rich + retarded and then slowly back it off until I am making good power with still a safe tune. If you start dialing things until you hear knock and then try to backtrack you can cause yourself some big problems. At 20-25 psi you dont hear knock, the timing goes out and thats IT for your motor. Seriously there is isnt much room for error up there, detonation is extremely damaging- I wouldnt want to hear it at all. So that said, I dont think a more sensetive knock sensor is really worth it. You can do the same thing with the ultimate by having the fuel + timing react if the AFR goes out of wack with the O2 correction tables.

Someone correct me if I'm wrong on this, but thats pretty much my idea on the subject.[/quote]Fiz yeah man. I know. I've never really tried to hear knock anyway, but this time I'm going WB + knock sensor (either stock one or some other "better" one) to keep it extra safe.

$200 for the Innovate MS LC-1 seems good enough for some extra peace of mind. I can even remove the stock O2 and use the narrowband signal on the LC-1 to feed the ECU for close loop operation. That way I don't have to solder any more bungs to the downpipe.

But your question still remains... will the AFR react fast enough to prevent or eliminate knock with the AFR maps? What if I'm only running lean on 1 cylinder... this is were I think logging knock would be helpful.

[Structure240sx]

timing will kill a motor alot faster than afr's. just make sure they are decent.

you rather have a few extra degrees of timing taken out to prevent detonation

[WDRacing]

Most ecu type controllers will have an adjustable knock frequency. So you don't get a bunch of retard just for a slightly noisy motor. My injecotrs are 5 times louder then the stock ones alone, not to mention the new valvetrain. SO figure out that aspect first, then see use a dataloger to record timing retard. Once your setup for that..slowly add timing to the motor until it starts reading the knock and see if it will back off the timing for you. You can do this at idle without messing up the motor. I was running so much timing advance one time I couldn't even hardly start the damn car.

If you start to here a loud rice crispy type noise, then you're getting quite a bit of knock and the ecu should be pulling out alot of timing.

Hope that makes sense??

[doug200t]

also stock Nissan ECU's only read up to 4k and anything after that they do not adjust for...

[huguetpj]

Yes it does. I have some timing maps posted by Fiz and Enthalpy (shoot me if I'm wrong) some time ago. I believe you can setup the response on the emanage due to knock so not to over do it. Taking this into account I was planning to do the following.

1. Setup my base timing at 10deg (18*0.5=9deg retard)2. Adjust the fuel curve all the way up to 18PSI (no timing retard on Emanage)3. Do some runs to get an idea of MAF readings vrs PSI (if I'm not using a MAP by then)4. Setup the timing map on the Emanage to retard 0.5deg per PSI above 3.5k revs, since I'm not boosting below that.4. Start setting base timing towards 20deg base timing logging for knock. If knock is detected I'll increase retard on the Emanage and keep setting base timing toward 20deg.5. Log base knock levels and setup Emanage accordingly to retard on knock

Now does THIS make sense?

Quote »Most ecu type controllers will have an adjustable knock frequency.[/quote]So by this you mean it would be ok to use the stock knock sensor?

[huguetpj]

you rather have a few extra degrees of timing taken out to prevent detonation

Should I use 0.5deg per PSI or should I go with a higher retard at higher PSI levels?

[WDRacing]

Your tuning for timing wrong, well wrong in my eyes anyway. You want a high base timing with a progressive timing curve right up till you hit boost. Not retard timing and then advance it till you see knock.

Start with a 20* base just like stock, then have it ramp up very similar to the stock map. Having to retard timing based on rpm instead of load and boost sucks. If I understand you correctly.

I would retard .5 degree's per lb of boost but not until you've reached 4 psi or so.

I was always told that around peak torque you have the timing retarded the most then you can add timing back in, not alot, after the torque either flattens out or slopes off.

[huguetpj]

I was planning on starting @ 10deg base timing and 0.5deg per PSI just to safeguard my engine and add base timing until I logged knock then start fiddling with the emanage retard/advance map so I can set the dist @ 20deg BTDC.

By progressive you mean start at 20deg base and add timing until I hit boost - any idea how much? logging for knock I guess -, then go back to 20deg base until 4PSI and then start taking 0.5deg per PSI, right?

Anyway what I meant by the 3.5k remark was that I know I don't build boost before then, so below 3.5k I can keep base ECU maps or even add a bit as you have said (progressive?).

I will be tunning by load or pressure (if I get the pressure sensor that is). If I tune by load I'll try and make a table of rpm vrs maf V vrs PSI to try and simulate tunning by pressure. I'll probably buy the sensor anyway since I really want to eliminate the MAF altogether.

I also came accross this page, very interesting ideas: http://www.innovatemotorsports...s.php