Has anyone done this purposely or accidently? Did you get a check engine light? What if anything did you notice happen?

I just read that disconnecting the knock sensor on a QR25 will cause the ECU into retarding timing across the rpm range.

So, I was thinking this might be useful for N20 depending on how much it retards and the side effects. May be a lame idea, but IF I can find the knock sensor I may give it a try with my OBD software.

 

its gonan kill ur gas mileagge, and have crappy acceleration

 

Been reading Sport Compact Car huh?

 

Haven't tried disconnecting yet (will try tomorrow) but I did try inserting a 470K ohm to simulate a working knock sensor today. I am using my OBDII gizmo to monitor the timing and there was absolutely no diff, 12 deg at WOT before and after. So my knock sensor is not picking up knock and retarding the timing.

I will try disconnecting tomorrow on my way to the track and see what it does.

 

I thought you said you were getting between 18-22 degrees before. now you're getting 12?

Does the amount of advance you get at WOT vary a lot with conditions or something?

 

Not sure Steve, I didn't log it before but I remember what it was. This time I did it in 3rd gear (auto) so it wouldn't downshift and held for about 6-7 seconds. Then I stopped and put in the resistor and tried again immediately. I was more concerned with the diff before and after vs the reading I got before. I will watch a little closer in the future and see if the readings vary.

 

I got 18-23 degrees in a 60-90 mph run in 3rd. Then on another run on the same drive I only got 10 degrees.

Then the other day I was below 2000rpm in 4th and was getting on it a bit and had absolutely ZERO low-end. But as I was rolling off the throttle I could feel the car surging forward. Unfortunately I didn't have my scanner hooked up then, but I'm almost 100% sure it was timing related.

I've been able to correlate this strange laging and surging I've been getting with timing advance, and I'm also getting the KS code so I guess there is something up with my KS but it isn't gone completely.

I don't have any 100%-known-to-be-working baseline timing data though, so that's what I'm trying to figure out.


I hooked up to our 2002 Toyota Highlander today (1MZ-FE V6) and that sucker gives mid-20 degrees of advance at WOT (26 degrees usually) and holds pretty steady.

 

I will keep a closer eye in it now. Ice has a good idea there though if it will retard timing for N2O. Problem is I went another route to ensure I don't need to do that by running race gas and so far it works quite well but its all about experimenting and trying this and that to see what works best so tomorrow at the track I will try some different combo's and see what happens.

I am more of a believer in 1/4 stuff than dyno, especially with an auto because of the limited rpm range you can use, the dyno really is only a confirmation of what I think I already know.

 

Cool.

People are getting the J&S to retard timing according to boost, but IF the ECU automatically retards a set amount(say 10-degrees) this MAY be useful via a switch for N20 or even via a relay for FI cars with any gizmo that activates at a set RPM, PSI, etc...

It may be a CRUDE, but a cheap way to back off the timing for a SHORT amount of time.

They(SCC) disabled the knock sensor by removing it, but leaving it connected via a 500K resistor to eliminate the overly sensitive QR25 sensor. It went from a very inconsistent dyno car to one of the most consistent, because the ECU was constantly playing with the timing.

I've see the timing advance up to 60-degrees on several WOT runs via my OBD software. Why is your guys advance so low?

 

Are you sure about that? Mine hits 63.5 degrees, but not at WOT and not for more than an instant.

I wouldn't be surprised if the VQ30DE-K engines run more timing, though. It's the same displacement, the same compression ratio, yet it makes 12 lb-ft more torque. Maybe some if from the intake manifold and from the internal changes to the engine, but I bet they might have thrown some more timing into the mix also. Engine control systems in 2000 would be way more advanced than in 1995.

 

Tried it this morning on the way to the track.
1. Knock resistor connected
2. 470K Ohm resistor
3. Disconnected

Got the same timing at WOT for all three. 11-12 Deg advanced.

 

You got that from compact car I can see. I was gonna ask that dame thing on this forum.

 

I've had my KS replaced with a 470 kOhm resistor for wuite a while now. My KS was dead and this brought my gas mileage back up to where it should be.

There's no need for extra ground wires like SCC describes. The black lead in the KS harness is a chassis ground. I just stuck the leads of the resistor into the harness and taped it up.

 

Mardigrasmax has stated in a different thread that the KS does not affect timing at WOT throttle. This is why you're seeing 12 degrees advance under all circumstances at WOT, Jime. This is also why you don't want to rely on the KS to pull timing when running NOS.

 

I'm not sure if this will work, but here is an example I think of one of Kev's runs:
http://us.f1.yahoofs.com/users/76027...n232.AXdH28APh

 

You guys are monitoring base ignition timing or something different. The spark advance is what I'm seeing go from 15-degrees to 50-60 at WOT and redline. The ECU has to be advancing more than 11-12degrees.

I didn't get around to ganking mine, but I'm still going to try it since you didn't have any problems.