Tuning with Knock Sensor

[70SSElky]

I am putting together my new hayabusa motor for my sandrail. I am nervous about getting it on the dyno and hurting it during the tuning stage.

I see that Turbo XS has a Knocklite that is supposed to detect knock if it is set up right. Don't know if it will work on a bike motor. We will use the wideband a/f sensor but I am still worried about how much timing to pull, water to inject etc. I plan on pushing over 20 lbs of boost so .... I would love to have some knock detection to warn me if I am getting off in my settings.


Has anyone tuned with a knock sensor on a busa motor? If so what seems to work and where would you mount the sensor??

 

[Mr Bogus]

I think that there are enough "good" tuners with turbos that the additional funding to purchase and setup a knock sensor is pretty much a waste..

It could save your bacon at some point (overheated motor starting to rattle) but honestly I think if you get a guy that has experience tuning a high boost motor, and you are not an idiot running the thing ballz out for minutes at a time (20psi is not for extended boost periods on most motors), you should be able to bypass the hardware..

I ran a number of VW Turbo motors at Glamis and Yuma (25/35 psi) and they were only good for one trip.. (Jugs,pistons and rings were junk after about 5-10 hours)

If this has to live for extended periods out there, you might want to talk with your motor tuner about "life span" of the motor in those conditions... Water injection is going to be a must I bet..

knock sensors are usually mounted directly into a large casting such as on the block.. the crystal used inside has to "feel" the harmonic of detonation to retard the timing.. They are highly susceptible to "phantom" noise issues as well.. we test them by tapping the block with a screw driver and watching the timing retard..

 

[70SSElky]

This is a Glamis set up as you described yours but the hayabusa motor has been awesome compared to my VW motors. It will be on a dual stage boost so that the high boost will only be for short peroids (like a drag run or a hill shot and only against the big boys!!) but I still need it to stay together.

I am going to keep the motor at 10 lbs or so for low boost and I have a switch which will toggle me to my second stage my boost, bring in the timing retard (Schnitz), and yes, water injection. All of this will also be triggered by a hobbs switch in my boost line set at 10lbs so. I will have a "normal" tune to 10 lbs and then above 10lbs, the timing will start to retard and the water injection will start to climb (also boost regulated) so I defenitly have some tuning to do!! That is why I was wondering if a knock sensor would give me a early heads up if we were getting off during the tuning process.

 

[Commuta_Busa]

I think your better off starting your tune on the waaay fat side and trimming things up to a better a/f ratio. Relying on a knock sensor is sorta like having a low oil pressure light. Most of the time, by the time the light comes on, and you react, it's to late.

 

[70SSElky]

Completly agree with starting way fat and working it down. But I am concerned with how much timing I need to pull and how much water I need to inject. These are going to be directly related to "knock" or more realisticly "detonation". I mean, you can have the A/F right on and if you have too much timing...... well you know. BOOM!

 

[cdhoroho]

what type of fueling control are you running and if you design the kit right you can get by with not needing to pull timing out till close to 20 pounds of boost if any at all

a w/a plenum would be a great addition and id recommend a standalone or secondary setup for best tuning

 

[OZBooster]

I used a "knocklink" a couple of weeks ago when tuning a turbo buell, at its minimum setting it picked up knock easily .
On a 4 led scale i could set its background noise level as the first led, at peak rpm, anything above that was knock, first runs at a guessed timing/boost reduction gave a full audible and bright full scale knock warning, had to remove heaps of timing on the buell (std comp 5 psi boost), once we had it below the audible knock level, the knock link still showed a lot of knock esp in the mid range, cleaned up good . but picked up lots that i would have never known about..
About to try it on one of my gsxr's thinking of making a "extended " cam cover bolt and see if i can seperate cam noises from knock.not many places on the Suzuki engine to mount the knock detector where it may work well.

 

[70SSElky]

OZBooster, I have looked at the knocklink and the main difference I see is that you can only set it at one RPM as you mentioned. Supposedly the Knock Lite is supposed to "Map" a range. You set it at idle, mid rpm, and peak rpm. Then it maps a chart for knock reference, then you set your sensitivity. But it is nice to hear that it seemed to work for you. I just didn't know if these would work on a bike engine. Did you set the sensor in gear or with the motor in neutral or in gear. I am assuming that you would need to do it in gear to allow for the tranny/chain noise to set your threshold?? Also did you use the Bosch style with the bolt through sensor?? I am thinking that with the bolt through it would give more options for mounting.

By the way, I am not saying one is better than the other. Just letting you know my reasoning for leaning toward the Knock Lite versus the Knocklink. If you have heard different, I am listening!!

And yes, secondary fuel system with a stand alone controller to control the injectors from boost/rpm input. I also understand that I may not need to pull timing out untill later in the boost. I really don't want to assume that though. If a knock sensor would work it would take a lot of the guess work out of when to pull timing and how much is actually needed.