rithsleeper

Im at a total brick wall here. I can't find any info on how knock sensors are used in anything but street engines or forced induction/nitrous. Do people use them in road racing? How important are they do get a perfect tune?

Most reference I find is to protect from a bad batch of gas but I doubt dirt track guys use them, or NASCAR.

How imperative is it that the timing is close to the edge or max advance without detonation? When testing timing will you continue to gain power till detonation occurs, or will their be no power gain from say 36-38 degrees advance but detonation doesn't occur till 40 degrees?

Im using the holley commander 950 and it has a built in unit but the tech at holley said don't use a knock sensor cause its hard to calibrate and if seems that the built in system is pretty basic. However being offered a unit from j&s safeguard by a forum member is so enticing but really expensive (especially right before race season)

Im not worried about damaging my current L98 but building my 383 and not having every bit of protection makes me nervous. Any info would really be appreciated.

Oh yea, I also talked with j&s safeguard about how his unit is used and be said he doesn't get feedback usually unless there is a problem and he doesn't know anyone who uses the unit purely for road racing...

John Anthony

Paul of Paul's Automotive Engineering had a Mustang that he road raced in the mid '90's, using one.

http://www.paulsautomotiveengineering.com

rithsleeper

Is this the norm for fuel injection? What about the c6r or c7r? Do they use one?

jstout

You have several issues to consider. Potential damage is the biggest thing, and you want all the protection you can get if you are road racing. Second, the more timing you have in, the harder the engine will be to start when it is hot. If you spin and stall the engine, you may not be able to restart on track. That could be disastrous. If you have a red flag and temps are really up, again, you may be stuck. Road Racing pretty much demands that you put the engine on the ragged edge. You are going to be pushing it anyway without putting it in a situation that could be harmful. Just my .02 Jerry

6SPEEDZ

The GT1 engines in the C6R used 4 knock sensors. This was done so that if knock was present in one of the cylinders it could retard just that one cylinder and continue to run full timing in the others.

rithsleeper

I don't know why I have had so much trouble finding people referencing their experiences with knock sensors except stock applications. As much as I don't really have the budget for it I think going with the j&s safegaurd might be the best solution and safest. It also can only regard one cylinder at a time.

Solofast

We are using the J&S safeguard system on a research engine and it does the job. It not only can adjust the spark on one cylinder that is knocking, but you can also put the data into a data logger and adjust the spark if so required.

For road racing a knock sensor is a good thing since some cylinders (the back ones) tend to run hotter than the others and are more prone to detonation. The J&S system will retard the spark only on cylinders that are detonating and that will protect them from damage.

If you are WTW racing I see it as an advantage in that you will have more reliable power than the car would have if you didn't have the box.

Road racers tend to worry more about grip, exit speed and power coming off the corner because these are the biggest things that influence lap time, but if you can run more advance and not have knock you should have more power everywhere and that's not a bad thing.