Keydiver users! (knock gauge question)

[forcefed86]

Keydivers websight has been down for a week now so I thought I'd ask you all.

So I installed my new key diver chip. 750cc injectors and 2g maf. Car runs well. I have it set at 20lbs right now. Meth injection coming on at 14psi. (7gph nozzle)

2nd or 3rd gear WOT pulls at around 4000rpm the knock gauge will jump up 1 bar then to the 0 mark. But by 5500 or so drops back to no knock all the way to redline (7k)? AFR's are right around 11.5:1 during the entire pull.

Is this something I should worry about? Or is it just "the nature of the beast"?

 

[habitatguy187]

I'd get a logger and check it out cause this time of year + fmic + meth injection +e3 @ 20psi should = -20 knock count.

 

[->PrOjEcTGS<-]

Keydivers websight has been down for a week now so I thought I'd ask you all.

So I installed my new key diver chip. 750cc injectors and 2g maf. Car runs well. I have it set at 20lbs right now. Meth injection coming on at 14psi. (7gph nozzle)

2nd or 3rd gear WOT pulls at around 4000rpm the knock gauge will jump up 1 bar then to the 0 mark. But by 5500 or so drops back to no knock all the way to redline (7k)? AFR's are right around 11.5:1 during the entire pull.

Is this something I should worry about? Or is it just "the nature of the beast"?

I've got a very similar setup.

Try adjusting your meth to come on at a lower boost pressure. You have to remember that just because your boost switch is set to 14psi the meth takes a little while to pressurize and get to the nozzle and be effective. Therefore, you might not be seeing meth in the cylinders until you're at 18-20psi. I've got mine set to come on at 10psi and I run about 25-27ish psi. This way you'll see the mixture at the cylinder by about 12-15psi, right when a 16g has the greatest propensity to knock. Fast Spoolup...

Also, what mixture of meth are you running? 100% meth? 50/50 water/meth? Washer fluid? Tweaking this will also help more meth = more fuel. More water = more knock suppression & more heat removed.

Check for leaks in your meth injection tubing. I've been having problems with my instant fittings. After I replaced these I noticed less knock and a richer mixture.

 

[gorf]

I have noticed that my logger tracks the knock gauge. As I get more knock my logger shows timing being pulled. I talked to Jeff a little about this, each bar on the knock gauge is 7 counts of knock. If you are not seeing any knock from 5500 up, IMO it sounds like you are running very well, especially if you are at 11.5 afr. On my car so far I have had the boost up to about 25 psi with no knock but according to my wideband I am running 10 afr. If I start pulling fuel to get it to read leaner, then I start seeing knock.

 

[forcefed86]

Having the meth inj point to high is the only thing that makes sense to me. I'll try lowering my injection pressure to 10psi and see if that helps. I run 100% meth.

If that doesn't help I'd assume it's just false knock? If the engine starts detonating i would think it would get worse with more RPM?

The chip says it was burnt for an 11:1 AFR. And 37psi fuel pressure. Maybe I'll try cranking up the base pressure a bit and see if more fuel helps me out any too. I'd think with the 100% meth I should be richer than 11:1.

Thanks!