Safe Knock On A Stock Rb30?

[leeroy_25]

Hi guy's can anyone say what is a sensible knock value to tune to on a stock RB30 bottom end with Rb26 head using an Apexi ECU. IIRC the Apexi triggers the warning at 40 as standard. If you are reaching mid to high 30's under load often will this kill the bottom end or is it still relatively safe? I know my old RB26 reach 40's after it was tuned and I think they reset the knock warning to much higher.

Cheers

Lee

[JonnoHR31]

60 is the standard flash engine light value.

i use 60 as a general limit. my motor died after leaning out and pinging (around 200 on a pfc), but that was running 25psi boost at over 300rwkw on a 100% stock bottom end, i would never reccomend it if you want it to be reliable

[leeroy_25]

200! I didn't even realise you could get readings that high! I checked and my ECU is set to go at 40.. I just like to know these things for piece of mind. I know everyone says knock is bad but I never really know ow much is normal and how much is bad!

What rpm were you running your stock bottom end too out of curiosity? Was it a self built motor?

[JonnoHR31]

256 is the highest knock value for a pfc

yer was a self built slapper, was revving it to 7000rpm

[R31Nismoid]

I've never seen more than 30-35 on mine. Only time i do is it i tap the limiter or something which obviously upsets things.

Otherwise i'd be around 20-30 just putting around.

40-60 would mean a wayward cell or two somewhere. Nothing major and not going to break stuff instantly but attention is required.

[leeroy_25]

Thanks guy's for the replies. It puts my mind at rest. I would say it is generally around 30-35 and every now and then I might get a high 30.. just hit the 40 once! Will have a look into it.. Main reason I started asking is I just found I have a compression issue on one cylinder and I am trying to figure why! It's only done 900miles, been run in gently and just had a tune to 0.8 bar and only been revved to just over 6k! I am hoping it is a duff valve but it sucked/blew some oil through the breather into the turbo inlet so its not looking promising.

Cheers

Lee