stage 3 keydiver compression ratio how much does it affect ## ecu programing

[cbr600teardrop]

i have a stage 3 keydiver ecu and it is programed for 7.8 c/r and im putting in aether 8.5 or 8.0 c/r with a with a .50 thick mls head gasket should i have my ecu reprogrammed for the higher c/r or should i be OK and also how do i figure out what c/r they are for sure because i bought them from a friend and they don't remember and i called the company they custom made them and they don't know either they are brc bored .020 over

 

[bling5tatus]

If I had to guess this is most likely an adjustment on the timing table.... more aggressive for lower cr pistons and less for higher cr.

 

[hdoerr]

If your mods list is correct you don't have anything to worry about. By the way, when I ordered my keydiver stage 3 chip there was never a question of comp ratio just octane value, boost level, fuel pressure, timing and fuel maps. I would contact Jeff at DSMChips.com and go over your chip with him.

 

[rbwtrans]

I've never had a "stock" c/r. Ecu adaptives generally take care of everything.

 

[cbr600teardrop]

cool thanks guys ill talk to jeff and make sure and yea my mod list is correct with a neo and a wide band o2 and egt and act 2900 street with a fidanza flywheel soon to be added

 

[toofast82]

The 1g is very aggressive and is not ideal for 8.5:1 running any decent amount of boost, let alone 7.8:1. If you go with 8.5:1, you may want to tell Jeff to program a 2g timing map.
I would recommend having him lean out the fuel maps some as well, because the stock ones are like 9.3

 

[cbr600teardrop]

ok because i was thinking about having him re program it for 8.5 and a 2g maf but if they are 8.5 and i go with a .50 thick head gasket want it only be 8.0 c/r and thats only .2 mor c/r than stock

 

[toofast82]

ok because i was thinking about having him re program it for 8.5 and a 2g maf but if they are 8.5 and i go with a .50 thick head gasket want it only be 8.0 c/r and thats only .2 mor c/r than stock

If you plan on running more than 14-15psi, you will still want to run a little less timing around 6k rpm where its 24*timing. I also notice it is very aggressive for high boost on pump in the 4k-6k rpm range.

 

[cbr600teardrop]

ok thanks guys ill definitely get it reprogrammed then befor i get it all put back to gather.