Hey there everyone, long time reader, first time poster here.... My mate has a VR with a 5.7L stroked motor, flowed heads, 9.5:1 comp, and what he says is a fairly lumpy COME cam and memcal upgrade to suit. Only thing is, the car bucks/bunny hops at anything under 1500rpm, which makes it a pig to drive around in traffic. Other than this, the car drives fine and pulls hard to redline. Car is making around 300KW. Is it a bad tune/memcal from COME making it do this? Will a cutom tune fix this, or is it something else? A workshop has suggested a custom remap (I have no idea what kind of device they use) or going to a full standalone computer (Haltek) for like $2000. Any advice on this is appreciated. Fixxer
my money is on a crappy c.o.m.e tune - they're always pretty ordinary, i know mine was and it had a rolling idle that would annoy me to no end. go for a custom kalmaker tune, in my opinion you'd be foolish to get a piggyback or standalone aftermarket ecu when you have a perfectly good one already with the delco pcm.
Ok, great, I will tell him about Kalmaker. I saw one shop say it was around $800 for a cutom tune. Also read that big cams with low manifold vacuum stuffs around with the ECU's control of idle and low rpm mixtures, and that tuning using TPS may be better in low rpms. Anyways, thanks for your help. Fixxxer
yes it is hard to have a steady low idle with a big cam - i know if my car gets below 1000rpm too much it becomes very shakey and the iac has trouble keeping it under control. but its still do-able with a good tune by someone who knows there stuff. was the c.o.m.e. tune an off the shelf deal or was it made up on c.o.m.e.'s engine dyno using your mates engine?
It was an off the shelf deal... the motor never got anywhere near c.o.m.e. The stroked motor was built in Brisbane, QLD. BTW, have you gone with Kalmaker, or just used c.o.m.e? Where did you get it tuned, how much? Fixxer
