i have a Lt4 hotcam and i just changed my original rockers too some scorpion 1.6 roller rockers and its suppose too go from a .492/.492 lift too 515/515 or 525/525 lift. My question is how big of a difference is there gonna have too be made in the current tune too make it run good with the new lift?

 

The engines VE will change. But I don't believe by much. Try it and see how it is.

Get a data log of before then after. Look at the BLM values to see the magnitude of change. Can then change the VE table to suit.

RBob.

 

Hard to say if it will be much different. When I went from stock 1.5's to aftermarket 1.6's, I ended up running a bunch leaner but I had changed the injectors at the same time which had a different spray pattern. Car didnt run the same on the injector swap at first then started to feel better. I tried tuning and it didnt respond at first but eventually started working right again from what I could tell. They may have just been stuck from sitting around for awhile, i'm not sure. No idea what happened there, so I'm not sure I would contribute my air fuel change in rockers alone but the car made 8whp more with the rocker swap on stock L98 with bolt ons...even when running much leaner.

 

ok cool ty for the info, so getting the extra .033 lift out of a cam only make 8 more hp?

 

On my stock motor it made 8hp but on others it may make more, it may not make any. All depends on what the motor wants

 

just put the 1.6`s on and it sounds meaner and has a deeper sound but doesnt pill out as much off of the line or have as much throttle response, any reason this could be? Im thinking maybee needs too be retuned?

 

Could be fueling issues or it could be false sensation. Are you sure its really not running as powerful as before? Sometimes a small change like that is hard to notice. Since you have the mindset that the mod should increase power a good bit, you are expecting more out of it when driven and when it doesnt perform to those expectations, you start to think something is wrong when really nothing is wrong. I had that happen to me before. I'd do some logs and some more driving to see if it improves. Verify the lifter preloads are all set right.