Unless you stick it on the rollers you won't tell the difference. Does your car have a stock exhaust? Is the ignition fit. Are all the hydraulic lifters giving you all the valve lift of the cam? Without the dyno your shooting in the dark. My car when bought did 112 at the wheels. ( V disappointed) When the mixture was put right. ( It was too lean) it made 116. With the faults corrected & a Dansk exhaust & a modernised fuel system it did 140 (Still no chip) Going for remap now ( to save some fuel on cold start as it's way too rich.) I expect 140! Maybe 145 as the fuel map is not right. How do you know that you are giving your car the correct amount of fuel without checking the mixture on the dyno. Dyno time is cheap compared to wasting money on ineffective mods. I've seen cars fitted with modifications make less power at the wheels. But the owners thought it faster because it sounded better or they'd spent lots of cash so it must be. Get the picture.
