I have a c35 S1 rb25det manaul laurel, running an apexi fc and few small mods boost controller, fmic, cat back and air filter.
During the map time on the dyno, results where very low. The tuner was expecting figures closer to the 290 range and instead it came around 236. Since then compression, engine timing and many many other things have been checked and all came out correct.
The only thing that is puzzling me is that the base timing is set to be 15 degrees. This was done from the loop wire at the back of the car. This shows at 15. Then checking the white centre wire into the coil on no.1 still shows 15. But through reading where many people have suggested the ht lead directly onto the sparkplug tactic for accuracy, there is then about a 5-7 degree difference in ignition timing???
It seems as though a lot of people get the same result either way, so people swear by each method. but with this amount of deviation between the 2 it could be a cause of low power. Compression is fine, standard AFM is almost maxed out, it does not lean out so fuel is there, compression is correct, 7 heat range iridium plugs, they are aftermarket coil packs from in japan...
Any help or information about why this occurs, or any other ideas would be brilliant as i've got a long way to go with this car but i need the base to be correct.
Thankyou