After a full Skunk2 cam/vavle train install on my friends GSR we got it running pretty good. Tuned the AFC and played with the cam gears, its running well.

But we were suggested by a shop to advance the timing possibly 15 degrees.

What exactly will this do? Are the gains worth it? or is it playing with detonation?

LMK, thanks guys

 

Advancing the distributor timing will allow the spark to occur earlier in the combustion process, permitting more time for flame propagation, thus allowing a more complete burn and more power extracted from the gasoline. The 'downsides' which aren't really downsides is that you need to run high octane gas to avoid detonation, which you need to do on a GSR anyway (the higher the octance, the more you can advance it).

It's a free mod that is good for a few horses, moreso on modified motors. Too much advance can cause detonation, even with 93 octane, so use a timing gun and be VERY careful when setting it.

 

Tegs are usually alright to 18 deg. adv.