I'm running a 4v 4.6 w/8.5:1 compression. I truly have no idea on what turbo, was purpose built by an older guy who has since passed away. I run 22 degrees of timing in a MSD MOD-6 box and take out 1° for every pound after I hit 4 pounds. I have an air to water intercooler using river water, usually around 65-70°, and a CSU blowthrough 750 carb. I use 91 octane. I was researching water injection and realized that by using both water/air intercooler and blowthrough, I am probably getting very cool intake temps. Haven't measured them. My question, with that kind of cooling and never going above 14lbs of boost, should I be taking out that much timing? This is in a jet boat and hearing detonation is damn near impossible. Thanks for any help or pointing in the right direction.

 

seems really aggressive retard to me. You don't mention afr or boost (other then not going over 14) but with that timing I would expect a 4v to be in the high teens for timing and I would not be surprised if it even landed in the low low twenties.

So assuming 14 psi, your at 12*'s on a 8.5/1 compression, afr in the low 11's, 70-ish IAT's 4.6 4v. That certainly sounds "safe" to me.
For comparison, the last turbo 4v I ran on the dyno last week was a 10-1 4v, air to air, 18#'s 11.2-1 afr and showed a great timing mark on the plug straps at 18*'s. Car made 630-ish rwhp on pump premium.

All that said only you can decide what to do with your stuff, and if the setup you have has been reliable and meets your performance goals, cool.

 

Fastspec2, thank you. I idle about 13.8:1 AFR, into the boost and it gets into the 11.5:1 range. It comes on boost around 3,500 rpm if I'm just cruising. A bit sooner if I give it full throttle. Jet boats are constantly under load, kinda like pulling a trailer uphill all the time. I was thinking I'd be pretty safe keeping more timing due to the fuel evaporation cooling effect of the blowthrough which I had never taken into account before.

 

You can either use an electronic knock sensor or some chassis ears to listen for knock. I like usin chassis ears myself. Mine have 4 channels so I can attach the probes to different areas to listen.