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90nova 08-17-2017 03:16 PM

Supercharged Plug Reading
 
6 Attachment(s)
Wanted to get some opinions on how my plugs are looking so far. Have a new to me setup and am looking for tuning advice. All the plugs look similar and have about 8hrs of run time on them cruising between 28-3300rpm. Need to get hydraulic steering installed full throttle run can happen. Plan on getting an 02 bung installed over the winter for a wide band gauge.

The motor combo is as follows:
Gen IV .060 over 454 with je inverted dome -14.5cc pistons 7.6 to 1 with 118cc chamber
Merlin Heads with 119cc chambers.
Crane 731cam 226,236 at .050 duration .587 .610 lift
B&M 420 megablower pulled 1:1 (Seeing a little over 7lbs of boost)
Twin Holley 750 carbs (jetting unknown need to pull one apart)
Stock merc distributor with V6 module and total timing set to 31deg
exhaust is EMI thunder manifolds with custom tails that extend all the way to transom
Plugs are NGK R5673-8 gapped to .035
I can supply more pics/info if needed, thanks in advance!

Jason

SB 08-17-2017 04:48 PM

Okay from here at rpms/throttle you've been running, but get a light and magnifying glass and look down into plug. Don't want to see specs or tiny balls of aluminum, because if you do, that's aluminum missing from the pistons. Re-read after you pull WOT for first or second time.

Unlimited jd 08-17-2017 04:49 PM

8 hrs at that rpm range only thing you'll see on those plugs is if it's detonating or not. Total timing doesn't really matter because your not getting to it.

90nova 08-17-2017 05:24 PM

Thanks for the replies. I've always had a wideband 02 in all my vehicles which let me see the air/fuel. First time with forced induction on a boat. Didn't want to melt this thing down until the end of the season! Lol

Wobble 08-17-2017 09:41 PM

The plugs do look good. Have you considered installing a couple of egt probes? Cruise rpm's wont tell you much about WOT.


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