Blownchevelle68

Bought a '04 Z in July this year, stock with exception of Blackwing, LT Dynomax kit with X pipe and high flow cats, stock TI exhaust and a tune by unknown vendor (all done by previous owner)

Car has always ran great however later in the year after a hard run I noticed what sounds like pinging occasionally, which I assume is detonation on hard runs into 4000 rpm and above, intermittently. I've always used 93 octane (however being in Iowa there is only a couple stations in my area that carry 93 and supposedly a local speed shop has done some testing on the fuel and are not quite up to par)

I purchased some off the shelf octane booster which has alleviated the knocking that I can hear, for the most part. Previous owner never had this issue but he did live in another state where fuel could be better grade.

I'm wanting to get a data logger to record these instances next spring and figure out my next step, specifically be able to send a file off to a reputable tuner. What do I need to look into purchasing? Not wanting a dyno tune as I would rather log a file and review it periodically through the year. Maybe I need to learn EFI Live, not sure how much I would really alter anything once I have it set.

tblu92

Not un common for a 12 year old car to begin picking up some strange detonation or pinging---Mostly due to carbon build up in your combustion chambers--- or the previous tuner was too aggressive on the timing table----especially if in winter cold air it was fine but in hot summer air you picked up some pinging
The only way to know for sure is to purchase a data logger--Either from HP or EFILIVE
to see exactly where and why there is some spark knock OR some unwanted timing removal-----
However I would recc. the following before you panic about pinging
1. Do a "fast" cleaning of your intake system with a bottle of "Seafoam"
2, dump another whole can into a full tank of premium fuel
then see if the detonation goes away after the tank empties
PS: also i would check your spark plugs-----On an un boosted engine I would only use a set of NGK TR55's gapped at .040 and NOT .060----
Carbon'd up plugs will cause detonation as will as a too cold of a plug-- as a cold plug will have a tendency to foul and build carbon even faster
PSS: Adding a "catch can " to your PCV system also will eliminate pingingby removing oil injection into your intake manifold--- The unwanted oil in your intake again causes MORE carbon build up and pinging

Blownchevelle68

Thanks I'll try the seafoam treatment-I did notice adding a can of generic octane boost did take care of the problem but not wanting to run that all the time either.

Will change plugs as well---Right now it still has factory plugs.