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Discussion Starter · #1 ·
Got the engine dyno tuned in late June at a local shop. Posted results on ffcars.com:


Did not drive the car very much after the dyno tune due to work and life schedules. Have driven it lately and think I'm getting occasional detonation when engine has been running for over 20 minutes and am cruising down the hiway at 55 - 65 mph. Suspect combination of 92 octane gas and heat soak from the 1.5L KB blower at 8 psi may be causing this. Also, I do not know what the dyno tuner set for total ignition timing.

What is the total timing on your KB setup? Dynotuner is out of town this week so I may hook up a timing light and actually measure total timing advance. It can be difficult to find 93 octane around here so I've a couple of options to consider:

A. Set base timing to desired total timing and leave spout out. Drive car till attain heat soak and check for detonation. Continue to lower timing till no more signs of detonation. This would be my new total allowed timing.

B. Do not alter current timing and add octane booster to the gas tank. Any recommendations on octane booster?

As a winter project I've considered adding a bypass to the KB setup. This dropped air temperature measured by the AIT sensor from 187F to 171F as noted in the hyperlink below. Not sure if that is a significant drop in temperature to justify the work. Thoughts on this?


I've also have the configuration file for the Diablo chip used in my dyno tune in case anyone have the software to examine it.


8,266 Posts
Jerry I replied to your e-mail.

13 Posts
if it's for sure detonation.

Most if not all tuners tune off 10* of base timing. for a quick fix why not back it up 2*

It should solve your problems for now.

Or add timing and throw some alky/water injection.

I'm still in the air of what I'm going to do with my kb 1500 set up in order to cool it down. I haven't really ran it on the street but I know once I start datalogging the air temps are gonna be through the roof with the 2 3/8's and 6.5" pulley combo.
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