Not runnig a knock sensor, can I just set the timing to 25 degrees in all fields?

[Markolc]

I have an LT1 I just dropped into my car, and am running it with DFI. Now the problem is that I *just* put in a new cam and replaced the cat with a test pipe. Now when I drive the car. there's a metallic sound that I can't tell if it's the motor pinging, or just exhaust running through the test pipe. I just finished putting in a CCXE 230/236 cam and am using a timing map that never went above 40 degrees in any field, and most timing was around 30 degrees total timing, which I understand is a little low for an LT1 anyway. But what really bothers me is that the metallic exhaust sound seems to quiet when I set the timing to 25 degrees in all fields...but the motor does feel a little more sluggish responding, but still makes good power. I'm not running lean (around 13.5 to 1 or less at all times it looks like) and I run 93 octane fuel. Should I not worry about the metallic noise, and just possibly accept that it just may be the test pipe causing the new noise, and not pinging?

Another question, If I give it to shop like Cartek to dyno tune my car, will they be able to do it without the knock sensor? I mean Ford's don't run a knock sensor so it shouldn't be a big deal then right?

 

[TurboTR]

Well the easiest way to answer that would probably be to put in a full strength batch of C16 and re-test. If no change then it's likely noise as you suggest. If it stops then she's probably knockin'

If you tune it with no knock sensor then you'll have to rely on the tuner knowing from experience how much timing to run under all conditions, or worst case just their ears If they really know what they're doing it's not a huge deal, but they should be conservative and err on the a bit too little timing side when in doubt. Another way to be absolutely sure, and the best method IMO when doing new combos or pushing the limits is to monitor the cyl pressure during testing. This requires some pricey equipment, but it's the best way to do things if available. Not many will have it available though, outside of engine mfgrs and research institutions.

TurboTR

 

[Markolc]

What's C16? I'm running a DFI v6.32, btw.

 

[TurboTR]

C16 is a 116 octane VP race fuel that many of us use for high boost/nitrous duty

TurboTR