On a 2V low compression nearly stock 4.6L mod motor, what it the highest total timing that you would ever expect to see on 91 octane fuel? 87 octane? 93 octane? What about a 4V higher compression nearly stock motor?

I ask because I log the timing advance data with my Predator and see higher than expected total timing. I am currently running 91 octane with the diablo performance HP tune and seeing numbers as high as 50DBTDC. I am nervous about detonation. There is all of this hearsay about listening for detonation and the PCM pulling timing if detonation does occur and monitoring detonation with the Predator but the bottom line is that my diablo software combined with my '02 GT does not offer the correct PIDS to truely monitor detonation and I want to know for sure if detonation ever does occur. I want to run the highest and safest possible timing and NEVER experience a single stroke of detontation. Is this realistic?

I am enjoying the extra power that the Predator has given my GT. I'd like to NOT back the timing off if it means loosing power and I can't really find anything better than Shell v-power 91 octane within a reasonable drive. I'd like to feel better about the detonation risk.

 

Only the 4V engines have knock detectors.Detonation is something you will have to listen for.A dyno tune can help find detonation,there will be an unexplained loss of power.

 

This is disapointing. After researching the topic of detonation, it seems that many engine computers can back off the timing if detonation occurs. How can it be that a 2002 Mustang GT doesn't have knock sensors to help back off timing if detonation occurs? Strange. If I understand it correctly, detonation could occur in a low compression 87 octane engine if things are less than ideal in the ways of load, altitute, gas quality, carbon depsonsits, lean fuel mixture and etc. So it seems that all modern engines should have knock sensors. Very disapointing. Thanks for the info.

 

Good question. How does an EEC know when to back off the timing?

 

all ob2 have the ability to retard timing..

 

Perplexing. In 2002 Ford created an engine which could be destroyed by detonation because it either has no knock sensors or they do not feed into the EEC. The diablo guy says that it does have knock sensors but my particular EEC doesn't use it?!?!?!?!?!??!?!?!? By now you have figured out that I would like to run my timing up as high as possible without detonating. If I get a bad batch of fuel some day it would be nice to know that the EEC can do something intelligent about it. I plan on running Shell v-power as much as possible. Only 91 octane fuel is availbe in my area period. Some day on the road I may have to use Joe Smoe's 91 octane and it may not be consistent with Shell. If my EEC doesn't pull timing, I guess I'll just be feeding piston material to the Pro-Chamber and Magnaflow!