I recently had a tuner install and dyno tune a predator on my truck. That day, at the tuners settings, it had a little detonation so he backed off the timing the 10% allowed and it was gone. He said put some different gas in it and it should be fine to run the timing back up. I tried some different gas yesterday and now it has pinging with the timing backed all the way down. Today the temps were nice in the Northeast(70-75). My question is, could the little bit cooler air be hurting me or do I need to find better gas or should I have the a/f adjusted? It was tuned on a 90 degree day.The detonation only seems to be occuring under boost and above about 80mph. I do have a 4lb pulley. The a/f looks to be around 12/12.5 from 4500rpm on up. Can I adjust the a/f n the predator and if I can should I take it - or +. Thanks for any suggestions.

 

You can add fuel, I believe 10-15%.

The cooler day gave you a better denser charge causing detonation since you were riding that fine line to begin with.

 

So you'r saying on the Predator go up or + 5 or 10%? And when you say fine line what do you mean? Thanks.

 

Your tuner should have fixed it in the tune itself not using the predator's minimal adjustments. They don't allow enough changes to have any real effect, they just let the owner play tuner and make himself feel good.

 

Go up on fuel the maximum amount it allows, because it is minimal. What MisterGadget said about having the tuner correct the situation is good advice. What I am suggesting is an interim fix. What I meant about a fine line was that your timing and fuel mixture (or both) were tuned so close to the edge of detonation on that hot/muggy day, that better quality air put you over that edge into detonation, and a leaner mixture. I would suggest you back down the timing (via your tuner) by at least two degrees.
Your A/F should be 11.7-11.8 area for added safety. Your A/F will make a little more power, but once again, on colder crisp days, you will be even leaner yet, and that can be a bad thing.

 

ttt

 

Unless you can afford a new engine, I would immediately stop putting the engine under boost and get the tune corrected -- by someone other than who you have been using.

For a daily driver, having the tune anywhere near that close to detonation is insanity. And your "tuner" should know better.

 

Ya, what da Pimp Said .
A/F's in the mid 12's on a 70 something degree day
IS EXTREMLY DANGEROUS

 

From Nightriders post, it sounds to me like the dyno operator was tuning the truck using the Predator itself, and not using the CMR software. If that's the case, this is no surprise as Diablo's factory loaded tunes are quite aggressive on timing. I'd strongly suggest getting a custom tune made for it as opposed to using what comes with the Predator. We can make you a custom tune, if you are interested let me know.

 

Hey Sal around how much would be a custom stock performance tune set me back, if you don't mind me asking. You could E-mail me the price if you don't feel comfortable revealing it here.

Thanks...AKA....DA BOLT

 

ttt