Tuning For Lope

I'm gonna be upfront and say that I bought a bigger cam for the "cosmetic" factor. Mainly, I wanted a lopey idle, like you'd see on a typical cammed V8. Hate me all you want, i know i'm not the only one out there that's been disappointed with the sound of the cammed hemi's. They make good power, but they don't sound right. After many years of stuffing around, I've decided (in a fit of drunken-ness) to publicise the "cure" as it were.

THE CAR IN QUESTION;
2005 5.7 Hemi. Stock apart from Crower "Spartan Max" cam (Thanks to Inertia Motorsports for being so helpful), forged pushrods and 6.1L exhaust springs. Tuning via a HPTuners setup and AEM UEGO wideband.

OPEN LOOP TUNING;
The cure to your problems.

For one reason or another the "torque demand" tuning system doesn't seem to cope well with bigger cams. Once i'd adjusted for the changed airflow, i could get a fairly decent idle at 700-800rpm (No lope and Boooriiiiing). Stock idle speed on the other hand lead to a really consistent "hunting" idle (down and up every few seconds). I noticed that this was matched with the mixture changes. Essentially, when the computer is trying to maintain "closed loop" functionality, it varies the fuel mixture which in turn varies the idle speed and characteristics. HOWEVER;

This doesn't happen when you turn off the o2 sensors and force the car to run in open loop. You can run the engine at whatever mixture you want and change the idle behaviour. Want a really lumpy idle? Run lean. Smooth idle? Run rich. The main downside to this is that closed loop is disabled permanently (unlike on GM cars) so the overall performance tends to suffer unless your tune is really "on point".

I'm not saying this trick is for everyone. When my car was my daily I used an "open loop" tune, but now that it's a second car I use the "shenanigans" tune with the lumpy idle. And as always
Kind Regards
CAF.

post you tune