Thought on current setup...

[ggradtech]

I’m getting a custom dyno tune Friday..... I’m hoping for some insight/understanding with the tuning for these cars.
I bought the car with what I NOW know was a “canned” SCT tune. It’s a long story about the car. Original owner wasn’t able to be questioned about the history of the mods or tuning.
I installed wideband as soon as I purchased the car. The car has 3” upper, 6 lb lower, 80lb inj, JLT intake, Diablosport MaFia, stock MAF sensor, Metco idler setup, stock Eaton and stock TB I assume.
With the MaFia installed (and with SCT canned tune) the car runs a tad lean at WOT on MaFia setting 2 and with fuel set to “10% rich at WOT”. With MaFia removed, the car runs really rich. Under 10.0 with that fuel set to “0% rich at WOT”
I’m just curious as to why the Mafia leans out the canned tune so much? With the WOT SCT fuel setting (Mafia now plugged in and installed) set to “10% rich”, car still runs lean with that extra 10% rupiah setting at WOT.
With the Mafia REMOVED and the canned SCT tune set to “standard” or no extra fuel, the AF ratio is really rich/fat.
Like I said..... I’m getting the custom tune Friday.
I’m just looking to get an understanding of this.
Another separate question......
The dyno shop can tune with either HP Tuners, or SCT. I already have the X4. I can “return car to stock”/sell the X4 and then just get an HP tune or use the X4 for the new custom tune. All answers welcome! Thanks

 

[01yellercobra]

The MAFia changes the MAF curve. It's used when the current MAF doesn't have enough range for the set up. It needs to be accounted for in the tune. The canned tunes aren't set up for the MAFIA.

I would ditch that 6lb lower. It's not doing you any favors. I don't think I've ever seen that pulley combo, but I'd imagine it's overspinning that blower a tad.

I would talk to your tuner about which software to use. I don't think HP is as popular for these cars.

 

[ggradtech]

The MAFia changes the MAF curve. It's used when the current MAF doesn't have enough range for the set up. It needs to be accounted for in the tune. The canned tunes aren't set up for the MAFIA.

I would ditch that 6lb lower. It's not doing you any favors. I don't think I've ever seen that pulley combo, but I'd imagine it's overspinning that blower a tad.

I would talk to your tuner about which software to use. I don't think HP is as popular for these cars.

Thanks for the reply...... I see in your “sig” that you have Bassani X and Stingers. Do you have any drone? I have the Bassani X and Bassani CB. I don’t care for the drone I have and the system is also too quiet. I want to get either just some mufflers or a new CB, B
but I’m concerned about the drone issue.

 

[CobraBob]

Exhaust drone can be a royal pain the butt. Unfortunately, eliminating drone or reducing it dramatically can take time and money. There's no easy way outside of installing an exhaust system on an identical car model with an identical exhaust system. Back in the day, I had a Magnaflow catted X-pipe and either a Magnaflow catback or Bassani catback (can't remember). I was getting horrendous drone between 2100-2300 rpms. Someone recommended I switch to a Steeda catback (made by Borla) so I took a shot. It worked 100%! Drone was non-existent, the exhaust note was a tad lower at idle and low RPMs, with a similar loudness at WOT. I was lucky to find a solution so quick. Not everyone fares as well. Your best bet is find people who have NO drone and set what exhaust setups they're using.

Here some very good information from CJ Pony Parts.

From CJ Pony Parts
Exhaust drone is an annoying, monotone sound and vibration that occurs in some aftermarket exhaust systems. It’s usually caused when the frequencies of the engine and exhaust are aligned at a certain RPM (typically 2,000-3,500 RPM). Drone is most noticeable at highway speeds, not during acceleration or low-speed driving. Exhaust drone is caused by the sound frequencies of the engine and exhaust resonating with each other. When the resonance frequencies are the same, they're likely to create a pressure wave. This is why drone occurs at a specific RPM (which is different for every car and exhaust). Not every aftermarket exhaust system is going to have drone. In fact, most don’t, and many are specifically designed to combat the phenomenon. Some people are happy to trade sound and performance for some drone on the highway. Others are more comfortable with an aftermarket system that’s engineered to have no drone at all.

Getting rid of (deleting) your muffler has a good chance of causing drone. It’s true that the primary job of the muffler is to lower your volume, not change the pitch or tone. However, there are also acoustic properties within the muffler itself. The baffles can change the frequency and affect drone.

Do Resonators Reduce Exhaust Drone?
One of the primary purposes of a resonator is to reduce exhaust drone. In addition to creating a tone that engineers think will sound good for the car, a resonator mitigates frequencies that would otherwise cause exhaust drone.

This means that one of the best solutions for solving exhaust drone is to change or add a resonator. If you’ve deleted your resonator as part of an exhaust upgrade, consider adding it back. Or select a cat-back exhaust kit with a resonator specifically designed to reduce drone.

Remember that resonators and mufflers work together. You can probably get away with not having one of them. But deleting both will greatly increase your chance of experiencing exhaust drone.

How Can You Reduce Exhaust Drone In Your Car?
The exact cause of exhaust drone isn’t always easy to isolate. Adding a resonator is the best way to get rid of drone. A muffler also has a good probability of success. If you don’t want to go with either of these components or haven’t gotten results, you can try adding sound insulation or modifying other parts of the exhaust system.

Add Noise Insulation
One solution for exhaust drone is adding noise insulation. This won’t address specific frequencies, but it will make things quieter and reduce vibration. Sound deadening can be used to reduce overall decibel level in the cabin. CLD (constrained layer dampener) tiles and other noise insulation, like Dynamat, work well. Even simple things, like keeping your spare tire in its place or using carpeted floor mats, can have an effect. Personal Tip! While it won't make a huge difference in your case, adding one of my silicone shifter base gaskets can help a bit because it reduces noise and vibration emanating from the transmission and surrounding pieces and passing through the shifter into the cabin. Inexpensive and effective noise/vibration reduction mod.

Add Resonated Exhaust Tips
Resonated exhaust tips are designed to slightly change your exhaust note. Since your tailpipes can be a cause of drone, changing the tips is a way to dampen or adjust the frequency. They don’t make a massive difference, but the modest tweak in acoustics might be enough to get rid of exhaust drone. Plus, they’re affordable and can add style to your exhaust pipes.

Additionally, installing exhaust tips of a different size can change the overall length of your exhaust piping. Changing the length of the pipes is a surefire way to change the frequency. However, it’s not cost-effective to try dozens of different pipe lengths to find the right one.

Change the Entire Exhaust System
Another, more drastic solution is to change out your entire exhaust system. If you don’t want to mess with your resonator and muffler (or already tried), an entirely new system could be in order. No-drone systems have become very popular, and many companies offer different technologies to help cancel out drone.

Unfortunately, there will have to be some trial and error if you’re dedicated to getting rid of drone and still having a loud exhaust system.