Originally Posted by Turbo301
I don't know if that's exactly true: even after having Solo measure and adjust my J's, there's a drone (a resonance) at about 70 km/h that can get quite beastly under load (with all 8 cylinders in). It's beatifully quiet on the highway, though.
Solo can correct me if I'm wrong, but I'm of the impression that you can either tune for quiet at highway speeds or quiet at city speeds, but trying to tune out resonances across the whole RPM range is not really viable (discounting four cylinder mode). Is that true, or do I have some more adjusting to do?
70km/h = 40mph? 6th gear, 1100rpm? This is actually the engine "lugging", and more a product of the car should NOT be in such a tall gear at that speed. If you flop over to manual mode 5th gear, the sound goes away, right?
The SOLO J-pipes target the natural L76 resonance in v8 mode of drone at 72mph (probably 110km/sec, highway speeds) where the real drone at this speed, on my exact test-car was headache inducing and
If you had a custom tune on there, you could request that they tweak the TCM tune to allow for the 70km/sec (or 40mph) to NOT lock up the torque converter .... which would avoid that spot altogether, and your lugging issue would be solved, solo exhaust system independant.
Ya see, the J-pipes are a certain length to target a corresponding certain frequency.
Take off the J-pipes altogether and cap the "branches" where the J-pipes were. Then take it up on the highway and you'll see what drone really is. That's what the J-pipes target.
If you're not willing to custom tune it to avoid the "fuel economy numbers mandated 40mph/70kmsec 6th gear idiotry that comes with the factory program on these cars.... then grab a laptop with a freeware sound collecting program and measure the hertz of the drone at your speed, and tune your J-pipes to that. Sure, possibly you will re-introduce the 70mph/110kmsec drone by adjusting this, but if you do most of your driving at 70km/sec then you can effectively tune out THAT FREQUENCY instead.
For me, my tuner made 40mph or 70km/sec to be 5th gear by default.... and I do not share the same issue you complain about. Likewise, my car at highway speeds is near stock quiet in v8 mode which is how I run all the time. I have a mach unbalanced with J's, along with HFC's and Kooks LT's, and it's the best of both worlds -- I love it.
Try it and report back. I personally had just about forgotten about the 40mph lug THAT SOME CARS have a problem with... mine was not an issue.
Not all g8's react to teh same mods identically... keep that in mind too.