R36 Deleting the exhaust drone accomplished!

[damo_t]

Mr R36,

Those videos are great. That rasp is fantastic in the first two (+2 cat, +1 j pipe, -1 hot dog) videos.

In terms of posting pics, I usually upload them to Photobucket and then copy and paste the [IMG] link they provide in to your post.

I did notice that the cruising pics are just under 2k rpm, if you are in the band between 2k - 3k rpm and cruising at about 100km/h on a freeway, is there much cabin drone then?

Cheers,
Damo.

[dannyjak]

Hey Damo, as Colin mentioned, I think the cats are necessary for the rasp, looks like we wont get it without changing the cats.

Mr R36,

Those videos are great. That rasp is fantastic in the first two (+2 cat, +1 j pipe, -1 hot dog) videos.

In terms of posting pics, I usually upload them to Photobucket and then copy and paste the [IMG] link they provide in to your post.

I did notice that the cruising pics are just under 2k rpm, if you are in the band between 2k - 3k rpm and cruising at about 100km/h on a freeway, is there much cabin drone then?

Cheers,
Damo.

[damo_t]

Hey Damo, as Colin mentioned, I think the cats are necessary for the rasp, looks like we wont get it without changing the cats.

Yup, I agree with you. Just wanted to let him know that I loved the rasp that he is now getting.

For me, I just want to get rid of the drone that I am experiencing and it looks like the right J-Pipe configuration will do the trick (just wanted to confirm that there is no drone between 2k - 3k rpm when cruising on the freeway).

[Elmura]

Hey Mr R36. I watched ur videos. Sounds good most of the time but I did catch drone between 2-3k RPM in the video https://www.youtube.com/watch?v=cUBzQujAsCk around the 4 sec mark.
I measured it at 100Hz to 150Hz which is the usual drone tone.
When u get a chance, can you record a motorway / highway run at speeds 100, 110kph and 120kph.

Also, you mentioned in one post a phantom O2 sensor post cat??? Am I understanding correct that the exhaust shop deleted the O2 sensor or replaced it with a resistor or similar?

[Mr R36]

I haven't tried a freeway run yet so i'll do that but just from experience there is far less drone than pure suitcase delete and i suspect actually measuring the necessary length of a j pipe based on wavelengths etc will make a greater difference. I will probably look into that more later on.

I think there will always be some drone being a 3.6ltr V6 and my aim isn't to rid all of it - just the annoying bit which I'll film today.

Re phantom plugs

Yes they installed two so the warming lights don't come on. The oxy sensor isn't touched rather they changed the plug that reads pollutants or whatever. So the exhaust has an oxy sensor next to the cat and one right after that reads the differences between the two.

In short they aren't necessary from my understanding but rather just there to avoid lights coming on.

[OilBurna]

Is this legal doing all this?


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[Mr R36]

The high flow cats are legal I've been told. The rest regarding noise i would think is also legal as the noise level is more or less stock when driving normally.

Ps excuse my naughty driving in the vids... it's for science and the greater good

[Steve]

Is there much pop and crackle on the overrun?

[Mr R36]

Not really. I assume you mean crack/pop when we back off on the throttle. This is caused by excess fuel burning in the chamber so i gather you could either tune the car to run richer or get larger injectors. but this is getting out of hand ha

[Mr R36]

Drone test 1 and 2.

I tried getting as much drone as possible by going 2-3k rpm range on 6th gear uphills, cold and wet. The short answer is it does drone. Not as bad. The frequency is more or less the same but the amplification is less. And in practice i wouldn't often catch myself driving uphills at 100kmh on 6th anyway. Flat 100kmh seems to be fine. I will however down the line consider a more engineered J pipe, suitable helmholtz chamber or go for a dual system exhaust (1 exhaust per 3 cylinders) if anybody is interested in taking my current setup. I've just bought an air intake too so i'll give that a whirl to see what differences are made to the sound.

P.s VSO827 has checkednout my car and we did film a comparison of a single middle muffler delete vs my current setup. both of our verdict is that a single muffler delete bares more drone

R36 exhaust drone test 1: https://youtu.be/cHpT3fe3Trw

R36 drone test 2: https://youtu.be/OcIXXZ9a0mw