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I have to agree 100%. The dumps are VERY LOUD, but i can tell the car is much faster. Over the weekend I am going to work on fabbing something up that still dumps under the car but quieter. There is actually a lot of space on either side of the transmission in front of the axle, so I am going to see what kind of mufflers i can fit. I am going to also come up with something for the stock exhaust outlet hole (some sort of diffuser or grille plate) to clean it up a little bit. I feel like this would be the perfect setup once completed. Saves about 45lbs too!
I've measured the area you're talking about, and as long as you're up for fabbing, there's room for fairly long 5" resonators on each side. Would cut down on quite a bit of the jarring drone from the catless X and lose nothing (power-wise) in the process versus another chambered muffler.
My calculations still put me way too high on the dBa scale, so I passed on the idea. May be just the ticket for you, though.
Well, as some have you have seen recently, I am getting down the home stretch of bringing my M7 ECS car into the 9s. Today, I think I found the last piece of the puzzle, which may help all of us. First thing first, if you have a NON-Npp exhaust, throw it in the garbage. Here are some pics why:
Stock outlet
Inside of muffler from inlet, goes in 6" and stops. Perforation is the only relief for airflow.
Also, on both NPP and non NPP, exhaust inlet is 2.25 id after afm butterfly. I recently purchased a NPP and I know a lot of people are running this exhaust with good results, but I can almost gaurentee that there are significant gains after measuring and examining these as well.
I decided today that I will not be running an axle back at all, and running turn downs instead before the rear axle. I also trimmed the neck down area at the end of the ARH x pipe and attached the turn downs here. Now the exhaust is true 3" until the very end. The new setup is very loud, but the power is SIGNIFICANT. I will be back on dougs dyno shortly for back to back results. After driving the car today I can say that a real 3" exhaust for this car for anyone with a blower would be a worthwhile investment. B&B seems to be the only one on the market at this point.
Keep in mind, I ran 10.3 at 137mph on the non-npp mufflers, and they were screaming for dear life. It also made 740whp before they were removed. Stock cam. ECS kit with 2200sl upgrade. Stay tuned.
Full 3" turn downs
HEY! Thanks for the in-depth review, tech info and pictures. Also congrats on your times and power level, you have far surpassed the Z06.
Just for knowledge, if possible could you please post the horsepower level after the muffler removal with just the mods you have now. It would be interesting to see what level of restriction (besides a decent amount at your power level) that the stock mufflers pose. Also, I have the Z51 with NPP. In your opinion from what you have seen what do you think the power loss would be to retain the NPP mufflers?
Quick update from today's project. I wanted to tone down the turndowns, and I think I found a happy medium between terribly loud and civil. Picked up 2 vibrant quiet resonators, oval, 14" in length, item number VIB1142. I modified some of the bends right after the hanger on the end of the ARH pipe to bring the pipes closer together and the following is the result. It sounds AWESOME. These are full 3" straight through, but have a substantial amount of sound deadening inside. Don't mind my unpretty welds, can't do much better with a homeowner mig welder.
Bingo - my thoughts exactly on the resonators. Well done, my friend!
Thank you! If you run the like this and change the x pipe angle after the hanger, there is approx 20" long of room to play with on either side of the trans. I like this setup much better than the original turn downs as well because the exhaust is no longer anywhere near the fuel tanks!
Man I need a set of 18s, went to the track and went 10.7 @133 with a crappy 1.8 60ft. You still liking those 265 mickies?
Nice time! As far as the mickeys..love them! They do get worn quick though, I am sure I will need a new set every season. I need a drag alignment as the car has a decent amount of camber stock and is wearing the insides way quicker. They seem to get worn faster on the highway the most just cruising more than anything.
Last edited by c6switchblade; 05-23-2015 at 08:47 PM.
Nice time! As far as the mickeys..love them! They do get worn quick though, I am sure I will need a new set every season. I need a drag alignment as the car has a decent amount of camber stock and is wearing the insides way quicker. They seem to get worn faster on the highway the most just cruising more than anything.
I agree 100%, if you just use ET Streets at the drag strip they will last a really long time. When I ran them on my mustang every day they wore out really quick.
IMO getting an entire summer out of a set of drag radials that work as good as ET streets is phenomenal, those are some insanely capable tires.
Also I can't wait to see the dyno and track numbers.
For anyone wondering what the sound signature of these Vibrant 'Quiet' resonators are like, they're extremely similar to the sound from the 24" x 5" Magnaflow round resonator. The normal (non-quiet) Vibrant resonators are similar to Cherry Bombs and have a nasty tone and rasp to them.
I've had extensive experience in resonator use from my last track car - I went through over a dozen in different combinations trying to make it under a specific limit without resorting to chambers - it ended up taking a very custom 28" x 5" oval nightmare).
This VIB1142 is a more compact (14" vs 20" or 24") solution vs. the larger Magnaflows - just wanted to chime in since some of you might not have used or even heard of Vibrant. Their quality is actually quite good for the price, and is readily available on Amazon.
Nice time! As far as the mickeys..love them! They do get worn quick though, I am sure I will need a new set every season. I need a drag alignment as the car has a decent amount of camber stock and is wearing the insides way quicker. They seem to get worn faster on the highway the most just cruising more than anything.
What kind of 60 fts have you seen with them? Have you gotten into 1.5s?
Quick update... Got my HPT pro setup today with wideband after the exhaust swap, my AFRs are up dramatically to 13.8-14.1 from the 11s. I will not be driving the car anymore until the car is retuned, but this is a huge change. I was also only datalogging in 2nd gear and when I saw the AFRs i shut it down. I also made a grille for the stock exhaust cutout in the bumper and I have already received a ton of complements on it! Painted metallic textured black and matches the stock diffuser almost perfectly.
Last edited by c6switchblade; 05-26-2015 at 03:10 PM.
Here is a quick video for everyone to get an idea of what the exhaust sounds like. It is no louder than NPP open with long tubes and has an awesome tone! Just doing some testing on this run, the car runs 10s every time now without even trying.
Here is a quick video for everyone to get an idea of what the exhaust sounds like. It is no louder than NPP open with long tubes and has an awesome tone! Just doing some testing on this run, the car runs 10s every time now without even trying.
05-22-2015, 07:27 PM
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