[SPLATT]

I just picked up a one owner 16 2SS M6 car for a daily. Being a longtime gearhead I'm looking to do some mods that will enhance the power the car already has giving it better drivability without sacrificing much in the way of gas mileage. At this time I'm not looking to open up the engine and do internal mods or add boost. I just want to stick to bolt-ons and a tune for the time being and not too loud for any exhaust mod(I'm old and loud is only fun for short periods of time now).

[2SS Capt]

Originally Posted by SPLATT

I just picked up a one owner 16 2SS M6 car for a daily. Being a longtime gearhead I'm looking to do some mods that will enhance the power the car already has giving it better drivability without sacrificing much in the way of gas mileage. At this time I'm not looking to open up the engine and do internal mods or add boost. I just want to stick to bolt-ons and a tune for the time being and not too loud for any exhaust mod(I'm old and loud is only fun for short periods of time now).

E85 is probably your easiest route...

[arpad_m]

Originally Posted by 2SS Capt

E85 is probably your easiest route...

E85 will reduce his gas mileage by 25-30%, which he probably doesn't want, given his OP.

Keeping it "not too loud" rules out headers, too, he doesn't want FI or opening up the engine either, nor anything that changes drivability, which leaves only the intake tract... all I can think of is a cold air intake, maybe a new intake manifold, plus a tune, which will not add a lot of power. The car being an M6, nothing to gain around the transmission either.

All in all, with these very strict constraints, I'd just add a CAI and a tune, lean back and enjoy the car practically as-is with the 5-10 added hp. Not really worth the money IMO, but getting an MPVI device and being able to tweak the car in the future may have some value. 2016 M6s are relatively cheap to tune, too, it only takes 2 credits (vs 9 for my 2018 A8)

[6spdhyperblue]

Yeah most sense would be to tune and get that intake manifold off. The LT2 is superior and cheap. Make sure to get a tune to rebalance the timing cyl to cyl and other tweaks after the manifold swap to get the most out of it

[SPLATT]

Originally Posted by 2SS Capt

E85 is probably your easiest route...

E85 is almost nonexistent in my state. The nearest location for it is not convenient for me.

Originally Posted by arpad_m

E85 will reduce his gas mileage by 25-30%, which he probably doesn't want, given his OP.

Keeping it "not too loud" rules out headers, too, he doesn't want FI or opening up the engine either, nor anything that changes drivability, which leaves only the intake tract... all I can think of is a cold air intake, maybe a new intake manifold, plus a tune, which will not add a lot of power. The car being an M6, nothing to gain around the transmission either.

All in all, with these very strict constraints, I'd just add a CAI and a tune, lean back and enjoy the car practically as-is with the 5-10 added hp. Not really worth the money IMO, but getting an MP VI device and being able to tweak the car in the future may have some value. 2016 M6s are relatively cheap to tune, too, it only takes 2 credits (vs 9 for my 2018 A8)

What makes these cars louder with headers? Anything I put headers on in the past weren't any louder until I put louder mufflers on.

Originally Posted by 6spdhyperblue

Yeah most sense would be to tune and get that intake manifold off. The LT2 is superior and cheap. Make sure to get a tune to rebalance the timing cyl to cyl and other tweaks after the manifold swap to get the most out of it

The LT2 manifold is on my radar.

[arpad_m]

Originally Posted by SPLATT

What makes these cars louder with headers? Anything I put headers on in the past weren't any louder until I put louder mufflers on.

When I said headers, I meant long tube headers (because I consider shorty headers a total waste of money, stock is pretty good for what it is), sorry for being terse.

To be 100% honest, I don't know the exact reason why long tubes are louder. I do know they have thinner walls (making the high pressure fuel pump tick louder), and I imagine the different, simpler exhaust routing as well as deleting the secondary cats are the main reasons; after all, the car only has 2 (or zero) cats instead of 4 after installing these headers.

In terms of volume, I'd say my car is ~25% louder on the outside than stock at idle and cruising, 50% louder at WOT, and cold starts are like absolute thunder while warm starts remain tame. Inside the cabin there is very little difference until I lay on the pedal, and it's tangibly (but not oppressively) louder at WOT, a very enjoyable experience. I still have the original "big suitcase" NPP exhaust with the valves.

[SPLATT]

Originally Posted by arpad_m

When I said headers, I meant long tube headers (because I consider shorty headers a total waste of money, stock is pretty good for what it is), sorry for being terse.

To be 100% honest, I don't know the exact reason why long tubes are louder. I do know they have thinner walls (making the high pressure fuel pump tick louder), and I imagine the different, simpler exhaust routing as well as deleting the secondary cats are the main reasons; after all, the car only has 2 (or zero) cats instead of 4 after installing these headers.

In terms of volume, I'd say my car is ~25% louder on the outside than stock at idle and cruising, 50% louder at WOT, and cold starts are like absolute thunder while warm starts remain tame. Inside the cabin there is very little difference until I lay on the pedal, and it's tangibly (but not oppressively) louder at WOT, a very enjoyable experience. I still have the original "big suitcase" NPP exhaust with the valves.

I get that shorties aren't worth doing, I've never used them myself on my old school stuff. I've also never did long tubes with anything with cats either. With the stock NPP I have set it to the track setting which I find about perfect. If I found an exhaust that was that volume level in the lower volume settings that would be perfect. It would give me a sound level that I can daily drive but I can open it up and be obnoxious when the mood hits.

[arpad_m]

Originally Posted by SPLATT

I get that shorties aren't worth doing, I've never used them myself on my old school stuff. I've also never did long tubes with anything with cats either. With the stock NPP I have set it to the track setting which I find about perfect. If I found an exhaust that was that volume level in the lower volume settings that would be perfect. It would give me a sound level that I can daily drive but I can open it up and be obnoxious when the mood hits.

I've heard several of the higher end Gen6 Camaro exhausts, and the Borla S-Type sounds like it could fit your bill. It has that late 60s, early 70s deep, growly bass tone, and is only thunderous at WOT.

Then again, exhaust sound is very subjective; for example, neither my wife nor my kids made even a comment about my setup (except for the ground shaking garage cold start, heh), it's perfectly usable, no drone in the cabin, I can even hear tire noise over the exhaust when cruising in tour mode.

Our county doesn't do emissions testing, but I don't want to abuse our freedom and be that guy with the stinky and raspy cat delete. I run Kooks green cats and leave catless shenanigans to the few coal rollers and Honda/WRX bros in the area

[SPLATT]

Originally Posted by arpad_m

I've heard several of the higher end Gen6 Camaro exhausts, and the Borla S-Type sounds like it could fit your bill. It has that late 60s, early 70s deep, growly bass tone, and is only thunderous at WOT.

Then again, exhaust sound is very subjective; for example, neither my wife nor my kids made even a comment about my setup (except for the ground shaking garage cold start, heh), it's perfectly usable, no drone in the cabin, I can even hear tire noise over the exhaust when cruising in tour mode.

Our county doesn't do emissions testing, but I don't want to abuse our freedom and be that guy with the stinky and raspy cat delete. I run Kooks green cats and leave catless shenanigans to the few coal rollers and Honda/WRX bros in the area

I'll have to go to some Camaro meets and listen for the sound and volume I like. Sounds clips on a video help some but don't tell you what it fully sounds like. While my state no longer has emissions testing anymore they do abide by California emissions requirements. There has been talk recently of bringing the testing back.

[bishopts]

long tube headers, catless x pipe, tune, done
stock throttle body flows fine, stock intake flows fine, stock intake tube looks ugly but does the job fine. stock size tires will make you work for a good launch.

[RideWithDanger]

I have full bolt ons and did it all at the same time with the tune to save time and money. Highly recommend it.

Rotofab CAI, 95mm LT5 TB, LT2 intake, Kooks catted headers, full resonated AWE Touring catback.

The car is a monster. And while its possible to be even quieter, the exhaust is surprisingly tame when cruising. Cold starts are pretty loud, and obviously getting on the gas can get loud, but just cruising I can have a normal conversation with my wife and my kids can be asleep in the back. Drivability is just as it was in stock form with the exception of track mode being a little more aggressive. Thats all up to the tune though.

[KingLT1]

Originally Posted by arpad_m

E85 will reduce his gas mileage by 25-30%, which he probably doesn't want, given his OP.

Keeping it "not too loud" rules out headers, too, he doesn't want FI or opening up the engine either, nor anything that changes drivability, which leaves only the intake tract... all I can think of is a cold air intake, maybe a new intake manifold, plus a tune, which will not add a lot of power. The car being an M6, nothing to gain around the transmission either.

All in all, with these very strict constraints, I'd just add a CAI and a tune, lean back and enjoy the car practically as-is with the 5-10 added hp. Not really worth the money IMO, but getting an MPVI device and being able to tweak the car in the future may have some value. 2016 M6s are relatively cheap to tune, too, it only takes 2 credits (vs 9 for my 2018 A8)

E85 reduces fuel mileage but when you compare the cost difference (at least in my area) vs 93 octane, Ethanol is slightly more economical. E85 cost 2.29 a gallon in my area, 93octane is 3.85. That is 1.56 a gallon difference makes Ethanol again slightly more economical to operate. Doesn't apply to the OP since he stated that it's not really available in his area, but I still wanted to address this for others following along.

[OB0001]

Originally Posted by KingLT1

E85 reduces fuel mileage but when you compare the cost difference (at least in my area) vs 93 octane, Ethanol is slightly more economical. E85 cost 2.29 a gallon in my area, 93octane is 3.85. That is 1.56 a gallon difference makes Ethanol again slightly more economical to operate. Doesn't apply to the OP since he stated that it's not really available in his area, but I still wanted to address this for others following along.

E85 is awesome, In Michigan E85 is everywhere ! My Daily Driver 14 Regal GS loves it and I run it all year with no problems even in negative temps.

[SPLATT]

Originally Posted by OB0001

E85 is awesome, In Michigan E85 is everywhere ! My Daily Driver 14 Regal GS loves it and I run it all year with no problems even in negative temps.

For whatever reason E85 is just not easily available in Washington state. Depending on what information source you use the nearest pump is either 45 miles or 95 miles away from me. It's more convenient for me to get ethanol free 93. If I wasn't concerned with gas mileage it would be getting the full treatment with a cam swap full exhaust and a supercharger. I know, why did I buy it and be concerned with gas mileage? I daily drove a 3/4 ton 4x4 for 18 years at 13mpg for 50+ mile round trip commutes so at 20+mpg is a good improvement for me and like to keep that.