tacticalwg

I own a 2011 Grandsport A6 W/ NPP Exhaust, my question is I only plan on installing headers and nothing else so what size headers are best and will it run better without a Tune? My Chevy dealer is ok on headers but not tune.
Please advise?
Thanks,
Paul

tennblkc6

1 3/4 headers. and yes...the car will perform better with the long tubes AND a tune.

haljensen

Your dealer may be OK with headers but your dealers boss (GM) isn't. Headers will kill your Warranty since you messed with the pollution controls (O2 sensors deleted or moved).

tacticalwg

Thank you for taking the time to reply. I sure don't want to avoid my extended warranty.

turboed

Lol thread diggers.

magutierrez

Hi, my car is a 2013 C6 A6 LS3 with factory NPP. I did LG Motorsport 1'7/8 Super Pro Headers. Before install the car put down 366RWHP stock, after install. I went to 393 RWHP/391TRQ. kEEP in mind this is just headers only, no other mods whatsoever, stock air box and dynoed at 5000+ feet of elevation.

Seadawg

Good info, but the OP originally posted back in 2013. Your info may not help him, but should help others looking to do it now. Here are what LG SuperPro 1 7/8" headers with high flow cats did to mine:

rwag

2012 GS A6 with ARH high flow cats x-pipe NPP with Varaam and tune 419 rwhp.
1 3/4 HEADERS.

Red89gt

What size headers did you go with?

njedwardz

On my '13 A6, I went from 366/380 to 439/451 RWHP/RWTQ with a set of Pfadt 1.75" LT's and midpipe w/ cats, Halltech MF107R, 160 stat, tune by Lethal Racing in Lafayette, LA. Dynocom dyno. So a little over 70 HP gains. Unfortunately, you won't be able to find these headers anywhere anymore, but I would think you should be able to get 50-55 hp out of any good set of longtubes and a tune, and an extra 5-10 out of a good CAI and a tuner who knows what they're doing with the MAF tuning.

Really looking forward to seeing how the Pfadt's perform once I throw a bigger cam in...hoping for 500RWHP without doing any head/crank/block work.

NMMike2012GS

If you check the forum vendors you'll see the Pfadt headers are now available again. I'm contemplating a set myself but have yet to decide if they are worth the extra cost as opposed to a set of 4 into 1.
Mike

njedwardz

I wasn't aware of that.

I can assure you that the fit and finish of the Pfadt headers are exceptional, and from what I've seen, the power advantage is indeed there. Whether or not the cost is justifiable will be your call; I mostly went with them because of my research into the tri-y design (better exhaust scavenging, etc.). According to my shop, my car was one of the lowest baseline LS3's they've run, and one of the highest that they've run with just boltons/tuned.

Oh and they sound incredible too (but I have a set of B&B PRT's as well...)

C7/Z06 Man

NO DYNO, only "real world" track results with a heavy Grand Sport (A6) and a 260 lb. driver = Approx. 3570 lbs.

There is a "formula" (within 1-2%) if you look for it using the cars weight with driver and mph at the end of the 1/4 mile to figure out real "Wheel Horse Power".

MY GS with: 1) 1 3/4" 4 into 1 headers running stock mufflers 2) OEM air intake converted to a CAI 3) Intune "93" canned tune 4) sticky tires, put down 125 mph in the 1/4 which is over 500HP, do the math.

Curb weight 2010 GS (A6) + drivers weight + 1/4 mile speed = RWHP

njedwardz

Sorry, but the math doesn't work. My car (440rwhp) does 11.97 in the 1/4 on street tires (don't have the time slip on me). Also, you're not going to get 130 hp out of headers, a stock diameter intake, and a canned tune. No amount of bolt-on modifications will get you there, at least not on an LS3 that I'm aware of.

That number IS ACCURATE for engine horsepower, however. Why? Because my car makes around 510 at the flywheel.

What type of headers do you have? A 60 hp increase is still impressive, especially with a canned tune.

C7/Z06 Man

I may agree but look for that 1/4 mile formula. My car has been 11.32 and that takes some hp with a stock converter and full weight car except for the headers and rear rims/tires I borrowed. You will find my Grand Sport time slip (Grand Sport Man) in the C6 fast list for more info.

PS: 11.4 on all Bridgestone runflats that weigh more than the OEM Goodyears (rotating weight). 3 lbs more each for the rear and I think 2 lbs. each more for the fronts.

njedwardz

Hmm...think the extra half second and 5 mph could be due to the slightly different gear ratios (2.56 vs 2.73) or possibly just strip conditions. Edit: and wider tires

Still awesome numbers for a near stock car. I have a bit of work (practice) to do before I get to low 11's

C7/Z06 Man

I had good air that day.

C7/Z06 Man

I have a question? My car still holds the GS "stock" record @12.31 and now with the mods that I have listed above has gone 11.32 and over 9 mph faster; So how much hp does it take to pick up approx. a full second and 9+ mph in the 1/4 mile in a 3570 lb. car?

PS: Horsepower is in the MPH not so much et. They say if you can get the mph than you can get the et.

Example: A car that is doing mid/low elevens with the addition of a good high stall torque converter may pick up a half second or more over the stock converter with no other changes, also a good converter due to the additional torque multiplication and "possible" better high rpm coupling (efficiency) may add additional mph over a stocker, too. Not all stock or aftermarket converters are created equal. High stall aftermarket torque converters are usually a smaller diameter & physically lighter (less rotating mass/weight) than the stock units which can add both acceleration & mph.

C7/Z06 Man

So let me take a stab at answering how much HP it takes for each tenth of a second faster but remember the faster the car goes and the more it weighs will up the HP requirements per tenth.

The last article I read on this subject said the average "rule of thumb" was: 13 HP per tenth of a second.

"Stock" my cars best was 12.31.

So to get to 11.91 would equal = 52 HP (4 times 13)

I added "just" a homemade CAI and my best went from 12.31 to a 12.01 best.

According to the 13 hp per tenth rule of thumb average of the article and I have also read somewhere that a tenth is also equal to 1 mph. So that 11.32 or approx. 1 whole second pickup from stock and the 9+ mph makes sense i.e. 1 second = 10 mph.

Bottom line: 10 times 13 = +130 HP on that good air day to run that number.

dmoneychris

My '08 w/MN6 went from 374 hp to 412 hp w/LT headers, a CAI & a tune (38 hp. at the wheels). It was also, after the parts & tune, making 402 lbft at 4700 rpm.