Max possible NA power gain staying legal?

LarThaL · 10-28-2012, 01:25 PM

As the title says....what is the maximum possible NA power gain while staying emissions legal? Dinan Stroker doesn't count.

BPMSport · 10-28-2012, 01:59 PM

Depends on what state you're in.

In California, pretty much no gain...

We get to be the C in CARB legal where as everyone else is less strict "ARB" legal.

I think technically even changing the rear section here is against the law.

FormulaMMM · 10-28-2012, 03:47 PM

Semi-educated guess: filter, pulley, tune, catback (if you believe that adds a couple) for maybe 20-25 bhp'ish.

roastbeef · 10-29-2012, 04:01 AM

resonators that use factory cats, pulleys, exhaust, intake... each claim around 10hp, but we know those numbers are merely claims. but you can do ricer math and say you have 450+ hp.

CSanto · 10-29-2012, 08:28 AM

Filter is negligible
I'm not crazy about changing drive pullys

I'm not crazy about catless because of the smell, and carbon emissions.

Pretty much just HFC X-pipe and a Tune...Probably about 20-30 whp.

pbonsalb · 10-29-2012, 09:06 AM

How legal does the legal have to be? M3DCTBT is in the Boston area and tunes. He says he can get about 425 rwhp (non dynojet) out of an M3 with 300 cell high flow cats plus other mods and pass plug in OBD2 inspection. I have not yet seen Dynojet results, but even 400 rwhp SAE dynojet through 300 cell cats would be pretty good.

10-28-2012, 01:25 PM	#1
LarThaL Colonel 336 Rep 2,940 Posts Drives: 2011 M3 Join Date: Apr 2011 Location: West Springfield, MA iTrader: (0)	Max possible NA power gain staying legal? As the title says....what is the maximum possible NA power gain while staying emissions legal? Dinan Stroker doesn't count. __________________ **Audi S6 Audi S3 * Porsche Cayman GTS* --Former BMW M3 owner**
	Appreciate 0 Tweet Quote

10-28-2012, 01:59 PM	#2
BPMSport BimmerPost Supporting Vendor 3387 Rep 7,542 Posts Drives: Harrop M3 / F10 M5 / F82 M4 Join Date: Apr 2008 Location: SoCal iTrader: (9) Garage List 2000 BMW M5 [0.00] 1990 BMW 735i Turbo [0.00] 2008 BMW M3 [7.50] 2015 BMW M3 [0.00] 2015 BMW M5 [0.00]	Depends on what state you're in. In California, pretty much no gain... We get to be the C in CARB legal where as everyone else is less strict "ARB" legal. I think technically even changing the rear section here is against the law. __________________ -----\| Like us on Facebook \| Instagram \|\| Tuning Information \| Remote Coding \|----- ----Visit us at www.BPMSport.com - Emotion. Driven. \| Toll Free: (888) 557-5133----
	Appreciate 0 Quote

10-28-2012, 03:47 PM	#3
FormulaMMM Brigadier General 3663 Rep 3,422 Posts Drives: E90 M3 Join Date: Oct 2011 Location: Midwest iTrader: (2)	Semi-educated guess: filter, pulley, tune, catback (if you believe that adds a couple) for maybe 20-25 bhp'ish. __________________ M4 GTS, GT3, C63 S \| E90 M3s, E39 M5
	Appreciate 0 Quote

10-29-2012, 04:01 AM	#4
roastbeef Lieutenant General 11586 Rep 12,728 Posts Drives: E92 M3 Join Date: Nov 2010 Location: Orange County, CA iTrader: (4)	resonators that use factory cats, pulleys, exhaust, intake... each claim around 10hp, but we know those numbers are merely claims. but you can do ricer math and say you have 450+ hp. __________________ Instagram; @roastbeefmike
	Appreciate 0 Quote

10-29-2012, 08:28 AM	#5
CSanto Brigadier General 638 Rep 3,039 Posts Drives: 2015 BSM/SO M3 Join Date: Feb 2009 Location: New York iTrader: (3)	Filter is negligible I'm not crazy about changing drive pullys I'm not crazy about catless because of the smell, and carbon emissions. Pretty much just HFC X-pipe and a Tune...Probably about 20-30 whp.
	Appreciate 0 Quote

10-29-2012, 09:06 AM	#6
pbonsalb Lieutenant General 5237 Rep 10,617 Posts Drives: 18 F90 M5, 99 E36 M3 Turbo Join Date: Feb 2011 Location: New England iTrader: (4)	How legal does the legal have to be? M3DCTBT is in the Boston area and tunes. He says he can get about 425 rwhp (non dynojet) out of an M3 with 300 cell high flow cats plus other mods and pass plug in OBD2 inspection. I have not yet seen Dynojet results, but even 400 rwhp SAE dynojet through 300 cell cats would be pretty good.
	Appreciate 0 Quote