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      04-01-2013, 02:19 PM   #1
FormulaMMM
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Drives: E90 M3
Join Date: Oct 2011
Location: Midwest

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Akra Evo + Velos (real world gains) vs Stock DCT accel. data

The acceleration data is below. Little background info --

I've been regularly running at Gingerman Raceway in South Haven, MI for years now. First with my old E39 M5, and over the last two seasons with my E90 M3. It's been fun charting my progress as a driver, and also the M3s increasing capability as mods have been added. I started stock, added a front bbk, then a square setup with RS3s, and most recently this spring an Akra Evo w/ Velos Designwerks tune.

There has been some question and skepticism with regard to how much "real world" gain there is with a full exhaust and tune. I've seen many suggest that 30-40 brake horsepower, and -50 lbs. wouldn't reliably cut lap times. Here are my results --

On the back straight at Gingerman -- between turns 10b and 11 -- I never exceeded 120 mph pre-exhaust + tune in any conditions (and I've run in them all). This past Saturday with the Akra and tune I hit 124 mph.

Similar story on the front straight between turns 11 and 1 -- I know that I'm up 2-4 mph there.



End result is that I shaved between 0.5 and 1 second off of my previous best laps. The only new performance variable introduced was the Akra and tune.

I had the pleasure of running on Saturday with Richard (Richard@M-World) and Klammer. Richard let me borrow his Aim SOLO for a session, so we had some data post-event to compare.

The following is the acceleration data between turns 10b and 11.

Richard has KW Competition coilovers, and I'm on stock EDC suspension, so coming out of the corner it's not even close. With the coilovers + greater skillzzz he's on the power earlier and has almost 4 mph on me in no time.



By the time we close in on 100 mph and the top of 3rd gear, that margin is 0.2 mph. I then lose ground on the 3-4 shift @ around 100 mph (DCT ), but then I've closed the gap to within 0.1 mph by 120 mph.

Not sure what's up with my acceleration dips. I wasn't consistently full throttle, or perhaps hitting some headwinds. On my other runs the acceleration is more steady.

So I hope this data is useful for guys wondering if a full exhaust and tune is "enough", and what kind of real world gains can be expected with this mod. Also, some full exhaust + tune butt dyno validation.. Obviously there are far better ways to cut lap times, but it's nice to know that a full exhaust really isn't just for sound.

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M4 GTS, Z/28, GT3, C63 S | E90 M3s, E39 M5