# Dyno run after installing Akrapovic exhaust



## David.Yu (Jun 28, 2001)

Holy moly!

I went back to Surrey Rolling Road recently to get some figures on my custom WG3 tune done by Thistle and Ben at GTC.

It measured a very respectable 566.6hp (flywheel) on a very conservative Dyno Dynamics rolling road. 
This is up from 547hp using the original Cobb Stage 1 as shipped with the AccessPort.

I then had the full titanium Akrapovic Evolution exhaust system fitted, replacing the Milltek Y-pipe and stock cat-back system.
With no further remapping, on the same dyno and in similar conditions it just registered at 590.8hp!










I am completely blown away, I never thought an exhaust could make such an increase!
Suffice it to say, I am a very happy chappy!

(Although it does mean I am going to be loathe to give it back to Performance Parts after my review loan period, which I guess,%2


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## EvolutionVI (Sep 6, 2005)

Good exhaustsystems make power,others make just noise:chuckle:


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## bhp (Sep 13, 2008)

excellent, thank you for reporting back your findings, what db's does this system put out? might just have to wait for the GTC offering that will have noise control via a remote switch


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## Kislik (Oct 11, 2008)

wow, one of our cars here goes to Dyno next week, setup is WG3 mapping and GTC exhaust. rest stock, so will see


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## GTaaaaaarrrrrr! (May 4, 2006)

Very impressive :bowdown1::bowdown1::bowdown1: Almost makes it worth the money :chuckle:


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## thistle (Oct 27, 2007)

Send a log to Ben of a red line pull when you can to make sure it isn't lean and knock is OK. Injectors could be on the edge.


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## David.Yu (Jun 28, 2001)

thistle said:


> Send a log to Ben of a red line pull when you can to make sure it isn't lean and knock is OK. Injectors could be on the edge.


Hi Thistle, I've been doing some live monitoring of knock and it seems pretty good. Very occasional spike to -7xx, but normally more like -3xx.

I will do some datalogging when I can get some traction. This beast breaks loose in all gears in this weather!

Would changing injectors add more power?


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## thistle (Oct 27, 2007)

Won't really add power, just safety if you are already maxxed out. Check the injector pulse width at 6000 isn't much more than 20ms and at 7000 isn't much more than 17ms, and also that the AFR in the logs doesn't show much leaner (higher) than 12.2.

But we'd prefer to see a log for ourselves when things melt.


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## ChuckUK (Jan 1, 2009)

Does this run have the downpipe cats?


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## David.Yu (Jun 28, 2001)

Sorry about the fan noise.






Chuck, no downpipes, just Cobb, K&N drop-in filters and the Akrapovic system.


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## ChuckUK (Jan 1, 2009)

So if we know a y-pipe is good for circa 15bhp then this adds another 24bhp, a total of 39bhp over stock. 

Seems a lot of an exhaust.


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## Litchfield (Feb 26, 2008)

Excellent results David


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## Mark B (Jul 28, 2004)

Some of it might also be from the engine loosening up?


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## tomgtr (May 24, 2008)

Or was it freezing cold in there?

Great result anyway. Waiting desperately for next March bonus round. :squintdan


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## David.Yu (Jun 28, 2001)

ChuckUK said:


> So if we know a y-pipe is good for circa 15bhp then this adds another 24bhp, a total of 39bhp over stock.
> 
> Seems a lot of an exhaust.


I doubt a Y-pipe adds 15hp without remapping.

When we originally went to SRR, we had a completely stock car and mine with the Milltek Y-pipe and there was only a 6hp difference with my car being on 3000 miles v Rich's car which was only on 1500 miles.

There was no mileage difference between my two most recent runs.
Temps were 10c for the 567hp Milltek Y-pipe run and 4c today, so yes a bit colder but that is all "compensated" for somehow. Supposedly.


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## ChuckUK (Jan 1, 2009)

So do you think this excellent result is due to the exhuast brand or the fact you have changed the whole system, would GTC give the same result?


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## David.Yu (Jun 28, 2001)

I have no idea, although I'd guess the 90mm GTC Race system should be pretty good. The Akrapovic is only 86mm.


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## peterpeter (Feb 24, 2008)

blimey david, your car must absolutely fly now.

My standard car (with y pipe) feels monumentally quick. How much difference can you feel with and extra 100 hp?

BTW, how was charlie? whats he driving now?


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## srandall (Mar 31, 2006)

David, do you have stock air filters, and what was your original horsepower when stock?


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## David.Yu (Jun 28, 2001)

Got some lovely K&N replacement filters from Dave at Thule Roof Bars, Roof Boxes, Cycle Carrier, Snow Chains, Roof Rack, Bike Carrier, Thule Roof Box : Fasteronline.

Power was 512hp with just the Milltek Y-pipe on the same dyno.


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## srandall (Mar 31, 2006)

So, I am guessing 506hp before the y-pipe, compared to nearly 591hp now, a 85hp increase. If you are getting faster spool up of turbos at lower rev's it probably feels like more.

Very nice!


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## GTaaaaaarrrrrr! (May 4, 2006)

How did the torque figures pan out David? Can I see just under 600lbs/ft on your dyno sheet?


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## David.Yu (Jun 28, 2001)

Yup, 580lb.ft. Meaty!


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## Steve (Sep 21, 2001)

Nice David, look forward to seeing this "monster" out at CC say the 13th Feb ?


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## bazza_g (Sep 10, 2009)

must not read threads like this, must not read threads like this, must not read threads like this.... :thumbsup:


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## Cris (Sep 17, 2007)

Akrapovic make some lovely kit. Very active in the bike world. Used to (and probably still do) supply MotoGP teams.


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## charles charlie (May 3, 2008)

bazza_g said:


> must not read threads like this, must not read threads like this, must not read threads like this.... :thumbsup:


Give in to the dark side........


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