Full Akra Titanium Exhaust Worth it for V4S?

spooky · Jan 22, 2023

SuperDomestique said:
Yeah I’m not so sure that stock exhaust and cats cause the engine to run lean or less reliable. This logic is a bit dubious

I don’t think anyone’s saying that the stock exhaust and cats cause the engine to run lean. I’ve heard about engines being mapped to run quite lean for emissions purposes with various vehicles recently, so I guess there’s some logic to the exhaust change with the new map being better for the engine if it’s not set to run lean?

craig bush · Jan 22, 2023

Mayhem said:
The full akrapovic line should let your engine breathe more properly as you wouldnt run as lean as with double catalyst exhaust originally installed.

My understanding is it’s actually the opposite - adding an exhaust and letting the bike breathe more easily will likely make it run leaner. The main tuning change needed after installing an exhaust is adding fuel. That’s why the canned (generic) tunes offered with flash devices are sometimes referred to as “fat” maps.

Alkhater · Jan 22, 2023

Stock exhaust doesn't cause the engine to run lean, it has nothing to do with it.

Manufacturers stock tunes are rich to comply with emissions because lean mixtures produce more NOx (Nitrogen Oxide).

Freeing up the exhaust will cause the engine to run less rich but most of the time the engine gets a tune with the new exhaust.

Tuning is what ultimately determines the fuel mixture, not the exhaust.

You can have the stock and run a lean tune... but, with less fuel and a catalytic converter you'll run into heat issues sooner than you would with a free flowing exhaust.

craig bush · Jan 22, 2023

Alkhater said:
Manufacturers stock tunes are rich to comply with emissions because lean mixtures produce more NOx (Nitrogen Oxide).

My understanding is opposite - stock tunes are lean throughout most of the rev range to lower emissions and increase fuel economy.

SuperDomestique · Jan 22, 2023

craig bush said:
My understanding is opposite - stock tunes are lean throughout most of the rev range to lower emissions and increase fuel economy.

My googling agrees with @Alkhater. Lean air-fuel ratios cause higher NOx levels. Rich will cause more CO levels

5-Gas Diagnostic Chart

Walker explains the exhaust gases produced in the combustion process, what to expect at the tailpipe, and the tips for reading exhaust gas analyzer results.

www.walkerexhaust.com

Steven31371 · Jan 22, 2023

craig bush said:
My understanding is opposite - stock tunes are lean throughout most of the rev range to lower emissions and increase fuel economy.

Every time I’ve logged and then retuned from the factory tunes with the Woolich it’s running rich. The Woolich auto tunes it to make it run a less rich air fuel ratio. It doesn’t really have to add much fuel because it’s already rich.

Alkhater · Jan 22, 2023

craig bush said:
My understanding is opposite - stock tunes are lean throughout most of the rev range to lower emissions and increase fuel economy.

This is correct at low to mid rev range… I shouldn’t have generalized.

craig bush · Jan 22, 2023

Steven31371 said:
Every time I’ve logged and then retuned from the factory tunes with the Woolich it’s running rich. The Woolich auto tunes it to make it run a less rich air fuel ratio. It doesn’t really have to add much fuel because it’s already rich.

Help me understand - how does allowing the motor to breathe (i.e. get more oxygen), cause the air:fuel ratio to drop (i.e. get richer)?

SuperDomestique · Jan 22, 2023

My logic is that stock exhaust w cats is less free flowing than a full aftermarket exhaust and therefore choked at the exhaust-side so the engine can’t be as efficient. Air in has to equal air out. Also stock map is closed loop so it’s using the O2 sensor to adjust to ideal. I think that’s why it’ll run lean w stock map and full exhaust.

@DeussenEngines could enlighten us

spooky · Jan 23, 2023

Alkhater said:
This is correct at low to mid rev range… I shouldn’t have generalized.

That was my understanding - mapped to run lean at the revs that matter for emissions testing. All ‘corrected’ by the map supplied with the exhaust and the bonus of removing the restrictive parts and thus giving more power (because the V4 desperately needs more power).

Steven31371 · Jan 23, 2023

spooky said:
That was my understanding - mapped to run lean at the revs that matter for emissions testing. All ‘corrected’ by the map supplied with the exhaust and the bonus of removing the restrictive parts and thus giving more power (because the V4 desperately needs more power).

I have the sprint track air filter and the Spark WSBK exhaust straight off a WSBK team truck and a Woolich tune to optimize it, I suspect all that MAYBE added 2 to 4 whp. But I did a lot of stuff to add some mechanical anti wheelie so there is less electronic intervention for anti-wheelie which cuts the power we already have. So driving hard off an apex I suspect my bike has 10 to 15 real world more hp driving off an apex than the other ducatis at the track yesterday, and 30 to 40 more hp in that initial drive phase than most of the other bikes there. It’s so much ‘affective’ power that it’s throwing me off the back end of the bike as I transition back into the saddle from being off the side of the bike at lean. I literally have to hold onto the handlebars to stay on the bike at full throttle coming off an apex, and I’m 250 pounds in full gear. And absurdly there is even more ‘affective’ power available because I’m using DOT approved track street tires (SC3) and am loosing traction with the traction control activating and cutting the power a bit. Moving to SC2 slicks next track day so it’s gunna pull even harder off the apex, which is barely imaginable. It’s already BONKERS power, even pulling my 250 pounds around. This bike doesn’t need more power, the stock setup is barely containing the power it has lol, and if you do what I did: Longer Pierobon swingarm, Superleggera wings with a more aggressive lower wing rake than the factory Superleggera, and stickier tires, you have a lot more ‘affective’ power because you have less electronic intervention.

At the track this bike feels like a fire breathing dragon that is trying to go so fast it throws you off it’s back haha,……more power

SuperDomestique · Jan 23, 2023

Get more hp with the secret sauce oil than an exhaust haha!

RickD996 · Jan 23, 2023

Steven31371 said:
I have the sprint track air filter and the Spark WSBK exhaust straight off a WSBK team truck and a Woolich tune to optimize it, I suspect all that MAYBE added 2 to 4 whp. But I did a lot of stuff to add some mechanical anti wheelie so there is less electronic intervention for anti-wheelie which cuts the power we already have. So driving hard off an apex I suspect my bike has 10 to 15 real world more hp driving off an apex than the other ducatis at the track yesterday, and 30 to 40 more hp in that initial drive phase than most of the other bikes there. It’s so much ‘affective’ power that it’s throwing me off the back end of the bike as I transition back into the saddle from being off the side of the bike at lean. I literally have to hold onto the handlebars to stay on the bike at full throttle coming off an apex, and I’m 250 pounds in full gear. And absurdly there is even more ‘affective’ power available because I’m using DOT approved track street tires (SC3) and am loosing traction with the traction control activating and cutting the power a bit. Moving to SC2 slicks next track day so it’s gunna pull even harder off the apex, which is barely imaginable. It’s already BONKERS power, even pulling my 250 pounds around. This bike doesn’t need more power, the stock setup is barely containing the power it has lol, and if you do what I did: Longer Pierobon swingarm, Superleggera wings with a more aggressive lower wing rake than the factory Superleggera, and stickier tires, you have a lot more ‘affective’ power because you have less electronic intervention.

At the track this bike feels like a fire breathing dragon that is trying to go so fast it throws you off it’s back haha,……more power

Or, Steven, you can set the stock bike up well, and it doesn't wheelie xx

Also, carrying more speed through a corner, picking the throttle up earlier, means your rate of acceleration on corner exit isn't as great, which also helps antiwheelie.

Although, one thing I've forgotten, and is probably the greatest factor, is swingarm position. The post 22 bikes, and V4R, have significant advantages here...

SuperDomestique · Jan 23, 2023

RickD996 said:
Or, Steven, you can set the stock bike up well, and it doesn't wheelie xx

Also, carrying more speed through a corner, picking the throttle up earlier, means your rate of acceleration on corner exit isn't as great, which also helps antiwheelie.

Although, one thing I've forgotten, and is probably the greatest factor, is swingarm position. The post 22 bikes, and V4R, have significant advantages here...

Rick, one does not simply walk into Mordor. You buy your way in

I’m totally kidding Steve

DeussenEngines · Jan 23, 2023

SuperDomestique said:
My logic is that stock exhaust w cats is less free flowing than a full aftermarket exhaust and therefore choked at the exhaust-side so the engine can’t be as efficient. Air in has to equal air out. Also stock map is closed loop so it’s using the O2 sensor to adjust to ideal. I think that’s why it’ll run lean w stock map and full exhaust.

@DeussenEngines could enlighten us

Since most late model Ducatis feature a secondary air system the engines don’t run as lean anymore in part load. The trick here is to inject air into the exhaust before the O2 sensor and catalyst so that in the cylinder you can run a little bit rich mixture but still maintain the correct and a bit leaner chemical air fuel ratio for proper catalytic conversion. “All Ducatis run lean” really is a myth by now. There is a small closed loop area that actually runs a bit lean but it’s only like a 2000 rpm range max. Most higher load and rpm ranges are often set up too rich. In the high load, low to mid rpm there are sometimes some lean spike areas on some models. This said, there is no general trend that the calibrations are set up too lean or too rich as most of the time it is a mixture of both.

craig bush · Jan 23, 2023

DeussenEngines said:
Since most late model Ducatis feature a secondary air system the engines don’t run as lean anymore in part load. The trick here is to inject air into the exhaust before the O2 sensor and catalyst so that in the cylinder you can run a little bit rich mixture but still maintain the correct and a bit leaner chemical air fuel ratio for proper catalytic conversion. “All Ducatis run lean” really is a myth by now. There is a small closed loop area that actually runs a bit lean but it’s only like a 2000 rpm range max. Most higher load and rpm ranges are often set up too rich. In the high load, low to mid rpm there are sometimes some lean spike areas on some models. This said, there is no general trend that the calibrations are set up too lean or too rich as most of the time it is a mixture of both.

Thanks for sharing this insight @DeussenEngines

Its Tricky · Aug 21, 2023

Pinwheel said:
If any of you Akra owners could share some before and after experiences, I would appreciate it.

Thanks!

Hi Pinwheel,

Just replying based on my experience so far. I bought the 23 V4S in June. I ordered the full Akra lower exhaust and had it installed through Moto Union (Ducati dealer) Milwaukee in the US. Flashed to try and maintain the warranty. Temperature wise it runs cooler, although the heat dissipation to the inside of my right leg is ridiculous. Sound wise? I can best explain it this way…my bike now sounds pissed off. Save gas? Nope…I’m in higher rpm’s now so it didn’t help. I have a cbr 1000rr that runs hot, but down around foot level. Cost? $6200 for the exhaust and $1650 for the install here in the US. Most fun I’ve had on a bike since my 954rr.

Mayhem · Aug 21, 2023

My engine still runs hot even with a full akra. Never really had the original for a long period of time so i cant really compare. But for sure it is better to get rid of these doubke catalyst crap choking the engine

Full Akra Titanium Exhaust Worth it for V4S?

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