• Welcome to the BMW R18 Forums. Member registration disables ads and allows you to post and share. Register Here.

Exhaust Servo

  • <i class="fa--xf fal fa-check "><svg xmlns="http://www.w3.org/2000/svg" role="img" aria-hidden="true" ><use href="/data/local/icons/light.svg?v=1758297946#check"></use></svg></i> Discussion starter Discussion starter Chasing_Adventure
  • Start date Start date
kindzadza said:
Hey everyone! I've had an R18b since 2023. I'm not entirely happy with my stock exhaust. I drilled out dics in the baffles, but didn't notice much of a difference. Meanwhile, my neighbor recently brought from USA a used R18 with a Vance exhaust, and it sounds absolutely amazing and surely very different from stock r18. The sound is MUCH more voluminous (what you rightfully expect from 1.8L engine) and it growls even when the throttle is in a stable position. Hence you don't need to rev every time you want to hear your engine.
As we are not in contact with prevoius owner we puzzled for a long time over the reason for such a difference?
Thanks to this forum we found out that the previous owner removed the DB Killer from the exhaust and installed the Healtech ese-bm1 emulator recommended here. So the combined result is great! The good thing is that you can always roll everything back if not pleased.

By the way, other guys here are curious would the servo removal give any results with just standart fishtails?
Click to expand...

It plays only a limited role as db-reducer because the valves are (partially) closed at low throttle openings only. Additionally the flaps are open on starting. As such it does not affect the sound in the least when starting or gassing it.
Also apart from idling/low throttle use the V&H would be just as loud with/without the servos.
 
The Hattech pipes from Hornig are terrific from an optics point of view. I could remove the decibel killers for more thunder.
 
There is a blip in the Hp curve. I have always thought (no facts) that is because of the baffles.

All I can say is, if you remove the baffles and the cat, and get the Brentune it is f’ing hold on crazy. .
 
I would love to remove the cat, but that is a bit more of a chore than I want to tackle.
It would be nice if a 3rd party set of chrome header pipes were available.
 
Gr8adv said:
There is a blip in the Hp curve. I have always thought (no facts) that is because of the baffles.

All I can say is, if you remove the baffles and the cat, and get the Brentune it is f’ing hold on crazy. .
Click to expand...
Here you go

 
The caveat with an open exhaust and removing the cat is that the valve timing is designed for back pressure. It may very well be that the torque hardly improoves if at all.
It will also change the harmonics completely and introducing a or several flat spots is not unexpected.

No ecu tune can compensate for a mismatch of valve timing and exhaust design.

Bottom line is that removing all from the exhaust will for sure be véry loud but is very unlikely to make the engine run better.
 
Last edited:
Petrus said:
The caveat with an open exhaust and removing the cat is that the valve timing is designed for back pressure. It may very well be that the torque hardly improoves if at all.
It will also change the harmonics completely and introducing a or several flat spots is not unexpected.

No ecu tune can compensate for a mismatch of valve timing and exhaust design.

Bottom line is that removing all from the exhaust will for sure be véry loud but is very unlikely to make the engine run better.
Click to expand...
Your post may be good in theory but I can tell you that my real world experience has shown that it is not the case. Opening up the exhaust does not eliminate all back pressure, it only reduces it. And along with freeing up the intake with an open filter it makes more power. The Brenn tune only smoothed out the torque curve and eliminated the dips present in the OEM tune.
These bikes are engineered to meet the Euro 4 emissions and sound standards. To think that that the ride ability and power is optimized from the factory is just silly. Sure a set of cams would be the next step and certainly would produce a larger power boost but as of now I haven’t seen any made available.
My R18 as currently configured will just about toss you out of the saddle under hard acceleration with zero flat spots in the rev range.
 
MilwDave said:
To think that that the ride ability and power is optimized from the factory is just silly.
Click to expand...
Within the framewrok of regulations it is. On matching all the links of the proverbial chain.
For homloogation the regulations are considerably more restrictive than the periodic inspections. The difference is where the potential improvements can be found.

For the rest I think we are again sinking in the mires of semantics. P.e. between drilling a bigger hole in the end baffle and fitting straight through absobtion damper lies a world ´opening up´.

And anyone can do with his/her bike as he/she wishes.

I will restrict myself to the servo delete and slight opening up of the intake with the fingers crossed it will pass periodic inspection.
 
p.s. anyone put a ´derestricted´ R18 before and after on the same dyno yet?

I have seen the BT one:


3.6% more torque and nice elimation of the dip I have not noticed on the road.

p.s. with which/what exhaust is it on the Dyno?
 
Last edited:
Petrus said:
Within the framewrok of regulations it is. On matching all the links of the proverbial chain.
For homloogation the regulations are considerably more restrictive than the periodic inspections. The difference is where the potential improvements can be found.

For the rest I think we are again sinking in the mires of semantics. P.e. between drilling a bigger hole in the end baffle and fitting straight through absobtion damper lies a world ´opening up´.

And anyone can do with his/her bike as he/she wishes.

I will restrict myself to the servo delete and slight opening up of the intake with the fingers crossed it will pass periodic inspection.
Click to expand...
Where you live could hinder your ability to modify anything on your bike.
I’m fortunate to live in Wisconsin where there is no motorcycle emissions testing and you’ll only get a sound violation if you ride like an imbecile.
 
kindzadza said:
Hey everyone! I've had an R18b since 2023. I'm not entirely happy with my stock exhaust. I drilled out dics in the baffles, but didn't notice much of a difference. Meanwhile, my neighbor recently brought from USA a used R18 with a Vance exhaust, and it sounds absolutely amazing and surely very different from stock r18. The sound is MUCH more voluminous (what you rightfully expect from 1.8L engine) and it growls even when the throttle is in a stable position. Hence you don't need to rev every time you want to hear your engine.
As we are not in contact with prevoius owner we puzzled for a long time over the reason for such a difference?
Thanks to this forum we found out that the previous owner removed the DB Killer from the exhaust and installed the Healtech ese-bm1 emulator recommended here. So the combined result is great! The good thing is that you can always roll everything back if not pleased.

By the way, other guys here are curious would the servo removal give any results with just standart fishtails?
Click to expand...
I just removed the cables from the actuators. And locked them open. No codes. Or faults.
 
Petrus said:
It plays only a limited role as db-reducer because the valves are (partially) closed at low throttle openings only. Additionally the flaps are open on starting. As such it does not affect the sound in the least when starting or gassing it.
Also apart from idling/low throttle use the V&H would be just as loud with/without the servos.
Click to expand...
I disabled the exhaust servo on my R18B and am quite happy with my stock exhaust (with drilled discs). MUCH better sound (still not obnoxious), better torque, more stable and smoother at idle, and it idles without clutch till lower speed on 1&2 gears without stalling, which is often needed. My love for the bike is reignited. Waiting for Vance and expect even more. My recommendation to everyone is to try at least since its free and requires 5 min
 
Dpolo1 said:
I just removed the cables from the actuators. And locked them open. No codes. Or faults.
Click to expand...
not that it matters, but I would expect error codes to be logged..... so a gs111/dealer/obd reader etc would see them.... but nothing on the instruments.

Off course what that might mean to a dealer would vary...... depending on the country you are in/their attitude/what you are asking for etc.
 
I removed the cables completely. Then open the flappers100% . And locked in position. The actuators are still connected. No faults 4000 miles.
 
You must log in or register to reply here.
Back
Top