Is servo needed to run stock exhaust?

nemom109r said:

A side query. Has anyone done a comparison with operating as it should and with SET valve constantly open?
I'm very keen to see a dyno comparison.

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99.9% of all dyno graphs you will see are done at 100% throttle position.(WFO)
So you will see no difference at all with or without the SET valve functioning on most dyno runs.
Unless you were to do them with & without the valve, both at the exact lower throttle position, its not going to give you any usable data for comparison.
The Set is open all the way at higher throttle positions, so it is the same when the servo is disabled and the valve is open all the time.

I agree with Zoom's statement above
The main reason manufacturers install the exhaust valves is to reduce noise at lower throttle positions to meet government guidelines and keep the city dwellers from complaining.
If they were installing them for more power or torque then they would not also restrict the ECU in those areas at the same time.

As far as the comments about restricting the exhaust for more low end torque. If these mods are static, then you are also killing your top end at the same time.
Which is why the SET has a servo module to open the valve at higher throttle positions.
But then again, Suzuki limits the top end in the ECU as well......I think the engineers might be bipolar.

BCS
LGB/FJB

Zoom said:

BCS, regarding the comment about the SET valve and full throttle. I was wondering, does the SET valve open solely in response to throttle position, or is it also rpm related? I was thinking if it was also rpm related (valve wouldn't open fully below a certain point) that it would show up on a dyno graph since they record from lower rpms too.

I have no idea but I figured you had done enough dyno runs and ECU work to know if there was a relationship.

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Well to be honest I have never seen any written spec stating that anywhere and the software I use to flash the ECU's does not reference or data log the exhaust valve position feedback. Its racing software, so the stock exhaust is not a variable. It is usually hanging from the rafters in the garage as a decoration.
Easy enough to see in real time if someone who has a stock exhaust wanted to test it out though. Just connect a voltage meter to the EXCVA position sensor and give her a rip.

But logically you would expect it to be fully open well before that point.
The secondary throttle plates are at 100% way, way long before then and the fuel map value for the injector pulse width is just as wide at lower RPM as it is in higher RPM's when you get into the upper TP ranges.
So it would not be logical at all to have the intakes wide open bringing in as much air as possible and the injectors pouring on the fuel, but then purposely have the exhaust dampened down, instead of free flowing.
We would be slipping back into those bipolar engineering ideas by doing that.

If there were even the slightest gain to be had at WFO by doing such a thing, the pro drag vehicles would have it incorporated in their exhaust.
You can bet the farm on that.

BCS
LGB/FJB

nemom109r said:

Was looking at VP's but have heard a little bad feedback.

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The only issue I have personally seen with the velocity pro is the heat shield cracking over time.
Honestly I believe this may be due to bad motor mounts causing the engine to buck and move more than intended and not a actual flaw with the exhaust.
I have been running the VPR exhaust for a few years now and my heat shield has cracked on the rear header pipe.
And yes I do need motor mounts done on my bike, but have been putting it off for way to long now.

The only other type of complaint I have heard, is one guy from Australia posted that he order one and the paint did not hold up or something like that.
But he is the only one I have heard make that complaint, so possibly it was an isolated incident.
Mine is chrome so no issues with paint on exhaust there.

I really like the VPR exhaust myself and would not hesitate to purchase another one.
I may contact Hard Krome and see if I can purchase a new heat shield for it. If not I will either remove the heat shields and wrap the exhaust or just purchase a new one. (or maybe both eventually)
But I have 6 or 7 other exhaust hanging from the rafters at the moment, just waiting their turn to go on the bike. So will have to see what direction I end up going next, who knows? Have been so busy lately I rarely get a chance to ride at all.

We also have many customers who purchase ECU tunes for the Velocity Pro exhaust, so they are popular in the 109R community for sure.

BCS
LGB/FJB

nemom109r said:

Hey B, are you running long or short?

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I have the VPR (short velocity pro) on the bike now.
But I have also had the long version velocity pro on the bike some years back as well.

I also have a sideburner exhaust, which is the same as the velocity pro, except it turns out to the side instead of being straight our the back.
The sideburner is made in a long and short variety as well.

You can also look at the Freedom Performance Combat 2 into 1 exhaust.
It is a little longer than the short velocity pro, but a little shorter than the long velocity pro, and it looks good on 9 as well.
Below is the Meancycles link with just about every exhaust for the M109R out there.


BCS
LGB/FJB

Here is the long and short velocity pro on Big Bird side by side for comparison.
They are all about the same honestly.
Just get the exhaust that suits the look you want for the bike.
I will say that if your ride 2 up, your passenger will appreciate the longer pipe more.
But personally I like the look of the shorter pipe better.

BCS
LGB/FJB

A few more photos.

BCS
LGB/FJB

Here is a couple of my 07 as well with the Velocity Pro Race (shorty) and Richards 07 with long straight 2 into 2 pipes.
And my 07 with Cobra Swept 2 into 2.

BCS
LGB/FJB