Good Morning,
@av8ingtom - I think @rabtech and @Slingrazor pretty much summoned it up, but definitely check all of the exhaust connections from the header to the tip. If there is any air getting into any of those spots you will definitely get some popping. If you have any other questions, just let us know.
Dave
Does this hold true even with plain old Chevy engine? Mine started popping immediately after tune up. Welter exhaust had just been 'repaired'.
I would tighten the manifold bolts and work my way back. It can't hurt to tighten them all down a little bit more.
May even want to check the O2 sensor and make sure it's tight. If you have changed spark plugs recently make sure your gap is correct. While you have them out checking the gap take a picture of each one and post it here. I would be curious as to how rich the engine is running.
I went and loaded the video you sent to our YouTube account, let me know if I can post it here so others can hear the popping noise you are getting. Here is a little explanation though of what is going on in the video -
Typically when idling most cars will target a stoichiometric air/fuel ratio, which is 14.7:1 air to fuel ratio. For some reason, which we have not entirely figured out, on the Slingshot you will get a lot of popping from the exhaust while targeting that normal air/fuel ratio at idle. On the Slingshot, a little richer air/fuel ratio closer to 13.5:1 makes the idle a little smoother without these pops. In the past Bob has tuned the forced induction Slingshots to run at that richer idle air fuel ratio. He has done that by running the idle of the Slingshot in what is called "open loop", which means that the ECM does not use the O2 sensor in the exhaust while at idle to achieve this air/fuel ratio. Instead, in open loop the ECM simply looks up the fueling on a fueling map in the ECM and injects a fixed amount of fuel without any feedback from the O2 sensor. The disadvantage of open loop tuning for idle is that because a fixed amount of fuel is injected, the air/fuel at idle can vary depending on conditions and we tended to be a little richer than we wanted and had some complaints about fuel smell from the exhaust. What Bob has been working on lately and is now incorporated into the newer tunes is closed loop idle fueling. Previously, we were only able to run closed loop fueling at idle and have the ECM target 14.7:1 air/fuel, but Bob has been able to figure out how to shift that value and now he can have the ECM target a little richer value and also control the idle fueling. This means that we are able to get more consistent idle fueling, while still being able to run it a little leaner at idle than we were able to do with the open loop tuning, which helps to get rid of some of the rich fumes some people complained of.
The little bit of popping in the video that @av8ingtom sent is going to be normal with one of the closed loop tunes. We are balancing between running it really rich at idle and having fumes and running it closer to 14.7 and getting lots of popping. Me and Bob spent several days on the dyno after Maggie Valley and typically in closed loop we were seeing low 14's air/fuel at idle which is a nice compromise, although on some Slingshots there may be some light popping.
Let me know if you have any other questions,
Dave
May even want to check the O2 sensor and make sure it's tight. If you have changed spark plugs recently make sure your gap is correct. While you have them out checking the gap take a picture of each one and post it here. I would be curious as to how rich the engine is running.
New spark plugs installed in Maggie Valley when the DDM super charger was installed. I will double check all exhaust bolts and flanges again tonight. Just rechecked the torque on all header nuts before Maggie Valley trip.
I can pull the plugs and look at them and take pictures. Slingshot runs great, just need to find out what is causing this popping noise from exhaust. I will try to use my Garmin Virb camera tonight. Not having any luck with my dead ass I-Phone.
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I went and loaded the video you sent to our YouTube account, let me know if I can post it here so others can hear the popping noise you are getting. Here is a little explanation though of what is going on in the video -
Typically when idling most cars will target a stoichiometric air/fuel ratio, which is 14.7:1 air to fuel ratio. For some reason, which we have not entirely figured out, on the Slingshot you will get a lot of popping from the exhaust while targeting that normal air/fuel ratio at idle. On the Slingshot, a little richer air/fuel ratio closer to 13.5:1 makes the idle a little smoother without these pops. In the past Bob has tuned the forced induction Slingshots to run at that richer idle air fuel ratio. He has done that by running the idle of the Slingshot in what is called "open loop", which means that the ECM does not use the O2 sensor in the exhaust while at idle to achieve this air/fuel ratio. Instead, in open loop the ECM simply looks up the fueling on a fueling map in the ECM and injects a fixed amount of fuel without any feedback from the O2 sensor. The disadvantage of open loop tuning for idle is that because a fixed amount of fuel is injected, the air/fuel at idle can vary depending on conditions and we tended to be a little richer than we wanted and had some complaints about fuel smell from the exhaust. What Bob has been working on lately and is now incorporated into the newer tunes is closed loop idle fueling. Previously, we were only able to run closed loop fueling at idle and have the ECM target 14.7:1 air/fuel, but Bob has been able to figure out how to shift that value and now he can have the ECM target a little richer value and also control the idle fueling. This means that we are able to get more consistent idle fueling, while still being able to run it a little leaner at idle than we were able to do with the open loop tuning, which helps to get rid of some of the rich fumes some people complained of.
The little bit of popping in the video that @av8ingtom sent is going to be normal with one of the closed loop tunes. We are balancing between running it really rich at idle and having fumes and running it closer to 14.7 and getting lots of popping. Me and Bob spent several days on the dyno after Maggie Valley and typically in closed loop we were seeing low 14's air/fuel at idle which is a nice compromise, although on some Slingshots there may be some light popping.
Let me know if you have any other questions,
Dave
Will be there an upgrade for the ones which where just installed?
Will be there an upgrade for the ones which where just installed?
I can check with Bob, but my understanding is that everyone that had theirs installed at Maggie Valley has the latest closed loop idle fueling.
Display More
I went and loaded the video you sent to our YouTube account, let me know if I can post it here so others can hear the popping noise you are getting. Here is a little explanation though of what is going on in the video -
Typically when idling most cars will target a stoichiometric air/fuel ratio, which is 14.7:1 air to fuel ratio. For some reason, which we have not entirely figured out, on the Slingshot you will get a lot of popping from the exhaust while targeting that normal air/fuel ratio at idle. On the Slingshot, a little richer air/fuel ratio closer to 13.5:1 makes the idle a little smoother without these pops. In the past Bob has tuned the forced induction Slingshots to run at that richer idle air fuel ratio. He has done that by running the idle of the Slingshot in what is called "open loop", which means that the ECM does not use the O2 sensor in the exhaust while at idle to achieve this air/fuel ratio. Instead, in open loop the ECM simply looks up the fueling on a fueling map in the ECM and injects a fixed amount of fuel without any feedback from the O2 sensor. The disadvantage of open loop tuning for idle is that because a fixed amount of fuel is injected, the air/fuel at idle can vary depending on conditions and we tended to be a little richer than we wanted and had some complaints about fuel smell from the exhaust. What Bob has been working on lately and is now incorporated into the newer tunes is closed loop idle fueling. Previously, we were only able to run closed loop fueling at idle and have the ECM target 14.7:1 air/fuel, but Bob has been able to figure out how to shift that value and now he can have the ECM target a little richer value and also control the idle fueling. This means that we are able to get more consistent idle fueling, while still being able to run it a little leaner at idle than we were able to do with the open loop tuning, which helps to get rid of some of the rich fumes some people complained of.
The little bit of popping in the video that @av8ingtom sent is going to be normal with one of the closed loop tunes. We are balancing between running it really rich at idle and having fumes and running it closer to 14.7 and getting lots of popping. Me and Bob spent several days on the dyno after Maggie Valley and typically in closed loop we were seeing low 14's air/fuel at idle which is a nice compromise, although on some Slingshots there may be some light popping.
Let me know if you have any other questions,
Dave
Please post the video. I think it will answer a lot of questions in the future.
Thanks Dave.
Popping from @av8ingtom exhaust at idle -
Wow that bike is running super smooth.... I wouldn't even consider that a popping sound. It just sounds good.....
Thanks Dave. I have not been able to get the video to post.
Wow that bike is running super smooth.... I wouldn't even consider that a popping sound. It just sounds good.....
@rabtech I had no issue with it in Maggie Valley. Maybe the higher altitude, but I would think that would cause it to be a little on the richer side if anything. The noise did not start until Saturday and only after the engine is warmed up. The sling has always ran very well since the DDM super charge install and it still does. Just needed to know about the little pop- pop sound.
Tom
Mine does the same thing when hot at idle
The sound is slightly different because of the side exhaust - sounds cool though!
Mine runs very smooth at idle, it pops "like a Gunshot" ones in a while when getting of the gas pedal or when shifting up or down. It wakes the pedestrian up so. 
I only have CAI and 1320 Header with stock muffler. Mine sounds the same after warmed up. When we were first texting @av8ingtom, I mentioned the sound as a "burbling" sound. That's exactly the sound I have, but with different tone thru stock muffler.
I only have CAI and 1320 Header with stock muffler. Mine sounds the same after warmed up. When we were first texting @av8ingtom, I mentioned the sound as a "burbling" sound. That's exactly the sound I have, but with different tone thru stock muffler.
Thanks Brent. I now know that it is normal. Problem I had is that it did not do this in Maggie Valley, it only became noticeable after returning to sea level.
that is a perfect sounding exhaust, there seems to be a misunderstanding as to what popping exhaust is.
When you get a noise that sounds like a Smith & Wesson just went off then you have a reason to be concerned.
that is a perfect sounding exhaust, there seems to be a misunderstanding as to what popping exhaust is.
When you get a noise that sounds like a Smith & Wesson just went off then you have a reason to be concerned.
I know how a Smith & Wesson sounds and it is similar.
I know how a Smith & Wesson sounds and it is similar.
Now i see you post, mine was in reference to the video.
Since you did reference to a gunshot like sound when getting off the gas that is a real popping and does mean that your tune is running rich.
I wish we could have something like the Dynojet autotune module that completely cured my bike from popping, it monitors and makes adjustments on the fly .
At 1:15 in this video you can hear a real popping in the exhaust. And the poor person driving the car I was passing probably thought they had just been shot.
