[nick]

Do slip ons alone add horsepower to the bike? Or do you need the whole exhaust kit to increase horsepower? It's hard to find a clear answer anywhere online.

 

[krombopulosryan]

Where's AZFox? opcorn:

 

[Watcher905]

Yes it does. However, it will be extremely minimal, you won't be able to feel the difference. It's just for sound, looks and weight reduction.

Now if you want to get noticeable power, you'll need a full exhaust, high performance intake, and a tuner (piggy back or flash).

 

[AZFox]

Midpipe Upgrade (Potentially) Raises HP

Generally speaking,

upgrading to a slip-on affects sound rather than performance and upgrading other parts of the exhaust that are ahead of the silencer affects performance rather than sound.
​

That said, reducing weight also improves performance and the Ninja 400's stock silencer is bulky and heavy, so installing a slip-on is a weight-reducing modification. Installing a full system will reduce weight even more.

The reason a slip-on doesn't improve performance very much is because the silencer is positioned beyond the portion of the exhaust system where restriction and/or exhaust flow has the most potential for improvement.

Upgrading to a full system will potentially reduce restriction and improve flow (these are not the same thing), particularly in the "midpipe" portion of the exhaust. A full system will usually eliminate the catalytic converter, which may or may not be legally permissible where you live.

@Watcher905 is correct about an ECU piggyback device or a reflash being required to achieve full performance.

Consider also that you want to avoid a lean condition. Bikes tend to run lean from the factory, and de-restricting the exhaust and/or the intake can lean things out even more. For some bikes the lean condition is a critical concern and for others it's less of a concern. I'm not qualified to say how important this is for the Ninja 400, but others on the forum probably are.

IMHO a slip-on is a compelling mod because it improves sound, reduces weight, and looks good. A full system is less compelling because the Ninja 400 stock exhaust seems to be better than most, and replacing it contributes to a lean condition and I'd prefer to avoid that.

I'm lurking around waiting for some feedback from BoosterPlug pioneers.

Removing the airbox snorkels is another mod to consider.

Also related: PAIR valve removal

 

[nick]

Generally speaking,

upgrading to a slip-on affects sound rather than performance and upgrading other parts of the exhaust that are ahead of the silencer affects performance rather than sound.
​

That said, reducing weight also improves performance and the Ninja 400's stock silencer is bulky and heavy, so installing a slip-on is a weight-reducing modification. Installing a full system will reduce weight even more.

The reason a slip-on doesn't improve performance very much is because the silencer is positioned beyond the portion of the exhaust system where restriction and/or exhaust flow has the most potential for improvement.

Upgrading to a full system will potentially reduce restriction and improve flow (these are not the same thing), particularly in the "midpipe" portion of the exhaust. A full system will usually eliminate the catalytic converter, which may or may not be legally permissible where you live.

@Watcher905 is correct about an ECU piggyback device or a reflash being required to achieve full performance.

Consider also that you want to avoid a lean condition. Bikes tend to run lean from the factory, and de-restricting the exhaust and/or the intake can lean things out even more. For some bikes the lean condition is a critical concern and for others it's less of a concern. I'm not qualified to say how important this is for the Ninja 400, but others on the forum probably are.

IMHO a slip-on is a compelling mod because it improves sound, reduces weight, and looks good. A full system is less compelling because the Ninja 400 stock exhaust seems to be better than most, and replacing it contributes to a lean condition and I'd prefer to avoid that.

I'm lurking around waiting for some feedback from BoosterPlug pioneers.

Removing the airbox snorkels is another mod to consider.

Also related: PAIR valve removal

Exactly what I was looking for. Thanks.

 

[krombopulosryan]

This pipe is the perfect example of the kind of horsepower gain you can expect from just a slip on. Dyno results in the link.

Remus Slip on

EDIT: A "performance" slip on. I doubt those straight pipes or Amazon Anodized exhaust can expect the same.

 

[TwiggLe]

I might be in the minority here. But my main issue with an exhaust mod be it full or slip on. Is I think it makes the bike lose bad. Just all that bare space in there. I'm leaning towards trying out that amazon $150 slip on though still.

 

[AZFox]

These pictures show the stock exhaust.

 

[Warp12]

Forget about whether it adds HP. The question is, what are you looking for??

If you could get 5 hp more with the stock exhaust, quiet and all, would you take that over great sound and no hp gain?

Is the stock HP holding you back??

Just some things to think about....