How does a BAK function?

[Toku57]

I see a lot here have BAKs installed and like the performance gains they provide. Can someone explain how they function and what makes them better than the stock air box?

[Toku57]

Actually, I just found a Baron's video where he explains how BAKs smooth out air flow thereby increasing air velocity which in turn improves combustion, which makes the engine operate more efficiently.

Does that sound about right, or do different BAKs work differently?

Also, do BAKs typically provide bigger performance gains than a slip-on exhaust? For example, would a BAK with Ivan's re-flash typically provide bigger HP and torque gains than slip-on exhausts with the re-flash?

[redjay]

Go to Ivans webpage and check the HP and torque gains for the various configurations.

http://www.ivansperformanceproducts.com/vn1700.htm

[Toku57]

Originally Posted by redjay

Go to Ivans webpage and check the HP and torque gains for the various configurations.

http://www.ivansperformanceproducts.com/vn1700.htm

I have but unfortunately it doesn't have a graph for just ECU flash and a BAK to compare with ECU flash and slip-ons. Just a guestimate based on the graphs with ECU flash, slip-ons, and BAK suggest the power gain from either a BAK or slip-ons might be roughly equal though.

Was wondering if others who've tried both separately think.

[redjay]

I would do Ivans flash and a BAK. I am not a fan of loud exhausts but if I were I would still do the exhausts last if funds were tight.

[Toku57]

Originally Posted by redjay

I would do Ivans flash and a BAK. I am not a fan of loud exhausts but if I were I would still do the exhausts last if funds were tight.

That’s what I was thinking.

[Hillhouse]

Imo adding a BAC without changing the exhaust is a waste of time/money. what the purpose of allowing more/freer air intake if it can't get out of the motor.
That's why you do the exhaust at the same time. You want that exhaust not to be restricted, but along with less restriction comes more noise. There's always a trade off

[redjay]

Who's to say the stock exhaust is overly restrictive ? We tend to change exhausts because we want more noise, maybe not because they are overly restrictive.

With the bike I have (1300 Yamaha V Star) according to Ivans dyno graphs changing the stock muffler to a Cobra slip on only adds 2hp. The trade off is can I feel 2hp and is it worth the $400 that the Cobra slip on costs ?

[Framer]

Originally Posted by redjay

Who's to say the stock exhaust is overly restrictive ? We tend to change exhausts because we want more noise, maybe not because they are overly restrictive.

With the bike I have (1300 Yamaha V Star) according to Ivans dyno graphs changing the stock muffler to a Cobra slip on only adds 2hp. The trade off is can I feel 2hp and is it worth the $400 that the Cobra slip on costs ?

The heat is why I run cobra exhaust. As I remember there’s either no HP gain or just a little. There is a small toque gain.

Just remember and this is what Ivan said Until you hit 4000 RPM that BAK doesn’t do anything but make a little more noises.

[MAS Tequila]

To get the full benefit from any of the 3, you need to do all 3.

You want the exit to flow as freely as the intake.

Otherwise you only get partial benefit.

And you don’t want to be lean, so you need the flash.

You’ll think you’re on a different bike.

[Chuck A.]

I'll throw this in there per Ivans and my conversation..... He will reflash for a stock intake and you can run what ever filter and exhaust with it. If you change the intake it has a difference in the program of the reflash. SO if you are gonna do a reflash be sure of what you are going to do to the intake if anything,,,,, before the reflash.

[cactusjack]

Originally Posted by redjay

Who's to say the stock exhaust is overly restrictive ? We tend to change exhausts because we want more noise, maybe not because they are overly restrictive.

With the bike I have (1300 Yamaha V Star) according to Ivans dyno graphs changing the stock muffler to a Cobra slip on only adds 2hp. The trade off is can I feel 2hp and is it worth the $400 that the Cobra slip on costs ?

I think that was the case with the older 1500/1600 Nomads and the goat belly. Those were some small pipes. Not sure about the 1700's - it seems like they allow for more exhaust flow.

[Toku57]

Thanks all for some good things to consider. One other question - if initially I first got a BAK and then got Ivan's reflash, and then at some point later on decided to install slip-ons, would I have to get another reflash?