what Muffler to get for 2009 yz 450

is there a big difference in either of theses Mufflers if so whats the best one to get

1. Factory 4.1

2. Powercore 4 HEX

3. Q4 Hex

4. Powercore 4

 

and also does it natter what header I get

 

the mega,Power ect....

Anyone know the gains ect any info in each would be awesome

The Factory 4.1 is going to be loud, I installed it on my 10' 450 and it seemed open the bike up on the bottom end. With the stock exhaust it seemed to be corked up. I tried the Q4 before the the 4.1 and the Q4 is going to be more for off-road use, because it's not as loud(we all know that keeping sound levels low will help keep our trails open). Personally I felt like the Q4 corked the bike up more than stock. But that's my personal opinion.

I also heard the Powercore 4 is very loud. The new HEX design is supposed to lower sound levels, I haven't tried any of the HEX mufflers so I can't comment on those

I have had the Q4 and P4, the P4 was better

My new bike came with a MRD pipe and is awesome , way more power than the above. It's loud though...

Edited by WGP

I have a 2009 with a 4.1 & the mega bomb pipe on it & it doesn't seem that loud at all. It has a nice sound to it & the bike def has good bottom end. I had the same system on my kxf & it sounded softer than stock...

The header does make a difference on the '09.  I think it was smaller diameter than most of the aftermarket options. 

 

I was running a complete '06 Yamaha exhaust system and loved it.  My riding buddy had a Dubach full system which also worked great.  We did a comparison and couldn't tell any difference between the two.

 

--KT--

The header does make a difference on the '09.  I think it was smaller diameter than most of the aftermarket options.

 

Bigger.  Too much bigger.  The oversizing was done as a compensation for the restrictive muffler.  With that gone, it's too large to effectively contribute to optimum exhaust efficiency.  Use an aftermarket pipe, or a stock header from '06 or '07.

Bigger.  Too much bigger.  The oversizing was done as a compensation for the restrictive muffler.  With that gone, it's too large to effectively contribute to optimum exhaust efficiency.  Use an aftermarket pipe, or a stock header from '06 or '07.

 

 

I noticed you said "....or a stock header from '06 or '07."  What would the stock header from the '06 and '07 do with a stock muffler on the '09?  What if any performance gains are there?  What does the smaller header do for the '09?

The '08 header was added to the restrictive muffler to increase the system volume as a way of reducing the pressure that the muffler causes.  It was necessary so that the bike would have anything like respectable top end power.  If you took the earlier headers and installed it with the shorty muffler from the '08, the bike would fall on its face above mid range. 

 

The only possible use I could see for the '08-'09 header as something you would use as a choice might be if you wanted to run a really quiet exhaust system.  It might add power it that case.

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