Info on FMF Q4 for 08 YZ450

[dgiles]

Just picked a used 08 YZ450 currently with a stock exhaust. Loud is ok on race days, but we have a couple practice tracks in the area that require DB Dawgs or Q4 or similar quiet pipes. Is there much difference between the Q4 and the Powercore 4.1 other than the noise? It is a pain to have to switch pipes back and forth for certain tracks. Lastly, worth the investment to go with the header "bomb"?

[rdefonce]

Just picked a used 08 YZ450 currently with a stock exhaust. Loud is ok on race days, but we have a couple practice tracks in the area that require DB Dawgs or Q4 or similar quiet pipes. Is there much difference between the Q4 and the Powercore 4.1 other than the noise? It is a pain to have to switch pipes back and forth for certain tracks. Lastly, worth the investment to go with the header "bomb"?

I have the same bike, and I also have a Megabomb header/Factory 4.1 muffler, AND a Q4 I just installed for off-road riding.

I notice almost no diff in power between Megabomb header/Factory 4.1 and the stock header/Q4 muffler!!!

(that said, I removed the screen insert from the Q4, which I have heard takes power away)

For me, it's a big pain to switch back and forth because the Megabomb header is bonded/stuck to the mid-pipe, which must be somehow "unstuck" if I want to use the Megabomb with the Q4.

I took the easy way out and simply installed the stock header to the Q4. That combo works great!

[grayracer513]

I removed the screen insert from the Q4, which I have heard takes power away...

I can't speak specifically to the Q4 screen, but the Spark arrestor screen on either of my two DRD systems has no noticeable effect on power at all.

[rdefonce]

I can't speak specifically to the Q4 screen, but the Spark arrestor screen on either of my two DRD systems has no noticeable effect on power at all.

I also can't speak specifically about the SA screen in the Q4, since I have never ridden with it installed.

Perhaps I should try it one day . . .

[bsmith106]

Ive spent some time on an 08 yz450 with the oem, oem with db dawg and oem header with the q4 can. The stock pipie felt pretty soft in the low end especially for a 450. It sounds weird but soft low end scared me, it was spooky to ride a 450 that wouldnt pull from low rpms. This trait was amplified with the db dawg, but it was a bit quieter. With the q4 on,Ifell in love with the powerband for the track. After spinning alot of laps on my crf 250 im used to twisting it pretty hard to get out of the corners. I jumped from my bike straight onto the yz and found i could carry the front wheel out of rutted corners with precision, not to high without having to be too carefull with the throttle. its much easier to deal with a rutted exit when only the back wheel is in it and its spinning controllably. I was clearing every jump but the bniggest one {an 80 foot table} by the second lap. It was near the end of the day and the track was getting choppy, not my bike etc. I also liked how much quieter it was than my own bike. This was with the screen out. Overall quieter than stock, better power. Win, Win