Graves Insert vs FMF Q4 Loudness

Does anyone know or have personal experience with the difference in loudness of a stock exhaust with the Graves Hi-Flo Insert (my current setup from PO) and the FMF Q4? Personally I think the Graves insert is a little loud, but not sure how it compares to the Q4, and do not want to plug up the exhaust with the stock tip again. I've already got the FMF FI programmer, and usual mods (opened air box, exup removed, etc.), so my next thought was to look at exhausts. I like that the stock exhaust doesn't really require any maintenance, and also need the heat shield for bags, but on the other hand want every bit of HP that I can get! Thanks!

Another request would be for someone with the Q4 and a smartphone to grab a free app that measures decibels, and let me know and I'll just compare that to my setup. I've seen several YT videos showing comparisons between stock and various aftermarket exhausts, but none comparing the Graves insert with the Q4. Thanks!

Nothing, after market, will be as quiet as stock. If there was, it would be talked about endlessly.
Not sure about your insert, but in the stock exhaust pipe, has the potential to be quieter than anything else...imo.
Every other option will, likely, be louder.
Keep in mind, the quality of the tone produced, has a big effect on how loud it is perceived by you and others.
In general, the more low tone, the quieter. The more high tone, the further it travels, efficiently.
Quality of tone, takes this discussion in a different direction...

If you want to stay quiet, stay stock.
If you want to modify, go for tone...there is only so much performance to gain.
If you want performance, seek professional help.

Well I'm definitely not looking for either the stock sound or performance. The graves is definitely louder than stock, and according to its manufacturers claims, supposed to help it exhale. I've heard plenty of stock systems, and also know their inability to exhale sufficiently, so I am mainly curious how the graves compares to the Q4.

I had the graves and now have a q4. The q4 is definitely louder and it definatly flows better.. no more butterfly valve or cadillac converter in the q4.

Wow....$100 for that insert?

I can't imagine that a Q4 isn't louder than a stock pipe with that insert.

But the Q4, in my mind isn't too loud, and as far as most people here can guess, it's the least loudest of the aftermarket pipes available.

A few things to consider.

1) the EXUP isn't really an issue as it rarely ever closes. (there's video proof around here)
2) the stock pipe never needs to be re-packed
3) if you're interested in dropping weight the stock pipe needs to go
4) a Q4 will need to be re-packed
5) Q4 addition will likely mean you'll want to get an EFI programmer too - mo money mo money mo money

Thanks for the feedback. I have no complaints with the bike right now, so I'll probably leave it as is until I have an extra $450 to replace the stock system with the FMF Q4 and Powerbomb setup. Less weight and better breathing can't hurt! As stated earlier, the bike already has pretty much all of the other usual performance mods and the FI programmer, so the exhaust is really the "last thing" (yeah, right) I want to upgrade.

Also, I found a YT video where they compared the decibel levels of the Q4 vs Powercore 4, so I'll test my current setup to compare my numbers to those. I'll post my findings, in the odd chance anyone cares.

So I measured my setup tonight with an app on my iPhone5, no real method to my madness, and it showed 95dB at idle. FMF says the Q4 is max 96, with most under 94. This is what my gut feeling has been based on videos that I have seen. I also just discovered that HighFive over on advrider has already tested with a better device. Here's the info: Clicky

His findings actually indicate that the Graves insert is in fact louder than the Q4/Powerbomb setup, which is exactly what I was looking for.

Thanks for your input.

Also, don't bother with the aftermarket headers. The FMF models actually decrease power.

oic0 wrote:

Also, don't bother with the aftermarket headers. The FMF models actually decrease power.

You have what evidence of this????

I'd love to know for real if there are any advantages, or if you're correct, disadvantages.


You may save people a lot of money if you have proof.

oic0 wrote:

Also, don't bother with the aftermarket headers. The FMF models actually decrease power.

That's a big statement considering half the people here have dropped $$ on FMF headers. What's it based on?

motokid wrote:

oic0 wrote:

Also, don't bother with the aftermarket headers. The FMF models actually decrease power.

You have what evidence of this????

I'd love to know for real if there are any advantages, or if you're correct, disadvantages.


You may save people a lot of money if you have proof.

I can't find the post, but when thumper racing was sharing dyno results for their big bore kits they said the numbers on their kit in one of the graphs was down a bit because it had a powerbomb header on instead of the stocker. I figured they had probably dynod the bike dozens of times with different setups and would know. That paired with the threads saying the powerbomb is a smaller diameter were enough to prevent me from spending money on it.

You gotta find that thread.

Plus, smaller diameter where?

I had to use a mating collar to mate my Q4 to stock header.

It's my recollection the collar had to installed because the stock header is smaller than the FmF header pipe that was designed to mate with it.

Where are threads mentioning smaller inner diameter of FmF headers over stock headers?

According to HighFive's write-up on his swap, the FMF is larger.

Found it

Quote :

"There is a slight dip in HP and Tq from 6500 to 8800rpms. This is due to the powerbomb header. Using the stock header would have improved this area and we would have run at or above the GYRT through here as well. I didn't bring the stock header with me or I would have gotten a run with it as well."

-http://www.supermotojunkie.com/showthread.php?84451-GYTR-290CC-bigbore-for-WR250x!/page3&p=881677&posted=1#post881677

Note that is with a big bore kit, but if it flows less, it flows less.

A "slight dip" from 6500 to 8800 rpms....???????

What about the from 8800 to 10,500 ??????

Maybe the FmF rips the doors off the stock header from there on out.

And which header? Powerbomb or Megabomb?


oops....powerbomb....still find it hard to believe it's more restrictive...

Here is the chart that all of that was in relation too.

More depressing is when you read the rest of their post and realize a big bore kit, pipe, programmer, airbox mods, etc... made 4 more hp than a bone stock bike :( The +50% at about 5000rpms looks good, but still, 4 peak hp kinda blows for that much money spent.

Yeah - I wouldn't ever consider a big-bore kit unless something self-destructed in my stock engine.

On the flip side 4-5 HP increase is pushing about 20% more than stock. So relative to that a 15-20% increase in HP is kinda nice.

Still too much money for me.

As for the FmF header pipe deal I'm as skeptical as they come about it offering any advantages.
Which is why I've never bought one. Yet.


However, one graph, by one guy who was working on a big-bore kit rather than tuning for the actual pipe on a stock engine does not seal the deal for me.

Plus, there's plenty of pictures to show that the pipe diameter where the header mates to the muffler is larger on the FmF than it is on the stock header.

I can believe that maybe somewhere within the FmF header the diameters neck down, then get larger and perhaps that's done for back-pressure tuning and such, but generally speaking I'd NEVER believe the FmF header robs power due to being more restrictive than the stock header.

The graph does show that the dip only occurs in the one area of the power curve.
Everywhere else, the FmF header shows more power.

Also - I wonder what the Megabomb in that scenario would show?

Well there are the dyno charts that HighFive provided when he swapped his out. Sure, they're not shocking results, but I'm not sure what people really expect from a 250. To me, if you have the money and want to get every possible bit of performance you can out of your bike, then it seems like a worthwhile investment. At least it doesn't seem to be a total waste of money. But obviously that is subjective, and part of the fun of having choices like this to make! I haven't made up my mind yet, but primarily because of two factors: 1) it's a serious chunk of change to dish out, and 2) I like/need the exhaust guard on the stock exhaust. Sure, I could fab something, but for now Roxy is working just fine for me with the mods I have.