Exhaust question 300GP/18 and EC300/19

[Doc Brown]

I drove my buds 2018 300 GP model and my EC 300 2019 back to back. While the power isn't much different I felt the GP revs further while mine runs into "the natural rev limiter" earlier.

I think its the pipe. My KTM loved the FMF Fatty. Unfortunately on the GP's pipe it says just "FMF" but I have no clue which one it is.

Any ideas?

ta
Doc

 

[Jacob 'Berg]

Doc, Get the FMF "Fatty" if you want to improve your mid-top end power curve. The Gnarly will improve the bottom end, but will sacrifice some mid-top end.

I have heard from others, my local dealer included, that the factory Gas Gas pipe for the XC/GP falls somewhere between the fatty and the gnarly. I cannot confirm this myself.

Given that you are running the stock EC pipe, you will notice a definite improvement by switching to the FMF pipe. The Pro-Circuit is another option, but I do not know how it compares to the FMF pipes.

Another variable is the head, cylinder, and port timing on the GP which may differ from the 19 XC/EC models.

 

[Doc Brown]

Thanks Jacob, that's what I thought. The Fatty was stronger from down low to top on the KTM so I assume it will be similar on the GG.

Thanks again!
Doc

 

[GASGASCWB]

Doc, Get the FMF "Fatty" if you want to improve your mid-top end power curve. The Gnarly will improve the bottom end, but will sacrifice some mid-top end.

I have heard from others, my local dealer included, that the factory Gas Gas pipe for the XC/GP falls somewhere between the fatty and the gnarly. I cannot confirm this myself.

Given that you are running the stock EC pipe, you will notice a definite improvement by switching to the FMF pipe. The Pro-Circuit is another option, but I do not know how it compares to the FMF pipes.

Another variable is the head, cylinder, and port timing on the GP which may differ from the 19 XC/EC models.

Anyway, the FMF that comes in the GP is a GNARLY or FATTY?

I put the S3 cilynder head in my 2018 SIX DAYS and the bottom end was absurd!

But I feel that the mid-top end disappear...

FATTY be the best option in this case?

With FATTY, the bottom end continues great in my case or not?

 

[Jacob 'Berg]

Anyway, the FMF that comes in the GP is a GNARLY or FATTY?

I put the S3 cilynder head in my 2018 SIX DAYS and the bottom end was absurd!

But I feel that the mid-top end disappear...

FATTY be the best option in this case?

With FATTY, the bottom end continues great in my case or not?

I had the Gas Gas FMF pipe on my 2018 XC 250, beat the living crap out of it, and replaced it with a Fatty. I feel that there were some slight gains mid-top, which may support the theory that the Gas Gas FMF pipe that comes on the XC and GP is somewhere between the Fatty and Gnarly as far as the power curve goes.

Yes, I think that if you were looking to add some power in the mid-top end the fatty would be the way to go. I doubt you would lose much on the bottom end and you would likely not miss it much with the 300 and the higher compression head. Which insert are you currently using with the S3 head?

Honestly though, I would not spend the money on the Fatty if you have the FMF pipe that came with the bike. The minimal gain would be not be worth the cost.

You may want to look at changing the exhaust port timing by stacking base gaskets if you are looking to increase over-rev. Again you will be sacrificing some of your low-end power to achieve this.

 

[GASGASCWB]

I had the Gas Gas FMF pipe on my 2018 XC 250, beat the living crap out of it, and replaced it with a Fatty. I feel that there were some slight gains mid-top, which may support the theory that the Gas Gas FMF pipe that comes on the XC and GP is somewhere between the Fatty and Gnarly as far as the power curve goes.

Yes, I think that if you were looking to add some power in the mid-top end the fatty would be the way to go. I doubt you would lose much on the bottom end and you would likely not miss it much with the 300 and the higher compression head. Which insert are you currently using with the S3 head?

Honestly though, I would not spend the money on the Fatty if you have the FMF pipe that came with the bike. The minimal gain would be not be worth the cost.

You may want to look at changing the exhaust port timing by stacking base gaskets if you are looking to increase over-rev. Again you will be sacrificing some of your low-end power to achieve this.

My six days 2018 did not come with the FMF pipe.
At least there is no writing referring to FMF there.
Just the silencer...
I use the STD insert on my S3 cilybder head!
We do not have good quality gasoline here in Brazil.
If I use something with more compression with the gasoline that we have here, the bike will have a pre-ignition.

I asked about the GP pipe because there is a sale here in Brazil...
No need to import.
I emailed the FMF asking about the GP pipe and they did not respond to me until today.

The question is:

The pipe come in the GP model is the GNARLY, the FATTY or something between them and very similar to the pipe comes in the EC?

 

[Doc Brown]

The question is:

The pipe come in the GP model is the GNARLY, the FATTY or something between them and very similar to the pipe comes in the EC?

Unfortunately I haven't found anybody who could answer this question till today. As you say, FMF will not respond.

 

[Gottsell]

I have vanhassel exhust and love it. Much cleaner and liniar power on my -18 ec
300. Mounted -19 head with the new cdi mapping for the 18 also. And change the bearing in exhaust valve for better bearing and so there power.

 

[Greatdane]

Which bearing?

 

[Gottsell]

The bearing in the exhaust port in the cylinder, my was porly installed and the exhauast port did not go smooth

 

[Doc Brown]

I have vanhassel exhust and love it. Much cleaner and liniar power on my -18 ec
300. Mounted -19 head with the new cdi mapping for the 18 also. And change the bearing in exhaust valve for better bearing and so there power.

Where did you get that exhaust. Never heard of it...

 

[Gottsell]

Dutch i think, used it on yz144 enduro and yz 250x, great linear power.
Van hasselt exhaust. It is handmade

 

[Doc Brown]

OK, thx. will have a look ...

 

[GASGASCWB]

Unfortunately I haven't found anybody who could answer this question till today. As you say, FMF will not respond.

The XC/GP models comes with the same part number parts!

I think this pipe is a custom pipes for this 2 models...

Not GNARLY, not FATTY...

BE86001GG-CLJ-1 EXHAUST PIPE (EC)

BE86001GG-CMZ-1 FMF EXHAUST PIPE (XC - GP)

 

[GASGASCWB]

Unfortunately I haven't found anybody who could answer this question till today. As you say, FMF will not respond.

In conversation with two dealers, one here from Brazil and another from the USA, both almost say that the pipe that equips the GP model is an FMF FATTY!
It comes in the GASGAS GP for greater indication for thisbike to the ENDURO FIM...

 

[dzhitshard]

In conversation with two dealers, one here from Brazil and another from the USA, both almost say that the pipe that equips the GP model is an FMF FATTY!
It comes in the GASGAS GP for greater indication for thisbike to the ENDURO FIM...

It does appear to be a "Fatty" profile pipe but it is not a Fatty constructed pipe. I can tell that by weight difference in the hand. It's most likely GG's version of the FMF Factory Enduro pipe for the Austrian bikes. Basically a Fatty profile pipe with the heavier side wall material most people associate with the FMF Gnarly.

 

[Doc Brown]

The XC/GP models comes with the same part number parts!

I think this pipe is a custom pipes for this 2 models...

Not GNARLY, not FATTY...

BE86001GG-CLJ-1 EXHAUST PIPE (EC)

BE86001GG-CMZ-1 FMF EXHAUST PIPE (XC - GP)

Thank you. Logically the more race oriented GP would need a pipe giving more power and over rev so I also assumed its a "Fatty". But it isn't. What you say seems plausible.