Raptor720, we have hashed this out many times on this board about the CT kits. Alan will be the first to tell you that the Raptor is very restricted, and the gains with his kit are not just attributed to his 'full' exhaust. Opening up the airbox, a better filter, and proper jetting are key.

This is also the case with the GYT-R slip on setup.

However, it has been my experience that the CT machine (mine) has more power and revs quicker that the GYTR Carbon Tip exhaust equipped machine (close friend's). These machines are stock other than no lid, the Pro Design foam filter on the Pro Design flange and proper jetting which comes in the CT kits.

I believe the GYT-R tip is a proven upgrade, with impressive results, but you have to upgrade the other parts (just like the CT kit) to get those results.

In fact I would say you could judge the difference mostly on price. The GYT-R Carbon tip is pretty expensive, and if you totalled up the pieces you get in Alan's kit, you should be within $100 of either setup with the CT being more expensive.

I found that buying the 'kit' you get detailed instructions, researched jetting, and proven results. I would definately buy it over again. If it was not available, I would go with the GYT-R setup now that I have seen the results, and I know the setup.

Gary660R, I remember reading that article also, which made me hesitate in getting the CT exhaust. But I think the setup didn't have the other modifications (ie. the rest of the kit). I think they were comparing the stock setup with the CT setup only, no other mods. I don't know if they did the jetting either. But once you open it up and jet it properly, it will clearly make the difference.

At least this has been my experience.

RM

 

RM,

I appreciate your post and agree with your points for the most part. My main issue with CT (setting aside any personal issues) is his dyno ads running against a completely stock system. What I would like to see is his pipe vs. a tip -- any tip for that matter-- that is properly jetted with air box mods.

Sure the full pipe may give a couple of ponies way on top but the substantial loss of torque in the running rpm range is my objection. Instead of comparing to the carbon fiber tip, lets use the metal tip or the HMF or ???. I would rather spend the extra $$ on a drop in cam and be that much ahead of the other guy.

 

I agree that the comparisons should be equal if you are trying to determine which is the best 'exhaust' setup. Like I said, the GYT-R Carbon tip and the CT Racing full exhaust are really close. I would love to see the dynos of them both. And the other types of setups as well.

The big bang for your buck is to open up the air intake with a proper filter kit and jet properly. I read in a post where someone did just that, and left the stock silencer. I bet you get 5-10 hp from that alone.

RM

 

The HMF slip on dyno'd at 4 wheel thunder was my unit before Eric shipped it to me in New Zealand some time ago. We where all suprised on just how well it performs for the $$$$ agains't the full BG system. I agree with all the other statements that you have to open up the airbox, get a decent filter in there and personally I like the Dynojet kit. Removing the airbox lid and adding the proflow made a huge difference in throttle response and top end rev ability or freeneess to rev out....... I'd rate the proflow / modifying the airbox as a must do mod, combined with the HMF slip on as the most bang for the dollars spent.

Head pipe, my understanding is that FMF pretty well stayed with the stock diameter ? or only very slightly larger, but they and trinity have go for the long primary length, so there is something in that for sure. Harry at Trinity is a smart dude and is not coloured by "what works on a 400EX is the only way to go" attitude some of the other builders seem to struggle with.

Be interesting to see the GYT head pipe, anyone got any Photo's ??

Keep the ideas and info flowing, this is a great thread.

Kiwi

 

I got my bike dyno'd today with the FMF head pipe and FMF powercore IV spark arrester. you can see my bike and dyno results at the link at the bottom ... Dyno was a EC997a Eddy Current Dyno....

 

Raptor720

The best way to screw up low engine speed performance and driveability is to install a high lift cam. High lift cams a purpose built for drag racing or other high engine speed driving.

By the way, exhaust "velocity" has very little to do with engine performance. The important characteristic on the exhaust is proper tuning of the pressure waves in the exhaust system. It's called Helmholtz Resonance tuning and applies to both the intake and exhaust systems. It is accomplished by changing lengths and diameters of the tubes.

Intake velocity is critical because a certain velocity is needed for proper fuel mixing.

Do you know that the stock Yamaha head pipe is the optimum tuning when some modifications are made on the intake side(airbox etc) or just for the stock system?

 

Raygun,

Obviously we both know about exhausts. I make things simple here because that is all that is needed. When I talk about exhaust air speed, it is critical for the reasons you mentioned. Instead of going through the exhaust gas temp, sound wave times, etc., it is easier to say that the problem I have found and proven is that when people put the off the shelf big head pipes on the Raptor they are loosing some major torque only to gain 2-3 peak hp.

On the intake side, it is clear that you also realize that the length, shape and volume of the port is critical. So, what is your point?? Do you have any information that would be helpful to the masses??