Throttle response STOCK vs Free Flow Mufflers

[Big_Phil]

Ok...I want to be clear. Clutching "delay" is one specific thing, and I think many here are describing this...I completely agree with wanting more engine braking, higher revving at slow speeds, all that stuff will have the sled feeling more peaky and quick hitting.....I dont feel the sled is lacking at all in this respect, especially with a tune.

But this is NOT the issue IMO....I first thought I could clutch around it too, but after many tries with the help of alot of goodies from Buddy Dale at dalton, I came to the conclusion the "delay" happens way before it has anything to do with clutching.

Its a thumb to engine delay IMO....it can be "heard" by the ear easily when sitting still or even riding down the trail, you watch your thumb mash it, and hear a brrrrrrrooooooommmmm.....Im trying to type out the delay in letters..LOL....

If I could video two take offs, SW vs my 1200 4tec, there is nothing but GO vs a marked time delay until GO on sw.

The more I watch the stocker vs modded sled in video....I truly think it has to do with the LESSER backpressure on these free flowing exhausts....I agree with you SJ on the slight blipping as he is trying to give us a sound test....but He sorta blips them on all, and while its not perfect timing and is closer blip on stocker, you can HEAR the marked delay time with your ear. I never like to use the word BOG but it rather reminds me of an old school BOG sound on a dirty 2s engine that has not ever had its main jets cleaned.

You can watch the last sled how it sounds, and after the delay the sled then transfers and lift skis....while the stock sled transfers right away, and has less of an audible BOG sound delay. Really makes me think exhaust/no backpressure.

Good part is, next season will have a stock sled of my own, and I can take video to hear what takeoff is like vs modded....and get to the bottom of this...and if it ends up being a muffler thing, I will talk with the gurus at Sandale to see if they can come up with a way to help reduce this...I want more then anything to have snap, then top end.

Its the nature of a turbo engine, it will never be as snappy as naturally aspirated. If you've ever driven a nytro/viper with exhaust and k and n filters, the throttle response is so quick its almost telepathic. My turbo nytro now spools quick, no lag really, but its not as good as it was naturally aspirated. When check my data logs, my sled hits full boost in less than .4 seconds.

Shorter intake routing will make the turbo spool faster, aftermarket tunes should be able to make the turbo spool quicker. The biggest thing with the throttle response might be the boost recirculation or whatever its called.. Ive never really worked on a sidewinder, so cant say for sure how it works. But having an appropriately sized BOV in the correct location can make a huge difference in perceived lag, especially in on/off then on again throttle situations.

Im sure most of this will be figured out by next season. It took a few seasons to get the tunes figured out for the 1100 turbo motors.

 

[Mighty]

By the way.. I almost hate to admit it, but I snowchecked a 850 Freeride - first non-Yamaha sled for me in 20 years. I don't know if I'm selling the sidewinder yet, but either way, I'll have some good options for what to ride next year!
/QUOTE]

 

[ROCKERDAN]

So Dan,would you say the bog sound would be worse on a larger 3" sandale vrs a 2.5 sandale for this delay,both with tune?

Im not saying anything is for certain.....what I do know is how the sled I worked on reacts on trail, its something I can never live with. So I hope its maybe just that machine. But in this new video I posted from Excell, I can "hear" that sound where that split second delay is(the one I worked on was much worse though)....and you can see how the sleds nose tries to jump, but then the delay is there so it doesnt jump and bring skis off ground til abit further down the trail, and by then you missed the knoll you were trying to flick your sled off....

Tuners can test all they want for huge power and speed and we all know the huge power is there in mid and top end.....But what Im hoping is to bring an awareness to what I think makes for a much more fun sled on trail....and maybe tuners will try to "tune" more for response and not just top end.... Someone like Allen who is a clutch guru totally understood me in our talk awhile back, and I think it has alot to do with turbo delay, but I believe it got alot worse when going to a free flow muffler, and after asking over and over for guys to please take videos of their takeoff, I finally saw this vid and it sorta shows what I was thinking it might.

If it is due to more free flow, and therefore there is less "bog" with stock muffler, then that is something I will notice right away with new stock sled next season....then I may try to get with muffler gurus to design a more trail friendly muffler with more backpressure down low...and a valve that opens up to free flowing for top speed.

Either way, its something that for me means alot....many will never even notice this on bigger trails, but my tight system around my local trails, I LOVED the snap of my 1200 iTC, it would launch off knolls even better then a 2s. So to get onto a SW from my sled, it felt like it had massive bog. Instantly noticeable by anyone.

Dan

 

[ROCKERDAN]

I wonder what DD muffler works like....I believe they are the only one that Ive seen so far, that has a divorced turbo outlet, and I wonder if this would have a backpressure effect? Assuming that the flowing muffler is the culprit.

I keep watching that video, you can click with your mouse on timeline, the first stocker, then instantly the 3rd sled run, back and forth....the more I do the, the more you hear the delay/difference......and that is an excell sled 3 and not near as bad as how the one I was riding was, each muffler may have more/less.

 

[SRXracer]

I know.. I'm still not sure what I'm thinking! I guess there is a new belt for next year, and new clutch calibrations.

I'm keeping my fingers crossed, and, like I said, i don't know if i will be trying all that hard to sell the sidewinder (but the viper sitting next to it really does need to go!).

 

[thor452]

I know what you are speaking about here it is something that Yamaha has been making better and better in the NA sleds ride a 07 apex back to back with a 2011 or newer and you will feel the difference right away its as if the sled knew before you touched the thumb flipper that you were going to. I refer to this as the sled has ESP. I wonder if an exup valve would help this in a sidewinder or if it mostly came from the valve and timing changes I that motor? seems to me that one would adjust with seat time to hit the flipper that half second sooner like we used to have to do back in the day before exhaust valves in two strokes.

 

[SaskAttack]

SRXracer, just a heads up as all new stuff has issues. I am from western Canada and we have a regional website called SnowandMud, go to the skidoo section and have a read on gen4 . Its interesting.

 

[WinterWolf]

I know.. I'm still not sure what I'm thinking! I guess there is a new belt for next year, and new clutch calibrations.

I'm keeping my fingers crossed, and, like I said, i don't know if i will be trying all that hard to sell the sidewinder (but the viper sitting next to it really does need to go!).

Yes my dealer that's selling me my 18 RTX 50th told me there is going to be a new belt specific for the Turbo Winder, and Clutching will be adjusted/calibrated improved. Little adjustments here and there is all that may be needed to really address the little quirks that the first year machine had.

 

[sxr70001]

This discussion makes me think of the time that I put a much larger exhaust on my truck. It really improved my top end and the ability of the engine to rev freely, but I also lost some low end grunt which took away from the fun factor. Like being able to launch as hard or spin the tires easily. All other variable staying the same, free flowing exhausts typically move the power band up the rpm range some. That's all I have. cheers

 

[ROCKERDAN]

Yes my dealer that's selling me my 18 RTX 50th told me there is going to be a new belt specific for the Turbo Winder, and Clutching will be adjusted/calibrated improved. Little adjustments here and there is all that may be needed to really address the little quirks that the first year machine had.

Any real evidence to support his though? I have heard things similar to this, about the 18s getting tweaks here and there. But still nothing of true substance. I know my dealer has hounded Yammie all winter about belt/clutch issues and they reply with "we never heard about that". LOL.

I would love to have some updates, but noone "in the know" seems to know ANYTHING.

 

[krm]

The Gates belt for me has worked better than the Yamaha belts .

 

[WinterWolf]

Any real evidence to support his though? I have heard things similar to this, about the 18s getting tweaks here and there. But still nothing of true substance. I know my dealer has hounded Yammie all winter about belt/clutch issues and they reply with "we never heard about that". LOL.

I would love to have some updates, but noone "in the know" seems to know ANYTHING.

I obviously have no concrete evidence either unfortunately...just sharing what my dealer told me.

You would think however some things would be addressed that were causing issues. And belt and clutch issues seem to be of priority in the 17's.

 

[indysnake1]

do you have a part number for gates belt

 

[Doowithblue]

40C4313 for the 8Jp equiv.

 

[Shagnos]

[QUOTE="ROCKERDAN, post:
, I LOVED the snap of my 1200 iTC, it would launch off knolls even better then a 2s. So to get onto a SW from my sled, it felt like it had massive bog. Instantly noticeable by anyone.

Dan[/QUOTE]

Sounds like you need to keep it......