Tial External wastegates

Here's a few things to throw out there....

So if you put your external on the belly or cone of the pipe then you are infinitely changing your stinger size throughout the tune of the pipe..... Which in turn changes the tune of the pipe and would mess with your tuning,boost curve and fuel curve... Maybe not so much down a drag race track but what would this act like in the Mtns with continuous riding, extreme temp changes and big changes in Elevation?

I have seen first hand the power and response tight housings and external gates can make and it is impressive.... But on the flipside when you tighten your tolerances with all these variables you also tighten the the tuning window of the sled..... This is probably one reason your looking for releasing additional heat off of the piston due to your set up....Gus I'm not saying you aren't correct and I give credit where it is due but with all my turbo experience and the way we mountain riders abuse these sleds I have found to leave things a little "loose" so to say....

I run a .86 external (28 series) on the 800 and I know Im not quite as responsive as a .63 but I have found how to gain it back in clutching... With the .86 on the 800 I have held the thing WOT for about 2-3 min in the Deep and she stays right in tune.....

Something I always try to remember is when you tighten things up and start squeezing every little ounce of performance out of your sled then you better be able to tune the thing and keep everything in check... Gus and these other guys that have years and years of experience... its no big deal to them but for a guy like me.... I want the thing Dummy proof!!!! As simple and reliable as possible while still giving me a good arm workout for the day!!!

Thanks for all the good info guys.. its fun to get on here and actually learn something....

its always a shame to see how some, ( ken ) can run their fingers without so much as a real world test to back up what they type.

The fuel curve is not changed in any negative manner as you typed it is.
The timing curve is not affected as you typed it would be.
The users who have gone to my system are no longer seeing det or o2 changes on long pulls.
The users are also reporting much better on off throttle response ( as we found when testing ) yrs ago.

poll the USERS on here of what they see in the field. not the guy who thinks he sees bigfoot.

Do some real world research or testing , its better than keyboard testing and eliminates the Gino's from making bad decisions based on mirages from the NEW to them data acquisition system.

In the early 90's I was part of the dynomite development program, having 300 readings per second of data will blind you when you are new to it. Once you learn to spot the mirages novice errors like the charge temp fiasco and anti intercooler propaganda you are now spewing .

gus bohne said:

its always a shame to see how some, ( ken ) can run their fingers without so much as a real world test to back up what they type.

The fuel curve is not changed in any negative manner as you typed it is.
The timing curve is not affected as you typed it would be.
The users who have gone to my system are no longer seeing det or o2 changes on long pulls.
The users are also reporting much better on off throttle response ( as we found when testing ) yrs ago.

poll the USERS on here of what they see in the field. not the guy who thinks he sees bigfoot.

Do some real world research or testing , its better than keyboard testing and eliminates the Gino's from making bad decisions based on mirages from the NEW to them data acquisition system.

In the early 90's I was part of the dynomite development program, having 300 readings per second of data will blind you when you are new to it. Once you learn to spot the mirages novice errors like the charge temp fiasco and anti intercooler propaganda you are now spewing .

Click to expand...

Gus,

could you elaborate a little more on EWG placement. I see the center section of the pipe as the most ideal location for the EWG due to superposition of the pressure waves in the pipe (high pressure ratio and EWG flow). However how does this affect the return pressure to the cylinder?

TTT

I am considering doing an external gate this year, would like the talk to continue on, thanks guys!

It seems to me as years ago the 670 had a side exit stinger pipe. Seemed to work fine. It seems as though the wastegate in the side of the expansion chamber would matter. The pipe is still able to do it's job. I seem to agree with Gus's theory. I have followed him for a number of years and he is very consistant on what he says works.

agreed pipe center section is better!

the gate has no effect on stinger size or how the reflected wave acts. I have all my proof on papre from field testing and at dynotech, Ive used that method to reduce the heat wave SEEN by the pistons exhaust face since 1990. Ive also gone back to a std style stinger placement of the external gate and tested it at JIMS and on the snow. same results as back in the 80's it works but not as good as a center dump gate.

remeber, this is a waste gate NOT a stinger and plays NO ROLL in pipe pressure over boost what so ever. It only acts to lower the heat wave on the piston face and ring. pipe pressure is still a function of stinger AND a/r.



Even on my buddys trail triple cat 900,, 3 friggin gates, 1 on each pipe. its so much cleaner and easier to tune. but still 3 friggin gates !!!! oh my. but ya gotta do what ya gotta do when your running 3500 foot snow drags at 20 psi to make it live all yr long and not need rings and not see the idle rpm wander from rings loosing tension from being annealed from heat.

As always anyone who subscribes to dynotech can see all my proof, those who feel I am off ,,,, please prove it. my proof is right there.


I do agree that drags and trails are 2 very different things. Now that I closed the shop and went back to a 40 hour gig I will trail ride the old carbed turbo 2 strokes much more and have the tails and go pro to share.

ttt

So as we know TSS has changed the way they are feeding the turbine on their kits.. They are feeding the turbo from the center section and say its improved the bottom end and the makes the sled run more consistent and easier to tune.. I think they had to play with the cone cap and size of the new stinger/flange exit. I am sure the shorter charge tube makes the the sled faster to respond. They are also using a internally gated turbo and some off brand KPA turbo too. Is there magic in this?? Who is gonna try it? I will try it if it will improve the throttle response..

Here is the link for the Tss video
http://www.youtube.com/watch?feature=player_embedded&v=k6R9h90Nrh4

Polarisrocks said:

So as we know TSS is changed the way they are feeding the turbine on their kits.. They are feeding the turbo from the center section and say its improved the bottom end and the makes the sled run cleaner easier to tune.. I think they had to play with the cone cap and size of the new stinger/flange exit. I am sure the shorter charge tube makes the the sled faster to respond. They are also using a internally gated turbo and some off brand of turbo too. Is there magic in this?? Who is gonna try it? I will try it if it will improve the throttle response..

Here is the link for the Tss video
http://www.youtube.com/watch?feature=player_embedded&v=k6R9h90Nrh4

Click to expand...

My take and someone correct me if I am wrong.

A. By going mid mount you are either having lots of exhaust go around any sort of elbow sticking in the pipe, or you have a massive elbow taking up the pipe, and changing how your reflective wave acts.

B. turbos spool off of pressure differential, so take there cat mid mount it takes from the expansion chamber and dumps back into the expansion chamber. Where is the differential?

C. By going mid mount and closing off the end of the pipe and you are asking the exhaust to go to the back of the pipe and then work it's way back forward before it can exit. You have exhaust reversing acting against any sort of flow / effiency...

Hopefully I can try one this year.

The tss idea makes sense, turbos are driven by heat expansion, not just directly pressure or flow. Mount the turbo in the expansion chamber voila, more expansion from chamber to turbo creates better spoil, not nearly as much expansion is happening.

A turbo is driven off of pulse waves and exhaust pressure.. with the 2 strokes we have less pulse waves and more pressure.. So if the pressure is key. Putting a nozzle on a hose increases pressure velocity very similar to the stinger to the wheel..