Impulse axys

[skibumm]

Thank you for the info (sincerely)

My take... and more food for discussion.

My quandary does not come from external vs. internal WG functionality. It lies with the claim that the location of the WG exit from the sled helps with snow-restricted exhaust scenarios.


IF dumping the WG to a different location (free air) 'uncorks' the engine in deep powder... The exhaust stream from the turbine is choked off... and the WG is dumping to atmosphere... the Turbine is not getting any of that energy that exits the WG... simply put...if the WG is dumping enough to 'uncork' the exhaust it's not turning the spool.

When the exhaust is corked-up from deep snow on the Impulse units... the Boost control is not directing the WG to open... it is opening because the exhaust back-pressure becomes greater than the seat pressure of the WG valve/spring and the WG is PUSHED open by the exhaust backpressure.

Regardless of WHERE the WG dumps... it is still diverting energy from the turbine.

With a WG that returns it's 'dump' back to the exhaust DOWNstream of the turbine... the WG can't be blown open by exhaust back pressure.

I hear the impulse works well.... which is why it still makes me wonder about the deep snow advantage of a separated dump location. Keeping the exhaust from getting plugged in the first place makes the most sense.

I'm very familiar with how a waste gate works... and the benefits that some external can have over some internal wastegated turbos.

How the ext WG is mounted also has a lot to do with the efficiency... an ext WG mounted at a right angle to the exhaust flow will have a disadvantage in terms of efficiency to one that is mounted for more laminar flow from the exhaust. Most external WG mfgs (TS, Tial, Turbonetics etc) recommend NOT mounting their WG's 90˚ to the exhaust stream.

The new Borg EFR turbos are very efficient with their well designed/routed internal WG....Contrasted with the Garrett internal WG's that were designed originally for diesel engines, I believe, from the 1970's.



Also...Travis... are you working for Impulse?



.

I don't work for Impulse, I'm just a very happy customer!

 

[skibumm]

Ultimately, I think we got a little bit off topic when it comes to the external wastegate. Impulse uses this because we think that it is more efficient system. Especially when we're talking about lag. Theoretically the turbo should spool up quicker especially in an 800 CC snowmobile scenario, if it has an external wastegate. As far as placement goes, it is there for cleanliness ease of install and to reduce extra piping and complexity. If it happens to, under certain circumstances, help in a deep snow bog situation then that's just a cherry on top.

 

[skibumm]

There's no denying how clean this setup turns out.

 

[gmustangt]

Do you have any pictures of the airbox?

 

[skibumm]

No, but I can get some.

 

[chrisco]

looks like it will be a good kit, but for us Canadians it is priced out of the market. As a Polaris Performance shop that does a ton of turbos this is not even an option at that price.

 

[skibumm]

looks like it will be a good kit, but for us Canadians it is priced out of the market. As a Polaris Performance shop that does a ton of turbos this is not even an option at that price.

I appreciate the fact that you can only purchase what you can afford. Having said that, back when I used to ride Yamahas, and having been to Revelstoke about 20 times I've seen more $50,000 snowmobiles up there in Canada than I've ever seen down here in the states you Canadians know how to get your priorities straight. $40,000 sleds in the back of a $750 pickup. I love it

 

[acutah]

Couple clips from this weekend!

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<iframe src="https://www.youtube.com/embed/3dpPUoD18p0" allowfullscreen="" width="560" height="315" frameborder="0"></iframe>