Info for building an intake

portgrinder · Aug 28, 2017

fooling around today

two different intake boots. both with no filter on the end. the one that was 6 inches long made 4hp more than the one that was 16 inches long. measuring power at the front spocket.

thought it was something to pass on.

Idcatman3 · Aug 29, 2017

portgrinder said:
fooling around today

two different intake boots. both with no filter on the end. the one that was 6 inches long made 4hp more than the one that was 16 inches long. measuring power at the front spocket.

thought it was something to pass on.

Might want to include the specific bike it was on, as I'm sure that makes a difference.

Sheetmetalfab · Aug 29, 2017

Idcatman3 said:
Might want to include the specific bike it was on, as I'm sure that makes a difference.

Shouldn't there be a filter on the tube?
Seems that would make a difference also.

Unless you run your bike without a filter?

portgrinder · Aug 29, 2017

kx5

filter loss is the same, and ontop of the loss that the tube adds. just trying to illustrate the point that you want your intake setup as short as possible.

M5- · Aug 30, 2017

I'm surprised that there was that much difference. That's pretty significant.

M5

Idcatman3 · Aug 30, 2017

portgrinder said:
kx5

filter loss is the same, and ontop of the loss that the tube adds. just trying to illustrate the point that you want your intake setup as short as possible.

Any idea if "As short as possible" is best, or if there's a "tuned" length to shoot for? That much difference makes me think there's some harmonics going on at one or the other of those options.

byeatts · Aug 30, 2017

portgrinder said:
fooling around today

two different intake boots. both with no filter on the end. the one that was 6 inches long made 4hp more than the one that was 16 inches long. measuring power at the front spocket.

thought it was something to pass on.

Was thinking about some cross fins in the tube to straighten the flow?

portgrinder · Aug 30, 2017

not sure if its resonance or just restriction. either way shorter solves that. less restriction and it would resonate at such a high frequency that it would never matter.

Hawkster · Aug 31, 2017

multiple velocity horns within the intake would help eliminate the turbulence .

Crap I'm on a roll , that makes two , a spiff will do please :face-icon-small-hap

byeatts · Aug 31, 2017

Hawkster said:
multiple velocity horns within the intake would help eliminate the turbulence .

Crap I'm on a roll , that makes two , a spiff will do please :face-icon-small-hap

perhaps Portgrinder could dyno that?

byeatts · Aug 31, 2017

byeatts said:
perhaps Portgrinder could dyno that?

Some have claimed the Yeti intake loss power, I believe it allowed better air flow which leaned out the motor, and once fueling is corrected it will be fine,This has happened on sleds as well. The Yeti tube is almost same length as the KTM air box with much better flow.I ran the Yeti intake last season on a 2017 450 KTM and ran very well, Stock box plugged quickly.

Wheel House Motorsports · Aug 31, 2017

There is a reason OEM intakes bell out insanely quickly to a very large filter area. these guys running mega long intake extrensions with with filters out by the rear fender are giving up power for sure. You want to basically do a 2.25" (throttle body) to 3 or 4" silicone expansion with a filter as close to the motor as possible.

I know it has been verified by seat of the pants as well as dyno that the Timbersled TSS intake reduces power. their kit is almost a foot until its 3" diameter tube.

pumping anything through a tube, length means drag means reduced flow means less HP.

byeatts · Aug 31, 2017

Wheel House Motorsports said:
There is a reason OEM intakes bell out insanely quickly to a very large filter area. these guys running mega long intake extrensions with with filters out by the rear fender are giving up power for sure. You want to basically do a 2.25" (throttle body) to 3 or 4" silicone expansion with a filter as close to the motor as possible.

I know it has been verified by seat of the pants as well as dyno that the Timbersled TSS intake reduces power. their kit is almost a foot until its 3" diameter tube.

pumping anything through a tube, length means drag means reduced flow means less HP.

OEM must bell out quickly as there is no room to extend, Fender is inches away, cant hang hat on that, I believe its a matter of straightening the air flow and diminish turbulence , only a dyno will tell the story, The Yeti is short and can be even shorter if needed.

M5- · Aug 31, 2017

You need to keep in mind that Portgrinders motor is a 2 stroke. 4 strokes are much more sensitive to modifications to the air intake path. I built a carb heater for my buddies WR last year, it is a real nice piece but the bike wont run with it on as it deleted the rubber boot that also protects the air intake jets at the bottom of the carb. We may fool with it this year but he is going YZ so likely we wont get to it.

M5

BendBrapp · Sep 3, 2017

My experience from last season on intakes. I had purchased a used/demo Timbersled ST with TSS. I mounted it up to a 17' 450sxf. I ran the TSS snorkel intake for most of the season. With a little ABS shrouding and trucker tarp, I was able to keep the intake happy on the light blower powder days.

After some time with my PR2 ECU, it was recommended I modify things to go back to the stock intake. Right around this time I found myself riding in snow that was numerous densities and moisture content. The TSS intake became inundated and performance suffered. I had bushings made to flip the TSS shock, and modified a new factory air box. Removing minimal plastic, resealing the hole, and sealing all factory air intake ports was completed. I then installed numerous snow blocking inlets to both sides of the airbox. The inlets were part of a Ski-doo engine venting kit. This resulted in cleaner and more power throughout the power band and never had a intake issue again.
PR2 has dyno proven numbers of the stock intake vs TSS snorkel. I'm guessing the length and shape drastically affect power.
Here are a few pics.

jrlastofthebreed · Oct 31, 2020

Thought Id bring this up again with all the intakes advertising HP gains. Does anyone have any DYNO charts or direct comparisons between different snorkles and stock? Can you list the bikes they were on as well?

wwillf01 · Oct 31, 2020

I don't have anything recorded but we lost hp with the snorkel type... that being said if it does not stuff with snow its always better than stuffed with snow... with the Selkirk I was able to keep the intake filter dry enough we ended up using a basic k and n cone filter with a dryfilter... it was worth 2 hp over any option. This was on an modified 18 450sxf.

Sent from my SM-F916U1 using Tapatalk

n16ht5 · Oct 31, 2020

I have a pod directly clamped to the throttle body, but wonder if a 2-3" silicone adaptor to a pod would act like a velocity stack...

wwillf01 · Nov 1, 2020

I use a metal velocity stack of about 2 inches... about a horse or so but it all adds up

Sent from my SM-F916U1 using Tapatalk

cisco · Nov 1, 2020

BendBrapp said:
My experience from last season on intakes. I had purchased a used/demo Timbersled ST with TSS. I mounted it up to a 17' 450sxf. I ran the TSS snorkel intake for most of the season. With a little ABS shrouding and trucker tarp, I was able to keep the intake happy on the light blower powder days.

After some time with my PR2 ECU, it was recommended I modify things to go back to the stock intake. Right around this time I found myself riding in snow that was numerous densities and moisture content. The TSS intake became inundated and performance suffered. I had bushings made to flip the TSS shock, and modified a new factory air box. Removing minimal plastic, resealing the hole, and sealing all factory air intake ports was completed. I then installed numerous snow blocking inlets to both sides of the airbox. The inlets were part of a Ski-doo engine venting kit. This resulted in cleaner and more power throughout the power band and never had a intake issue again.
PR2 has dyno proven numbers of the stock intake vs TSS snorkel. I'm guessing the length and shape drastically affect power.
Here are a few pics.

i am thinking about doing same thing and cut bottom out to let snow out . drill side cover and out frogsking material . all my friend hare telling me to go C3 intake and gut the stock plastic out . ktm 500 2018 on yeti 2021

Info for building an intake

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It seemed like a good idea at the time

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