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Discussion Starter #1
Hey guys I recently made and printed a intake like a chimera intake and I notice a very noticeable loss in low end. I was wondering if any other pod intakes like that have a noticable loss in low end or if it was just my design
 

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I think it depends on the length of the intake tube. If you look at the Dinger intakes, seems like the longer it is, the better it is for low end torque. The shorter the intake tube, the better it is at the top end. I think tooter (on this forum) runs a modified Dinger intake where he extended the length even more so that he gets more torque down since he's using his Grom to commute.
 

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Discussion Starter #4
I think it depends on the length of the intake tube. If you look at the Dinger intakes, seems like the longer it is, the better it is for low end torque. The shorter the intake tube, the better it is at the top end. I think tooter (on this forum) runs a modified Dinger intake where he extended the length even more so that he gets more torque down since he's using his Grom to commute.
Gotcha mine is pretty short
 

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Discussion Starter #5
Is this all you have done just an intake?

Length of intake runner...

Fueling...

Miles with new intake for Ecu to adjust your fueling...
Just the intake and reset the ECU and put quite a few miles on it to adjust. Nothing with the fuel or the length of the intake
 

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Most intakes are short to gain top end horsepower, but you give up low end torque to get it. Mine is extra long and my engine pulls from 3,000 rpms without lugging.
86088
 

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Most 3D printed material is highly permeable or porous... even the professional rapid prototype stuff. You may be running the equivalent of an extremely short runner.
 

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Yes, this was the point I was making.

Years ago I had a rapid prototype intake manifold made for a Kawasaki 600 4cyl used in an open-wheel car. The motor didn't perform anywhere near how I had modeled the flow when it was on the engine dyno and the reason for this was later determined to be the porosity of the prototype material. I wasn't guessing - I'm telling you this is almost certainly what is happening given my experience with almost an identical problem.

Intake length on these motors is huge... like nearly camshaft levels of powerband adjustment. I'm sure exhaust is too, but it's more challenging to tune unless you really want to mess around with pipe lengths and such.
 

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When we developed our Mtake, we did a LOT of testing, and it's SHOCKING how runner length effects the power delivery. Any downside you're seeing is a product of that and/or accurate fuel tuning. 3D printing often ourselves, I'd be Leary of running a 3D printed intake long term, due to possible breakdown w/ heat and chemical exposure.
 

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Intake length on these motors is huge... like nearly camshaft levels of powerband adjustment. I'm sure exhaust is too, but it's more challenging to tune unless you really want to mess around with pipe lengths and such.
It is.
I've been constantly experimenting with intake and exhaust design practically since the first day I owned my Grom. I went extremely long on the intake and discovered that the effect came on too low and too far out of the stock cam powerband. Shortening it to the present setup, the effect is night and day. I know this because with the shortened intake, the Winter gas mileage has consistently increased from 125 to 132 mpg, and the engine is even more responsive down to 3,000 rpm.

I understand I'm going exactly the opposite direction as everyone else, but I'm actually onto something. I've got a metal lathe arriving tomorrow and ordering a pulse TIG welder so I can pursue my ideas further. :)
 

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It is.
I've been constantly experimenting with intake and exhaust design practically since the first day I owned my Grom. I went extremely long on the intake and discovered that the effect came on too low and too far out of the stock cam powerband. Shortening it to the present setup, the effect is night and day. I know this because with the shortened intake, the Winter gas mileage has consistently increased from 125 to 132 mpg, and the engine is even more responsive down to 3,000 rpm.

I understand I'm going exactly the opposite direction as everyone else, but I'm actually onto something. I've got a metal lathe arriving tomorrow and ordering a pulse TIG welder so I can pursue my ideas further. :)
You're tuning the intake which is cool. I think of it like the SWVR (standing wave ratio) where there is a perfect length or like an instrument where the pitch is perfect when the resonant length is correct. This is why pulling off snorkel etc often makes things worse.
 

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Yes. :) You're exactly right.

The intake valve opening and slamming shut abruptly creates pressure/vacuum waves which travel to the other end of the intake and are reflected back again to the valve. The harmonious "scavenging" effect can push more air/fuel mix into the cylinder within an rpm range. The length of the intake determines the elapsed time, so longer is lower rpms and shorter is higher rpms. Most guys are wide open throttle winding out their engines to redline all the time, so short intakes (and exhausts) work best for them.

I found the sweet spot (3,000rpms to 6,000rpms) for how I ride just by hit and miss. I'd try one length and then another while logging gas mileage average as my indicator of efficiency. I can also feel the changes, but gas mileage works best as it can register results FAR more subtle than my seat of the pants riding. :)

Honda factory dyno tested their intake design to make sure it's best for all around use, so it's made that way for good reason.
 

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The single cylinder and (stock) 2-valve design makes it really easy to mess with this and see (and feel) immediate results with only 1-2 wideband logs and some quick fueling adjustments. The intake diameter and throttle venturi matters, as well.

I haven't reviewed the math, but the following page seems to summarize the fluid dynamics pretty well for intake/exhaust tuning:

 

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Any photos of your intake? Curious to see what you designed. Would be nice to see more options on the market.
 
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