How to adapt the LTR tube?

[Duster]

OK... welcome to the KFX450R "XC Intake" mock-up #1...


I had to start somewhere, and since I could not see a huge difference between the FuelATV intake and the FCI intake (for woods use) I decided to do my first mock-up on borrowed parts I could modify/adapt easily. Rubber tubes, adapters/flanges, and hose clamps just make them easier to work with for the first try.

I was going to go with the 400EX tube, but decided to pick up an LTR tube also. I want to get them both here side-by-side to evaluate. I may pick up an LT500 tube also.


But anyways, since a lot of people have adapted the LTR tube... please tell me what I will need to hook it up to the throttle body.

It sorta looks like it might not reach? Might have to couple the throttle body rubber tube and the LTR tube together with a section of solid pipe/tube to clamp to?

Is the KFX rubber booty and the LTR tube small end the same size?
(2" I.D.???)

What is the large end diameter on the LTR tube?.... 3"????

[tscracing]

I forget the actual dimensions, but I made a aluminum adapter to connect the stock kawi rubber boot to the LTR boot. I then made a aluminum ring to fit inside the large end of the ltr tube, which then fits inside the stock rubber adapter at the front of the air box. without the ring, tightening the hose clamp at the box would collaps the ltr boot. You have to move the whole stock air box towards the back a few inches.

[Duster]

OK... now question is.... is the Kawi boot and the LTR boot the same size where you used the aluminum adapter?


As far as the box, I'm going custom.
But I would like to know if the box end of the LTR tube is 3" ?
(it's not here yet to compare to the EX tube)

Anyone?

[tscracing]

I will have to check, but I know that it is close.

[KAWIRYDER]

I was thinking that someone had explained how to do the ltr tube and had pictures with a detailed materials list on here.

[Duster]

Quote: Originally Posted by KAWIRYDER

I was thinking that someone had explained how to do the ltr tube and had pictures with a detailed materials list on here.

I thought so too...


For the record, it turns out the TB end of the LTR tube is 2" ID and the filter/box end is 3.25" ID.

Each end has a 1/4" step-in though...
About 3/8" in on the TB end.
About 5/8" in on the filter/box end.

So with some trimming of the ribs on the tube for clamping, it's pretty adaptable.

[Duster]

Now, here is the LTR tube v/s the 400EX tube.

The 400EX tube is overall larger. It's longer and straighter.
It has more large diameter area too.

But I'm not sure the path would actually be any straighter once actually hooked up... and it's not really round the whole distance... more oval.

I don't know which one will make more power, but I think I am going to build the first mock-up off the LTR tube. Then I may build another on the 400EX tube... or another tube/hose... or a custom formed aluminum tube.

I would have started with the FCI tube, but the information on the tube was not really "forthcoming" I guess you could say... and to be frank, there is just not enough difference between anything from plain 2" to the FCI to matter that much on a first mock-up... or for woods work in general I don't think. The difference is way up high in the RPM range past peak.

Anyways, I can't get any further on this because I can't seem to get my damn bike back from the shop!

Here's the v/s pics...

[KAWIRYDER]

So duster from what you can tell which one will be a better fit?

[Duster]

For what "I" want to do, I "think" the LTR tube will be a better fit.

I think the 400EX tube would need like an adapter with a 22.5° turn or something.
Not a big deal there.

It looks like it would push my box connection BACK an additional 2" beyond where the LTR tube will though. And that might cramp what I want to do. I'm not sure though, because I don't have my bike here for a dry-fit.

I may end up trying both to see what the power difference is, if any.
Length, shape and diameter are all part of how they tune intakes for max performance.

[Duster]

The LT500R tube is still out there to explore as well....


Like I said though, from dynos I have seen of various tubes and filters...
Man I really don't see a massive difference.
Not for an XC intake anyways...

Guys running drags, dunes, and MX... well the larger diameter and tuned shape of the FCI tube really seems to be in favor on those hard pulls clean to the rev limit in every gear. Maybe as much as a pony or two way up there...

I would have tried the FCI tube... I just couldn't get enough info for a starting point.

But there again, those drag, dune & MX guys really don't have a need for what I'm doing here, so....