air box mods and boost pipe

[georgew4714]

Hey guys , i know there's alot of info on this but mostly in the early posts of this site where most of the pictures are lost.

The plan is to go up to a 1.625 ID boost pipe. Im planning on going to 1100 tbs next year and am trying to plan for the future . How have you guys modified the airbox to allow bigger plumbing ? My thoughts are to just open up the holes and weld in stubs to allow the use of straight silicone couplers . Also has there been any proof that moving the inlet to the middle of the airbox helped with airflow distribution ?

[tack1000]

Hello George

There are some parts on the bike that bigger is not always best. The transfer pipe is one of these parts if you're plan is less than 200 hp.
A 1.5" pipe would be better suited to keep the air flow high and the rubber inlet is that size as STD which makes it easy to fit.
Albeit the holder has the inner part of it dropping down to a smaller size.

Both Lorcan an myself have made way more than 250hp on the STD airbox, however we had different ways of getting the pipe into the box. His was on the opposite side but as per the STD inlet.
That being facing straight at the back of the box. Mine came in on the side (both on the right side to get a better flow from the IC) and I've also tried 45 degrees on both sides.

Although I've run some CFD models I've never tried any other airbox other than STD but with lots of different versions on the intake.
Non of which seam to be give a marked improvement over any other. Apart from the pipe size, that has been proved too big is not best.

So I recommend a 1.5" pipe.

[youngblood]

+1
I went down from 50mm (2.0) to 38mm (1.50) much improved response and tick over.

[Betterthanfabio]

I just measured the outside of a standard one and its a bit under 1 and 1/4 inch.

[georgew4714]

Thanks guys ! I had measured the stocker and depending on which inlet i measured did range from 1.09 to 1.187 inch. Also measured the id of the charlies blueprint stocker and it measured 1.250 also.

Your concerns with too big a pipe matched mine . I have heard and read people going to 1.75 - 2 inch and it not working out so well . That's the reason i was going with the harder to source 1.625 id pipe.

Just to be clear are you guys suggesting 1.5 od. with an id. of 1.375 or are you suggesting 1.625 od. pipe with an id. of 1.5 ?

[youngblood]

George

38.1mm OD(1.5in) = 35.1mm ID(1.38in) with a 1.5mm wall thickness that's what I use. This is Stainless tube not Aluminium?

[georgew4714]

Yeah 1.5 mm or .060 wall thickness is what i was going with. I am planning aluminum though to save a pound or so . Its a little easier for me to work with also .

[Mang]

Middle of the box makes it hard to get to the cm chain adjuster

[youngblood]

George

This is mine in stainless painted black?

[longfiredragon]

George, I to used the 1.5 mm OD aluminum with the 1.38 mm ID, I have had no issues, response seems to be great. In fact I believe it is one of the more noticeable mod.'s you can make in the way the bike makes power.

[georgew4714]

Ok guys , you sold me on the 1.5 " size . It's easier to source and if i can use the original rubber inlet to the airbox that's a big time saver. The ultimate goal is around 170-180 horse and i don't ever see my budget allowing me to hit 200 horse .
The airbox mods were more to do with how i was going to connect the bigger plumbing . Thanks.

Longfire , good to see you back around and boostin.

[georgew4714]

Was just thinking , what was the ID of Grumpys kit ?

[longfiredragon]

It is on here George, but just going by my failing memory, Grumpys were a 1.5 OD.

[Dirck]

~
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~~~Feeder thread here George ---> http://www.750turbo.com/forum/viewtopic ... =feed+pipe

[Charlie @ Evergreen]

G wrote:Hey witch, I think You mean 1.5" I/D, As it was made from 1 5/8 tubing. Glad you like it, quality is what I strive for.


Which is what my new setup building special. Waiting on powedercoat