I've finally fitted my prototype airbox and done a road test. Before, at full throttle from 3000 - 4500 RPM it would growl protestingly but not pull too well. Suddenly at 5000 it would spring into life. Now it is "quiet" from 3000 upwards and power rolls on very smoothly. Success.

It pulls through the midrange well too. Freezing fog in the dark is not the best time to test it's effect on top end power but briefly in 2nd it didn't seem too bad.

I'm inviting comments and opinions.

It has a K&N filter in the box with tubes going into either end of the filter from the front and rear of the box. This is to give plenty of airflow into the filter. The two ends are 50mm ID and each of the 4 carbs is 40mm ID, so there should be no restriction on airflow. I'm just worried because one hole faces backwards.

What should I make the real thing from? Varnished 3mm ply is probably not good for long term use.

There are a couple more pics in my archive if you want to look.

[Edited on 21-12-2006 by smart51]
Rescued attachment airbox_rear.JPG

Seems ok to me. Would it be possible to run a cold air feed to the front of the car somewhere? This would sort any issues they may be from the backwards facing hole (although I don't think there are any) As per the material, 18/20 gauge ally would do the trick, you could either get it tigged somewhere, or use UHA (?) tape and rivets. OH, also ,good to see it works, as I may do something similar to mine, once it works.

Are you going to varnish or stain?!

quote:

---

Originally posted by Howlor
Are you going to varnish or stain?!

---

It's a shame you can't sneek that top piece a little bit higher- have you got a chokes worth of height between the top and bottom for the airbox where the trumpets should be? It would be a shame to strangle the breathing after all the hard work... Obviously bonnet height can be a limiting factor...

I'd cover it in a couple of layers of uni GRP with bi for the edges and leave it as is... Could even spray it up to make it look right pretty.....

Be careful you don't get any birds nesting in it

Do you have trumpets on the carb bellmouths?

Looks like he used the original rubber connectors which have a small 'bellmouth' type radius to them.

If you made a wooden frame, you could cover it with fleece and then cover that with resin/Glass fibre.

Not sure what the method is called but I believe its used alot by the bass boys to make their sub enclosures.

I'll try to find some sort of link

Edit: heres one


this is better


[Edited on 22/12/06 by scottc]

The top of the box is just clear of the bonnet. The foam filter that I had in there before actually touched the GRP. I don't have the trumpets fitted to the bosses for the same reason. If the low head room does restrict air flow, it's hardly any worse than it was.

I could GRP the box but I don't want it to be heavy. If I set my mind to it, I could just make a GRP box I suppose.

make it out of GRP, will probably be lighter than the plywood one, and you can sand and paint it the same colour as the rest of the car.
Just need to get the RAL number from Marc.

My airbox is standard Yamaha fare with a K and N filter...

I managed to cut out the port spacing plastic and then glue it in with steel reinforcement inverted and then recessed a further 15mm deeper into the airbox. This lowered the overall height of the airbox by 15mm.

I still needed to cut a hole in the bonnet but the box only protrudes by 35mm. This'll be covered with MNR's bulge.

This allowed me to use the standard rubber trumpets affecting low end performance. There is no way that I can see of using the standard trumpets and MNR's bonnet without cutting a hole in it...

Your effort looks good though Smart! Any way you'd consider cutting a hole in the bonnet to accomodate the standard trumpets?

Any chance you've got a picture of the internals of the box?

Chris.

Made mine from Aluminium sheet, then fibre glassed the inside, and sealed/rivited the top on.
Cold feed from the front through a remote filter.
Works very well with current standard jets, but only pulls to 10k, as it really needs re-jetting,

Steve
Rescued attachment Airbox.JPG

I don't want to cut holes in the bonnet, I don't like the look of scoops. I am going to try to make some sort of trumpet but obviously smaller than the Yamaha ones.

No pics of the inside. It's basically just a box. Nothing to see really.

quote:

---

Originally posted by smart51
I don't want to cut holes in the bonnet, I don't like the look of scoops. I am going to try to make some sort of trumpet but obviously smaller than the Yamaha ones.

---

Easy Fix, just use the std rubber trumpets and roll them over.
Gives you a nice rounded edge, doesn't cost a penny.
Mine have been fine so far.

Steve
Rescued attachment Trumpets.JPG

Its a good idea but I only have 3. I guess they're only about a fiver from a dealer. I might see if I can get another one.

I can't believe how much taller the trumpets are on the non injected R1. Mine are about the height of yours when folded over and the panel filter is still too tall

i have just fitted this to mine, it was a lot cheaper than a sbd or jenvy version and the filter was a steal off e-bay aswell


I havnt had it mapped yet but it was a doddle to fit.

Cheers Mark

The weather was a bit nicer today and so I've been out doing a bit of testing. The airbox isn't so goot at high RPM. In 1st. its hard to tell if there is any effect but in 2nd you can tell slightly that it isn't happt above 11000. In 3rd it is more noticable. You need a race track to test the other gears.

I guess that it is having to suck harder to draw the air in, creating more vaccum, drawing more fuel. Rejetting with smaller mains would work, restricting the fuel to match the restricted air. I don't want to do that.

The air inlet pipes are wider, shorter and straighter than on the Yamaha air box. The volume of my box is larger to match. It seems to fit the fact that 144 mains seem a bit big such that 140s awould probably be right. The stock R1s have 130s or 135s I think.

Would fitting small trumpets to the carb mouths and to the box inlet pipes help much or do I need a bigger filter/inlet pipe?

If possible, try to get a bit more space between the carbs mouths and the box, as this will seriously hinder air flow. You want to aim for a gap off at least the same width as the inlets (ie 44mm as a minimum, but bigger is better) Also, whilst 2 x 2" inlets is ok, having 3" openings would help eliminate any problems there may be.

Nice work Colin. Im definately trying to retain some form of airbox I just dont like induction noise to that extent.

Id be interested any pics of how youve done yours Winston, sounds like a good bit of DIY.

I noticed these and wondered how well theyd go if fed with cold air from the front - comments?

Rgds

Rich

[Edited on 24/12/06 by RichieC]

I've got about 38mm of room between the bottom of the bellmouth holders and the top of the airbox which is a bit less than the 41mm diameter. I can raise the lid of the box another 5mm and still clear the bonnet.

If I make some curved trumpets that angle away from the lid, that might help too.

quote:

---

Originally posted by RichieC
I noticed these and wondered how well theyd go if fed with cold air from the front - comments?

Rgds

Rich

[Edited on 24/12/06 by RichieC]

---

Im not sure how much gap there is above the filter element inside the box but it doesnt look like it adds much overall height.
Not even sure exactly how much space I have under my bonnet.

Rich