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Inspired by supaninja and Dale M, I will post some progress on my own ITB project.

As an introduction, the plan is to convert my 1835cc that I have build entirely based on the excellent advice from this forum, to ITBs.

There are a couple of reasons why I want to do this, but the main one is that I want to use T1 stock cooling, and then my centrally mounted plenum will not work.

The plan goes something like this:

I have sourced a set of 40mm ITBs from ebay for around $90, and I here is a shot of one of the pairs:


I plan on using a set of standard IDF manifolds, and these little babies in stead of fuel rails:


Then, today, I finally received a set of spigot flanges from a local motorcycle shop. They totalled about $50 for all 4.

The diameter is perfect for the ITB:


And the bolt pattern is quite a good fit to the IDF pattern:


There are a couple of issues, however.

The first is as Dale also points out, that the cc distance between the barrels is smaller on the ITBs than on the manifold, so I plan on simply separating the ITB, and then elongate the throttle shaft.

The other issue is that the inner diameter of the ITB and flange is about 8 mm smaller than the IDF manifold, so there will be a step that probably is not very good for the flow, so I will give that issue some thought. I have a couple of ideas,, not necessarily involving jb-weld

The issue with cable vs linkage is still open in my mind.

So am I heading in the right direction here?

Awesome Grelland!

It might be easier to make weld plates shorten the manifolds just a little bit till they line up with the weld plates. That might also solve the ID difference between manifolds and spigot flanges.

Those injector holders look good, I'm going the more traditional route, but yours should be just fine.

I'm waiting on the Al plate to make my weld plates then off to the welder. I'm going to change the linkage on the right TB. I got an extra pulley from a older set of TB's laying around, that should be a simple install. My weld plates will have some extra length on it to bolt a bracket to it for the right TB.

I'm just mentioning all this to get the wheels turning in your head

Those look excellent.... What are boots for ???..... Suzuki wants $38 each for the ones for GSXR 1k ... IF the inside diameter of those are correct (48mm maybe), the price is extremely good, I think I will dive in for those other wise I was looking at used boots on ebray...

Dale

Dale search around the net for:

M-VM40-200K
or
VM40-200K

The ones I found are less then $20 a piece.

First hit-

I had a small hour in the garage today and after measuring and considering my options, I went with supaninjas idea, and cut down a standard IDF manifod to where the cc spacing is about right. As it turns out, the ID of the runners are quite close to the 40mm in the TB's so this will work well, I think

Here's the assembly stacked for a mock-up:



I cut the flanges off the piece I cut off, and these will be welded on top of the shortened runner:


I need to build up the ID with weld, as I want the ID to be smooth, and the flanges are way too large.

Seen from the side this gives extremely low manifolds:

These will probably be too short, but I will put some "air horns" on top of the TBs to get the proper runner length for this engine.

Next thing is the placement of the injector bungs, and I might end up with simple weld-in bungs and normal fuel rails, as the manifolds became so short.,...

So I have two options on placing the bungs; non of them are ideal....:

In my mind the top side placement is probable more to my liking....

Dale

I think that will be the only one that will work, as the manifold is so short. Look at the notch where the tin normally rests, I will need to place the bungs almost through the flange to clear the tin and shelves in the engine compartment...

Did somebody say air horns?



Those are temporarily mounted (silicone couplers and clamps that i had laying around), i took it for a test drive. Let's just say i'm going to be running without a engine lid for a while...they are friggin awesome!

BTW, I would try to mount the injectors on the outside if possible. If you can't fit them then just keep them in the TB's.

That's what I was gonna say, don't the TB's have a spot for injectors already?

ya but they are at a crappy angle, mine spray the bottom of my TB's.

Grelland, are those the CB TBs?

And what are those injector holders from?? They look awsome!

Max

Injector holders are found in this thread...

http://www.shoptalkforums.com/viewtopic ... 3&t=137760

Dale

Spray from the tangent (option two). Like the Vanagon angle.

Those manifolds look to be short enough for a type 3

They for sure would work in my type-1 KG.

Max