The layout is the same. The silver throttle plates are electronic controlled. They are connected using a single shaft to a large rectangular box with a wired plug. No idea on its function. It could very well be like a varioram causing an increased air speed at low throttle.

The brass plates are the primary setup. The injector will spray right on them at WOT. the way the TB necks down is different than mine. It appears to neck with a greater angle above the secondary throttle plate (upper) and less uniform(conical) as depicted in the picture. Other notable changes are that the two mounting rails are depicted on the right side. My TBs have them on oppesite corners and it ends up being part of the injector bung casting.

I think 38mm is kinda larga for 125cc/cylinder. I guess they don't want air flow to be the limiting factor. this might be why you need that secondary plate. Lots of air flow changes between 1500 and 13000 rpm.

The smaller butterfly is variably controlled for better mixing at low flow velocitie. There was a tech article on it in Motorcyclist or Cycle World when it come out. I've got the article saved somewhere...don't ask me to hunt for it. It'll take me weeks to get to it.

The the idea is not new, sequential butterflies have been used before. There is a large throttle body (like that used in single throttle FI systems) available out there. It does it mechanically with sequenced linkages.

I found more information about the setup. From a Suzuki site. ..

The injector is supposed to spray onto the plate.

"The individual injectors are positioned at a steep, 60-degree angle relative to the centerline of the throttle body throat, and are aimed so that the fuel spray hits the primary throttle valve when it is between halfway and fully open, improving fuel atomization. At smaller throttle openings, the air rushing around the partially closed throttle valve is turbulent enough to ensure excellent fuel atomization."

and here is some more about teh SDTV (Suzuki Dual Throttle valve.

"the SDTV system opens the secondary valve the right amount to match intake area to current engine operating conditions, maintaining optimum intake velocity, in turn producing more efficient combustion, smoother power delivery, and cleaner exhaust. The SDTV system works like a digital CV carb, and is especially effective in the on-off-on throttle conditions typically encountered entering and exiting corners."

that's cool info, Jamie. It should be noted that some of the suzuki ITBs have SDTV, some don't (don't know what years)

Here is a quick update on progress. I realize its been a while.

I have been waiting for a cost effective solution to adapting these ITBs to the heads. My design is simple. I used the PMO insulators that I currently have on my webers as a template. For those who don't know, they have the intake shape with a bump-out to cover the injection port. I am having them CNC cut in Al. I will then weld a section of Al pipe to these intake plates and the ITBs on top. Finding the right diameter Al pipe has not been easy. Also finding a local CNC machine was not easy or cost effective - until a good friend of mine told me they have one at his place of employment. He is kind enough to cut me some out for test purposes.

Once I get these parts I will weld them up, set the spacing and design a linkage. I am planning to use a weber linkage since its easy to find. MFI linkage is another option.

sounds good Jamie. Keep up the good work!

Jamie,

When you setup the ITB's to correctly orient the injectors the linkage attachment points are opposite one another.

http://forums.pelicanparts.com/uploa...1100295180.jpg

You are going to have to do some serious fabricating to the weber linkage or fabricate new throttle plate shafts to make this work.

I will be very interested in what you come up with. As of now I am scrapping the Suzuki ITB's and going with the weber throttle bodies as they mate up directly with the carb linkage

YOu are correct if you attach to the end of the ITB! However, when I extend the current throttle shaft I will make a new arm in the MIDDLE throat and attach the ball stud there. Should work as the weber shaft just moving everything back a bit and using a shorter connecting rod off the bell crank.

another option is cable driven. Its easy to parallel two cables.

I would like the weber setup but $$$ dictates my fun.

I'm bumping this back to the top to see if anyone ever continued with this idea. And what the results were if you did. If no one has gone further, and still has some GSXR 600 throttle bodys hanging around I would like to buy them as I have some ideas of my own ;)

Robert,

I have the system mocked up but not fully assembled. I decided to take my targa apart for paint and then my son arrived and has uprooted my time in the garage.

The biggest hurdle is the linkage. There are two solutions. One is fab an adapter plate that mounts the throttle bodies to a weber manifold. Then you can mount ball studs on the TBs and use a weber linkage. I have some parts cut in plastic for test fitting. The TB will fit directly into this part and will look similar to a carb or TWM setup when finished. Velocity stacks will be mounted to the tops on a similar flange to create an ITB sandwich. :)

The other method is to mount the TBs directly to the intake. This gives a direct shot but requires a bit more fab work. This setup will allow the use of throttle cables. You will need to mount a CIS linkage plate to the engine that will serve as the linkage rod to throttle cable connection point. A bracket to secure the cables will be fabbed that allows for cable tension adjustment. this route allows one to use a push/pull cable arrangment similar to the GSXR, though it does not gain anything.

For this setup I have some aluminum adapters that bolt to the head. i found some thin-walled aluminum tubing that has the same ID as the head. The tubing press fits into the adaptors. The TB is then welded to the end of the tubing. The TBs are then bolted together using spacers through the stock mounting points. Extenders are needed to connect the TB's butterflies. I have a few sections of tubing welded to the TBs and have mock fit them on a bank of heads but that's as far as I got.

I do plan to continue this project but it will be next spring before I get to it.

Here are some pictures of what I have come up with so far.

http://forums.pelicanparts.com/uploa...1161289544.jpg

http://forums.pelicanparts.com/uploa...1161290350.jpg

The adapter on the bottom is the stock 600cc Suzuki mount, the mounting holes are the exact correct spacing to fit the head studs, they just need to be opened up a little. The stack is an aftermarket item for Webers, and the inside diameter fits exactly over the top of the throttle body, the length is similiar to the set of T stacks I have, and they are available in various lengths.

You can also use the 750cc Mounts on the top of the throttle body, and then mount a set of MFI stacks

The injector shown in the second picture is from a Honda and fits as long as you use the Suzuki o-rings. There are quite a number of Japanses cars these use these type, I have a set from a Toyota Supra Turbo coming (440cc) as the Honda and Suzuki ones are a little small for anything more than ~ 200hp

I am just waiting for a couple of other prices I picked on e-bay to make and appearance, and then I will pull the current 2.2 out of my car and use it as a test dummy for fitting purposes, both with the weber manifolds, and straight to the heads.

I'll post something more when I hit that stage.

On an english site, I've seen a throttle set up that uses 2 cables (one for each bank of ITB's or carbs)
IIRC they modified the pedal and the cables ran over the center tunnel (race / rallye prepped 911s)

Where can you get those stacks? what is the price?

I bought them on Ebay, they are Empi's.

any updates here?

I am still looking for another set of 600 gsxr stacks, I paid $50.00 for the first ones but haven't been able to pick anything up lately as I keep getting outbid. May just have to bite the bullet and do a Buy it Now on a set of the $125.00 ones. In the meantime I was looking into what to use for the FI controller. Did some looking a MS but ended up picking up a Tec-1 complete with dual plug setup for a VG price from another Pelican. However the biggest slow down is the weather, and the house renovations. The weather because the car is in an unheated garage at the moment, and the house because I am spending all my free time on it. Hope to get back to this in the new year and try some things out on my old 2.2 motor.

I have finally had a chance to work on this again.

Taking a cue from TWM and their 3003 weber replacements which use the same spacing as webers and mount to weber manifolds I decided to try going that way as it puts the throttle bodys close together and should make the linkage issue easier to solve.



First thing I did was get a set of manifolds. I removed the studs, drilled the stud holes out and pressed aluminum rod in to fill the holes. I then used JB Weld to fill in the depression in the tops of the manifolds.

http://forums.pelicanparts.com/uploa...1173652567.jpg

Once that had dried I flattened the tops and drilled and tapped new holes to match the Suzuki Throttle body boots

http://forums.pelicanparts.com/uploa...1173652690.jpg

Bolted these down and then attached the individual throttle bodys. I used steel rod and washers to fasten them together at the proper spacing.

http://forums.pelicanparts.com/uploa...1173652798.jpg

This put them close enough that I could just bend the throttle tabs to reconnect the throttle shafts.

http://forums.pelicanparts.com/uploa...1173652851.jpg


One of the advantages of doing it this way is that you can use a stock air filter setup if you want, or standard K&N filters.

http://forums.pelicanparts.com/uploa...1173652904.jpg

http://forums.pelicanparts.com/uploa...1173652919.jpg

Of course you can also go a little wilder ;)

http://forums.pelicanparts.com/uploa...1173652949.jpg

SO what is left to do? Well I can use the stock cross linkage, but I need to fabricate some linkage arms for the throttle shafts on each end, and then make an appropriate length connection to the main shaft. But that should not be to hard. After that it is just a matter of fabricating a fuel rail and the usual required items for EFI. I haven't touched the weber manifold port sizes as I am going to test this on my 2.2T motor first.

I just need to find a 45/64 drill to tap my fuel rail for fittings. :)

I am going to try to pull my 2.2 out of the car next weekend so I can mock everything up on the motor. Hopefully I can get the throttle linkage finished and see how everything fits.

Thanks for the update. :)

What are you going to use for engine management?

I have a brand new MS-II ECU if you're interested.
:D

looking good. Im guessing now that you have the right spacing you can cut some spacers as opposed to using washers.

were you going to use the suzuki injectors?

I talked with a buddy of mine about this setup, hes into Megasquirt and said it would work no problem. So if TerryBPP is offering, that might be a good option consider.

Do these have the throttle body position sensors?

Thanks again for pioneering this and posting updates.