GSX-R1000 ITBs

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GSX-R1000 Throttle Body and F22B1 Intake

These are a set of 2003 GSX-R 1000 Throttle bodies. Measuring 51mm at the trumpet and 46mm @ the throttle plate. Now some may say that these are the measurements for a Hyabusa, so be it, I got these TB for the price of 1000’s…cheap $80 delivered.

First sep was obviously to clean them up and get rid of all the bits that I will not be using.

They came with the secondary throttle bar still attached but not the the valves. I removed the bar and was faced with the fact that a hole in the side of the throttle bodies would not be a benefit so I filled the holes with JB weld.

Before JB weld
and holes filled
Well after doing this I saw that there was a bit of room to clean up the JB weld and maybe enlarge the throttle body opening.
So I honed them out about 1mm making them 52mm at the trumpet and 47mm at the throat.

Then polished them.
Then I had to go about deciding what to do with the stock GSX-R fuel injector locations. They could be of some use in the future, so for now I decided to just leave them be. Possible a future water/meth/N2O injection setup.
I did not make the injector bungs any bigger or modify the seal in any way.

The runners and stock F22 manifold.

This is where I started with a stock Upper and Lower IM.
After I disassembled them here is what I had to work with, got to love So Cal car parts not a spot of rust or aluminum pitting.

After a few hours of cutting, grinding and fine-tuning. I get my lower manifold ready for runners.
It was a long wait for my custom bent aluminum runners. You wouldn't believe how hard it was to find 1"7/8" I.D. aluminum tubing in this city. It's not a common tube size or material for refineries, paper mills or breweries. lol Not one shop in the city carried this tube size. After some searching I found some and have made my request for 4 14" pieces w/40°. I want my ITB runners with a bit of an angle.

Here is where it all begins, the hours of fabrication. These are all the parts that went into making my ITB's, Runners and Fuel Rail.


here they are with those unbelievable hours of fabricating and grinding to get the angles right as well as the curve. I had to make it so that there would be as little bend in the inside track of the runner as possible. Some may have noticed that the runners I started with were a lot longer...well that's how long I needed them to achieve the curve without being to badly crushed in the bender. The amount that they did flatten matched the oval shape manifold ports 100%. I now have enough pipe to do 1 or 2 more sets depending on the runner length. I only used one and a half of the four.

Fitted with the bottom half of my ram air GSX-R air box. All measurements were double and triple checked to ensure this thing will fit snug in the available space.
Finished intake and throttles. I had my runners welded directly to the throttle bodies. The runner length is measured specific to my engines target RPM range and VE%.It will make use of second wave harmonics at this length.
It looks like cylinder No.1 has a big bend from the outside. From the inside I was able to make it straight enough for what I want. Here is a valves eye view up the No.1 runner and throttle.

If ITBs aren't your thing. Why not try a larger throttle body.

Secondary Fuel Injection (Cumulative 2 Stage)

I made my own adjustable brackets and mounts so that I could fit the smaller GSX-R fuel rail and injectors inside the air box. I will be using the factory 240cc saturated GSX-R injectors.
Adjustable mounts to allow a bit of variation in the injector placement in the velocity stack.

The last part of the ITB induction setup was to cut the GSX-R air box so now it has one large opening vs the two separate openings it had and then fit the top to make sure everything fits.
It looks like a cartoon whale looking to swallow you up. I'm sure this should be more than enough of an opening.

Awaiting the completion of the hood scoop and the running of the fuel lines.

Looking for injectors?