So I got a good understanding of what worked and doesn’t work using GSXR TB’s. The first iteration was with the 04-05 gixxer 600 TB’s (38mm) on modified type 4 fuel injection runners. The design was flawed, but I still managed to make 35-40mpg on a recent trip! The manifold design looked good on paper, but reality is cruel mistress and I had numerous problems sealing them to the TB’s and it didn’t take a lot to pop them off the mani’s. The also had way to short intake length. So back to the proverbial drawing board.
- 06-07 GSXR 600 throttle bodies (40mm)
- 03-04 GSXR 1000 #24 injectors
- custom fuel rails, I made them🙂
- custom pulley (my buddy Devin on STF made it, it’s sexy)
- idle set screw from a 00-03 gsxr 600 TB (I just happen to have it laying around)
- custom bolt plates between TB’s and IDF manifolds (one of the guys in the club made them on his CNC plasma cutter)
- Spigot flanges (4), mates the TB’s to the bolt plate… KHS-004
- modified Weber DCOE 45 velocity stacks (4), silicone couples and bolt clamps
- fuel system is now all -6an, Performance Products FPR, black fittings, and black braided lines…sexy
- reused my cable linkage, but made a new custom bracket for the right TB
- some porting of the IDF mani’s and bolt plates
Sounds like a lot going on, but it was about a full days worth of work and it was for the most part all bolt together. The big improvement on the design is use of the spigot flanges and bolt plates. I get a real solid mount for the TB’s and it is fairly straightforward to mount to IDF manifolds, which also makes this setup universal for all the ACVW platforms both type 1 and type 4 engines.
I am using the 06-07 TB’s which are basically a similar design to the 04-05 TB’s just a little bigger. They also have 8 injectors instead of 4, so I had to plug 4 extra holes and I removed the extra rail mounts. There is still the extra holes to fill for the servo choke plates. The 04-05 TB’s use a progressive oblong pulley and the 06-07 TB’s use a round pulley. Devastator on shoptalkforums CNC machined me a very nice round pulley. I “modified”, AKA chop sawed the return spring bracket behind the pulley. That was one issue I didn’t get right on the 04-05 TB’s and had to use a extra spring. No extra sping on this version. I also didn’t like idle set screw I used on the first version. This time around I set screw from a junk 00-03 TB that I pillaged a pulley from. I had to get a oddball 5mm x .5 tap, mcmaster-carr to the rescue. That turned out awesome, it looks completely factory…nice!
The big problem is the 75mm center to center of the gsxr 600 TB’s and 90mm center to center of the IDF mani’s. The bolt plates are 3/8″ so there is room to do some porting. I only did a light porting to smooth the transition. There is still plenty of meat on the mani’s if I want to try and make a straight shot for the air. I’m trying to create some turbulence to see if I can get better atomization and vacuum. Seems to be working, I have more vacuum at idle and in cruise, but WOT I’m seeing atmosphere. I also make some paper gaskets for between the heads and mani, and bolt plates and manifolds. I went with a fancy hardware choice to mate everything up too. I used SS flat head cap socket bolts for the bolt plates, and metric flanged button heads for the spigot flanges. All are 8mm x 1.25, that’s the same size and pitch as the original studs on IDF mani’s.
I could have just modified the metal rails that are stock on the 06-07 TB’s and used the original injectors but I have a set of gixxer 1000 injectors that I have been wanting to run. The 04-05 and 06-07 TB’s use injectors with 11mm inlets. the 03-04 1000 injectors and most cars use 14mm inlets so now I have a lot more injector options. Also the 600 injectors are #18 and the 1000’s are #24, I have been wanting to try out e85, I now have plenty of inj overhead to mess with ethanol. The rails are extruded aluminum from RMR, I got it from their ebay store. It was $5 a foot because it was supposedly damaged, even though it looks fine to me. I used this to machine the rails for the inj http://www.rossmachineracing.com/injectortool.html a bit pricey but it does a fine job. The plan was to use -6an, so I used a 9/16-18NF tap on the inlet/outlet of the rails. There is supposed to be a grove machined for the oring AN fittings, I didn’t want to pay $300 for that so I just JB welded the fittings on. That is ghetto but it works well. The last step was to make a bracket to mount the rail to the TB, unfortunately the 06-07 TB’s only have one mounting boss per TB, so the mounting bracket has to be perfect or a car-b-que can result. When everything was done, I cleaned the rails up on my drill press using scotch pads, the result was a nice brushed finish.
The longer intake run and the bigger bore creates a sexy growl when I’m on it. I cruise and idle with more vacuum now, so much so I re-indexed all my maps to take advantage of it. I haven’t taken it on any big trips yet but I expect the same or better mileage. I do have a lot smoother midrange and did not lose any throttle response. The verdict so far is this version is all win. I have a long trip in another week of so, I’ll use my GPS to try and get a accurate mpg.
Here is a fun little video, that’s about 20 minutes of tuning http://www.youtube.com/watch?v=Mp4p3V3jKoA