Suzuki GSXR 750 quad Throttle Body Install on 2.3 L Duratec

[JohnStranahan]

I polished the ID with 8 inch long by 3/4 inch wide Sanding Cloth Strips wrapped around a 1/8 inch brass shaft about 2 inches long in the Dremel. The high air flow produced by the single flap wheel allowed the ABS to sand to a fine white powder instead of melting to black furry balls. Worked 'Great. There is a nice smooth S bend in this runner.
John

[JohnStranahan]

I built the airbox top bracket with a heavy steel strap. The strap uses an existing nut that Suzuki plastic welded into the cover. There will be a second bracket at the very bottom of the airbox attached to the engine. The two vacuum ports in the box will be used to connect up a vacuum can. The center inlet is the original Positive Crankase Ventilation (PCV) or crankase vent for the motorcycle. I will use it for the same purpose except it will feed into a can instead of a small semi open filter compartment that exists in the box. The second inlet will be routed to a large manifold vacuum port. The combined Manifold Absolute Pressure and Temperature sensor MAP will attach to this can through the top of the box for easy access.

My thoughts are these. The crankase vent on the Focus feeds directly into the manifold which is past the single throttle body. This imperfect vacuum is what the MAP/Temperature sensor reads. A large vacuum port size will insure good vacuum. The fact that the can will be inside the airbox should give a reasonably close to factory temperature reading.

The strap needs some paint.

Note I received my new narrower 5/16 x 2.25 inch maximum clamps. This really improved the appearance and connections for the shortened throttle bodies.

The interior porting and polishing of the intake manifold is complete. It needs just a small touch to a couple of ports after mounting the throttle bodies for a close contact fit.
John

[hemet2.3]

SO SO buitiful.

[fbmx24]

This is great, I love seeing stuff like this. Reminds me of the set-up I have seen on some of the old corollas.

[jon.k]

Amazing work John.... This is such an interesting thread, I love seeing your work.

I do have one question though.... I noticed in the pic of your manifold with all 4 TBs going into that intake housing and being fed by that 1 inlet..... Why did you decide to go with a single intake housing leading to each TB instead of exposing each TB out something like this:




I'm sure you know what you're doing but just wanted some clarification....

[iwannagofast]

To filter the air?

[brads03zx3]

He is using the stock MAFS.

http://forums.focaljet.com/6347280-post6.html

[JohnStranahan]

Thanks for the posts and positive comments guys.

The question is mostly answered above. I'll add a bit. I plan to use a larger Cosworth Mass Air Flow Sensor (MAF) tube with the stock Ford Computer and MAF plus a tune. The single inlet is thus required to meter the air. To have multiple inlets in say an oval air filter housing you would need an expensive after market computer to replace the stock computer; this computer would use a fuel map alone to run the motor and would not need a mass air flow sensor.
In addition I plan to keep most of the emissions features of the stock engine including EGR, idle air turbulence, ability to run in a closed loop where the engine computer uses output of the O2 sensors to continuously remap the fuel curve. In other words the computer learns as you drive.

Right Now I am working on a vacuum chamber that I plan to plastic weld into the upper portion of the inlet housing right where the housing has a stock chamber for the motorcycle crankcase ventilation. This will have a large port to engine vaccum from each manifold runner and will include positive crankase ventilation air and possibly idle air motor air. It will hold the combined Absolute Manifold Pressure/ inlet air temperature sensor through a hole at the top.
I am still thinking about this a bit. I am looking for some vacuum hose barbs that would be suitable to use in the plastic manifold on the bottom side. I don't like the 1/4 inch hose barbs that require a huge (1/2 inch or so) threaded hole much.
john

[phongshader]

I have a quick question on the orientation of your throttle bodies. I hope I'm mistaken but it looks like you have them mounted backwards on the manifold. Aren't the injector bungs supposed to be pointing in the direction of the head? The throttle bodies taper from 52mm to 42mm into the intake manifold so if they're backward you'd lose a whole bunch of effeciency. Please tell me I'm wrong!!

[JohnStranahan]

I found a photo of these bodies on the motorcyle engine. It appeared that the secondary throttle plates were inboard of the primaries. The primaries are a gold color, the secondaries a steel color. I have seen other pictures as well as a video of different models with these reversed.

In any case I have removed the larger diameter portion of the throttle bodies. They are a straight bore now. The injector bung will only be used to inject Exhaust Gas (EGR) so fuel delivery is not affected. The stock ford fuel injectors in the head will be used.

This orientation puts the throttle linkage where the cables are and improves the appearance by putting EGR plumbing below the throttle bodies out of sight. I can clamp them on either way though.

I measured the part I cut off. It is 44 mm Id on one end and 49 mm ID on the big end. The 44 mm ID is now at the Manifold inlet. The taper is removed for the most part.

John

[jon.k]

You're wrong..... there I said it! hahaha

I'll let John answer that one....

[ZX3TUNING]

LOL @ Jon.K

[jon.k]

Good one! (Y)

[PCP_TwilightZX3]

this needs more mass production immediately

[jon.k]

John, do you have the scematics for this??? you might be able to make some money for those Duratec people out there. I would imagine this would fit both the 2.3 and the 2.0?

[Lifeguardjoe]

subscribed

[JohnStranahan]

Jon.k-Not sure what is wrong or what needs explained?

There is a rough schematic drawing of the manifold earlier in the thread. Don't really know if it is going to work well yet. Getting closer. Probably will be a Christmas install to test it. I purchased the large vaccuum barbs, 3/8 hose x 1/4 pipe. These have about a 1/4 inch hole. Installed through the bottom of the plastic manifold they will supply sufficient flow to keep a good vacuum in my vacuum tank. This is all to feed the combined MAP/Temperature sensor values close to what the stock engine manifold provides it.
John