dpf22

Ok, wasn't sure where to post this, so I figured I would put it here with the more adventurous and experienced crowd.

What I am doing with my motor is adding an actuator diaphram to actuate the third set of plates that cover the secondaries on my TII Throttle body. Its an S5 TB and I already have the mounting details figured out using components from an S4 N/A TB. What I am going to do is have my standalone open them at an rpm where I am satisfied that the airflow into the secondaries will be of sufficient velocity to not drop the torque. I would also be doing this a few hundred rpm before the injector staging point so as to make sure that there is air moving in the secondary runners before the rather large (1600cc) secondaries stage.

Basically I am wondering if anyone has tried this (or some form of it) and what their impressions were of how it worked (good or bad). I am just looking for input right now as my motor is still being reconstructed.



For anyone who would like to know, here's what I am doing with the motor.



Pineapple racing med. streetport primaries and secondaries on stock s5 irons.

Light cleaning of the intake manifold to smooth some of the bumps, transitions, and casting flash.

Med Street port exhaust ports, also pineapple racing (slightly advanced opening, better transition to port size)

Modified s5 trottle body, "ported", (smoothed the edges and transitions) and an s4 third butterfly set and diaphram w/bracket.

8.5:1 rotors

insert really big turbo "here"(GT3574 .96 a/r) Divided runner manifold as well.

Balanced rotating assembly (CLR Motorsports if anyone wants to know)

RX-8 Stat gears

Blah blah blah. The important parts are mainly the ports and the manifold really.



If anyone would like to give some input it would be great. I am one to experiment with things a bit. I am also up for discussion as to why this would/wouldn't work.



Anthony L.

hsmidy

ya might have some trubble running rx8 stat gears and older 13b rotors, just grab 20b stat gears

dpf22

Ah, but at the same time, there are several people running that combination without problem. I dunno, I have heard yay and I have heard nay. I haven't bought them yet as I am waiting for my rotors and counterweights to get back from balancing (that and money ).



Anthony L.

hsmidy

all the guys i know who are running rx8 rotors over here are using the same "breed" rotors and stat gears because of a difference in gear pitch.



plus if you got with rx8 stat gears the rear gear doesnt have an oring groove so you can either get one machined into it or run some silicon around it.

dpf22

Honestly I had never been able to confirm the gear pitch thing. If anything, I'll just buy standard hardened gears. It's not a huge deal really.

Any comments on the throttle plates idea. Seems to be a dead topic...





dpf22

hsmidy

as far as i can under stand it your throttle plate idea sounds a whole lot like a boosted 6 port engine, i dont know how much of an effect it will have but yeah maybe for the hassle of getting it running right etc it might not be worth it.

Jims5543

Contact this guy:



JR, at Just Racing Fabrications



772-343-0510



Tell him Jim sent you. He makes a FD throttle body that flows 30% more air.



I have one on my car and the low end torque is remarkable. Its seat of the pants better. Honestly its that good.



He is also modifying a FC motor to accept RX8 rotors and stat gears. It takes a bit of work but it is doable if done right.



He has no internet presence because he is too busy leading the way. If you catch my drift, too busy yo type about it and busy making it happen.





He is located in PSL Florida and is a good guy that is not cheap but honest.

dpf22

Actually, it took me all of about a half an hour with a couple of my throttle bodies and a drill and some screwdrivers to make the bracketry work. There really isn't much to it if you are willing to mix'n match parts. Also, it completely cuts the air off from the secondaries instead of making the secondaries larger with the 6PI actuators. 6port engines don't cut flow to the secondaries, they just change the profile and effective volume of the secondary ports, not runners. These are related, but completely different if you think about it.

Think of the difference between something like vtec and toyota's tvis system. VTEC changes cam profile to a much more aggressive profile once target rpm is reached (6port motor). Actuate it too soon, and the engine falls on its face (low velocity because of high lift and long duration lobe at lower rpm). TVIS (toyota variable induction system) found on the early 4age engines (my dad's '86 mr2 for example) has 2 runners per port. One runner is closed during normal operation and sub 4600rpm operation. Once 4600rpm is reached, they snap open. You get a noticable movement in the powerband and a nice change in the intake note as well. Open them early, and the engine doesn't fall on its face. It just has less torque and won't feel as willing to accelerate at low-mid rpm's. (some people would consider the afformentioned as falling on its face)

What I am aiming at doing with this throttle body modification is similar to the TVIS (or variable induction system) is to add some velocity by not opening the secondary throttle plates at all, say till about 3500 rpm (that is a hypothetical rpm btw).

You can significantly increase velocity by doing this (or so I believe) and keep torque up. it allows me to floor it without opening the secondaries untill I feel there is sufficient velocity to use them. I run a megasquirt for an ems and making the rpm based circut to do the job is as easy as a trip to radio shack for a tip120 transistor and some wiring monkeyness on the circut board. then all I need is a vaccum solenoid that is normally closed and opens when actuated. I have been running this system with good results for the last 2.5 years or so now (megasquirt) and actually use it for my e-fan circut and boost control circuit.

Also, a higher flowing throttle body makes no sense if the higher volume kills velocity. Thusly why I am making an experiment out of this. I won't be the first person who has done something like this, and have heard that the dividends are great in the area of torque where it counts.

BTW I am using an s5 intake manifold and doing this with the stock s5 turbo throttle body using components from earlier models. I would use an FD upper intake manifold, but matching the ports isn't something I feel like doing at the moment and I don't like the idea of adapter plates (too much turbulence in my mind)



Anyways, its late (or early) and I need some sleep.

Agree? Disagree?

I wanna know why .

I preffer to know why/how things work as opposed to just "knowing" that they do/not.



Anthony L.

dpf22

Pretty dead. Hmmm, thought there would be more people at least arguing about what they think about what I'm doing with the secondary throttle plates. Ah well.





dpf22

hsmidy

best bet man, do it and put up a dtno sheet of before and after....thatll get people talking