I've noticed when my TB's are closed (no throttle) there is no air able to get through at all. There also doesn't seem to be an
adjuster aka carbs. GSXR ones I've just listed for sale seem to be the same.
How does MS handle idle? Does it need an air bleed to tickover at closed throttle position?
Thanks,
Steve
Sounds like the throttle stop screw is missing.
Idle works the same as with carbs, speed adjusted by throttle stop screw.
The air bleed is to speed up the idle when cold by allowing in more air, but thats all.
Edit: you can see the stop in my throttle bodies below. Screw with the plastic ribbed screw on
[Edited on 3/11/09 by flak monkey]
quote:
Originally posted by flak monkey
Edit: you can see the stop in my throttle bodies below. Screw with the plastic ribbed knob on
Like they said re-idle air. There is an adjuster to leave the butterflys just open a tiny tiny amount. This seems to be standard on GSXR600,
GSXR1000, zx10r. Actually my gsxr1100 carbs had the same mechanism.
Regarding IAC (Idle Air Control) with MS on these it is tricky!
GSXR600 have a manual cam that has a cable that opens the throttle slightly. I have used that and connected it to a choke cable (a la bike). I tried
connecting this to a central locking servo and was going to drive that from the MS, but that servo wasn't appropriate (I decided I was just
building in future problems).
On the GSXR1000 there is a cam on the end of the secondary throttle spindle. This does the same thing as the GSXR600 cam, but is under computer
control. Unfortunately there is a drought of knowledge concerning driving the secondary butterflys so the trail is dead.
If you are using Alpha-N (and so don't need a MAP take-off) then you could use the pressure sensor take-offs and let extra air in that way with
one of the standard MS solutions. The problem with this is that you don't get masses of air in that way (although maybe these could be drilled
out).
Matt
Hmm, they have got lift up jets much like the choke on carbs that allow air through.
This had a plunger on it that I suspect was connected to the coolant circuit to act like a choke...
that bit has the cable adjuster much the same as the carbs.. I took it off cause it fouls the ST injector rail.
Were the throttle cable attaches has blind screws locked in...
[Edited on 4/11/09 by coozer]
where did those TBs come from?
They don't look like GSXR to me (well not the early respaceable ones that I have got).
I guess different ones use different approaches.
Matt
They are Honda CBR1000RR body's, less work than the GSXR ones I'm selling...
Sussed it, idle control... had to ditch it caused it fouled the ST fuel rail... a rethink needed here me thinks....
I'm glad you sorted it out.
The CBR1000rr come in 2 pairs don't they. ALso don't you need the right adapters for the inlet manifold? Any other tricks in using them in
a car?
It seems that with every iteration the throttle body designs get better.
(i.e. no secondary Throttles on first GSXR750, secondaries and manual fast idle on early gsxr600, control of fast idle from the secondaries on
GSXR1000), unfortunately as time moves on the parts are less interchangeable and flexible. It isn't a great surprise that they get cleverer and
more specific to their intended application, but it would be nice if they could gain functionality whilst also being easily integrated in our
project!
Idle control isn't so clever on the GSXR ones, a separate fast idle circuit would be an improvement.
Matt
2 pairs Matt? Theres two pairs of injectors, one set in the body's and another row along the back of the air box pointing straight down the
inlet!
As far as the inlet goes I've just used silicone hose but doubled up the tubes on the inlet with a sleeve over the original. Apart from that,
pretty much the same as any other.
The bodies are conventional with 1 butterfly and trumpets! Thats why I've used them instead of the GSXR ones.
The fast idle is separate with jets opening to let more air in. The throttle adjust cable was on that circuit allowing air in at idle...
Just need to make it work on the car without fouling the ST injector rail...
Steve
good to hear that this is going to work for you.
By two pairs I meant that they weren't separable into 4 separate bodies, but that 1 and 2 were connected, and 3 and 4 were connected. That can
make spacing difficult for some installs.
I am familiar with the second set of injectors, actually i am thinking of picking up a pair and popping them onto my engine. Megasquirt can control
it easy enough, and there is supposed to be a bit of a power boost.
The only issues is that I would need to build a new air box (not too bad), and that I am a little bit worried about the potential fire hazards
Matt