HAILERS2

There's an argument on another forum going on as to whether a JDM.........I said, JDM turboII throttle body has or does not have the double throttle diaphram and the cam/damper/spring and rod set.

So if BUMPSTART or ANYBODY out there has a jpg of a JDM throttle body for a TurboII engine..............please post it. Like I say, we're interested in wheter it has a double throttle diaphram and the linkage to the number two set of throttle plates.

One fellow says his JDM has no double throttle diaphram and the number two secondary plates open and shut exactly at the same time as the primary throttle plate and number one secondary throttle plates. He says his number two secondary stay wide open no matter what the conditons are. I'm just curious if this is so.......and why would JDM have number two secondary plates if they stay wide open all the time.

87 t-66

iTrader: (133)

i can get a pic when i go home for lunch in a couple hours if nobody has posted one

87 t-66

iTrader: (133)

$40 if anyone wants it

beefhole

iTrader: (29)

Off topic...
I actually found an S5 TB with a mechanical OMP linkage, and a thermowax with that weird vacuum router. Thing is, the thermowax was definitely S5 as it had the firewall facing coolant hose pipe. I can post a pic later.

RotaryRocket88

iTrader: (7)

Is that an S5 throttle body above? I can take a picture of my S4 JDM TB later. The tertiary throttle plates are connected to the same linkage as the primary and secondary plates, but it has an interesting little delay valve that forces them to open later/slower. It's a triangular metal diaphragm that sits on the bottom/front of the TB.

beefhole

iTrader: (29)

That's an S5 TB above. It has the firewall facing thermowax pipe and the throttle stop screw has that "cylinder" on it.

HAILERS2

Thank you 87-T66. Those two jpg attached are what I was looking for. The first one shows the flat black cam that rides on the nipple of the dashpot and also shows the spring/rod linkage to the number two secondary plates whos function is to delay the opening of the outer set (number two secondary) of plates when you step on the pedal. That part of the throttle body has nothing to do with the double throttle diaphram which I notice is missing on that JDM throttle body like a person on another forum mentioned.

The second jpg attached shows how the outer set of secondary plates are closed and will not open til the pedal is stepped on and then they will open a touch after the number one secondary plates due to the black cam/damper etc.

Thanks to all. And, yes, if Rotary Rocket88 can post a jpg of a series four JDM turboII throttle body, please do so. Much thanks to all.

S2-13BT

I have a S4 JDM throttle body sitting on my bench... Thing is, i'm doing the 'dreaded' TB mod so it's all in bits... It's all there though.

Can take pics if needed. My car is a S4 imported from Japan to Aus, so it's all JDM.

HAILERS2

Yeah, please do if you can find the time. I notice today there is a post by a fellow with a turboii and he needs to up his idle (his BAC has been removed) and I suggested he find his throttle stop screw and backoff the 8mm size nut on it and turn the screw into the linkage to increase the idle speed. Unfortunatley I don't have a jpg laying around right now showing that stop screw so I just gave him *words* to up his idle and no jpg. Thank you .

bumpstart

later JDM still has the wax cam,, just lacks the vacuum thermoswitch and double throttle dash pot that holds off secondary operation when cold

warm,, the throttle delays work all the time ,, following behind the main throttle plate movement
and is set via the dashpot which adds drag to a black plastic bob weight

these are found on N318 updates and also on s5 n370 ,, though there is trivial differences in the two TBs and they are not exactly the same
( mainly TPS differences,, but s5 TB also requires a shorter mounting stud on the bottom of the pattern to the UIM )




early s4 t2 ( jap and aus ) have a wax cam ,, and a thermoswitch ,, and a double throttle diaphragm which allows vacuum to hold out secondary delay operation when cold

- but as above,, the secondary delay throttles always follow behind the movement of the primary throttle
they are never locked in the open position
and,, in mazda words,, is provided to prevent a lean condition during rapid acceleration

these TB's are less common,, but are obvious to ID from the added vacuum can that is working on the delay mechs

i seek these TB's out,,, clever use of the vacuum delay , hooking it to primary runner vacuum ,, amounts to boost / load demand secondaries ,, something akin to the way the secondaries work on the old nikki carb
this will do wonders down low for a motor with large ports,, or a 6p turbo

HAILERS2

i seek these TB's out,,, clever use of the vacuum delay , hooking it to primary runner vacuum ,, amounts to boost / load demand secondaries ,, something akin to the way the secondaries work on the old nikki carb
this will do wonders down low for a motor with large ports,, or a 6p turbo
************************************************** *******************

That's a fact. You made my 6P turbo a useful car again by me doing that. Next to Casey Stoner your my Aus hero (humor, please)

Japan2LA

iTrader: (256)

My favorite TII TB is the one from the JDM N337 engine..

Best of both worlds with that one...

j9fd3s

iTrader: (3)

actually a really nice upgrade for the s4's is to buy the S5 thermowax unit. it goes right on.

RotaryRocket88

iTrader: (7)

Here's my S4 JDM throttle body. It's on the car, so these are the best shots I could get. The engine did come with low impedance injectors, so I would assume it's '87-'87.5.





The delay valve on the tertiary plates has no vacuum hookup like you would see with the US double throttle setup. The plates move regardless of engine temperature. The black plastic piece sticking out the side of the valve/diaphragm is a vent to allow it to pull in/push out air.

This TB doesn't match either of the descriptions bumpstart gave, so there may be a few variants out there.

HAILERS2

Rocket88 ............does your outer set of secondary plates delay opening or open the same time as the inner set of secondary plates? I assume there is a delay and that's what that triangular outfit with the black vent is all about.

That spring with rod is what my series four USA delay the opening of the outer set of plates. Those items plus the flat black cam riding on a damper.

I was unaware of all these types of turbo throttle body. Seems they all have the delay of the outer set of secondarys though. No sense in having a outer set if they open the same time as the innner set of secondarys. Thank you .

bumpstart

rocket 88 shows the early TB i describe
,, though the triangle vacuum pot is usually hooked up to a vacuum from the primary runner ,, and a NRV in the hose ( and vacuum thermoswitch )
so no boost can be applied to it ( in contrary to how i hook them up )

there is two variations that i have seen with that triangle pot , one sans plastic bob-weight
and a model still with it , both had vacuum and NRV and vacuum thermoswitch

the variation with the bleed cap over it is a third ,, suggest that one of them may be for auto transmission
( a jap only s4 thing , oz cars didnt have the t2 s4 auto option )

if i get a chance later i will get some pics up


and another one for you,,
have you guys noted the TPS orientation on ( i think ) vert s5 TB's
there is a variation that swaps the outer and inner positions of the two TPS
, the bracket is bent differently,, and the cams arranged to rub correctly on the new TPS positions

arghx

iTrader: (3)

I suspect the vacuum delay was on automatic transmission equipped JDM cars. I know the auto transmission USDM (only nonturbo was available with A/T) have a vacuum delay system.



So you have a vacuum line from a primary runner going directly to the double throttle vacuum diaphragm? Or do you have a one way valve in-line so it only sees vacuum? I'm tempted to try this.

bumpstart

it is interesting that many diagrams show the dash pot with two vacuum lines ( and two diaphragms )
,, but i have never seen one in the flesh that wasnt on a NA TB
the T2 Jspec stuff is see ( import engines here are common ) either have a single type vac pot ,, or none at all


for setting up the boost delay secondarys-

remove the NRV,, so primary runner vacuum holds them shut
,, load releases the vac pot and allows the secondary delays to follow slowly as far as the primary is open
( set the amount of drag from the dashpot )

boost will amount to blowing the secondary delays open
( as far as the primary throttle blade angle allows )
and so defeats the delay mech

setting it up can occasionally be tricky
,, selecting the wrong port ( purge , or from the secondary mezanine ) from phelonic spacer can amount to a car that tries to accel when you lift throttle
and some engines may be prone to a sort of cruise control 5th ,, ie,, lift off and the car tries to continue at that speed
clutching in releases the engine load and the problem stops

these are cured with a T and pill bleed ( to the purge port ) , or a pin ***** in the vac line to the vac pot

HAILERS2

On my six port turbo car that had no torque whatsoever below a couple of grand, I took Bumpstarts suggestion. I just ran a vac line from the bottom nipple on the back of the throttle body directly to the double throttle diaphram.

Now at idle the vacuum keeps the number two set of secondary throttle plates closed all the way and keeps them closed for quite sometime when driving from full rest. Acting like what the aux port actuators did to a lesser extent and made my six port turbo a useful vehicle when just driving in the neighborhood to go shopping etc.\

I use nothing in the vauum line. No check valve etc.

S2-13BT

Here's my S4 JDM in bits...

S2-13BT

...And some more

S2-13BT

Last two.

bumpstart

s4 with the triangle vac pot , and sans any plastic bob and dash pot

it is entirely feasible this is the TB that that is of controversy as in the OP
the spring mech is still there,, just the plastic bob and dash pot isnt ,, and if the vac pot is also removed then the secondary delay throttle will work very closely behind the primary throttle
-- however it will continue to mimick the primary throttle position and never go WOT by itself without the primary throttle also being WOT


s4 without the vac pot,, but with the plastic bob delay ( dash pot has been removed here )



s5 ,, without vac pot ,, but with plastic bob delay and dash pot


s5 ,, with a different vac delay,, and with the plastic bob delay

i have a few more including some NA ones buried somewhere -

having a look over them,, if the vacuum delay was intended to be hooked up ,,( auto )
then the wax cam mech will have the thermoswitch mounted into the large recess provided in its side

the same wax cam is used on the s4 and s5 turbo and NA variants
but the position of the coolant nipples changes
( a cast port is provided in each location,, the nipple will be pushed into the outwards facing port on s4NA and on s5,, and is in the port that runs parallel to the TB inlet on s4 T )


and here is the turbo TB mech stuff out of the aussie s4 workshop supplement
note the single diaphragm vac pot

bumpstart

sorry if image shack tries to deal you a pop up when you enlarge it

these following scans are also from the australian s4 workshop supplement , this time from the NA section
this has a bit more detail as to the intent ( having separate manual and auto version delays )

the NA section of the manual is at the front,, and covers things in more detail
,, while the turbo section deals only with the changes between NA and turbo and lacks the finer stuff

arghx

iTrader: (3)

So the nipple you used pulled plenum vacuum as opposed to vacuum from a single rotor? How much boost can the double throttle diaphragm handle before it breaks? It has to be able to handle 19-20 pounds max...