Jeff20B

iTrader: (13)

Is the thermo wax really needed? I'd kinda like to be able to drive it when cold.

Which hose goes to where? Does the waterpump hose go the the lower nipple on the TB, and does the hose from the rear plate go to the upper nipple on the front? Just answer with a yes or no. Thanks!

SPOautos

You can run the rear plate nipple to the back of the water pump or cap it off, either way. Dont run any coolant to the tb and just leave the coolant nipples on the top and bottom of the tb open.

I suppose your asking how you CAN run the coolant lines and not how they are run stock. Stock the rear plate lines goes to the top of the tb and the nipple of the bottom of the tb goes to the back of the water pump. What I told you above is basically just bypassing the tb and running straight from the rear plate to the water pump. Some people just cap the rear plate nipple off all together.

Stephen

Jeff20B

iTrader: (13)

Is it even needed for cold driving? Can I get away without it? From reading your post, it seems I can. I'd prefer to not use it if possible since it means one less thing to go wrong.

RETed

Do the "TB mod" to it and tune the stand-alone to compensate for the transition.


-Ted

Jeff20B

iTrader: (13)

Ah, my stand-alone does have fast idle solenoid control and warm up enrichment.

Is there a screw I can turn to diminish the thermo wax's influence over the throttle position? Also, I'd like to remove the secondary choke-like butterflies. Are they supposed to stay closed when cold or something?

I noticed something about the dashpot. It has no influence on my TB at the moment. It's as if the throttle isn't closing far enough to activate it. Is it being held open a little by the thermo wax?

Is there a link where I can read about the TB mod? Thanks.

Edit: I think I found it. http://fc3spro.com/TECH/HOWTO/TBM/tbm.html

RETed

There is a way to keep the damped double plates but eliminate just the cold-start thermowax system - just remove the fast idle cam but keep everything else.



-Ted

Jeff20B

iTrader: (13)

The vacuum diaphram thing on my TB was damaged in shipping so I removed it. Now those secondary butterflies can flap in the breese. Should I rig something to hold them open full time?

Is the fast idle cam the one with the screw that touches the thermo wax? Is it what you're talking about?

Jeff20B

iTrader: (13)

Ah, I see what you're talking about. This 'transistion' is a bit like going from vacuum secondaries to mechanical on a carb. It teaches you how to be a better driver, or to have an educated foot at least.

I capped off the nipples on the engine and will adjust the little screw to whatever is best to get a decent idle. Or should I remove the fast idle cam? Is that the fast idle cam? Or am I looking in the wrong place? Sorry, I'm about as familiar with the hardware on the TB as I am with a haltech.

RETed

Yeah, having them inconveniently shut on you while driving will make for...uh...and interesting driving experience; you'll lose power suddenly without warning.
At the very least remove the throttle plates and leave the shaft in...

That is correct.
It's is the half-moon thing with the adjustment screw that contacts the thermowax itself.
Remove this half-moon thing, and it will never trigger the fast-idle.
If you leave it in, there is a chance it will jam the throttle slightly open to make for an elevated idle which you cannot knock back down - kinda annoying. :P


-Ted

RETed

That is correct.
It kinda forces you to drive smoother.
At least with the Haltech, you can adjust the "throttle pump" settings which adjusts fuel delivery on throttle transient - anytime to jab at the gas pedal suddenly.
The Haltech can minimize or eliminate this "bog" due to the throttle abruptly opening.


I would recommend to remove the fast-idle cam.
It sounds like you got the proper part.

Here's the problem...
To remove the thermowax itself (3 screws?) will expose one end of the throttle shaft.
So, if you remove the throttle plates and shaft, this leaves you with a big hole in the side of the throttle body.
On the TB Mod, I plugs these holes with 1/8"NPT plugs - drilled and tapped.
With this done, you can remove any other non-essential hardware off the throttle body.

If you don't go through all of that, this implies you need to leave the thermowax in.
If you change the coolant flow, this will not melt the thermowax to disengage the fast-idle cam.
Thus, at the very least, remove the fast-idle cam off the TB.

Hope this helps!


-Ted

Jeff20B

iTrader: (13)

Ah, now I understand what you're talking about. It looks like the fast idle cam is held on by a circlip. I'll go ahead and pop it off. I'll also remove the plates from the secondary throttle shaft.

When the throttle closes all the way without the fast idle cam being there, does a lot of air get sucked through the nipple at the bottom of the TB? I wanted to connect it to my oil filler tube. Is this a good idea for PCV?

Jeff20B

iTrader: (13)

I removed the secondary blades and the shaft from my TB. Since I'm not boosted, I temporarily plugged the hole with a vacuum cap. I left the thermo wax in place. I'll do the TB mod later. I also disabled the fast idle cam and locked it with safety wire to keep it from influencing closed and fully open throttle positions. I discovered that I couldn't remove it without removing the TPS. Therefore I pulled the sping up until it slipped off and then removed the smaller spring from the screw and spun it all the way down. It seems stable in its new neutral position and will not contact anything, even if excessive underhood heat melts the thermo wax.

I'll have to do a proper TB mod with internal smoothing, reshaping and removal of uneeded hardware some day. It's good enough for now.

Ted, did you do any TB mods to Sky's NA 20B?

RETed

Yes, it's been done.
Typically, for Haltech installs, I stuff the air temp sensor in one of the holes - usually rear one - and plug the other one.

The procedure is similar to the 13BT write-up I got on my webpage.


-Ted

Jeff20B

iTrader: (13)

Oh that's right; haltech comes with GM thermistors. Cool! I'm glad I took the time to at least remove my secondary 'choking' blades and shaft. If this engine produces anything over 200HP at the rear wheels, I'll be happy since I've spent so little on it so far.

Jeff20B

iTrader: (13)

One more concern and then I'll stop bothering you. How do I deal with getting a vacuum signal to my MAP sensor, fuel pressure reg, and brake booster? My idea is to hook the FPR to one of the nipples on the LIM like stock. Can I also hook the MAP sensor to the other nipple? I'm talking about the two nipples that appear to be connected down to the primary injectors. When I blow compressed air though one, the others seem to be connected.

For the brake booster line, can I hook it to the bigger nipple on the passenger side of the LIM? When I blow compressed air through it, it comes out of the two smaller ones on the other side, and up through the primary runners a little. My engine bay already has most of a brake vacuum line routed to the passenger side. It would certainly be convenient although maybe a little weird looking seeing an odd hose over there. Whichever you think is best.

RETed

Sutre, I think most of the fittings on the intake manifolds are after the TB - that's the key - after the TB.
This allows for a vacuum signal when the throttle plates are closed.
Watch out for some of the fittings on the lower intake manifold, cause some of them just run straight through the lower intake manifold and doesn't see anything from the intake path!


Our brake booster is connected to a custom NPT fitting that Paul Ko @ K2RD drilled-n-tapped with a brass NPT fitting.

We think the stock Cosmo runs an electronically assisted brake booster, cause we could find no vacuum fitting or diagram for it!



-Ted

Jeff20B

iTrader: (13)

That's cool because I have some NPT fittings and the taps for them.

How about if I added an NPT fitting in one of the secondary runners in the LIM for the brake booster, and either a small NPT in a primary runner for the MAP and FPR, Y or Teed together, or just try my luck with one of the stock nipples? Im affraid of reversion, but if it mostly affects the secondary runners, it should be ok. I'll have visual confirmation of the performance of the vacuum signal in my tuning software, so I have some options for the MAP sensor. For the brake booster, I know carbed rotaries have it on the rear secondary runner, so I'll probably just do that on this engine too. It worked when there was a carbed 13B in this car.

RETed

Take it from the "surge tank" from the upper intake manifold.
This gets you away from all the funky resonances from the opening + closing of the intake ports from the rotors and gives you the stablest vacuum signal.

I try to run all my vacuum hoses from the surge tank in the upper intake manifold.


-Ted

Jeff20B

iTrader: (13)

Ah man, mine's extremely close to the firewall. Otherwise I would have taken the vacuum from there. I'll have to think about it a little more.