Alternative Throttle Bodies

[Captain Obvious]

What alternative throttle body options are available?

Weber (and it's clone).

240SX

Q45

Anything else? Anything that bolts up and has the same internal throat bore?

What about from other manufactures? Doesn't have to be Nissan...

[Zed Head]

Which intake manifold? The intake manifolds changed sometime around 1979 or 80. They actually went to a slightly smaller throat with a different bolt pattern for the 280ZX's. You can't run a 1981 throttle body on a 1978 intake manifold, for example (I have both).

[240260280z]

[Captain Obvious]

I'm talking about the 280Z intake. Something that uses the same bolt pattern as 75-78.

What I would really like to find is something that bolts on and has provisions for an idle air valve of some sort. I'm musing getting rid of my AAR and instead replacing it with something built right into the throttle body.

Nice video Blue. Looks almost like a pupil. Wonder what the performance advantage is. Less obstruction when fully open? More linear flow vs position?

[240260280z]

I have a mustang TB that I bought in my early Z days before I was mechanically inclined. I'll try to dig it up and check dimensions. I'll try to take pics.

I am guessing that making an aluminum plate to adapt two different patterns would be all that is required to fit similar sized Tb's. Some drillings for ported vacum and fittings may need to be made but you have the tools for that (nudge nudge wink wink.)

Here are a couple of links that may help:

240sx throttle body swap - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z

Mustang GT throttle body users. One question. - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z

For the iris TB vid, I never knew they existed. Most of the flow is in the centre of a tube. The conventional throttle plate and shaft is actually a poor design but acceptable and safe.

[Captain Obvious]

Making an adapter plate is something I could definitely handle. I'm mostly concerned with getting something that has the same or close to the same bore diameter and already has an air control mechanism installed. I've looked over the stock TB for a location to mount such a device, but I've come up blank. That BCDD takes up the entire bottom side. If it weren't for that...

So there's a question for the collective... Every year from 70 all the way through 78 had some sort of vacuum controlled air bleed into the intake manifold. The carbureted years called it the throttle opener, and the FI years called it the BCDD.

Did that continue into the ZX years? Did the ZX cars have a BCDD or similar device?

[Zed Head]

They moved the BCDD to the bottom of the intake manifold in mid-80 or 81.

You could look through the various FSM's, EFEC chapters, to see what's out there. My 95 Pathfinder has an IACV mounted on the throttle body. But it also has throttle control by cable. And don't forget that the TPS is mounted on the throttle body. They went to sensors instead of switches eventually so you might have to rig something up there. And, the AAR heating block needs consideration.

Overall, looks kind of complicated to convert. Might be easier just to move it and hide it.

[superlen]

Captain,

FYI, the Q45 & 240sx was what I was planning on playing with while testing the ZFuel controller. For TPS, Potentiometer input or switches would both work, IAC is a pwm output so any two wire IAC will work. Bosch makes a few external IAC valves that would plum in similar to the AAR (in the same location, same wiring harness plug), but I get what you're saying in that a TB with built-in TPS & IAC would be the sweetest install.

Another possibility....I replaced the TPS on my Dodge Dakota the other day & looked at both it and the IAC. The IAC looks possible,with some machining of course, to meld into the bottom of the stock TB (replacing the BCDD was my thought). I do think it was be easier to use a new TB, but if one wanted to keep the most bone stock look possible this may be a route to pursue.

Len

[madkaw]

5.0 liter mustangs have 60mm TBs with IAC and TPS . You could make an adapter plate as mentioned and buy these Ford TBs all day for cheap. I've seen them as cheap as 25$ new- but they are all cable action

[TomoHawk]

You gotta remember that using a bigger throttle won't help any. The nottleneck is the tiny intake valve that is about 1/2 the size of the runner tube, so we are back to the more important problem of a better-flowing cylinder head, which most 'experts' say will never appear.

I think the only real advantage to using a different throttle is the possibility of the built-in AAR and an integrated AFM.

[superlen]

Steve,

The Mustang sounds like a good option. Do you know if the IAR is a PWM input?

Len

[Captain Obvious]

Thanks all for the additional input. I understand that there won't be any performance gains to be had by switching to a different throttle body. That's not the intent. As a matter of fact, that's why I would really like to find one similar in bore to stock. I don't want to change the flow characteristics. I just wanted to consolidate the function of the AAR into the throttle body like newer vehicles.

Incorporating the BCDD function would be a little more difficult because the control would have to be vacuum based as well as temperature based. Currently, the AAR is temp only, and the BCDD is vacuum differential only. If you use the same IACV for both functions, you'd need to control it based on both temp and vacuum and set the valve based on either.

Problem is... No other throttle body is going to have anything like the BCDD. The thought of moving it to the underside of the intake like Zed mentioned is interesting.