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conedodger

Just Another Damned Z Car Project Thread

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LOL! So the mounting pattern is not the same. Bummer. I was trying to dig into that for you, but didn't come up with anything concrete in time.

So is there enough meat to file the holes on the TB so you can get it to mount? Or is it just too far off?

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9 hours ago, Captain Obvious said:

LOL! So the mounting pattern is not the same. Bummer. I was trying to dig into that for you, but didn't come up with anything concrete in time.

So is there enough meat to file the holes on the TB so you can get it to mount? Or is it just too far off?

Looks like there is enough to work. I will run it by Rex, a 510 guy and machine shop manager Monday. It looks like it’s aftermarket because all the 350Z ETB’s I’ve seen have “Hitachi Nissan” cast into them. This one, nothing. We can try to make it fit and if we break it, we chuck it!

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Ok, even though I'm retired with the Covid situation, my anesthesia skills are in demand so I do a day or two a week of work at the hospital. The reason that is relevant is that I have not had time to examine the 350Z throttle body to see if I can just redrill it or if I need an adapter plate to make it work. My conclusion? I think I need an adapter plate. And frankly, as long as I have to make an adapter plate, I think I'll just make one that accepts the aftermarket 350Z 75mm ETB's that are out there.

I just don't think there is enough meat in the stock 350Z ETB to drill it out for the bolt pattern on our L28 intakes. 

Edited by conedodger

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Gotcha. Of course it's impossible for me to tell from just the pics, but from my end of the screen it doesn't look like there's enough meat.

But do you really need 75mm? Is there any downside for "too big"?  I'm thinking that because of the inherent non-linear nature of butterfly valves, that it could be twitchy at low throttle positions or something?

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17 minutes ago, Captain Obvious said:

Gotcha. Of course it's impossible for me to tell from just the pics, but from my end of the screen it doesn't look like there's enough meat.

But do you really need 75mm? Is there any downside for "too big"?  I'm thinking that because of the inherent non-linear nature of butterfly valves, that it could be twitchy at low throttle positions or something?

Here's my thoughts on the larger throttle plate. @duffymahoney is using ITB's and has more throttle plate square CM opening up all at once. I suspect that you're right and there is no advantage and perhaps a downside to too much throttle plate. I have to research more. 

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Will do @Captain Obvious, I am researching with the Haltech site on that. It is 'monitored' by the Haltech guys, but most often they don't do the answering of questions. Because of that, you don't know what you're getting. After all, there are far more experts on the internet than there are in the world by about 5 times! 

What I could use now, is a 2D file of the inlet side of the '75 intake manifold. The reason I need it, is because I feel I'm going to have to make an adapter to mate whatever Electronic Throttle Body to the factory manifold. My son, who is an architecture student graduating in May of next year has told me he can make me a working drawing that I can send to my friend Larry who is a CAD Machinist to make 2-3 adapters. (I can't be the only one who wants DBW right?) 

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Will do @Captain Obvious, I am researching with the Haltech site on that. It is 'monitored' by the Haltech guys, but most often they don't do the answering of questions. Because of that, you don't know what you're getting. After all, there are far more experts on the internet than there are in the world by about 5 times! 

What I could use now, is a 2D file of the inlet side of the '75 intake manifold. The reason I need it, is because I feel I'm going to have to make an adapter to mate whatever Electronic Throttle Body to the factory manifold. My son, who is an architecture student graduating in May of next year has told me he can make me a working drawing that I can send to my friend Larry who is a CAD Machinist to make 2-3 adapters. (I can't be the only one who wants DBW right?) 

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Will do @Captain Obvious, I am researching with the Haltech site on that. It is 'monitored' by the Haltech guys, but most often they don't do the answering of questions. Because of that, you don't know what you're getting. After all, there are far more experts on the internet than there are in the world by about 5 times! 

What I could use now, is a 2D file of the inlet side of the '75 intake manifold. The reason I need it, is because I feel I'm going to have to make an adapter to mate whatever Electronic Throttle Body to the factory manifold. My son, who is an architecture student graduating in May of next year has told me he can make me a working drawing that I can send to my friend Larry who is a CAD Machinist to make 2-3 adapters. (I can't be the only one who wants DBW right?) 

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Will do @Captain Obvious, I am researching with the Haltech site on that. It is 'monitored' by the Haltech guys, but most often they don't do the answering of questions. Because of that, you don't know what you're getting. After all, there are far more experts on the internet than there are in the world by about 5 times! 

What I could use now, is a 2D file of the inlet side of the '75 intake manifold. The reason I need it, is because I feel I'm going to have to make an adapter to mate whatever Electronic Throttle Body to the factory manifold. My son, who is an architecture student graduating in May of next year has told me he can make me a working drawing that I can send to my friend Larry who is a CAD Machinist to make 2-3 adapters. (I can't be the only one who wants DBW right?) 

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Haha! Nice glitch.

So this 2-D drawing for inlet face of the stock plenum... I don't have anything in electronic form, but I have a pencil sketch around here somewhere. Would that help?

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Might? I reproduced a Two piece Porsche rear fog light mount from a drawing on the inside of a box and made 50 copies... let’s see what Nicho can do with it.

A5ABE549-EA04-40DB-9890-68F95CAF998A.jpeg

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OK, I'll look for my sketch.

So I've got some questions about this adapter plate you're planning... With the mounting holes being "close, but not close enough", there is significant overlap between the original pattern and the scheme for the 350Z. That overlap presents a set of difficulties in making an adapter plate. It would actually be easier if the patterns were radically different instead of just a little different.

Are you planning to make this thing from multiple pieces and sandwich them together?
Are you planning to spin the 350Z throttle body a little (clock it 45 degrees or something) so that none of the holes interfere with each other?

Something else?

Sorry... I'm just having trouble picturing this plate.

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Well if you're going to make it two pieces, you really don't have to clock the throttle body if you don't want to. You can use flat head screws or counterbored bolts to hold one piece to the manifold. Screw that into place first. Then use flat head screws to hold another plate to the first and have threaded holes in the new pattern on the second plate.

Not really a good description.....

Anyway, here's my sketch of the original throttle body mount. Let me know if you can't read the dimensions and I'll edit the sketch to make them more readable:
P1170786.JPG

I made a spacer plate for the Sentra throttle body. The mounting pattern is the same, but the linkage interfered, so I had to move the throttle body out away from the intake by 1/4 inch. Here's a spacer plate made to the dimensions above:
P1170787.JPG

And here it is next to the intake hole:
P1170788.JPG

P1170789.JPG

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Glad to help. Hope it saves some time.

You may find that the holes in my plate are a tight fit on the mounting bolts with the geometries and tolerances involved. The holes in the throttle bodies I've messed with here use larger holes than what I put in that plate. In fact, they used two different hole sizes on the diagonal. Two of them are really sloppy, and the other two are tighter, but still not as tight as what I did.

Anyway, you may find that you need to open those holes up a little bit to get it to fit without interference on the mounting bolts. Depends on the accuracies of all the parts involved. On the factory floor, they just want things to fit without a fight and they made the mounting holes sloppier to guarantee that happened.

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So, a bit of finishing touches on the intake today. This is a 3M heat reflecting tape that I'm hoping will keep the header heat out of the intake. I will also wrap the headers down to the collector. 

Anyone have one of the factory heat shields for the brake aperatus that bolts to the bottom of the heat shield? I might as I have had a couple 280Z cars over the years as well but I'm no where near my parts garage...

IMG_1510.jpg

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Simply because I had all the parts handy, I took fresh measurements and ran some numbers:

280 throttle butterfly - 50mm diameter. This provides 1964 mm square area. The Sentra (96-98) throttle body as well as the 280ZX are also the same as the 280Z

Carbs butterfly (both round and flat tops) - 46mm diameter. This provides 1662 mm square area.

Now interesting (to me) is that the 1964 sq mm for the throttle body is shared between six cylinders, while the 1662 sq mm for the carbs is shared only between three cylinders instead of six.

So for the fuel injection, it works out to 327 sq mm per cylinder and the carbs work out to 554 sq mm per cylinder. The carbs provide significantly more butterfly area per cylinder than the fuel injection. Now I'm sure Nissan did their research and found 50mm diameter for the EFI was good enough, but the difference is still striking.

Working backwards from the carbs 554 sq mm per cylinder, you would need a 65mm diameter throttle body to get the equivalent area per cylinder.

I'm no in any position to draw any conclusions from the above, but I was moving some stuff around today and had all the parts handy at the same time.   :geek:

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On 11/1/2020 at 2:09 PM, conedodger said:

Anyone have one of the factory heat shields for the brake aperatus that bolts to the bottom of the heat shield? I might as I have had a couple 280Z cars over the years as well but I'm no where near my parts garage...

I am pretty sure I have one available, I picked up some 280Z parts a while back. I will confirm this afternoon when I am home from work. 

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5 hours ago, Terrapin Z said:

I am pretty sure I have one available, I picked up some 280Z parts a while back. I will confirm this afternoon when I am home from work. 

LOL David! We're on a roll! 

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I have an F54 block. Anyone know where the knock sensor went? I’m thinking I might be able to hook up a modern knock sensor to the Haltech ecu.

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Here’s a couple pics off my 83zxt engine I bought. Haven’t verified it but this might be it.

C6BC2235-6F06-4EC0-AF93-B8294EE80EFE.jpeg

108CB572-D35F-4328-9F09-9D99104EB1C5.jpeg

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