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Discussion Starter · #1 ·
Ok
I have a manifold, 40 DCOEs on the way, and I need some good advice. I know from previous threads that many think this is nuts (including Jesse) but I know that it has been done before, but I want to do it as right as can be. I even have seen a set of carbs and a manifold that you, Jesse, were thinking of mounting when the moon and stars were aligned, or I think that's how you put it. I had intended to do it simply (read cheaply) before, but I am now considering a piggyback ECU, like the E-manage ultimate.
My question is how to integrate that. Do I still use a MAP sensor to simulate the AFM input, or will the E-manage do that. I know I'm asking Newb questions and that I need to read up on the E-m ultimate, and I will, but can someone tell me if I'm on the right track? I am, at present, trying to assemble the rest of the components, re fuel pump, etc. Any info you can give will be appreciated, but, of course, the more the better.
Emotional connections to this project fully acknowledged.
Alden
 

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Ok
I have a manifold, 40 DCOEs on the way, and I need some good advice. I know from previous threads that many think this is nuts (including Jesse) but I know that it has been done before, but I want to do it as right as can be. I even have seen a set of carbs and a manifold that you, Jesse, were thinking of mounting when the moon and stars were aligned, or I think that's how you put it. I had intended to do it simply (read cheaply) before, but I am now considering a piggyback ECU, like the E-manage ultimate.
My question is how to integrate that. Do I still use a MAP sensor to simulate the AFM input, or will the E-manage do that. I know I'm asking Newb questions and that I need to read up on the E-m ultimate, and I will, but can someone tell me if I'm on the right track? I am, at present, trying to assemble the rest of the components, re fuel pump, etc. Any info you can give will be appreciated, but, of course, the more the better.
Emotional connections to this project fully acknowledged.
Alden

i am a little confused about your project...you want to ditch your fuel injection system and rig up some kind of engine managament to run carburetor's on your car? i do know that if you want to use MAP you will need a standalone of maybe a piggy back that fuji-racing sells but i do not know what e-manage can do so i wont speak for it. but if you wanted to do this i think you dont need engine management for carbs....anyways i am sure someone here knows alot more about this then i do.


cool project keep us posted!
 

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Alan, this is a very popular mod in Japan. Unfortunately, all the step by step swaps I've seen in Road&Ster magazine are in Japanese! I know you don't need a MAP sensor or E-manage since all you're using computers for is control of spark (carbs handle all the fueling issues) and the stock ECU is perfectly fine for this task so long as you're comfortable sticking with the stock advance curves. If you'd like to modify your ignition a little more I'd suggest an add-on ignition box from MSD that would give you a little more flexibility in where to add/remove spark. I know there was a big thread about this over at Miata.net about a year back because people were concerned about the ECU having different maps or strategies for pulling ignition timing based on load, temperature, etc. that might have issue if you're missing a few of the ECU inputs like the MAF and IAT sensors. I'll try to dig it up.
 

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Discussion Starter · #5 ·
From this thread:
http://forum.miata.net/vb/showthread.php?t=204869&highlight=dell'ortos
I had taken Jesse's advice that although the TPS or MAP sensor should work, that it won't be the optimal set-up for carbs. I know I don't need the ECU for fueling, but it does need to be fooled into thinking that it is still seeing an AFM.
Now, if Kyle, or anyone can tell me what Roadster issue(s) had step by step articles, I will buy those issues. I work with a lady whose husband is Japanese and works for panasonic as an East/West liason kind of guy, therefore fluently bilingual. I think I could get him to translate those articles for me. Maybe start out with the map sensor fueling the ECU and work up to alternate engine managent to make things even better later on. If I make this work, I shall make a good tutorial. There is also a Miata Club magazine (Summer 92 I think) that is supposed to have the article on carbs in it. Anyone have that one?
Best Always
Alden
 

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Why go carbs?

Fuel economy is poor at best
They provide incorrect fueling at different rpms.
When temps. change they cannot adjust accordingly.
They waste excessive fuel, which is getting very expensive.
They pollute the environment.
Idle issues are constant.
Require constant rebuilding & adjustments.

I don't get it.
On a Miata it would actually just be easier to install an IRTB and keep the fuel injection and stock sensors. Plus this set up would be more reliable and fuel efficient.
 

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Now, if Kyle, or anyone can tell me what Roadster issue(s) had step by step articles, I will buy those issues.
I can do you one better. I will scan the articles I have and send them to you in .pdf format. I just need to find the time at work to borrow the scanner as I don't have one at home.
 

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Why go carbs? I don't get it. On a Miata it would actually just be easier to install an IRTB... plus this set up would be more reliable and fuel efficient.
Different strokes for different folks. The Miata is largely about the emotional experience. Think of it not as ruining a perfectly good Miata but instead having a rust-free, leak-free Alfa-Romeo Spider or Triumph Spitfire. It's a hybrid of old and new worlds. Few "get" it and that's fine for those that do. Since when has modifying a Miata been a rational endeavour? Instead of trying to dissuade him let's help him out.
 

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Discussion Starter · #10 ·
Oh yeah, Kyle!
Those scans will be most helpful! The pics alone will be priceless. And then I, too, will be one of the pack who goes seeking those precious back issues of magazines I can't read. Maybe that's why we dream of this stuff, because we can't read it! Well put, to compare it to a rust free Alfa! Peter, thank you too, for your encouragement. The Tater is an inspiration and your props are additional fuel for my dreaming. Experimentation and the making of errors are necessary steps to innovation and learning. I'm frequently frustated when someone has done something that I want to do to my ride but he isn't willing or able to take the time to explain how he did it. Look at all of the DIY IRTB plans that have been written about on our forums that we never here the conclusion to. I know that time constraints can get in the way, but I intend to tell all regardless of how it turns out. The vintage roadster desire is fueling this. Like Kyle said, not all get it, that's OK. A few of us can already hear the sound of those vintage Italian twin-throats. I'm thinkin' a reproduction Elan fuel line set would fit just right on the pair.
Best Always
Alden
 

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I've got the info you need.

You do need a MAP sensor and a IAT sensor to run with carbs if you are planning on using the stock ECU paired with some kind of piggyback control. You need the MAP and IAT signal along with the piggyback to trick the ECU into thinking that you still have an AFM. The reason why is because you are still relying on the ECU to priovide timing. Unless you ditch the ECU all together and use an aftermarket ignition box, and coil packs to provide timing. But without the ECU, then you will need have a manual switch to turn on the fuel pump.

With the ECU part taken care of, then all you need is a set of carbs, manifold, low pressure fpr(adjustable), then you are set.

You don't neccesary have to use a TPS, even with the stock ECU, as long as you have MAP and IAT and the piggyback. Miata TPS is an on or off switch, only have minial control on timing. Of course it's better to have one, but in order to run, you don't need one.

Tuckin99, Pierce Manifold both make carb manifolds for Miata. There are probably more out there. I love the idea of carbs. There are issue that you have to deal with though. You have to choke them on cold start until the motor warms up. You have to re-jet and tune with large elevation change, and large temperature change.

Good luck on the quest, man. Someone needs to get it done. :)
 

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Here's some inspiration:



Oh regarding the AFM...I've seen some guys with carbs just leave the AFM somewhere in the engine bay, just to give a signal to the ECU. I'll try to dig up a pic...
 

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Kool!

Don't think I'm disuading anyone from realizing their dream of a vintage style Miata.
Geez I'm guilty of my own old-skool JDM dreams as well.

I simply question if it's really worth it, living with carbs.
I lived with an old '67 Firebird and would never wish carbs on anyone I like :D
 

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One day I dream I will have ITBs. But there's a pair of Webers just sitting in a box in the corner of my shop tempting me to get the other parts necessary to make them work. One day....
 

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Discussion Starter · #16 ·
Thanks guys
I take all advice seriously. Keep it coming. Your interest is a great help, but your advice is even better. I'm not one to rush ahead, but I do already have the manifold and carbs. I guess at least I need to get an adjustable FPR and the correct fuel line parts.
Ciaou
Alden
 

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Discussion Starter · #18 ·
Kyle
That is a beautiful FPR. I think it will find a home in my engine bay. Thanks for the heads up.
Alden
 

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Alden: Didn't see your post until today..... BTW I just sold my entire setup to CE28N :!: I guess I couldn't wait for the stars to line up ;);).

BTW did you buy the Pierce manifold? Can you take a pic of it? I've never seen one of those before.
 

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Trivia

DCOE stands for

Doppio Corpo (double throat)
Orizzontale (horizontal)
E doesn't mean anything in Italian but is Weber's code for the die cast version
 
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