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Just Some Dude in Jersey
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Discussion Starter · #1 · (Edited)
(This thread was split off from a thread about what the best intake manifold and CARB would be best for a 2.4 engine. We diverged and started talking about FI.)

As Keith said, I have a number of perspectives I can add to this discussion. I'm not in the mood for one my multi-paragraph, well thought out, dissertations, so I'm going to just throw out a bunch of random one sentence thoughts.

Quality gas without ethanol and the consequences of it in our fuel is making carbs a real PIA these days. Fuel injection seems to handle that stuff just fine.

You(Frozen Tundra) already have a manifold and throttle body made for a 2.4, it's the operating system and the sensor/idle devices that are hopelessly old school. I would say you should seriously consider just upgrading the operating system and the sensor/idle control. I'll wave the flag for the Classic Fuel Injection.UK company I'm dealing with because NOWHERE ELSE will you find a seller of FI systems who will personally work with you on an almost daily basis to get such a conversion accomplished. As far as which operating system is best, well, that could generate endless discussion. What I personally have discovered is that I REALLY need/needed help to understand all that FI stuff and there are shockingly few people you can turn to in the Opel world to help you out. Justin Thiel and Nathan Mazza on Facebook have been a great help. Jeff Herman/GoldGT has been of enormous help and there's probably no single person you can find who has more FI knowledge about Mega/Microsquirt and the setting up of FI than him. Uh-oh..........I'm starting to write paragraphs.........let me stop here.

After 40 years of Opels, what is really great about FI is that it starts up the same every time. No pedal pumping, crank for 3 seconds, pump some more, crank some more, none of that BS. Just reach in the window, turn the key, and start the car.

With FI your air fuel mixture will always be great and your plugs will be perfect all the time.

With the stock FI manifold, vacuum leak possibilities will virtually disappear.

The stock manifolds are huge and that hugeness has a benefit in reducing air pulse recoil. The stock manifold provides more than all the air you'll ever need. As the guy at CFI said to me: A throttle body is a throttle body, it's a pipe with a flap in it. A manifold is just a bunch of pipes full of air. Modern cars use a single throttle body because there's almost nothing to be gained by multiple carbs and multiple throttles and the single throttle is nice and simple and delivers all the air you need evenly to all the cylinders at the same time.

The stock manifold and throttle has all the numerous vacuum fittings that you need and has the cable throttle set up built in. The need for additional vacuum ports on my repurposed SSD wasn't something I was very aware of going in. You'll need ports for:
1) Idle air control
2) Vacuum compensator hose
3) A MAP sensor port. A MAP sensor will delete the huge, clunky, primitive, inaccurate, AFM that doesn't fit in a GT engine compartment very good. That one thing is why the stock FI sucks. With that deleted, you could just install a filter on your throttle body and you have a nice neat system that fits.
4) Brake booster

The stock FI's computer system can't really be altered in any way. There's no way to get into the programming to make changes or observe what's going on if there's a problem to diagnose. It's like reading the bible with all the pages glued together. You just have to have faith that it all works.

If you replace the oem computer/ECU you can have unlimited adjustment and troubleshooting. It mostly adjusts itself. The seller will configure it to get you started, so you don't need to do any of that stuff. He'll have all the fuel and spark tables already set up, you just need to hook it all up and start driving and the car gets better and better with each drive.

YES, I have had problems with my set up, but almost all of those problems are basically caused by me or my engine's situation. My set up is also custom from the word go, so it's to be expected that I'm having a bit of a slog. I have really only had 3 problems:
1) I needed to add a vacuum compensator hose from the fuel regulator to the manifold, even though all the fuel pump instructions said I didn't need it, it turns out that I did.
2) My timing chain was a whopping 2 teeth/20degrees of cam rotation off.
3) Whatever my current stuttering problem is. It could be something simple, like bad plugs/wires, or a vacuum leak, but it does not appear to be caused by the FI system itself, it appears to be another problem at my end of things. I'm fairly confident that if I can knock that problem out I'll have smooth sailing.

If I didn't have the above 3 problems, I would have been able to drive my car within ONE WEEK after install and I'd be happily driving right now.

You have let your car languish for quite some time now because of this engine/carb/FI thing, despite the rest of your car being cool and all fixed up and ready to enjoy. I don't get the sense that you enjoy the level of head under the hood every day for weeks that I am going through. I'm not enjoying it either. I'm not an engine guy, I just want the dang thing to run and never have to fukk with it. But I started off with a bit too much of a customized from scratch system and I didn't know about or have the additional vacuum ports needed to make it all work. I now know a lot more and I'm sharing it with you guys, so that you don't have to go through the learning process I'm going through.

If I had simply upgraded my Motronic system by basically tossing all of the stock stuff and only keeping the manifold and throttle body, things would be a lot easier. I may follow this path on my yellow car.

I don't know what my 3rd problem is. No clue. It could literally be the color of socks I'm wearing. Absolutely everything is on the table. But, like I said, if I had a couple more vacuum ports to start with and my engine wasn't cocked up, I'd have been running in ONE WEEK.

The stock manifold and TB you have, plus upgraded gadgets would be all you need. No welding on of raised port flanges and added ports installed. If your manifold fits like mine does, then you'll just have to EASILY bend a small area of the cowling for clearance. I don't know what your TB looks like, but if it's the stock 2.4 one, then you're good to go. If it's the older type with the big spring on the throttle, I'd recommend getting the newer type.

IF I can get my SSD manifold, 2 injector, thing to work and you like that set up, you can always change to that at a later date. You'll still have all your existing FI widgets to continue using. But it is inherently less efficient than the manifold and 4 injectors you already have and YOU can set it up for the more efficient sequential injection, rather than the batch fire mode I have to use.

You think this FI stuff is hard to get help for? Try finding a repair shop that has any clue how to adjust a carb. At least with FI, there are 1000's of guys out there who can diagnose FI issues and tuning and countless videos.

I could go on and on, but any other points and things I've learned should really be written up in my Throttle Body Adventure thread after I finally knock out my remaining issues and do a lengthy synopsis of how to do what I did.

I don't see how going with any form of a carb set up makes any sense in this day in age. It's ridiculous hard to find anyone who knows how to tune side drafts.
 

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What does " Irmscher tuned fuel injection set up" mean ? A stock LE Jetronic or Motronic would be my choice over an aftermarket system that is hard to tune. Our Monza has an LE2 Jetronic equipped 140hp DIN six cylinder H25E engine that starts and runs like any modern engine, despite being even more ancient than the Motronic equipped ones.
 

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Opel Tinkerer and Rescuer
1996 Opel Calibra
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Hi Vienny! Man all the OG's are still here. glad to see. Thanks for chiming in!
Same here and BTW..

Do want to mention, the 38DGAS was meant to be used on 2.8L+ 6 cylinders.

A lot of the mods we have to do to get the 38DGAS to work well on a 2.0L are because the 2.0L is basically a motor that is smaller than the 38DGAS was designed for.
 

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Opel Tinkerer and Rescuer
1996 Opel Calibra
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7,902 Posts
What does " Irmscher tuned fuel injection set up" mean ? A stock LE Jetronic or Motronic would be my choice over an aftermarket system that is hard to tune. Our Monza has an LE2 Jetronic equipped 140hp DIN six cylinder H25E engine that starts and runs like any modern engine, despite being even more ancient than the Motronic equipped ones.
He had ( has ? ) a i200 EFI off a Manta.
 

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69, 70, 72, 73 opel GT's. Only need a 71 to complete the set
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544 Posts
Out of curiosity...
If I were to make the patterns and core boxes to produce a tented intake like rally Bob has fabricated, how many people would be interested ?
Cost would probably be $300-$350.
 

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Opel Tinkerer and Rescuer
1996 Opel Calibra
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7,902 Posts
This is an example of one that was made by my shop.
 

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Opel Tinkerer and Rescuer
1996 Opel Calibra
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7,902 Posts
Out of curiosity...
If I were to make the patterns and core boxes to produce a tented intake like rally Bob has fabricated, how many people would be interested ?
Cost would probably be $300-$350.
Fabricated ? or just the core parts?

I was thinking of 3D printing a "mold" for lost casting or CNC. It would obviously have to be printed in parts and super glued together ( for testing obviously.. ) but once I have a model I should be able to get them made as well.
 

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Out of curiosity...
If I were to make the patterns and core boxes to produce a tented intake like rally Bob has fabricated, how many people would be interested ?
Cost would probably be $300-$350.
Are you talking about converting the stock 69-73 manifolds or making them from scratch?

It seems to be the next step for me, Vincent attests that the engine runs much smoother up top with some added power gains. $3-$350 sounds quite reasonable for a good quality intake to me. I’d definitely be interested.

Glad to see you back again FT
 

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69, 70, 72, 73 opel GT's. Only need a 71 to complete the set
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544 Posts
Fabricated ? or just the core parts?

I was thinking of 3D printing a "mold" for lost casting or CNC. It would obviously have to be printed in parts and super glued together ( for testing obviously.. ) but once I have a model I should be able to get them made as well.
I was thinking of making patterns and core boxes fir traditional sand casting. But there would need to be somewhat of a demand for them to offset the cost and time for making the patterns..... I'm not sure if there's enough interest in them though as there is other options out there....But it would be a fun project.
 

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Opel Tinkerer and Rescuer
1996 Opel Calibra
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7,902 Posts
I was thinking of making patterns and core boxes fir traditional sand casting. But there would need to be somewhat of a demand for them to offset the cost and time for making the patterns..... I'm not sure if there's enough interest in them though as there is other options out there....But it would be a fun project.
I have some of the balnks here and my 3D printer can make up to about 1/3 of the manifold.

So I could prototype the fit and such. Also there is already a Sniper single barrel adapter to 4 that could be used as the pattern for the top.

Wheel White Light Product Hood
Wheel White Blue Vehicle Car


I could then also fit the intake with a linkage that would work for it.

We could also make it "adaptable" to fit other adapters, like the two barrel sniper, or simply the Weber.

(3) Easy lost PLA metal casting │ How to turn a 3d print into metal │ ASMR - YouTube

Just saying.. I am been thinking along this line..
 
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Opel Tinkerer and Rescuer
1996 Opel Calibra
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Adapter for VW distributor to Opel. May have found a similar VW distributor that uses weights and a Hall sensor and the standard Opel shaft.. but I digress.

Long story short the manifold would not be too complex of shape to design and then cut in sections and print. I also found a place that can replciate the 3D prints pretty cheap in bulk.
 

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69, 70, 72, 73 opel GT's. Only need a 71 to complete the set
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We could also make it "adaptable" to fit other adapters, like the two barrel sniper, or simply the Weber.
Making it a 2 piece design to accept different tops for different carbs or what have you is a good idea.
But I would not recommend producing them using lost pla. I have alot of experience with lost pla casting and 3d printing. I worked with "printed solid" a local 3d printing and supply company to produce castings for customers for a number of years.
So it is with good reason that I would not use lost pla casting for this particular casting..
I would however use the 3d printer to produce the pattern and core boxes, or even a prototype intake for flow testing.. nothing like pressing a button and coming back later to a finished part, even if it's just for test fitting...
Purple Electronic instrument Hood Automotive engine gasket Audio equipment
 

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Opel Tinkerer and Rescuer
1996 Opel Calibra
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7,902 Posts
Making it a 2 piece design to accept different tops for different carbs or what have you is a good idea.
But I would not recommend producing them using lost pla. I have alot of experience with lost pla casting and 3d printing. I worked with "printed solid" a local 3d printing and supply company to produce castings for customers for a number of years.
So it is with good reason that I would not use lost pla casting for this particular casting..
I would however use the 3d printer to produce the pattern and core boxes, or even a prototype intake for flow testing.. nothing like pressing a button and coming back later to a finished part, even if it's just for test fitting...
View attachment 450160
I was just playing with the idea ;) Watching too much Youtube ;)

But yea, first we can get a prototype or two made and then work on getting it produced later.
 

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I'd be curious to see the flow tests of a tented vs flat bottom intake....
The tented bottom does not increase flow. It reduces plenum volume when the upper plenum is ported to increase flow. Thus, you gain airflow without increasing volume, so throttle response and torque are enhanced, in addition to mid and top end power. Improved vacuum and low rpm driveability were the desired goals with the tented bottom.
 
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