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Over carburated !!!!!

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I was looking for a pic of my set up but I don't have one handy. Basically, I machined an adapter that fits between the carb and the manifold where the spacer used to be. My injector is mounted beneath the carb and shoots up into the air stream. My thinking was that in this way, it crosses the air stream twice. When I had a Patton setup in my car, fuel pooled in the carb and the manifold. This did not greatly affect performance but it did bug me, and I did end up with an air filter full of fuel more than once. That complaint aside, I think the Patton set up worked pretty durn well, and in my foggy memory, seemed to perform better than my set up in some ways.

My next mission is to create a custom tuned port MPI manifold. I am not able to achieve the performance, drivability and economy goals I set for myself with my TBI set up. And also, being as about the only advantage the 1500 has over the A-series is its 4 intake ports, I might as well utilize them to my benefit.

Jack, the problem with the setup you sketched is that it would require some kind of sequential injection to work. With the A-series, your options are to mount the injectors as far away from the ports as possible with a balance tube or plenum between the injectors and the ports, or to use sequential injection... which actually is way more complicated than it is with a normal 4 port car because, from what I understand, the injection timing must change through the driving range to prevent charge robbing.
 
Morris, I thought about in a spacer as well. I don't have the time to make a dedicated intake right now. I don't like how a GM TBI injector spays either. It doesn't suprise me you had problems. That's why I want to use a port injector in a TBI configuration.

What kind of MPG were you getting w/ the Patton? Which ways did it perform better?
 
Some of my memories may be of the "Good ol' days" and thus inaccurate. I have not kept a journal sooo nothing I say her is verifiable.

That said, the Patton setup seemed to start much easier than my current set up. Also, once started, it was ready to drive. My current set up likes to sputter a bit before it's ready to go. It's still superior to cold carbs.

My current MPG tops out about 27mpg and averages in the 24-25mpg range. Bear in mind, this is averaged from Austin driving which is mostly stop and go most of the time.

I got as good as 29 mpg and averaged about 27 with the Patton set up, but that was on open country roads at 60 mph. So not really comparing apples to apples here.

As for spray pattern—I do not think it is as critical with TBI injection as it is with port injection. In a TBI set up, most of your fuel is going to end up on the bottom or sides of the manifold where hopefully warmth and air flow will make it quickly evaporate. In other words, it works just like a carb with a more precise fuel metering control.
 
Morris,
if you do a MPI give plenty of consideration to the length of your air intake runners.
 
Yeah! That's the fun part! Been awhile since I have done the calculations, but the optimum length for power at 3500RPM is LOOOONG! It's gonna be a blast figuring how to get all them long snakes to fit in there. I am thinking it's going to look like a french horn when I am done.

Of course, If I get lazy, 4 short, straight pips fed by a big fat plenum will be a big improvement over the disaster of a manifold that came on the car.
 
Morris said:
As for spray pattern—I do not think it is as critical with TBI injection as it is with port injection. In a TBI set up, most of your fuel is going to end up on the bottom or sides of the manifold where hopefully warmth and air flow will make it quickly evaporate. In other words, it works just like a carb with a more precise fuel metering control.
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That's about the MPG figures I'm getting w/ Su's and the DGV.

The GM TBI injector sparys big drops against the bore wall and they just run down. It's really pathetic. I could do a better job w/ a spray bottle. Rick could beat everything out there with his rattle can patters he's throwin' out.
grin.gif
 
Morris said:
That said, the Patton setup seemed to start much easier than my current set up. Also, once started, it was ready to drive. My current set up likes to sputter a bit before it's ready to go. It's still superior to cold carbs.
Click to expand...

Have you tried to fatten up cold start enrichment?
 
Yeah. The problem is you only get one shot to adjust your coldstart enrichment every morning. It takes quite a bit of dedication to get it dialed in. I had it working okay... but then I changed something and now it doesn't work so great. As mentioned above, I do not keep a log or journal of what I do so it could be a while before I get cold starts sorted out.
 
Morris said:
I had it working okay... but then I changed something and now it doesn't work so great. As mentioned above, I do not keep a log or journal of what I do so it could be a while before I get cold starts sorted out.
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Boy, does that sound familiar !!!! We may have been sepparated at birth. (although I think I'm a bit older than you.)
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]We may have been sepparated at birth.[/QUOTE]

Sometimes when I read this forum, I imagine a very charming and handsome race driver who traveled the country racing the TC he brought back with him from the war. As he went from town to town, he was always welcomed warmly by the ladies. And he always left them with something to remember him by.
 
Morris said:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]We may have been sepparated at birth.
Click to expand...

Sometimes when I read this forum, I imagine a very charming and handsome race driver who traveled the country racing the TC he brought back with him from the war. As he went from town to town, he was always welcomed warmly by the ladies. And he always left them with something to remember him by.[/QUOTE]


:lol:

What about a drunk guy in a '57 Chevy? Would that work?
 
JPSmit said:
has anyone thought of using the holes from where the air rail used to go?
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IIRC correctly, that would be right about where the exhaust valve site. Not the one you want to be spraying fual at :smile:
 
At least it'd be DRAMATIC!!! :devilgrin:
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]What about a drunk guy in a '57 Chevy? Would that work?[/QUOTE]

My dad used to pull his racing motorcycle (A BSA Goldstar 500) with a '57 Nomad.

We lived in Dallas at the time and I am sure he must of made it to at least Shreveport on occasion. Maybe we should post pictures of our dads and compare notes.
 
Hmmm, a swell time?
 
THe Old Bosh CV injection on the VW Sirroco had a cold start injector in the Manifold common area.Installed the Bosch FI in my 75 Sirroco No wiring harness so I had a hot lead to the injector and a toggle switch I would flip on cold mornings I'm talking -15 North Dakota Worked pretty good for about 2 years until the toilet seat thingy on the manifold stuck and the car burned to the ground.Stupid mechanical control fuel injection what a dumb Idea....
 
Morris, I would think your location would be better than Patton's. Keep at it till you get it right. Can you swticvh it back off quickly if it sputters and readjust before it gets warm?
 
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