Single 40 IDF Intake Build

[BFB]

72 in early summer in Missouri? Now i know your making shit up because early summer in Missouri is hotter than that, hell we hit 81 this week, pretty sure we were in the 40’s too though… but still , unless you were driving at night early summer here is way hotter than 70’s. And so what if it did have frost on the intake, just means there’s a cooling effect on the intake charge and temp difference from ambient which is actually good because the O2 is denser, unless your one of those ppl that runs an engine so lean its on the cusp of being a cutting torch already. And even if it did cool the IAT enough to be an issue the heat from the heat risers doesn’t provide enough heat to reach the upper part of the intake , below the carb , anyhow. And i doubt it heats the intake enough to change the IAT much more than what passing through the end castings would do. Ive run N/A with & without heat just to test this so you’re not showing me anything i havent already seen. The only intake i have seen that might have helped with getting heat all the way to the carb was one for a 32/36 that had the heat tube not just run along the base of the intake but went into the aluminum casting & up and back down the back side all the way to the carb base. THAT might actually provide enough heat to do something.
I know i can get a single center mount to run great without heat, i dont think id be so eager to post and prove my inability to not, just to TRY to prove your point that a carb needs a heated intake. That shit is just a bandaid for other problems ( again with the exception being cold climate)
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1

[rodeking]

You need to tell GM, Ford, Chrysler etc that they all screwed up when they used both exhaust and coolant to heat the intakes on their old carb'd engines.

[jimmyhoffa]

If you look at the historical temp averages over the last 5 years for June in St. Louis or Kansas City on Climate.missouri.edu you'll see that the average temperature trace crosses the 72°F mark at least 25 separate times. So it's safe to say for a morning commute, my statement of conditions where I had a problem was likely accurate within a few degrees, maybe better. Data always wins, as long as you're paying attention to it.

Correct, the only intake design worth integrating if you want the undeniably better drivability which comes with that, is the CB or old redline one where the heat is ported up to the carb base. The primary goal of all that is to hold the fuel in suspension UNTIL it gets to the end castings, which are wicking heat from the heads.
_________________
1974 Chenowth 2RL #1244 Street Legal
My other car isn't ridiculous.

[Brian_e]

[mondshine]

Couple of questions:
Why didn't you consider the CB "space saver" IDF intake manifold with their matching throttle cable rig?

Also. will you make any provision for heating intake air (like stock air cleaners do)?

[jimmyhoffa]

[DesertSasquatchXploration]

[DesertSasquatchXploration]

[chrisflstf]

Did you test the preheater tube for leaks?

The temp drop from the venturi effect is real - about 70F

Most charts indicate its worse below 70F and humidity above 80%. Where I live, that is almost never, so I can get away with it, for the most part. Its aways there though to some degree

About the low profile manifold from CB. I almost bought one of those, but in a bus, there is only room for an air cleaner about 1" tall. Its good for bugs and ghias though.

[DesertSasquatchXploration]

[DesertSasquatchXploration]

My beef with CB Performance is how rude the sales guy was with me. I emailed a simple question about getting the performance stock carb intake with-out the poorly drilled dual carb bolt pattern. Ill drill my own 34pict holes the dual hole pattern weakens the shit out of the flange. He told me they get them that way they have no control how they come. WTF really?? You have no control?? I'm out I want nothing to do with your products. Sounds like they are in bed with EMPI I HATE EMPI. Those holes look drilled in china to me. I have door handles and the oil fill from EMPI both are trash.

[NJ John]

Empi sell the identical intake.
_________________
1973 standard, yellow, lowered, 3” narrowed front, 1600 blo-thru turbo w/single dell 15.4@86, so far
11.41 et buggy. Long gone
Let’s go O’s! Let’s go O’s!
https://www.youtube.com/@AirSpooledGarage

[DesertSasquatchXploration]

Yes but they wont tell you its the same. I would respect them more if they just would admit its an empi casting or don't sell it at all.

So if CB sells the single IDF manifold for 180$-$200 and it falls apart off road then... I have to source thick wall stainless pipe press it into the CB casting pray to god it doesn't crack. I'm now in what 300$ screw that ill make my own. I'm down some MiG wire and a bit of co2/Argon gas mix so what.

[QRP]

The Opening where the carb sits is to big on all of those cast center mount manifold everyone sells, CB included.
That's why I also made my own.
Having the runners an even 1-1/2 dia. from the carb to the end casting makes a big difference in tuning and drivability.

If they make them to fit everything then it fits nothing IMO

But that's just my opinion and experience.

[modok]

I would hope making your own intake manifold is far more difficult than making a brace to support the carburetor.
I'm sorry, that's just simple thing to make. Common sense.

The stock carburetor manifold is supported by the heat riser tubes.
If that's not the case anymore, then you have to replace it with something.

Doesn't matter what brand, or if you make it yourself, it's just common sense.
You can brace it to the shroud, or down to the fuel pump, or connect it to the generator/alternator strap, ect.

[DesertSasquatchXploration]

[NJ John]

It needs a cool name, like CB would give it. Ramflo, super sucker….
_________________
1973 standard, yellow, lowered, 3” narrowed front, 1600 blo-thru turbo w/single dell 15.4@86, so far
11.41 et buggy. Long gone
Let’s go O’s! Let’s go O’s!
https://www.youtube.com/@AirSpooledGarage

[oprn]

[DesertSasquatchXploration]

Up and running!! My narrow band AFR is reporting borderline lean at a cruise so its safe, pulls strong with a 130 main and 160 air correction F11 I will dig into that later.

The idle was kicking my ass. First I had 58 idle jets way fat went to 48's much better 1 1/4 out on the idle mixture screws. But the idle speed screw was 1.5 turns in and air bypass screws a 1/4 out still idled like shit with fuel standoff like crazy. I then realized the butterfly's weren't drilled so pulled off the carb drilled them to .082 thousands. Wow what a difference 1 turn on the idle speed screw and the idle bypass screws are (very lightly seated). So now I just have to dial in the acc pump circuit and play around with the main circuit. Hope to have a YouTube video up soon.

[oprn]