Finally I got a chance to install my annular boosters.

Feelings:

Crisper throttle response

Engine feels "stronger" at the whole rpm range, as it did, but low end has improved considerably. Cured a mean lean spot I had on acceleration

jets needed some enrichment but also I used a diffrent high speed air bleed (slightly larger) and lower power valvle (6.5)

I picked up some extra 4" Hg on the low end during acceleration

Car ain't seems to be richer... I guess my MPG observation will tell

Very happy about how this tricky things changed my car.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Come on, Juan... You are teasing us. Are they made of Delrin?

Greg

He's not kidding! See Thread 1 and Thread 2.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I remember the threads. I didn't remember the details of the materials. This is seriously cool experimentation. Juan, I would really like to see how these are installed in your car!

Greg

I played with that idea for a while....

Let me see if I can find you the pix of the "new" installation method I came up with....

starting here....


this is the piece that holds the new boosters in place. I just cut the portion of the regular booster that goes into the carb main body, i drill and tap and here you goes.

front view:


top viev (note that this ain't my new boosters, this is an old pic just for illustration purposes)

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Boy, oh boy, re-engineering the carb for fun and profit (maybe???).

What I wonder is how much difference carb modifications can make on the lousy intake manifolds on slant sixes. I saw an article one of the current magazines on what seems like a "bucks are no object" slant project where they got 300 horsepower with a carb, and about 20 more HP converting to port F.I. on the same manifold using the same carb for a throttle body.

It took 13 to 1 compression and a ton of other tricks to get to that 300 mark, and no mention was made of what fuel they needed, but what was fascinating (to me, at least) was drilling the Clifford manifold for injectors and using the carb for a TB. Seems like that should be the closest to a REAL A to B test!

However, they'd already built this megabuck screamer and the MPI conversion only got an extra twenty HP. I'm STILL wondering what gains an MPI system can make on a moderate cost street slant. I know the answers are out there ... somewhere!

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'64 Dart GT convertible, 64 Dart 170 2-door post sedan in faded blue and rust (the Az Dart) & a sixty THREE Dart 170 2-door post sedan in faded blue and rust. (future project)
Early Dart Disorder (EDD) is real, and I've got it!

fun, yes. profit, to the gas companies. Every time I start tinkering with my carbs, there's a period of less than 10 mpg
Actually, even worse than spending extra money on gas, because I end up modifying all my friend's car blueprinting my latest trick for free and fun (and some nice friend quality time not to mention all those six packs and ain't meaning carb setup )

Call me old fashion, but I like my mills naturally aspirated. If I where to build a hot /6, I'd like one BIG cam (aiming for 110+% VE) and 5 speed manual close ratio trans coupled to a high numerical rear end ratio (3.53) and some cool carb setup like dual solex 32-36 staged or something like that. Don't like no turbo or juice. But that's just a matter of personal opinion, I like to drive my car every day and get troublefree service...
About the manifold, I reworked it to fit the 2300 39,6 mm throats bore with no restriction, radiused the inner flange and polished the inner and upper walls inside the runners (since gas is heavier than air, runs on the bottom and on the outer wall of the runner and keeping the raw cast finish in those areas helps atomization)
Whoa! 13:1 CR is high!
I think that a street mill would take great benefit from EFI, especially those with auto transmision. Again, not my thing, since I really like carbs

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Erm...who told you that one?

The slant-6 intake manifold design is considerably better than that of just about any other carbureted inline-six I can think of.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That was my thinking too. The long runners give a "ram" effect at higher speeds and the sweeping curves of the outer runners are much less restrictive than the typical right angle bends on other inline engines. As with any stock piece they can use some tweaking but the design is quite sound.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

The slant six intakes does fine is interesting to know. I have question
about hyperpak manifolds, what is the runner lengths?

170 & 225 is more common with mopar 2.2 & 2.5 than you think just think of slant sixes with two cylinders cut off and cu in is close even stroke & bore are different.

Second question, what is considered a RUNNER passage length where this ends at flange or at valve end and other end at plenum?

Sizing the plenum, from the Corky's book, says 2x the total disaplacement of a given engine. Does this apply to n/a as well? I'm not doing turbo.

Gathering info and parts to build up 2.5 16 valve hybrid with long runners and fuel injection. For torque.

Cheers, Wizard

other gains by swapping to mpi for the street are not quite measured by a dyno. things like better cold start and idle quality, less tuning hassles (especially from weather/altitude changes,) better throttle response, longer engine life, lower emissions and increased fuel economy due to better control of fuel mixture. just better all around. efi is still unpopular with racers, but it has it's place (check out the drake's simca.)

retrofitting an older engine for injection certainly doesn't seem for the faint of heart or wallet, but has become a more viable option in recent years with efi kits that have hit the market. also, brains can offset dollars in this department (look under the hood of lou's cars.)
with regards to efi, the phrase "having your cake and eating it too" comes to mind.

-james

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So how are the venturis working out????????

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

sweet. improved my highway mileage and low end bogs are long gone. I have all the car taken in little pieces because I'm doing a full resto wich would include erson 270º cam, MP 340 springs, some more head work, and in future instances 198 rods with 2.2 pistons, O/S valves head, and 6 motorcycle carbs. Keihins or mikunis. Haven't decided yet. I have all the 6 carbs and the first stages of the intake prototype.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

You have 6 Keihins & 6 Mikunis??

Are they CV (constant velocity) Keihins? CV carbs will correct for altitude to some degree, and because the carb opening is based on air flow, you should get better mileage.

Mikunis will have a better throttle response, but don't have the altitude correcting feature.

Both should have about the same HP and torque.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I have to BUY 6 of those. I'm still trying to make up my mind between mikunis and keihins. I like some features on them both and don't like others as well... (the price, I.E)

If by constant velocity you mean that "drum" thing that slides up and down when you hit the throttle, yes.

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.