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enough carburetor

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purple72Gremlin View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 6:21pm
Originally posted by Ken_Parkman Ken_Parkman wrote:

The biggest problem is that calculation everyone uses for carb sizing was written by someone who does not know what an engine looks like, what it does, or how it works. It is woefully incorrect.
I wholeheartedly agree with this...... I am running a 750 Holley with a torker....on a mostly stock late 360.....and I bet you it could handle a bigger carburator. Ive learned this the hard way. I run 650s on 304s..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 9:02pm
The turbo post was based on what I plugged into a number of calculations based on stock intake valve, estimated performance cam opening/duration, separation and estimated 83% VE. Arm-chair I know.

90% VE Tom, just wow, never thought that could be done.

Yes - more on the Weber. Your going to have play time to get idle down to 800 to 1000 RPM though. But if you can get 90% VE now, I doubt this will be much of a challenge.

With your obvious fabrication skills, tuning skills, I still think a turbo would be something to consider, another day when you get bored.



 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 9:52pm
Originally posted by InRogue InRogue wrote:

I would believe a 40 would work better

1600 cc VW beetles generally use two IDF 40's but 1600 cc == 97 cubic inches, mines 200 ci. and ported, polished, undercut valves, multi-angle valve seats, etc. we'll see, of course, but one IDF 44 is probably not excessive here.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 9:58pm
Originally posted by farna farna wrote:

So the venturii on the IDF and IDA are changeable, the DG series is fixed. With the height of the IDF/IDA maybe you should have used a side draft DCOE and a curved adapter. The extra length and curve would add some flow resistance though. How close is an air cleaner going to be to the hood?


I have a sort of complex cool air/filter system. there's an airbox attached to the hood. it lowers down over the carb. the airbox will have a K&N type rectangular filter. there will be a soft seal to a plate on the carb. that way I can run the carb horns open. I'll photo it all soon.

Originally posted by farna farna wrote:

I'd always thought a turbo with 3-5 psi would be great, but with the rather small sealing surfaces I wouldn't put more than 6 psi to it, and even then I think I'd want to copper o-ring the cylinders or use a solid copper head gasket (the later probably the easiest). Actually, I just looked up some info about copper head gaskets and they recommend a copper wire o-ring WITH the gasket! I've seen copper wire o-rings used with normal gaskets though.  4 psi would theoretically add about 50% in power over the base power, so should be adequate.

there's simply no room for O-ring between the siamese pairs! there's about 1/4" of iron between them on the block deck.  I'm favoring reliability over output. I can't afford the experiment! fixed income and all that. I'd do that to a 232 in a second though.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 10:00pm
Originally posted by Trader Trader wrote:

Just some light math, but still need the turbo, I like it "Turbo Tom":

the math runs into the casting: there's not enough of it to re-grind anything meaningful into the old cam! I had a stock cam reground (I forget, slightly increased lift and slight increase in overlap). this was before I realized that for the OHV< the thing to do is regrind a FLATHEAD cam! it's got a lot more metal...

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 10:05pm
Originally posted by InRogue InRogue wrote:

I always ran low boost, ...

I don't think anyone ever has ever ever ever added forced induction to this particular motor. this motor has severe head sealing issues. dunno if you've looked at it, but it's got problems! not enough head bolts, uneven erratic and variable spacing, 1/4" between siamese cylinder pairs which tend to leak with age. "blown head gasket" is #1 failure on these engines, all 125 hp of them.

there's a couple of books by Dick Datson that talks about all the potential of this engine re: turbocharging, but as far as I know it's not been done. 

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 10:19pm
Originally posted by billd billd wrote:


I'd add to that that an engine is MORE than just an air pump!

IF it's tuned correctly, you actually will flow MORE air than the engine would normally pump if it was operating strictly as an air compressor sort of situation.
There's scavanging, the inertia of the air, tuning the exhaust (to aid scavanging - pulling air in while the valves are open even just a little)

I also seem to recall area expert, Ken, posted about how carbs rated the same may flow far differently - and it's not just flow, what about venturi design? I seem to recall also that the Motorcraft 4300 had a better design than some of the carbs people swear are performance carbs.
(I still want to yank and toss that bloody Edelbrock that's on my 70 now and put a properly restored 4300 on it)


YES. this "CFM" thing we've all -- me included -- took as gospel for decades is probably not half there story. on top of your excellent (and complicating :-) issues, there's usage patterns. quarter-mile needs are completely different from "sports car" use plus individual habits and ...

the current DGV 38/38 mates to the Redline adapter (to so-called "YF" pattern of the trough plate). I spent a lot of time an effort mating and pinning it into an integrated flowing system, opening it up as much as possible. I have no real way of making flow visible; but it got a lot of attention. maybe I made it worse! lol. I don't think so.

my fear is that the 38/38 is actually adequate, and it's this adapter that is dominant flow-limiter. I'm sure it's is so, slightly, but all my research seems to indicate that two 48 mm bores is "correct" for 200 cu in. so dual 44m should be OK. 

I've already taken out the boost venturis and made them as close to perfect as possible. there's a lot of flash in there.  they are now spotless in and out, sharp edges, no more flashing occluding inner passageways. I'll put pics up soon.



Quote
Anyway, good luck! Go by real life and skip the simplistic calculations if your engine is not stock and you have good pipes, good scavanging and so on.

exactly. trying to look skeptically at the "lore" and go by measured results. 

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 10:27pm
Originally posted by Trader Trader wrote:

90% VE Tom, just wow, never thought that could be done.

that's a guess of course. I'd earlier assumed 80%, FWIW, and the few calcs I can do and match with reality seemed to agree. this head has had a lot of work, but who knows? 

it's all talk until I can get some numbers or something objective. with the Accusump (and so no oil pressure loss in turns) I plan on autocross again, and then I'll have a relative measure. ill do some 0-60 times. 1/4 mile is 17 sec more or less, but it's geared for fast highway. (I made one run once in my life ever, so it's a poor measure. it was actually nearly 18 sec by my reaction time was 800 mS! d'oh!)

Yes - more on the Weber. Your going to have play time to get idle down to 800 to 1000 RPM though.
[/QUOTE]

not sure what you mean here? idle's off the screws, nothing above the throttle plate. it will "idle" at 400 rom, but that's not very useful. I keep it at 700 generally. 


1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken_Parkman Quote  Post ReplyReply Direct Link To This Post Posted: Nov/26/2018 at 10:58pm
BTW top end race stuff is over 120% VE NA. To make more power you want to improve VE, so it is a target, not a given for a particular engine.

But not going to make huge VE numbers with the intake built into the head, but you have to try. Also BTW - that is one awesome project, and using a flathead cam core - brilliant!

Also carbs are hugely affected by induction system design - for example IR systems have to be way bigger cause each cylinder has to get its charge in a portion of a revolution and through only one venturi. Don't use plenum V8 carb theory in other applications, or IR theory on a partial or full plenum intake. I could also go on about pressure drop and carb ratings, but you guys are tired of me ranting about it and so am I.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/27/2018 at 1:48pm
I'm not tired Ken. Like being corrected and also like learning - every day.
Love to hear/read more on the pressure drop and carburetor ratings.
If you can reference some articles or books, I for one, would certainly read them! 
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