Dual carbs???

[yamahlr]

I still have a Mikuni sidedraft for the G54B. PM me if anyone is interested as I previously listed it in the for sale section. The 44s are what JB recommended in the day. I have a brand new Mikuni manifold and linkage kit that's why I'm selling the used one. The carbs can be had on EBAY fairly frequently buy a bit pricey The rebuilding kits and all other parts are available from Wolf Creek Racing in New York. Actually, we's the world-wide distributor for the PHH carbs. I have a number of articles from back in the day.The Mikuni carbs were generally thought of to be superior to the Webers because their mounting and ability to hold tuning and adjustment were superior.

[77amc]

HEY... PM'd..

I've got several pairs of carbs and more on the way.

Errol

[Rickdees]

Ever wonder why Grand Nationals were so quick, Draw thru turbo, ol skool. Still works very well and simple as pie.

[BradMph]

That V-Dub looks like it just swallowed a hummer and forced it down like a snake would, lol.

[Mandle]

In reading through suggestions, replies and posts, I think one major option is being seriously overlooked. It seems to me for the kind of money these people are spending, one could install a fuel injected motor mildy built, get better results and save money. Isn't this an insane amount of fab and expense to utilize antiquated technology?
I'm an amature mechanic. Maybe I'm putting to much faith in fuel injection?

[BradMph]

Computerized Fuel injection is better because it can adjust to conditions unlike a carb, otherwise new cars would still have carbs.

I think what your reading mostly is what people want to do independently with their modifications and what they are familiar with. You have old school and new school going on. Keep your faith and then make your own choices on what you like to do. You'll get good response either way you go I'm sure.

[77amc]

IS THERE ANYONE WHO SELLS MANDREL BENT ALUMINUM TUBING??

Son got permit and man.. I really thought that I'd have this truck running for him by now..
If I dont use that Dual intake manifold, I thought of a cheaper route by using stock intake and cutting it after it comes to a "Y", and use a mandrel "L"
to use a pair of single downdrafts sitting on top of that.

I've got a few sets of bike side drafts but for nothing over 750's though.

That Ol Rochester that I fabb'd to the Quest intake worked OK, just couldnt' get it to idle down under 1200.
I'll look at it more in a couple weeks.
E

[thehive]

The reason I went with the duel carb set up was purely for nostalgia, and to be unique.

[geezer101]

Don't get me wrong, EFI is the way to go if you're looking for a plug and play build. But there is something about old school carbies that has a craftsman aesthetic to it. A nicely built carby is a work of art in it's own right - and you don't have to have a wiring diagram and a degree in electronics to fix them...

[thehive]

Exactly, I could have DOHC Turboed my mighty max but that already been done, and quite a lot actually and I wanted to be different. And while I wont make as much power the WOW factor is deff there when you pop the hood and everyone sees multiple air cleaners

[noahwins]

As someone raised on computer everything, I like the old school look, too. Glad it's not another 4G63T swap.

Those dual sidedrafts will sound a lot better than EFI, too.

[geezer101]

There is something about hearing those secondaries crack open when you're sinking the boot into the carpet (and you can feel the mid range torque band coming out to say hello to you when you hit it right) EFI doesn't have the same magic to it...

[boozehero]

I know this thread is ancient, but here ya go..

https://www.lynxauto.com.au/lynx-manifolds/mitsubishi.html

https://www.dragtimes.com/parts/Mits...752525998.html

https://www.weberperformance.com.au/...roducts_id=539

Not sure if these are still available, but I do know the Aussies are way into this stuff.

[dash]

no secondaries in dual sidedraft carbs
nostalgia is about all you get.
Crappy obnoxious loud induction noise, draw attention
.....while mom in her minivan full of kids, laughing while leaving the noisy pickup in the dust
Probably too much carb for a street 4
Duals guzzle gas too. My dual mikunis (even with their jetting/tunig kit) were a total waste
A basic starion 2.6 or the mildest of DSMs.... are on another level, of quality, hands down

[xboxrox]

Don't get me wrong, EFI is the way to go if you're looking for a plug and play build. But there is something about old school carbies that has a craftsman aesthetic to it. A nicely built carby is a work of art in it's own right - and you don't have to have a wiring diagram and a degree in electronics to fix them...

Some audiophiles spend tons of money on old electron tube components to hear the better sound quality tubes provide over what transistors micro chips can do ~ newer is not always better ~ did you know electric cars & trucks were in use long before combustion engines came to being !! Electric motors make better power than combustion engines ~ if you don't think so then why did trains go from steam to diesel to electric..?

[geezer101]

^I've got a friend who has built his own tube amps and they do sound different. Getting tube valves are the harder part - he had to resort to using military grade tube valves from Russia!

[xboxrox]

TUBE VALVE ~ we don't need no stinking badges..! Opps wrong movie he he ~ I dunno whatza tube valve

google says: Same thing but how they say vauum tube in England ~ they say Tube valve

[dash]

On topic of: carbs vs efi..... newer IS always better. No comparison really

[xboxrox]

Does NASCAR still use carburetors..? If so, a simpler way of catching cheaters & equalizing or limiting the horsepower for a level playing field..?

Got my answer here ~ they use both but only manual transmissions
https://en.m.wikipedia.org/wiki/Fuel...tion_in_NASCAR

[geezer101]

Does NASCAR still use carburetors..? If so, a simpler way of catching cheaters & equalizing or limiting the horsepower for a level playing field..?

Got my answer here ~ they use both but only manual transmissions
https://en.m.wikipedia.org/wiki/Fuel...tion_in_NASCAR

There was but they found a way around it. They installed throttle plate restrictors in the 4 BBL adapter plates but smart asses made slide in cartridges so you could swap the restrictors out without needing to remove the adapter!

[xboxrox]

FWIW ~ I onced owned a car with twin side draft carbs from the factory ~ 1972 Datsun Sunny Excellent JDM model that I owned a few years while USN stationed me near Yokohama, Japan ~ fun cool car became worth more than the nice new Toyota Celica only because they made very few of this top model ~ the engine was 1400cc same as the 240Z Datsun SOHC with twin SD SU (Stewart Warner?) Single barrel carburetors and 4 speed manual tranny ~ I bought a air manometer from JC Whitney to synchronize the opening & closing of both carbs ~ using throttle linkage adjustment and matching how high the ball went up the glass tube got twin carbs matched ~ the gauge had a foam base to put over the throat of the carbs ~ it worked to make smooth even power BUWAAAAH

[Salteen]

there is such thing as too much carb. i think there may be too much carbueration going on. heres why:

first lets cover basics. head flow, camshaft, and displacement. exhaust system has some degree of effect but for simplicity's sake lets not include it, we know aftermarket exhaust helps power (it only begins to really effect when you have a moderate street motor and you have a stock manifold)

these motors are about 95% volumetric efficiency (higher if you install a bigger cam or a higher flowing head) and really wont rev out past 7 grand. they displace 2.0L or 2.6L which is about 122 and 158 cid respectively. so to formulate this we will take rpm x cid / 3456 x volumetric efficiency

if we do this, the 2.0 will require about 235 cfm of carb in stock form, the 2.6 about 300 cfm.

now with this in mind, 4 barrel carbs are tested at 1.5 inches of vaccum, 1 and 2 barrels are tested at 3 inches. so we multiply our result by 1.414

the ACTUAL CFM REQUIRED for a 7000 rpm motor (god forbid any street motor reach these rpm's) is about 330 cfm for the 2.0l and 420 cfm for the 2.6L

the average motorcycle carb flows something like 100 cfm for 200-300 cc single cylinder dirt bike engines. running 4 on a 2.0L may be slightly overboard but on a 2.6L that would be plenty.

now lets assume we never spin the engine past 6 grand (more reasonable). now our cfm drops from 330 and 420 to 285 and 365 for the 2.0L and 2.6L respectively.

also keep in mind having individual runner intakes will tremendously decrease low end performance for the sake of some top end power. probably not ideal to lose torque considering our trucks, it may be acceptable for a 2.6L. but a 2.0L will need some porting and a cam before it ever needs 400 cfm of carb (which if you wanted to use a 4 bbl, 400 cfm of single barrel carbs flows like a 282 cfm 4 barrel. so if anyone is looking to run a 4 barrel with vaccum secondaries on a intake with a shared plenum (ideal for intake scavenging and low end power) then a 300 cfm would be fine on a 2.6 engine.

also you can offset grind the crankshaft to a smaller rod size to increase stroke (although they are 45mm which is pretty small), and overbore the engine i beleive 1.5mm is the max and 2 is possible with sonic checking and you can resleeve it and go 3mm. 3 mm overbore would give you about another .1 L displacement. then youll need even more carb and a slightly bigger cam OR a ported head to offset losses in volumetric efficiency

to sum it up, its good for some hp gains but you could see your torque curve move out and drop low end power. if you put 4 100 cfm's on a 2.0l you could use a restrictor plate or port your heads / cam swap (ported heads i reccomend more as it increases power across the board, not just in one area). on a 2.6l you can do this fine and itll work out okay but you still have torque losses and the curve will shift further to the top end of the rpm's, which these motors were obviously not designed for.

[geezer101]

http://www.mightyram50.net/vbulletin...ing-lawnmowers

[SubGothius]

Well covered, Salteen. It's been conventional wisdom in my other Fiat-Lancia scene that -- aside from replacing their US-spec undersized 30/32 barrel carbs with their stock RoW-spec equivalent (twin 34 barrels) -- there's no point in upgrading further to dual Webers (4 larger barrels, 1 per cylinder) and/or hot cams, unless and until we've already rebuilt the block with high-compression pistons (going from US-spec 8:1 up to at least RoW-spec 8.9:1 or better) and maybe a bore-out, or else the better breathing of those hot carbs and cams just go to waste.

Plus of course, as you say, there's a tradeoff between low-end torque vs. high-end peak HP; what's good for one tends to be bad for the other. I reckon few of us will be doing any track time in our trucks where high-RPM peak HP would matter, and if we're using them for any sort of hauling/towing duty or just routine street driving, we'll use and notice and appreciate low-end torque a lot more. Torque is what we feel as that boot in our seat when we hit the gas; HP is how quickly the speed adds up at a given RPM, and a peaky curve that really only delivers when fully wound-out isn't much use (nor fun) on a working/street truck.

[Salteen]

http://www.mightyram50.net/vbulletin...ing-lawnmowers

i did a readup on this. some more thought has led me to think on how you can improve this system. a great way of improvement would be to basically copy the intake design of the crossram intakes on the old chrysler b and rb engines. they are a dual carb setup and the intake stretches out. i think theres a "short" 18 inch and a longer 32 inch intake not entirely sure. but its designed so that the intake manifold provides a supercharging effect at low rpm's and it makes pulses in the manifold each time the cylinder pulls its intake stroke. if you could manage to make a intake that turns up and reaches to the hood and then turns back across the valve cover, youd be in business but the crossram had half of each of its cylinders on a shared penum so i would build a "plenum box" at the end to help direct airflow, then mount your 4 carbs on. or dual webers or the such.



1960's chrysler crossram