Ultimate carburetor

Alright, so bear with me here, I have a question. I've been doing a bit of research on different carburetors and what not, but I haven't quite found what I'm looking for. So lets just say you could choose any carburetor(s) you wanted to put on say about a 230 cubic inch engine. Low RPM, looking for tons of low end torque, maybe good economy (not worried about MPG for cost reasons, I'm looking to have a very large mileage range between fill ups to increase the time I can travel without worrying about finding a gas station) What would be the best type? Small 4 barrel? 2 barrel? Dual singles? Don't worry about if there is an intake manifold that has the right bold pattern, thats not important. What would be the ultimate carb setup? Wild and crazy, realistic, lets hear your ideas.

The ultimate carburetor is fuel injection.......

No trying to be smart about it, but in reality, a carburetor is nothing more than a crude mixing device, subject to so many outside influences, that it is hard to get a one-size-fits-all carburetor.

Intake tract design is a huge factor first of all. The length, and size of the runners has a very big effect on mixture and velocity of what enters the engine.

Intake air temperature (ideally 140-160 degrees F) is very hard to maintain in an older thermostatic air cleaner system to promote the best combustion possible. Also keeping the intake temperature consistent is a must. That was done crudely for many years with heat risers and coolant circulation. Even EFE electrically heated grids were used too, but they proved to burn out in time.

Several smaller venturis are better than one large one, because the air flow is more evenly introduced and more efficiently atomizes the fuel to mix with incoming air. Ideally a 14.7 to 1 ratio of air-to-fuel is sought after, but next to impossible to maintain with a carburetor.

Carburetors are also subject to one factor that cannot be controlled: wear. Throttle shaft wear, and other moving parts make maintaining that 14.7 to 1 even harder. Couple that with engines of poor design to start with (i.e. large intake valves, huge camshaft durations and overlap) and they don't respond well no matter the good intentions to make them better.

Consider this as well: The last car to use a carburetor in production was a 1989 Hyundai Excel. The last truck was a 1993 Isuzu pickup.

Let's just say they have their limits. Efficiency is not one thing they were ever known for.

I totally agree with Randy, Use a 4.3 throttle body F.I. but a very good simple carb is the 2brl rochester off of say a 75 v6 buick, my 68 chev had one also. I installed a holly 4 brl and header w 2.5" exh on a 300 ford and boy did it wake up! I used to put a roch. 2 brl on it to pass emisions and it too worked well. With the holley and the overdrive trans it got (1/2 ton 84 f-150) 21mpg a couple times going real easy staying out of the last two venturies. The 2brl came off of that 3.8 75 buick.

For optimum cost vs performance/efficiency use a weber carb for a 258 motor. Better efficiency, 2 bbl and great offroad performance.

I forgot about that one, they have a lot of jetting differences, they came on v6 capris, and I'm sure many others. And the mounting flange might be closer to the civy 230 2brl
flange. Brandon, you have one of those don't you? A header and a proper supply of petrol and you've got one of those hot Argentine motors. COOL!

The Argentine motors didnt get hot until they made a new intake where the intake had 1 port per cylinder with MUCH more flow than the stock manifolds our trucks have/had...

Side draft Webbers!!!!!

In response to the original question....

The stock 1920 1 barrel has worse fuel mileage and less power than the approx 350 cfm Holley 2415 2 barrel I now have from a civvy 230...there was also a 2300 Holley 2 barrel used on civvy applications, also approx 350 cfm.

The 2 barrel has noticible power and mileage increases as one doesnt have to hold the throttle open as far or as long to get the same speed.

With a stock 230, roughly 9 MPG was the limit. With a civvy ignition, Selectros and the 2 barrel, these changes done in stages not all at once, netted 12.25 MPG highway and single tanks in excess of 280 miles without a stop.

NOTE: The change to the 2 barrel DOES lower the torque right off the line. One can still start the truck n gear with the starter button and idle along at 500 rpm in 1st gear but when taking off from a dead stop 2nd gear, high range, one will notice the engine lugging a little where it didnt with the 1 barrel.

So, for low end torque, as small a venturi or venturis as possible...if there is even a 300 cfm or smaller 2 barrel out there that would fit...

If you are willing to sacrifice a little on the low end you can get better mileage and power across the rest of the rpm range with approx a 350 cfm carb.

Find a way for the intake side of the head to breathe better and you can go higher...as it is stock, the ports from the intake into the head, when figured in area, are only a slight fractional size different than the throttle plates on the 350 cfm 2 barrel...I believe the difference was less than 1% in total area across both...real close.

I forgot to add, with the 230, the head design will pretty much limit anything you do. The port design is pretty rigid and not able to be modified for better flow.

X2 or x3 or whatever it is for weber.

I dislike electronics and will gladly sacrafic a smidge of economy in favor of less headaches.

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Originally Posted by saxon

A header and a proper supply of petrol and you've got one of those hot Argentine motors. COOL!

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Haha, if I could find a way to squeeze a couple more main bearings, then I might be close to the IKA motors. ;)

Currently I am running the 350 cfm 2-barrel carb, definately a major improvement over the stock single barrel. I'm only getting just shy of 10 MPG though on the highway.

The intake ports could be modified for much better flow if one had the tools and talent.

The water on the intake side of the head comes in from the bottom of the stock intake, in the middle of that side of the head and nowhere else. The intake side of the head is a big hallway that runs from front to rear with all the ports breathing off of that.

If one wanted to, take off the stock intake and cut into the hallway on the head and make ports that line up with the ports to the cylinders. Then drill and tap the outside of the head for bolts/studs. Make an intake that bolts to those holes and has ports on it that go from the side of the head into the ports in the head to the cylinder...so there would be a couple inches of port on the intake after the standard flange area.

You could also cut out the side of the head from front to rear and make a plate that fit the internal, to cylinder ports and allowed for a manifold to bolt to it...this could be welded in...

One could even start with an existing I-6 intake off something else and use its flange area back to the carb mount as a starting point and make the part in the head to fit the manifold from the other application.

If one wanted to add a turbo or other forced induction, this would be something that would really help the breathing.

It seems so strange to make a crossflow head with an unshrouded hemi chamber, great exhaust ports, lightweight and sturdy valve train and leave the intake area more restrictive than any engine one can think of...even down to half the cubic inch or less in size.

Yup, I thought about doing that, I've got a couple spare motors...I'm just not sure about welding to the head. Isn't it cast?

Yep...its cast...requyires more skill but do-able...

Could always bolt a flange to the outside of the head and use the extended runners.

Alright, just to help anyone who isn't sure what we are talking about, I have to share some pics of the bad-a IKA tornado that was found in the Torinos. They did some cool stuff with them. Interestingly, some of the pictures show what appears to be a comparison from what we have, the 2 port "hallway" intake, to what they ultimately did with individual intakes. Or possibly they may have even made some with our type of intake and then later came out with the newer version.

http://img383.imageshack.us/img383/1...rnado01nm9.jpg
http://img383.imageshack.us/img383/1...df50db0d17.jpg

http://img207.imageshack.us/img207/8...rnado02zp9.jpg
http://img207.imageshack.us/img207/8...eb9a81b2e8.jpg

http://img171.imageshack.us/img171/2...rnado03pt3.jpg
http://img171.imageshack.us/img171/2...03574427bf.jpg

http://img171.imageshack.us/img171/5...rnado04ej2.jpg
http://img171.imageshack.us/img171/5...76aa4037fc.jpg

http://img141.imageshack.us/img141/1...rnado05fy2.jpg
http://img141.imageshack.us/img141/1...65f2568c29.jpg

http://img141.imageshack.us/img141/2...rnado06zi1.jpg
http://img141.imageshack.us/img141/2...68ae7dd08a.jpg

http://img171.imageshack.us/img171/3...rnado07fk8.jpg
http://img171.imageshack.us/img171/3...e978059084.jpg

Turbo is hot looking!

I like the 2nd image with the header...better than I found for the other thread...

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Originally Posted by brute4c

In response to the original question....

The stock 1920 1 barrel has worse fuel mileage and less power than the approx 350 cfm Holley 2415 2 barrel I now have from a civvy 230...there was also a 2300 Holley 2 barrel used on civvy applications, also approx 350 cfm.

The 2 barrel has noticible power and mileage increases as one doesnt have to hold the throttle open as far or as long to get the same speed.

With a stock 230, roughly 9 MPG was the limit. With a civvy ignition, Selectros and the 2 barrel, these changes done in stages not all at once, netted 12.25 MPG highway and single tanks in excess of 280 miles without a stop.

NOTE: The change to the 2 barrel DOES lower the torque right off the line. One can still start the truck n gear with the starter button and idle along at 500 rpm in 1st gear but when taking off from a dead stop 2nd gear, high range, one will notice the engine lugging a little where it didnt with the 1 barrel.

So, for low end torque, as small a venturi or venturis as possible...if there is even a 300 cfm or smaller 2 barrel out there that would fit...

If you are willing to sacrifice a little on the low end you can get better mileage and power across the rest of the rpm range with approx a 350 cfm carb.

Find a way for the intake side of the head to breathe better and you can go higher...as it is stock, the ports from the intake into the head, when figured in area, are only a slight fractional size different than the throttle plates on the 350 cfm 2 barrel...I believe the difference was less than 1% in total area across both...real close.

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Are you still running the Holley 2415 2 barrel? Did you change the intake?

EFI exists in a 2 barrel setup already... its a bolt on affair..

2 barrel Holley EFI carb setup...

https://encrypted-tbn3.gstatic.com/i..._cV_Bm4DLhrufQ

https://www.summitracing.com/parts/h...-200/overview/

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EFI exists in a 2 barrel setup already... its a bolt on affair..

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Very cool. But pricey. And it might be a tad large at 670 cfm for a stock motor.

2k? *gulp*

I ran a 2415 holley on a civvy 230 2 bbl intake till i sold it...worked great. The factory also used the 350 cfm 2300 holley carb on the civvy 230. They make a 500 cfm 2300 holley but that is too big...unless you are looking to drown the thing... :)

We ran the Holley 2300 500 CFM on our stock car back in the 80s. It was a Chevrolet 230 CID, inline 6. But... it had a long duration, high lift cam so it was able to handle the induction. We also had headers and a gutted intake manifold.

All that being said, is their a long duration/high lift cam for the Jeep Tornado 230 CID? No, just asking, don't want one...

No cam choices that i have ever heard of...civvy and mil are the same grind. The argentine one probably had better if you are really heart set on it... ;)
The chebby 230 had intake manifold carb mounting holes big enough for the 500 cfm carb....i dont tnink the jeep 230 even has that, though i know i measured once the outlet ports on the 230 jeep manifold and figured the cross sectional area and then the cfm flow and it came out just above 350 cfm...like 362 or so...so anything bigger would be a waste in my book...

Quote:

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Originally Posted by brute4c

No cam choices that i have ever heard of...civvy and mil are the same grind. The argentine one probably had better if you are really heart set on it... ;)
The chebby 230 had intake manifold carb mounting holes big enough for the 500 cfm carb....i dont tnink the jeep 230 even has that, though i know i measured once the outlet ports on the 230 jeep manifold and figured the cross sectional area and then the cfm flow and it came out just above 350 cfm...like 362 or so...so anything bigger would be a waste in my book...

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I totally agree.

I have no intention to "hot rod" a Jeep 230. If for no other reason, it is a long stroke engine (torque) and to do too much to it would make it throw itself apart.

We used the Chevrolet 230 because of the crank balance offsets but a 250 would be more HP. Now some guys used the 292. It was a screamer but they all ultimately threw themselves apart.

I once hopped up a Chrysler 225 slant six in a Dodge Dart. Offenhauser 4bbl intake, hooker headers, 2.5" exhaust all the way to the back of the car, duals of course. The carb was a Holley 4160, about 400 CFM. It was a sleeper, street tires, Chrysler 4-speed, 8.75 rear but street gears, 3:23. I also had a Racer Brown Purple Stripe solid cam, basically a hemi grind. But I also took .055 off of the head and .050 off of the block, used a steel shim headgasket. (High Test Gas Only!)

Speaking of the head, I put '66 Buick GS 400 valves in the head, 360 MoPar valve springs and opened up the ports to match the valves, intake ports and header ports. The head diameter of the valves were identical to a Chrysler 318. But I could not use Chrysler valves because the stems were too long. The TRW engine parts catalog brought it all together since sizes of everything was there.

The car had Air Conditioning. It would freeze your arse out (oh yeah, R12 freon). But the duration of the cam made it lope a lot. If you cut on the AC at idle, it would kill the engine because of the overlap in the cam.

Lot of fun and somewhere, I have B/W pictures of putting that engine together.

(Hope I didn't hijack this thread!)

Sounds kind of like the factory hyper pack 6...real sleeper material...heck even a 2 bbl and mild cam wakes up a 225 over the stock 1bbls...

Gronk Performance is selling a two barrel Mastercraft 2100 conversion for the 6-230, and lucky me, I live about 40 minutes from Gronk, so I bought one ($315 delivered) and he came over and put it on for me last weekend ($100). Gronk is awesome, and the carb made my 230 come alive. I am very happy so far, as the truck came from Iowa, and jetted for that elevation, and I am here in Colorado Springs, so upgrading from the 1920 to the 2100, and jetting properly obviously helped!

You can find this mod on ebay here, and Gronk was great to work with. After I get my windshield back from my glass guy, I will be driving it more, and will report back to you all here.

Update: So I wanted to engine to look stock even though I have a MC2100 carb. The air cleaner needs modification to fit on top of the new two barrel carb. Lucky for us, the indentation on the bottom of the stock air cleaner is just a little larger than 5 1/8", so you can take a jigsaw with a metal cutting blade and zip out that center part, leaving a little lip, and then RTV in the 5 1/8" ring for the new carb (stolen from a cheapie Spectre air cleaner). Drill a hole in the lid (spin it to find dead center, mark with sharpie), and with the exception of a wing nut on the top of the lid it looks stock and hides the two barrel carb. Pretty cool. Now I have to find a crankcase breather filter and a union so that the crankcase and the fuel line breather can get clean air, but everything else plugs up as it did before.

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Originally Posted by ColoradoSpringsRob

Gronk Performance is selling a two barrel Mastercraft 2100 conversion for the 6-230, and lucky me, I live about 40 minutes from Gronk, so I bought one ($315 delivered) and he came over and put it on for me last weekend ($100). Gronk is awesome, and the carb made my 230 come alive. I am very happy so far, as the truck came from Iowa, and jetted for that elevation, and I am here in Colorado Springs, so upgrading from the 1920 to the 2100, and jetting properly obviously helped!

You can find this mod on ebay here, and Gronk was great to work with. After I get my windshield back from my glass guy, I will be driving it more, and will report back to you all here.

Update: So I wanted to engine to look stock even though I have a MC2100 carb. The air cleaner needs modification to fit on top of the new two barrel carb. Lucky for us, the indentation on the bottom of the stock air cleaner is just a little larger than 5 1/8", so you can take a jigsaw with a metal cutting blade and zip out that center part, leaving a little lip, and then RTV in the 5 1/8" ring for the new carb (stolen from a cheapie Spectre air cleaner). Drill a hole in the lid (spin it to find dead center, mark with sharpie), and with the exception of a wing nut on the top of the lid it looks stock and hides the two barrel carb. Pretty cool. Now I have to find a crankcase breather filter and a union so that the crankcase and the fuel line breather can get clean air, but everything else plugs up as it did before.

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This mod just made my watch list. Thanks!

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You bet. Will post photos this week.

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Originally Posted by ColoradoSpringsRob

You bet. Will post photos this week.

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Are you still happy with this upgrade? I'm thinking hard on it. [emoji846]

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