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Guest Message by DevFuse
 

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So, theoretically, why wouldn't a turbo on a carburator work?


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#1 JonOfScio

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Posted 05 September 2003 - 08:54 AM

So, people tell me this and that, this and that, about turbos and whatnot. I'm not looking for "well, you need less CR and carbed cars don't have it." I'm talking about just the carburator itself. I really don't think anything restricts the carb from working with a turbo.

Well, they put superchargers onto carburated systems, and the basic idea of the supercharger is the same as the turbo: forced air induction.

you can either do draw through, or push through.

So if you can put a supercharger on a carburated system, why not a turbo?

The idea of the carburator is that it has venturis, and when air passes through, they create a vacuum that sucks in fuel and spits it into the intake.

Alright... so, if you open up throttle, increasing air going through, then you get a bigger vacuum, pulling in more air. Then the only problem to have is that it is mixed right for air to fuel ratio.

Now, you're going to need a carburator that will handle the amount of CFM of the turbo/supercharger, and jets that will be able to jet out the newer higher amount of fuel. And I do believe that jet work is more or less a trial and error process. To much, runs rich, too little, runs lean, and the latter is the worst I do believe. (holes in the pistons.... yeah baby, yeah!)

So, as far as JUST the carburator goes, the venturi principle is like a build in MAF sensor on the fly. The air moving by makes the carb spit out more fuel... so... why wouldn't a turbo work? superchargers do?

And another thing, if I were to do this, I would of course put in turbo pistons. (duh)

#2 oobnuker

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Posted 05 September 2003 - 09:30 AM

Couple of things with carbbed turbo's. If you push through the carb, then the carb has to be sealed, etc. (throttle shaft, etc.), also the float has to be solid or it may collapse, and so on - things related to pressurizing something that wasn't meant to be pressurized. If you draw through the carb, then you are drawing fuel through the turbo, which could lead to interesting effects and has to be dealt with.

Also, you couldn't really intercool a draw through turbo, because the fuel would fall out of suspension and puddle in the intercooler. I suppose you could intercool a push through setup.

I have also heard of old school racers putting the carb in a pressurized "box" - that way it didn't really need to be sealed. This is all old-school crap.

I had a carbbed, 1980 Turbo Chevy Monte Carlo with the 1st generation Buick Turbo 3.8 V6 - what a crazy setup it was - draw through with a whacky plenum that the carb sits on attached to the turbo... These motors didn't make power until they became EFI...

Bottom line - I don't honestly think there are ANY advantages to running a carbbed turbo setup, and plenty of disadvantages. Tuning the carb to be driveable off boost with the primaries and then having much much larger secondaries for on boost, etc. Also, a relatively large carb CFM-wise while off boost, etc. Becomes a nightmare in my opinion...

It would be quite an accomplishment I guess, but for what? I don't think you would see the same results nearly as easily with a carbbed motor as you would with an EFI one...

#3 JonOfScio

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Posted 05 September 2003 - 09:53 AM

yeah, just trying to figure out if it's plausible or not.

didn't say I was gung-ho for it.

My second choice (the idea is to keep the NA block and heads, change pistons, cam, lifters, rods, springs, seats, valves)

is to drill the heads for injectors, and adapt a throttle plate to the intake. I could use an EA82 SPFI intake and get a throttle plate from an EA82T. Basically, using the EA82 engine components except for the long block and intake.

Now, I know that is feasable.

Add injectors to the heads... change fuel lines, pump, ECU, add a MAF sensor, use EA82 SPFI intake, see if an EA82T throttle body won't fit the intake... use the EA82T plenum, and turbo it, BOV and turbo timer, make my own inventive oil cooler for the turbo, grab an intercooler, make my own up pipe and down pipe and exhaust.

missing anything?

I know I could transplant an EA82T, but this would be more FUN, and a challenge.

#4 Nug

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Posted 05 September 2003 - 09:59 AM

Old school crap??? Vortech just came out with a carb pressure box for use with a centrifugal supercharger. A boost-referenced fuel system is required.
You can have blowers and carbs on your musclecar without having to cut a hole in your hood. And they make power!

#5 oobnuker

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Posted 05 September 2003 - 10:08 AM

"Old school crap" said in the most loving fashion.... :D

I just meant that, sure "muscelcars" to this day are using this type of stuff - old technology, or new spin on old technology, pushrods and carbs, etc....

But come on, a carb in a box, or a tricked out EFI system - or better yet, custom CIS setup??? My vote goes to INJECTION baby!!!

I don't doubt that these muscle cars are making oodles of power and so on and so forth, but a 2.65 liter Honda Turbo V8 formula one motor is not making 900 horsepower with a carb in a box...Hahahahaha!

#6 archemitis

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Posted 05 September 2003 - 10:22 AM

if you have a car that has an efi system readily available in junk yards... it just doenst make sense to turbo a carburetor. thats why there are NO production vehicles with a turbo carb setup. other than old school stuff. just doesnt make sense. and its more dangerous, and crappy tunability... the list goes on and on. EFI step into the 20th century

#7 calebz

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Posted 05 September 2003 - 10:56 AM

Soo.. Just curious.. What do we do for the 21st century(thats where we are now)

#8 Nug

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Posted 05 September 2003 - 10:59 AM

Oh, I'm aware of the thousands of reasons why efi and turbo go together like pb and j.

I'm just saying that carbs and turbos can work.
I like to keep it fresh in my mind that there is always another way of doing something. You always have options.

Just got back from the Bugout in Manasass, VA. The popular setup on the VW-style rails is to run a non-intercooled, carbed, draw-through turbo setup on top of the motor.

If you can get a VW style engine to put out 300-650hp, then I guess something is being done right.

#9 oobnuker

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Posted 05 September 2003 - 11:30 AM

SnotRocket - Awesome! Obviously they are doing something right!

For the 21st Century - Flux Capacitors!

#10 Nug

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Posted 05 September 2003 - 11:36 AM

http://www.hotrod.co...9738/index.html

Old tech baby! Yeah

#11 lumpycam

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Posted 05 September 2003 - 12:56 PM

check this site out !

Gator Supercharger

I found it while surfing the BYB , I've read thru and found it very interesting. I've always worked with suck thru roots type blowers and prefer a blower over a turbo. I would think some of us have the ability to come up with a setup for subarus.I've always wanted to find a large deisel turbo and belt drive it for my suby,and this site proves it can be done. They even talk about the best carbs to use on there forums.
IDEA! two suby turbos , one on each side, belt driven ,blowing thru carbys.muhaahaha!:grin:

#12 archemitis

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Posted 05 September 2003 - 06:20 PM

i love it when people make a big deal out of typos!

#13 Snowman

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Posted 05 September 2003 - 07:01 PM

A while back, I stumbled upon a website documenting someone's project, which was using a carbureted turbo setup on some inline engine. I think he was using a draw-through, and it actually worked pretty well for what he was doing after a bunch of tuning. The only thing is, he was just using this car for drags, not as transportation or even as a daily driver. He didn't have to worry about fuel economy, emissions, or reliability. It's the same way with those VW-powered sandrails. Carbs can be used with superchargers relatively easily because they are running above atmospheric pressure most of the time, and boost levels are a lot more predictable than turbos due to the fact that the supercharger spins at a given RPM based on how fast the engine is turning. A turbo can be spinning and boosting at all kinds of different RPMs based on a wide range of factors, which makes tuning for both on-boost and off-boost conditions quite difficult.

It's not impossible to run a carb and turbo setup, you just have to put a lot of work into it for the engine to run well all the time. If I had a bunch of time and a spare car or two to dink with, I would experiment with something like that. If you have the means, I say go for it. If you could make that work, it would kick butt. And I would bow down to you.

#14 JParuBob

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Posted 05 September 2003 - 07:27 PM

there was an article in hot rod magazine a month or two ago, and it was supercharger vs turbo, and they used a carb.

Basically, if you put the carb in a sealed box, it basically flows twice what it normally would... I'll get the magazine and type out specifics later tonight, but they made the most power with the turbo.

#15 soobme

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Posted 05 September 2003 - 07:47 PM

OK, I'm slow, but..........I went to that "gater" link, it sound interesting. But WHAT IS IT? I didn't see where to go to find out exactly what it is (IE what componants are in it, what's it cost, how do U mount it?):confused: :slobber:

#16 AKIRA

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Posted 05 September 2003 - 07:48 PM

there is a turbokit from kenne-bell availbale for the 231 buick v-6 that my dad and I are putting in his TR7, but we aren't screwing with that! so they must work good enough to be at least useable

my dad is pretty anti-turbo for some reason, thats why I am going to put a 9.5:1 turbo in my brat!:D actually it's for performance reasons that I am using it.

#17 MilesFox

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Posted 06 September 2003 - 01:49 AM

i think the cis would be the simplest an dbest suited applicatin.

or you could slap a turbo on spfi (in a car that is already spfi)
you would have to figure out how to plumb the fittings, and get more fuel. but it has been done

#18 the sucker king

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Posted 06 September 2003 - 01:57 AM

so i may be a ******* but...ea81 turbos were FI? i din't realize that. does that mean it's relatively easy to convert a regular ea81 to FI, being that the parts are out there. what other differences/obsticles are out there?

#19 the sucker king

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Posted 06 September 2003 - 01:58 AM

wow... you can't say d u m b a s s on the new board.

#20 A_DuB

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Posted 18 November 2004 - 03:14 PM

The problem with EFI is that if you need to check weather or not your getting gas to the cilinder there is no way to check and see if its getting there since its all electronicly conntrolled

#21 archemitis

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Posted 18 November 2004 - 03:52 PM

The problem with EFI is that if you need to check weather or not your getting gas to the cilinder there is no way to check and see if its getting there since its all electronicly conntrolled


huh?

#22 dave valiant

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Posted 18 November 2004 - 07:31 PM

Yes you can and it can work well and be reliable.Back in the 70's during the gas crunch alot of people started turbocharging Ford Pintos.My freinds father still has the one he did and it is his daily driver.In a drag race that pinto would smoke a WRX.He upgraded to a 5 speed and a better rear end and runs a T-3 turbo.He drives it all year round.I will try to get some pictures of the turbo setup on it.

#23 Skip

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Posted 19 November 2004 - 07:31 AM

Archi,
quote:
" thats why there are NO production vehicles with a turbo carb setup."

if you can find the time, do a Google for turbo'd Corvairs. They may have been called "Spiders".

The Roots s.chargers used suck through variable venturi carbs
(SU, Stromberg et al)
The tapered main jet needle made this possible.

#24 Dr. RX

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Posted 19 November 2004 - 07:54 AM

I wonder how I missed this posting. Looking at the ages of those who list them, it appears that I was running my turbo cars before most of you were born. Back in the good old days when nobody knew anything about turbocharging, we did a lot of weird things. My 57 Chevy had several engines in it, one was a dual quad, dual turbo'd 283, each carb had it's own turbo run off of one of the sides. The turbo blew directly into the carbs. At first it worked really well, but since we didn't know about having to seal the carbs, after awhile (a very short while) the pressurized carbs were leaking everywhere. The next setup was to use Hilborn injection, but again, the butterfly linkage was not sealed (pressurized) so there was blow by there to. I finally settled on a 327 with the Hilborn injection, and no turbos. But that didn't stop me from experimenting with turbos. Skip is right, the Corvairs had a carb turbo set up, and there were a few others, but they were limited productions since no one had really figured out who to get a turbo to work efficiently back then.

#25 MorganM

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Posted 19 November 2004 - 09:15 AM

Archi,
quote:
" thats why there are NO production vehicles with a turbo carb setup."

if you can find the time, do a Google for turbo'd Corvairs. They may have been called "Spiders".


You forgot a key part of his statements:

other than old school stuff.


It's just silly for manufactures to do forced induction on a carb now. Why would anyone really? With the advancements in EFI it makes little sense. Forced Induction EFI 2 WIN!!!!11111




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