14 replies to this topic

[zakats]

'because eldo's pictures aren't available anymore!

[BigOrange]

what do you want? Pics of a possible air box for a stock carb? An air plenum for side draft style carbs? Boost and carbs are not the easiest or most efficient way to boost an engine. Although really its all analog how can you go wrong. lol If you can settle with the happy medium of a carb turbo set up then your good to go. They are usually over carbed with no low end power with possibly even bogging. But top end power feels incredible. Also depending on your carb(s) you may need to have them built for boost, to prevent air pressure from going into the carb and preventing fuel from going into the engine. Also floats can get crushed as well. But for a lower boost set up it's not of grave concern. You can use a fuel pressure riser to help prevent boost induced fuel starvation and you can also gain some tune-ability to run a more efficient sized carb with a raising pressure rate to richen the top end fuel mixture. Really a draw through turbo set up would be awesome with a single side draft carb feeding the engine. Draw through is relatively easy and works well for lower boost applications.

Jegs sells a nice universal style collector for carb turbocharging.

Also a company in Florida makes boost friendly air plenums for weber style side draft carbs. I cant remember their name off hand but they have the worlds fastest carb turbo 4 banger. Google can help with your carb boost exploration.



Good luck That was my original dream for my wagon almost 8 years ago. Kinda wish I had done it and not sank a kings ransom into my car. lol

[1986rex]

sure would like to see some pics also and what needs to bee done i really wanna do this to mine

[EuphoricBlue]

Really a draw through turbo set up would be awesome with a single side draft carb feeding the engine. Draw through is relatively easy and works well for lower boost applications.

Draw Through - Annoying to start, harder to fine tune mixture, not practical to intercool, but does not need any special work to the carb. Just jet and go. Requires less parts.
Blow Though - Runs and starts like an NA carb, intercools like any other turbo, special mods required to pressurize carb and float bowl. Requires more parts

[bigboi407]

Draw Through - Annoying to start, harder to fine tune mixture, not practical to intercool, but does not need any special work to the carb. Just jet and go. Requires less parts.
Blow Though - Runs and starts like an NA carb, intercools like any other turbo, special mods required to pressurize carb and float bowl. Requires more parts

the Carbd Turbo setup "Sounds" nice but as ive always heard because the engine is a Carb and not Injected that the fuel mixture will NEVER be correct due to the rapid change of RPMs and the boost requiring the carb to provide more fuel than carb can produce, is that the case??? it was something along those lines

i would like to run dual webers on my civic, this thread made a turbo pop in my head, but it sounds like too much of a hassle to get a turbo to work on carbs... not that dual webers would work with a turbo.. just a thought..... i think id rather do a swap if i was gonna boost...

Edited by bigboi407, 14 October 2011 - 07:35 AM.

[EuphoricBlue]

the Carbd Turbo setup "Sounds" nice but as ive always heard because the engine is a Carb and not Injected that the fuel mixture will NEVER be correct due to the rapid change of RPMs and the boost requiring the carb to provide more fuel than carb can produce, is that the case??? it was something along those lines

i would like to run dual webers on my civic, this thread made a turbo pop in my head, but it sounds like too much of a hassle to get a turbo to work on carbs... not that dual webers would work with a turbo.. just a thought..... i think id rather do a swap if i was gonna boost...

This is going to be long...

It is true the mix will never be as good as FI models, but you can definitely tune it to be in the ballpark and on the rich side.

As for not being able to supply enough fuel, we're talking 5-10 PSI of boost here. The carb can easily supply enough fuel for that, but it does need to get modified for that.

-------------------------------------------------------
Draw thru carb: Since it works just like an NA setup as far as the carb is concerned, you just need one capable of making the kind of power you want. With a peak output of about 200HP from our engines, you have a lot of choices. It is tuned the same way as you would tune an NA, you'll simply need a larger power valve.

For all practical purposes, you are restricted to 1 carb per turbo, and no intercooling.
The shorter the plumbing between the carb and the cylinders, the better for starting and stability of idle and such.

-------------------------------------------------------
Blow Through: (This is the long one)

The carb needs to be sealed to pressurize for a blow through application.
The secondaries need to be made manual.
The power jet needs to be enlarged to supply enough fuel under boost.
You need a rising rate fuel pressure regulator and a pump capable of supplying ~10 PSI above the target boost pressure.

At idle and cruise you run on unmodified jets and the carb functions the same as it would NA.
Once you go WOT, you engage the enlarged power jet and the car builds boost.
Once you build boost the float chamber pressurizes but at the same time the rising rate fuel pressure regulator increases pressure thus maintaining the pressure difference at the needle valve within spec and it continues to function properly.

When you build boost the fuel is no longer drawn in, but rather pushed through the jets by the pressure difference between the float chamber and the intake throat. There is a natural pressure drop after the throttle valves(butterflys) And since the fuel pressure doesn't drop as rapidly as the air moves from the butterfys, there is a higher pressure in the float chamber than the intake manifold, thus fuel is pushed into the manifold. The size of the power valve determines how much fuel is pushed in.

You can also vary the pressure difference by installing a restrictor plate a few inches before the carburetor and feeding the pressure before the restrictor into the float chamber. The greater the restriction, the greater the pressure difference, the more fuel is forced into the intake manifold. This can be utilized for fine tuning the mixture, but is not mandatory.

Boost reference:
Float chamber > Charge piping before the butterflies
Fuel pressure regulator > Ideally, from the float chamber. But the same source as the float chamber reference works.
Boost gauge > Intake manifold if you want to see what the engine is getting / Charge piping if you want to see what the turbo is building.


That's the basics of boosting a carb...

Confusing enough for you?

[mugencrxpro]

Yes, very confusing.

[3gencivic]

hi there. well i belive other then eldo im the only one left that has any of the carb turbo info or pics. i also have 2 full systems thats im tring to sell as i nolonger own a honda.

i have the original system that he helped crxdan build. and a system a friend built to better me..

i will post up the pics in a few days as im going to be in the hospital on monday with the wife having our 2nd kid. ( reason im not woring on cars kids..)

it a duable setup and streetable.
i was only half done running it on 6psi with out any carb modds and it was nice. to drive. my setup was able to handle 12psi. and make about 200-240hp. lots of engine work done too. for that.

[3gencivic]

[zakats]

what do you want? Pics of a possible air box for a stock carb? An air plenum for side draft style carbs? Boost and carbs are not the easiest or most efficient way to boost an engine. Although really its all analog how can you go wrong. lol If you can settle with the happy medium of a carb turbo set up then your good to go. They are usually over carbed with no low end power with possibly even bogging. But top end power feels incredible. Also depending on your carb(s) you may need to have them built for boost, to prevent air pressure from going into the carb and preventing fuel from going into the engine. Also floats can get crushed as well. But for a lower boost set up it's not of grave concern. You can use a fuel pressure riser to help prevent boost induced fuel starvation and you can also gain some tune-ability to run a more efficient sized carb with a raising pressure rate to richen the top end fuel mixture. Really a draw through turbo set up would be awesome with a single side draft carb feeding the engine. Draw through is relatively easy and works well for lower boost applications.

Jegs sells a nice universal style collector for carb turbocharging.

Also a company in Florida makes boost friendly air plenums for weber style side draft carbs. I cant remember their name off hand but they have the worlds fastest carb turbo 4 banger. Google can help with your carb boost exploration.



Good luck That was my original dream for my wagon almost 8 years ago. Kinda wish I had done it and not sank a kings ransom into my car. lol

Inspiration- what works, what doesn't... etc

[zakats]

most of the pictures are too small to see, can you repost?

[3gencivic]

those are the best i have right now. some reason those were big and then now on this new computer there small files.
i no longer have the car eather so its not like i can go take pics again.

[87b16a ccivic]

those are the best i have right now. some reason those were big and then now on this new computer there small files.
i no longer have the car eather so its not like i can go take pics again.

I built a Suzuki carb turbo from scratch ran well had it on 15 psi before I sold it and bought my 87 civic.
Here's the link with pic if the pics will help.
http://www.cardomain...98-suzuki-swift

[zakats]

Neat! what sort of carburetor is that? did you modify anything other than jets?

[87b16a ccivic]

Neat! what sort of carburetor is that? did you modify anything other than jets?

yes i had to get the shaft pressure-rise and that was it.