BlueKitsune

Is it even possible to properly build an carbed turbo? (yes Im thinking of the Devil Z) I THINK the Devil Z had triple SUs and twin turbos. I dont even get how you can do that to be honest.

Skully

Don't know of the car you are speaking of, but yes you can build a successful draw trough turbo system on a carbed engine.

260zturbo

lol yeap i have this




sad part is i bought it and went with a different engine so now it just awaits for someone else. i was going to gut the carbs and drill injector holes so basically it would be individual throttle body setup. but never got around to it. mikuni carbs 40mm

BlueKitsune

Wow. That neat! Does anyone know if you can turbo Weber carbs?

And 260zturbo, Do you want to sell them? lol

NismoPick

Lots of dune buggy builders use turbo carb setups on VW engines. Relatively simple, but just not quite as tunable as EFI. I did a quick search on google for "weber turbo carb" and got lots of results.

260zturbo

yea you can turbo webbers why these have a all alum plenum attached to them. i would recommend a rebuild and a slight draw back is when it was shipped to me the chock valve housing was broke but they sell all new parts for webbers. yes these are forsale. i paid 550 plus shipping for them and i would take 500 shipped or something reasonable . the cannon intake itself is worth a pretty penny. sorry didnt mean to thread jack

BlueKitsune

260Zturbo, let me get back to you on that. I still have to get my 240z home first lol

And Nismo, I'll take a quick look. But I like the idea of triple carbs better lol

Ok how on earth would you tune a analog turbo Z???

PurePontiacKid

I would think a blow-through 4 barrel setup would be easier... but since you want to be like the Devil Z, the triples would keep it correct to the story

NismoPick

Get a wide band O2 and adjust the carbs.

BlueKitsune

To be honest? I dont want ANYTHING to do with V8 engines anymore, and everytime I think of a 4bbl I think of a V8 engine

Good idea still tho lol

BlueKitsune

I sorta figured that was about the only way. But wouldnt I have to run it rich tho?

NismoPick

If you mean running the carb more rich than if it were naturally aspirated, then yes.

BlueKitsune

Ah, so Would that make the O2 Read "Normal" then?

Yes I ask like a million questions, but I like to know everything I can before I dive into the work lol

NismoPick

Depending on how you tune it "normal" varies. Somewhere in the ballpark of 11-14 for a/f ratio

You should read MAXIMUM BOOST. It will definitely give you a good insight on building an old school turbo setup. I have it floating around ZDriver somewhere in pdf form if you feel like reading from your comp screen for hours.

lww

You want to turbo your triple carb'd 240Z? Get this book:

http://www.amazon.com/Maximum-Boost-...5561603&sr=8-1

A draw through turbo is easier, but a blow-through is "better" and can be intercooled, etc.

A draw through turbo is where the carb is "in front" of the turbo, so both the air charge and fuel charge go through the compressor on the turbo. This results in fuel "pooling" at the bottom of the turbo housing. You do get some intercooling effect as the fuel cools the air charge as it's compressed by the turbo.

A blow through, is where the carb is "behind" the turbo. So, the turbo takes the air charge and compresses it before passing through the carb. This allows you to put a conventional intercooler in the system but requires you to make the carbs "pressure proof" which they were never designed to be able to hold boost, in my case 21 psi... :O

I don't have any recent photos since everything was cleaned up and powder coated, but here's my intake, carbs and surge chamber:

BlueKitsune

Ah ok I didnt know what those terms meant! Thank you Iww. as for max boost in a blow through set up, cant you up the PSI in the carbs to counteract the pressure in the intake system by the turbo?

And Nismo, I wouldnt mind reading it on the PC if its free lol. Or I'll just print it all out in B&W lol

260zturbo

if your interested and wanna work something out just shoot me a email 260zturbo@gmail.com

BlueKitsune

Ok I'll be sure to give you a shout as soon as I Get my 240Z

lww

Well, seeing as how the carbs ARE part of the intake system, I don't see how you can "up the PSI" in them independently or I don't quite understand what you're trying to accomplish by doing that... It almost seems like you had a big thought but only part of it made it into your post...

Carbs are not designed to "hold" a pressurized air charge. They're designed to operate under vacuum from the suction that results from the piston moving down on the intake stroke and that vacuum is considerably less on the negative side of pressure than the boost generated by the turbo, even at moderate levels.

When you put pressure into something that's not designed to be pressurized, it tends to leak that pressure which makes it hard to predict how much fuel you need to mix with an unpredictable amount of air because of the pressure leaks.

One solution is to build a pressure "box" that fully encloses the carb to equalize the pressure outside the carb with the pressure inside the carb.

So, the turbo feeds into the "box" and the carb takes the pressurized air charge from the box that surrounds it. This tends to take up a lot more space and since the intake is on the same side as the exhaust in the L6 motor, that leaves more time for the exhaust heat to heat the excess air charge in the "box" making it even less in addition to creating an unpredictable amount of turbulence as the air charge transitions from the turbo piping to the "box" and again into the carb.

I've seen this done with turbo charged carb'd V8's.

BlueKitsune

Sorry, I meant to say up the fuel pressure...

And alright that makes sense to me. Hmm...