Thread: Turbo with a carb

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Ok, A SBC stroker 383 with a carb'd intake system. It will have a turbo on it. How serious is backfireing? And what can I do to solve this?

-Vance

It will have the turbo on the intake. Comments on blow threw carbs please. Also, can some one direct me to some articles to any related sites. Thanks

-Vance

Do you feel comfortable in doing this? When the system is right, it's dependable and a lot of fun. But it 's not for the faint or weak hearted. Backfire is as possible as a normally aspirated engine. If the thing backfires after you put the turbo on and it didn't before, it's not the turbo's fault. Too lean of fuel curve or a small problem that existed before you did the install is causing it. Weak valve springs or burned valve or misfiring plug and so on. Blow through systems work well when monitored and set with the right pressure sensitive fuel regulators. And these things need tuning to keep the carb from from making your day a bad one. Debris with these set-ups can dislodge and plug emulsion ports, boosters can creat a pressure problem and the carbs themselves require a rework to make it durable. Draw through set-ups are easier to tune and less complicated for the novice turbo kind of builder. Camshaft and compression decisions are a major player if you plan on some decent horsepower. What are your intentions and do you have a system picked out? Feed us some more info and let's steer you in a good direction.

Whether it'a a blower or a turbo, any internal weaknesses (weak valve spring, loose guide, etc) will be magnified by the increased pressure in the engine. One weak plug wire, or a couple plugs gapped wrong that is an annoyance in a normally aspirated car can end up causing a major KAPOW in a blower or turbo application. Make sure you run a boost gauge, the correct timing, correct valve adjustment, valve spring pressures and everything else. The increase in power also increases the build cost and the upkeep cost and time!!!!

Ok, It will be a 350 four bolt main Vortec block and Heads. Eagle 383 stroker kit. The block will get machined for the heads, magnafluxed acid dipped Bored 30 over Mic and ect. The heads will have new valves(not sure what kind yet) I will cut the seats, I am not sure yet if I can replace the guides yet(Vortec heads). Can someone send me a site or even a picture of a pull threw carb set up with a turbo charger. I am not sure what size turbo I will use yet, but it will be a garrett and it will have about 10 PSI.

-Vance

From mazdarotary.net:

"There are two types of choices in a carburetor turbo setup: “Suck-through” or “Blow through”. The Suck-through (or draw through) setup involves mounting the carburetor before the turbo inlet (usually in front of the impeller mouth). This means that both fuel and air are drawn into the turbo already mixed and then blown into the inlet manifold. This is by far the simplest way to set up a turbo, as the carburetor doesn’t need to be especially modified and tuning is quite easy. The main disadvantages are that you can’t use any intercooling with such a setup, as it is dangerous to run air/fuel mixture through an intercooler core. The reason for this is that fuel can condense inside the intercooler core and stay there – if you then have an engine backfire the intercooler can explode. As a result water injection is about the only option for cooling the charge air with this setup. This also corresponds to a blow-off valve because instead of just venting pressurised air, it would be releasing a fuel/air mixture which is very dangerous. The Blow-through arrangement, logically enough, means the carburetor is mounted after the turbo compressor, so the turbo only draws in air and then blows it through the carburettor, which adds the fuel. To use a carburetor this way it has to be specially modified so that the jets will still add the right amount of fuel. This means specially sealing the carburetor and pressurizing the fuel bowls to match the turbo boost. The good thing is than an intercooler and also a blow-off valve can be used with such a setup."

Blow-through carb sources:
http://www.tpcracing.com/C-race-Blowthrough.html
http://www.barrygrant.com/news/artic...oduct_015.aspx
http://www.csucarbs.com/
http://www.pro-system.com/blowthrough.html
http://www.proturbokits.com/store/sc...?idProduct=307

Here is a Mustang forum that they do alot of turbo's.

---> http://www.mustangforums.com/forumid_16/tt.htm

and here is a Chevelle forum that does turbo's Do a search, then ask.

---> http://www.chevelles.com/forums

Remember, the larger the turbo, the more lag you get, it's better to run twin turbo's, than one large one. It's a lot easier and and will run tuned for a long time, is if you switch to EFI or tbi, both blow thru.

Never run a set up that does Not have a blow-off valve ! I have never heard of any problem from a a valve poping under a hood! We make both internal and external blow-off valve exhaust turbo housings.

There is alot of new & used turbo's returned for rebuilding, (get a turbo that has a rebuildable center section, and that is oil & water cooled) because when they first started it, and rev it a little, they DON"T have a airfilter on it or all the tubes on, and the turbo will pick up a rag, small wrench's, screwdrivers, nuts, screws, loose wires, pencil from pocket and BOOM! it's junk! and you buy a new one.

Pat