Silly: How do you turbo a Carb'd engine

[MrBeef]

Hi there i curious as to how you would turbo a carb'd engine. For instance, a 4A-F.

I don't want to know about to stupid the idea is just. Just the background on how to do it. Cos in a EFI car the turbo forces more air in the air intake in simple terms. But as a carb'd engine doesn't exactly "suck" air in like a EFI car..you know it sucks becos u can hear the K&Ns sucking etc...


I just wanna know how it is done. Cos most rotors are carb'd and they can be turboed...


Cheers for any input

[Adamal]

Carb's and EFI work on the same airflow principle.

You put your foot on the gas and the throttle opens by a butterfly, allowing more air in.
The main difference between the two is the way the fuel is added into the equation.
With carbs, it's squirted into one area where it relies on the suction created by the piston drawing the air in to go into the right cylinder.

With an EFI system, the fuel is squirted directly over the individual intake ports.

At the end of it all, putting a turbo on a carb engine isn't that much different from having one on an EFI engine.
The only problem is getting the carbs right, as EFI is more acurate with air/fuel ratios and the air density/temperature.

[Lloyd]

With an EFI system, the fuel is squirted directly over the individual intake ports.

Only on multipoint fuel injection systems But you knew that


As far as turbo carby setups you have 2 options; suck through and blow through. Suck through setups have the carby before the turbo and use the vacuum created by the turbo to pull extra fuel out of the carby. Its the easiest one to put together but you cant run an intercooler and you'll have fuel being pulled through the compressor side of the turbo.

Blow through has the turbo before the carby. You have the carby completely sealed from the atmosphere and get a 1:1 fuel pressure regulator to bump fuel pressue up by 1 psi per 1psi of boost pressure so the carby still puts out enough fuel (rather than the boost pressure forcing air back down the carby). You can use an intercooler in this sort of setup. Easiest way to seal the carby is to just build a box around it

[Adamal]

With an EFI system, the fuel is squirted directly over the individual intake ports.

Only on multipoint fuel injection systems But you knew that

Of course... Just uhh.. Making sure you were on your toes. Yea