my question is can a gas engine create vacuum on a throttle bodied turbo motor? i went for a ride in a friends ranger with a bad ass four cylinder turbo and cruisin down the road it read 16 inches vacuum:confused: til he stepped on it, didnt think turbo engines could have that much vacuum

i hope i posted this in the right spot:o:

i ran into this issue 25years ago and yes i ran into problems i put a turbo on a 350 chev gasser and bolted the old q-jet carb on it. well just idleing around everything was ok . when you stood on it the thing would fall on its face. went around and around on how to hook up dist vacuum and got that fixed and still won't rev up. found out a q-jet carb senses load from the air chamber underneath it. on a normal 350 gasser when you stomp on it the vacuum drops and the flow of air pulling thru carb goes up. so the carb throws more fuel in to make things go. well on a turbo gasser when stepping on acc. pedal air flow increases turbo kicks in and causes big time vacuum under carb and the carb senses vacuum and cuts off the fuel. hence the falling on its face. long story learned alot back in the day but yes lots of vacuum under full throttle before turbo , after turbo positive pressure when stomping on it.

his was reading 15 inches after turbo just cruisin, doesnt seem right

yes thats what a [turbod] gas engine does...unless you are WOT the throttle plate still provides restriction and thus vacuum. When you go WOT the intake tract restriction drops to 'zero' and the exhaust gases coming out of the exaust ports are able to expand at a fast enough rate to allow the turbo to spool to a speed where it starts to provide positive pressure.

btw you cant do 'blow thru' turbocharging on any carbureated gas engine unless you surround the ENTIRE carb with a sealed chamber. If you simply attach a turbo to where the air filter goes, its not going to work at all...

ben

his was a electronicly controlled fuel injection system with throttle plates, 15 inches of vacuum just didnt sound right to me but i guess i was wrong.

btw there are special carbs out now that you can blow through the top, seen a few floatin around at car shows, most likely low boost applications.

yes thats what a [turbod] gas engine does...unless you are WOT the throttle plate still provides restriction and thus vacuum. When you go WOT the intake tract restriction drops to 'zero' and the exhaust gases coming out of the exaust ports are able to expand at a fast enough rate to allow the turbo to spool to a speed where it starts to provide positive pressure.

btw you cant do 'blow thru' turbocharging on any carbureated gas engine unless you surround the ENTIRE carb with a sealed chamber. If you simply attach a turbo to where the air filter goes, its not going to work at all...

ben

That and you need to jet 1 size higher, use viton seals, and get nitrile rubber in the carburetor floats.

Been there, done that, bought the T-shirt.

Oh, and 1 range colder on the plugs.;)

ya, what Juice said :D

ya, what Juice said :D

The carb was the easy part Ben.

The colder plug range.... cost me 4 pistons:mad: Learning from experience again:o:

wish i had a time machine , back when i did that work in 1980 i couldn't find anyone that had a real clue to installing a turbo on a 350 gasser. you two would have made it alot easier.

Ive got a meker with a 2300 turbo bad to the bone fast for a 4 banger..:D

wish i had a time machine , back when i did that work in 1980 i couldn't find anyone that had a real clue to installing a turbo on a 350 gasser. you two would have made it alot easier.

Honestly, I don't know what help i would have been. My turbo interests started in 1983:o:

well i could have just hung around for three or so years til somebody had some answers. i ended up with a knock in the motor pulled all the turbo stuff off and removed a head and found a piece of aluminum casting stuck in the piston right over the ring land. had to replace piston and resold turbo.

Ive got a meker with a 2300 turbo bad to the bone fast for a 4 banger..:D

www.rapido.com:D

Sooo many upgrades available for them!

Volvo 2.3-16 valve heads, more turbo of course, bigger injectors, Intercooler... ahh the joys of Fords 2.3L4 Turbo.:p:

I use to race 2300 (non turbo) I'm debating on putting this motor in a cj7 or a sport explorer.... just can't decide...