Turbo charging a tbi 350

[Turbo4whl]

@95 z71 Silverado I believe turbocharging your 350 is a fine idea! Yes, a blow through system would require major fuel system mods.

On the other hand, a draw through system would work well. The fuel mod would only be different injectors to accommodate the increased airflow. Your engine internals need to be good. Boosting a worn engine will create problems.

Someone might ask, how do I know this? Well here is the story. Back in the fall of 1981 I took delivery of my 1982 GMC 305 SBSS. In the summer of 1982 I installed a Shelby-Spearco turbo. Draw through system with the air plumbing that creates a down hill fuel system so there is no fuel puddling.

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These pictures are right after I finished the install and before I dressed up the wires/plumbing etc. I did need to add a wastegate, not in the picture.

About the turbo whine you want to hear, you will not hear what you might expect. Large diesel truck engines have large turbochargers that you can hear. You could add a microphone near the squirrel cage and run it through the stereo system.

 

[618 Syndicate]

That's where a Vacuum Referenced Fuel Pressure Regulator or in OP's case a Boost Referenced Fuel Pressure Regulator comes into play

Agreed, but if you have enough pressure and injector to support effectively double the stock output, tuning (choking down) the fuel to make it idle or drive at low rpm/throttle input is like a dark frikkin art!

 

[Supercharged111]

Agreed, but if you have enough pressure and injector to support effectively double the stock output, tuning (choking down) the fuel to make it idle or drive at low rpm/throttle input is like a dark frikkin art!

Only on the TBI setups because those 2 injectors need to support a massive amount of flow and they were never meant for that sort of use. I have 42# injectors in both trucks, straight out of an L67 supercharged 3800 and they idle easy peasy. Even larger than that, aftermarket 80# port injectors still idle like glass.

 

[618 Syndicate]

@95 z71 Silverado I believe turbocharging your 350 is a fine idea! Yes, a blow through system would require major fuel system mods.

On the other hand, a draw through system would work well. The fuel mod would only be different injectors to accommodate the increased airflow. Your engine internals need to be good. Boosting a worn engine will create problems.

Someone might ask, how do I know this? Well here is the story. Back in the fall of 1981 I took delivery of my 1982 GMC 305 SBSS. In the summer of 1982 I installed a Shelby-Spearco turbo. Draw through system with the air plumbing that creates a down hill fuel system so there is no fuel puddling.

You must be registered for see images attach

You must be registered for see images attach

These pictures are right after I finished the install and before I dressed up the wires/plumbing etc. I did need to add a wastegate, not in the picture.

About the turbo whine you want to hear, you will not hear what you might expect. Large diesel truck engines have large turbochargers that you can hear. You could add a microphone near the squirrel cage and run it through the stereo system.

Fuel required for boost isn't determined by setup, a draw through is gonna need just as much as a blow through.
You'll hear any turbo whistle if you spool it up!
Also, that is super cool that you have pictures. In 1982 that was very impressive.

 

[Supercharged111]

Fuel required for boost isn't determined by setup, a draw through is gonna need just as much as a blow through.
You'll hear any turbo whistle if you spool it up!
Also, that is super cool that you have pictures. In 1982 that was very impressive.

On his though that whistle would get choked out by the carb. I think it's retarded to want to turbo for the whistle. Sure it's cool, but not near as cool as doubling the output of your motor. Or more.

 

[618 Syndicate]

Only on the TBI setups because those 2 injectors need to support a massive amount of flow and they were never meant for that sort of use. I have 42# injectors in both trucks, straight out of an L67 supercharged 3800 and they idle easy peasy. Even larger than that, aftermarket 80# port injectors still idle like glass.

Granted my experience is largely with small displacement high revving 4 cylinder motors, but I think the reason you are able to get them to idle is the use of stock (but different application) injectors.

 

[618 Syndicate]

On his though that whistle would get choked out by the carb. I think it's retarded to want to turbo for the whistle. Sure it's cool, but not near as cool as doubling the output of your motor. Or more.

I see what you're saying about the noise.

Blower whine and turbo whistle are among the coolest automotive sounds, but yeah, not a good reason to want forced induction.

 

[Supercharged111]

Granted my experience is largely with small displacement high revving 4 cylinder motors, but I think the reason you are able to get them to idle is the use of stock (but different application) injectors.

4 cylinders get to a point they suffer the same way a maxed out TBI would: not enough injectors. The RX7 used 2 sets of injectors to get the low load stuff right back in the day. No stock computer that I know of from GM supports this.

 

[618 Syndicate]

4 cylinders get to a point they suffer the same way a maxed out TBI would: not enough injectors. The RX7 used 2 sets of injectors to get the low load stuff right back in the day. No stock computer that I know of from GM supports this.

The problem is controlling the low end of injectors that are big enough to support the amount of air the turbo moves. The number of injectors doesn't matter, it's flow.

 

[Supercharged111]

The problem is controlling the low end of injectors that are big enough to support the amount of air the turbo moves. The number of injectors doesn't matter, it's flow.

Sorry, I worded that poorly. A 600hp V8 will use smaller injectors than a 600hp 4 banger, thus making the half motor more difficult to tune at idle than the freedom motor. The 4 cyl will hit that limit at a given hp sooner than something with more injectors.