Staged Throttle Bodies

[someotherguy]

What about two sets of 4 ITBs off of a sport bike? People have been adapting single sets to little Honda cars for a long time.

Or Kinslers if you’ve got ALL the money lol

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ITB's are cool and all but where's the air filters?

Richard

 

[Orpedcrow]

ITB's are cool and all but where's the air filters?

Richard

Don’t need no stinkin’ filters when you’re that cool looking.

 

[Scooterwrench]

What about two sets of 4 ITBs off of a sport bike? People have been adapting single sets to little Honda cars for a long time.

Or Kinslers if you’ve got ALL the money lol

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Ain't that a purdy rig. Bet those velocity stacks can suck up a lot of love bugs.

Yep. Good ol' (well, not so good ol') Crossfire injection.

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Richard

I remember those things. I had one of those intakes and always thought it would make a good blower intake with an adapter plate.

I got over it!

 

[Komet]

Multiple throttle bodies are more trouble than they're worth, unless you're stacking them on a tunnel ram for the cool factor but even then they're not sequential.

A single throttle body and variable runner length will get you your low speed velocity and high speed volume, however.

 

[gearheadE30]

There are setups out there that use sequential throttle plates. I'm not sure if GM does it. there's typically a smaller throttle plate and then a linkage to a larger throttle plate. When you crack a single large throttle plate, the open cross sectional area jumps pretty quickly which can make driveability an issue. GM specifically dealt with this either by using multiple smaller diameter throttle plates or by using a half shell on one side of the throttle plate so that only one side of the butterfly cracks initially. I'm probably not describing this well, but look up the stock throttle on the Vortec GMT400 trucks and you'll see the lip on the throttle plate. That's what that plate is for.

All of this is to smooth out throttle tip-in and light throttle behavior while still allowing a lot of airflow at WOT. Modern electronic throttles have rendered this unnecessary.

You don't need multiple staged injectors to do what you're saying. You would use a mechanical linkage between two plates, and the TPS would be on the cam that the throttle cable controls, not on either of the plate shafts themselves. The MAP or MAF sensor would read total airflow or vacuum, it doesn't care how the throttle is set up. Tuning of your injection events would be the same process as any other setup.

The reason people use staged injectors is because massive oversize injectors have poor resolution at small pulse widths. So a set of smaller injectors for light load and a set of larger ones for high boost, fuel types that require high volumes, etc. The engine setup you describe isn't wild enough to need such a setup, even good size 38-42 lb/hr injectors will do idle and low load just fine and will be more fuel than you need if you're running a set of 8 multi point. TBI would be a different story, but if you're going to all this trouble to do a staged throttle setup, TBI style injectors shouldn't be on your radar anyway.

 

[Scooterwrench]

No not going through any trouble,just kicking the idea around.
Seems I recall the one of the Ford 292(4.6L)dual overhead cam motors having a staged throttle plate setup.

 

[Scooterwrench]

After doing some research seems a single 454 TB will do the job just fine if I decide to keep the fuel injection. K.I.S.S.

 

[95burban]

Sprint cars have been using mechanical stack injection for years, it’s touchy and would be horrible for street driving. But the newer stack injection I’ve seen on ls engines would be cool.

enderle makes a progress setup for injection hats for “street” cars with blowers, making it easier to drive. But again it’s mechanical injection. My boat has an enderle bird catcher and there is no part throttle, very violent.

Magnason blowers has a dual throttle body roots blower with dual progressive TBs, it’s for a ls engine so it has fancy electronics