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TBI intake air flow and TBi unit power rating?

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Old Aug 13, 2013 | 08:43 PM
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Fiero2m4's Avatar
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TBI intake air flow and TBi unit power rating?

Hi, I've got a 305 TBI camaro and doing a fair bit of work to It, got a set of heads, Cam kit and headers/exhausts, a lot of things I've been able to research and find out, but I can't seem To find what the intake of a TBi flows and how much power you could get using it?

Also wondering what the standard TBI unit can fuel upto? Can it fuel upto 350bhp standard? (It doesn't look big enough for it personally?)
Anyone have any ideas?

Thanks, Carl.

Last edited by Fiero2m4; Aug 14, 2013 at 09:26 AM.
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Old Aug 15, 2013 | 11:20 AM
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Re: TBI intake air flow and TBi unit power rating?

I have never heard of it being flow tested. As far as the TB itself it has been done. Be aware 2 barrells are flowed at a diff (depression?) than 4 barrell so cannot compare the #s.
My favorite manifold is the Edelbrock 2901 however I use a holley projection TBI unit. Just about any carb manifold will be better than stock. avoid an air gap design.
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Old Aug 15, 2013 | 12:30 PM
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pound's Avatar
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From: Beautiful Coastal New Jersey
Car: 1990 Firebird
Engine: 350 TBI
Transmission: T5
Axle/Gears: Auburn posi 3.73
Re: TBI intake air flow and TBi unit power rating?

Someone flowed the Edelbrock Performer TBI 3704 manifold in this thread. If you read down a few posts it is mentioned that the Edelbrock manifold flows "a hair better than the factory manifold with the same 2" bores."

I trapped 103 MPH with a 2" bore stock manifold and 2" bore TBI. Others have probably gotten more out of it. To get 350 HP you are going to need to do a lot of fueling work as the stock system is not up to the task. At the very least a new pump will be needed. Do some searching to calculate fuel and injector requirements.
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Old Aug 15, 2013 | 01:26 PM
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Re: TBI intake air flow and TBi unit power rating?

20 lbs fuel pressure with 75 lbs injectors will support 350 HP at 85% DC.
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Old Aug 24, 2013 | 01:08 AM
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Car: 1991 firebird
Engine: TBI 305 (built)
Transmission: T5
Axle/Gears: 4.10
Re: TBI intake air flow and TBi unit power rating?

I'm doing a rebuild now and bought some 68# injectors from CFM tech cause I can't find bb injectors ... I'm prolly gonna b around 325-350 HP if I can get the injectors to flow enought @ 6000 rpm ... How much fp would I need to run ? And what is the max FP these injectors are capable of ?
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Old Aug 26, 2013 | 09:32 AM
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Re: TBI intake air flow and TBi unit power rating?

68# injs at 25 lbs FP supports 257 HP at 85%DC.

75# same will support 283HP
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Old Dec 13, 2013 | 01:27 PM
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From: Macon, GA
Car: 1992 Camaro RS
Engine: Vortec headed 355, xe262
Transmission: T56
Axle/Gears: 9-bolt 3.70
Re: TBI intake air flow and TBi unit power rating?

Sorry to bump, but it's an interesting thread with good numbers in it, so I hope you dont mind.

These power numbers that are mentioned, are they flywheel or rear wheel? I imagine they are flywheel horsepower, right?
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Old Dec 13, 2013 | 01:56 PM
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From: Beautiful Coastal New Jersey
Car: 1990 Firebird
Engine: 350 TBI
Transmission: T5
Axle/Gears: Auburn posi 3.73
Re: TBI intake air flow and TBi unit power rating?

Yes flywheel horsepower.
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