Do I need a bigger throttle body?
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
even your 22lb injectors will run out of fuel before the 48mm will not flow enough air. 2 things FWIW. 1. When I was making 362rwhp 3000 stall etc. I switched from a 48 to a 52 and could not see any difference at the track. 2. The 502-502hp bigblock used a 48mm.
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Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
as written above....the TB will not give you HP. It is a air inlet only. Change the runners and plenum to get additional HP.You computer will compensate for any difference between a 48, 52 and 58 TB. Your better staying with the 48 with your current combination or only moving up to the 52 not the 58.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
48mm throttle body flows 783CFM. If its an early TPI the choke point is the MAF,
http://gmtuners.com/flow/
http://gmtuners.com/flow/
Team Owner
Joined: Sep 2001
Posts: 62,160
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From: Athens AL
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You do not need a bigger TB or an upgraded MAF.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I'd put a differential pressure gauge across the throttle body to measure the actual restriction (ie: pressure drop). Takes the guesswork out of it.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
90 & 91 = speed density, no MAF
Agree with Vader, you don't need bigger TB or MAF until the stock intake, heads, cam & exhaust are changed, Only then can the engine breath past 5K rpm.