52mm throttle body
Thread Starter
Drifting
Joined: Dec 2011
Posts: 1,439
Likes: 23
From: mesa az
52mm throttle body
My question is whether or not to install the bigger throttle body on my engine ? My modifications are as follows :
Edelbrock 3860 intake
SLP runners ported
Heads ported gasket matched
24lb injectors
Adjustable fuel pressure regulator set at 40.
Long tube headers
Dual exhaust 2.5"
High flow cats Flowmaster 44 mufflers
Edelbrock 3860 intake
SLP runners ported
Heads ported gasket matched
24lb injectors
Adjustable fuel pressure regulator set at 40.
Long tube headers
Dual exhaust 2.5"
High flow cats Flowmaster 44 mufflers
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
You can go bigger, but there will not be a gain. It is not like going from a 2 barrel carb to a 4. The TB you have on there now will support 400 HP without a problem and you are no where near that currently.
Melting Slicks
Joined: Nov 2010
Posts: 2,216
Likes: 113
From: Michigan
Just thinking over this myself the other day. 1st you can't compare a carb to efi, carbs depend upon signal for atomization and a injector does that job very well(maybe not so much in a batch fire setup like TPI). 2nd the NA engine can only draw what it can use and to say what it can use varies widely, mods, use, tune skill. IE look at all the basic TB efi kits like msd/holley, they are 1000cfm or bigger and some rated for like 200hp-600hp, so efi is more forgiving for oversize. Still that doesn't mean you want the biggest TB, because the faster it reaches what it can use in throttle position the less sensitive your throttle is.
I think for TPI it's a lot about if your MAF or SD. MAF obviously the restriction is if your using stock stuff(MAF,duct,airbox) and SD you can just use a big air filter on the TB. My car is a MAF car so unless I want to change all my stuff or convert to SD I'll stick with the stock TB for now.
edit: Oh and I also think size can effect your curve for the better and still have the same peak.
I think for TPI it's a lot about if your MAF or SD. MAF obviously the restriction is if your using stock stuff(MAF,duct,airbox) and SD you can just use a big air filter on the TB. My car is a MAF car so unless I want to change all my stuff or convert to SD I'll stick with the stock TB for now.
edit: Oh and I also think size can effect your curve for the better and still have the same peak.
Last edited by BOOT77; Nov 27, 2015 at 07:55 PM.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
I'm running a 383 with the high flow Accel intake, the same 3860 manifold, the same 24 lb injectors and a set of Dart pro 1 (180) heads , long tube headers ,and the 48 mm throttle body does just fine on my engine..
..WW
..WW
Thread Starter
Drifting
Joined: Dec 2011
Posts: 1,439
Likes: 23
From: mesa az
This answers my question best. I wish now I had stroked my L98. I have considered putting AFR heads on it to boost the HP but even then my stock throttle body would provide adequate air flow. I do have a open lid with a fresh K&N filter. I've never had it on a dyno so I don't know what my HP is now. I test drove a stock 1988 C4 and was thinking this is slower than new Fiat 500. She's a tire screamer now and grabs tire shifting at 2nd and D. A loud chirp on stock tires. I saw a ported to 52mm throttle body for cheap and considered buying it. It won't so end of story.
Team Owner
Joined: Jul 2004
Posts: 28,462
Likes: 3,288
From: Hartford WI
This answers my question best. I wish now I had stroked my L98. I have considered putting AFR heads on it to boost the HP but even then my stock throttle body would provide adequate air flow. I do have a open lid with a fresh K&N filter. I've never had it on a dyno so I don't know what my HP is now. I test drove a stock 1988 C4 and was thinking this is slower than new Fiat 500. She's a tire screamer now and grabs tire shifting at 2nd and D. A loud chirp on stock tires. I saw a ported to 52mm throttle body for cheap and considered buying it. It won't so end of story.
Notice the ads say "Up to 20HP gain". What they don't say is that you might lose power all the way to gain 20HP but the 20HP gain is going to be part of a system that NEEDS the air flow.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
My tuner told me the 48mm is enough for a maxed out 383 CID.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Team Owner
Joined: Jul 2004
Posts: 28,462
Likes: 3,288
From: Hartford WI
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Well, that is more objective data than you posted. Bottom line; if the TB doesn't make HP at the HP peak where air flow into the engine is greatest, then how is it going to make power anywhere else, where air flow is lower?? What do you think you'd see w/a curve?
Team Owner
Joined: Sep 2001
Posts: 62,153
Likes: 1,731
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Melting Slicks
Joined: Jun 1999
Posts: 2,931
Likes: 127
From: Ashland Alabama
Same here on using the stock tb.
I supercharged my 86 with the stock throttle body and did fine. I had more issues with the airfilter than anything. That thing would eat a stock filter and I could actually tell when the k&n needed cleaning performance wise. Only vehicle Ive ever owned that actually needed a k&n over the stock filter
My 87 is a 383 stroker with the stock throttle body and does great.
I supercharged my 86 with the stock throttle body and did fine. I had more issues with the airfilter than anything. That thing would eat a stock filter and I could actually tell when the k&n needed cleaning performance wise. Only vehicle Ive ever owned that actually needed a k&n over the stock filter
My 87 is a 383 stroker with the stock throttle body and does great.
Team Owner
Joined: Jul 2004
Posts: 28,462
Likes: 3,288
From: Hartford WI
Same here on using the stock tb.
I supercharged my 86 with the stock throttle body and did fine. I had more issues with the airfilter than anything. That thing would eat a stock filter and I could actually tell when the k&n needed cleaning performance wise. Only vehicle Ive ever owned that actually needed a k&n over the stock filter
My 87 is a 383 stroker with the stock throttle body and does great.
I supercharged my 86 with the stock throttle body and did fine. I had more issues with the airfilter than anything. That thing would eat a stock filter and I could actually tell when the k&n needed cleaning performance wise. Only vehicle Ive ever owned that actually needed a k&n over the stock filter
My 87 is a 383 stroker with the stock throttle body and does great.
OTOH, I was getting it dyno tuned and we ran with the cut out air cleaner and I without anything and got more power bare and lost like 4, IIRC, with cut out intake. Lost 1 or 2 with K&n open element which is why my stock cut out intake filter went to be recycled