SMKN TA 95

iTrader: (46)

I am in the process of building my race car, and I am not sure which way to go on the throttle body.

The motor is a 408, 13.8:1 compression, CNC 6.0L heads (330/251 @.650 lift), solid roller in the 27X/28X @.050, .765 lift, single plane Victor Jr. intake, NX direct port spraying 300-400......and hopefully the motor will make the power in the 8K rpm range.


I have been told to go with a 4500 flange(dominator style) and run a 2000cfm 4bbl style TB. Although most of the cars I see on here run a 4150 style flange and keep it around 1200-1500 cfm. I know if I use the 4500 flange one I will need to run an adapter........but I will be running a 1" spacer/blowoff plate from Wilson anyway, so an adapter wouldnt matter.

Do I need a 2000 cfm TB or could I get by with a 1550 cfm Tb from Accel?

skipperbisket

iTrader: (4)

i have a victor jr. on my solid roller 408 14.5:1 11* headed motor, carb plate system, precision turbos elbow, with accufab 90mm tb. cam is a bit bigger than what you have in your's and the 90mm tb should be fine. there are turbo small blocks making 1500+rwhp with a little ole 90mm tb. you will not be able to run the 4500 flange on the victor jr without a lot of needless machine work. if you want to run a horizontal tb, the accufab 4bbl, 4150 flange setup will be perfect.

LTLHOMER

iTrader: (10)

GMPP intake, precision elbow, accufab 90mm tb...but mine is a boost motor. Big difference compared to an n/a engine that needs to breathe on its own.

Ryan K

iTrader: (11)

I ran a 1000-1100 cfm 4 barrel unit on mine, I'd get the 4150 flanged unit as big as your wallet allows. If you see vacuum under WOT that is the indication that its not big enough...

383ss

iTrader: (14)

good info there.

I went with an accufab 1215cfm 4bbl style. hoping for around 600rwhp. I've searched and couldn't find any exact a calculaton of cfm needed for hp.

MRI-TEK

Does anyone know what the difference in cfm from a 105mm t\b to a 4bbl t\b lets say the 4150 ?? Considering either one will mate to a Victor Jr intake.. Dont think that will make any difference.

SMKN TA 95

iTrader: (46)

I have been looking into the Accel 1550 cfm 4150 style TB. At this point I am either leaning towards that one or one from Accufab.

Dave88z

Wilson also makes a killer 4bbl T.B. They are a lower profile then most other T.B.'s if you need clearance.
The victor jr uses a 4150 flange but adapters can be purchased to install 4500
"dominator" T.B.'s to 4150 intakes.
I have seen these adapters in 1/2" and 2" thicknesses, 2" looks like it would flow
better.
just my .02

MADMAN

iTrader: (4)

On my motor which was a 408 SBC with 15* heads and made right at 690hp I had a 4150 style t/b. I had Davinci carbs bore the t/b to flow more. Davinci got it to flow 1400cfm. I then switched to a 2000 dominator style unit. The motor picked up to 720hp from just adding air and of course fuel. I would spend the money on the dominator style unit.

ou812/z28

i run the dominator style flange and a 1300cfm mono blade. and i am only 396ci and the motor loves it,

DAPSUPRSLO

iTrader: (14)

If you wanna spend the money go for the 4500. If you don't just get the biggest 4150 that you can. It's practically impossible to over throttle body a motor with a direct port fuel injection setup (within limits of course).

The formula for CFM requirement is (Cubic Inches)(RPM)(VE/3456)=CFM Requirement

VE is a percentage (i.e. 115% is 1.15). Remember, most throttle bodies are rated at 28-25" of depression and they won't see that kind of depression with a good intake setup, therefore will flow less then what indicated. I'm going with a 4150 1550 cfm accel tb with my 434, sb2.2 intake, and 368 cfm c5-r heads. With a 105% ve and 7500 rpm I should be pullin 988 cfm so you can see according to just numbers i'm quite a bit over that. Good luck!!!

1QuickT-A

iTrader: (12)

I'm running the GMPP intake and the Accel 1550cfm 4150 style t/b.. This same motor put down 572rwhp with ported LS6 heads, a medium sized hydraulic cam, 11.5:1 compression thru a 6spd and a 9in...

Charles Cyrus

Any new information out there on this subject?

chrismorales75

I'd go with the 4500, if run a 4150 you might want to go bigger in the future which would require an adapter spacer, it may not matter, but you'll lose clearance hood clearance because I believe they are 2-3" tall.

I know with carburetted small blocks a lot of people run a 4150 flange with an adapter and 4500 vs. just a plain 4500 mounting flange, supposedly makes more power.

I am not sure if this applies to FI.

A friend of mine runs a 4150 flange with adapter and a 4500 dominator, the car runs 9.70's with a 406 on the motor and we are still tuning and working out the chassis so I think it works good =)

Dave J

iTrader: (2)

super vic intake and 90mm accufab tb here