Throttle body upgrade really worth it?

Hey guys,

So I see there are a few slightly larger throttle bodies out the for the 5.7l. I have to ask though, would there really be much of any noticeable gain from just a few mm larger throttle body? I just can't image it would be much of any difference for such a small change

Anybody have any Dyno numbers on these perhaps?

Interested as well but for the 6.4

Interested also.

Ever drank a milk shake thought a tiny straw then had one through a slightly bigger straw??? yeah principle is the same, especially if you have a force induction motor, its not just about how much air you can cram into the cylinder but how efficient it is. larger the bore better flow, less turbulent and more air.

Even a boosted motor that is restricted by intake and exhaust is largely effected even by 4-8mm

Makes sense I guess; anyone have any Dyno numbers on just a TB change alone on a NA or SC engine?

I have had a ported TB on a few different 5.7's and a 6.1 and only noticeable gain was throttle response imo. Now on my boosted 6.1 I defiantly felt a few extra ponies.

Note: 5.7 was a Charger and a 300, 6.1 was a Jeep SRT.

Almost every customer that has tested our 87mm unit at the track has picked up around a tenth in the 1/4 mile. I've had a few gain as much as .16 and 1mph in the 1/4.

but....

a larger throttle body can reduce low end torque and performance

so if you are racing, they might help, but for towing and daily driving it could hurt (fuel economy, torque) as it can slow down the air speed entering the intake

an example is my 454, it benefits from an 850 carb at the track, but on the street it is much more responsive with a 750

monteholic said:

but....

a larger throttle body can reduce low end torque and performance

so if you are racing, they might help, but for towing and daily driving it could hurt (fuel economy, torque) as it can slow down the air speed entering the intake

an example is my 454, it benefits from an 850 carb at the track, but on the street it is much more responsive with a 750

Click to expand...

Which would be true for a larger true bore throttle body, but we purposely taper the port on the back side of our TB from 87mm to 83mm to increase airspeed and retain tq and low end power.

This is something I have been considering because I have done CAI, exhaust, and tuner. Looking at what to do next, but don't want to lose low end power and torque considering I have a lift and 35's.

Not a expert or anything, however on my truck it was a noticeable improvement on throttle response. Great upgrade for a bolt on part IMO

R/T_Fire said:

Ever drank a milk shake thought a tiny straw then had one through a slightly bigger straw??? yeah principle is the same, especially if you have a force induction motor, its not just about how much air you can cram into the cylinder but how efficient it is. larger the bore better flow, less turbulent and more air.

Even a boosted motor that is restricted by intake and exhaust is largely effected even by 4-8mm

Click to expand...

It depends on how the hemi is boosted; Procharged hemis don't see a benefit from a larger bore tb because the flow velocity from a centrifugal SC is already so high and the TB is not the restriction in the system since the pressurized air is on the upstream side of the valve. With a positive displacement blower however the larger the TB the better because it needs to pull air into the intake plenum and volume is what's required, not velocity.

I had zero difference in performance when I ditched the 85mm BBK and went back to a bone stock TB with the D1SC. I'll be installing a 90mm BBK shortly to see if it'll make a difference with the new blower but also to try to fix a fluttering issue with the stock TB. My intake manifold is ported to 90mm so it'll bolt on with no protrusions into the volute, 85mm true bore is the limit for the stock intake manifold.

monteholic said:

but....

a larger throttle body can reduce low end torque and performance

so if you are racing, they might help, but for towing and daily driving it could hurt (fuel economy, torque) as it can slow down the air speed entering the intake

an example is my 454, it benefits from an 850 carb at the track, but on the street it is much more responsive with a 750

Click to expand...

This is true and the reason I wrote the big long throttle body topic on a different forum. Throttle bodies need to be sized to the engine, not just run the biggest one possible because you can. All the ported throttle bodies have a stock butterfly valve diameter so they all work with the stock displacement engine.

A ported throttle body is designed to help increase the positive static pressure inside your intake manifold through air velocity. It's very relevant in today's intake manifold design but limited with its relationship to friction. The faster the air velocity the greater the resistance of air to move due to friction. Throw on Moe's track intake, now you are using vehicle speed(dynamic air pressure) to increase the static air pressure inside the intake manifold. Either way you look at it, the name of this game is allowing a greater massflow through the engine thus producing more power. If you go to big resulting in to much air, then it will back up and start reverse flowing.

Great info guys! Yea I think I will hold off on the TB for my SC truck for the moment as it doesn't sound like it would be a worthwhile gain for my application. I'll put my money toward some headers and a water/methanol injection system instead

charonblk09 - Definitely let me know if you pick up an decent HP with that 90mm TB as I'm interested in the results.

Thanks guys