DeviLSh
Dedicated LVC Member
Bringing back and old topic here because I want to hear if anyone has thoughts on this. Recently um.... I dropped my stock throttle body so I am looking into replacements. I somewhat committed to the thought that no upgrade was worth it, but have recently revisited this idea as my car is not really a daily driver and I am willing to accept some compromise/trade offs.
This thread discusses that a stock F150 TB indeed works on our cars, but there isn't really a size increase benefit to it. As both LS and F150 TB's have a 70mm throttle plate but different before & after dimensions, making the oem TB swap moot.
I took measurements of the stock LS throttle and intake elbow. It is a tapered design but then flares back out before meeting the elbow. So it isn't a true taper in that it does not maintain or reduce an ID after the plate. It goes back up before meeting the elbow... see below:
Intake (K&N) I.D. = 82mm
TB Inlet I.D. = 82mm
TB Plate O.D. = 70mm
TB Outlet I.D = 75mm
Intake Elbow I.D. = 82mm
The path form air filter to intake mani elbow starts and ends at 82mm, but contracts in the middle. I get the velocity boost/venturi effect of the taper, but why flare it back out? And why not bring the TB up to 82, vs 75 to match the elbow inlet? Curious what Ford/Lincoln/Jag decided if anyone wants to speculate.
My initial and novice thoughts are:
-Power/Torque requirements
-Velocity or flow based inherent design to stock system components
- Drivability / throttle sensitivity (Lincoln customer?)
- Sound (Lincoln customer?)
- something beyond my comprehension - mpg, atomization, forcing the air to be centered... I am not an engineer here.
Replacements:
Stock LS replacements are from $150-350 depending on where you go and what reman/brand you trust. F150 is a bit cheaper and more readily available. Some Jag S-Types look to have different connectors.
BBK Offers two version for the F150, a 75mm (part# 1758) and an 80mm (part#1759) for the 4.6 and 5.4 F150's, respectively. They also offer a 70mm V6 stang that looks like it would work but apparently the 3.9 TB exceeds this in size. Maybe a non starter there. All three of these appear to be parallel in nature, and not a tapered design. Stock F150 ones are tapered, so BBK made some sort of decision to not carry that through.
So - i've reached out to BBK to see if this taper vs non taper went into their design intentionally. I thing regardless of what we speculate or deduce from their response or our own hypothesis, its going to be hard to say "well what works on the mustang/f150/other engine, will likely work on the LS in the same way." But, Maybe... its worth a shot.
Questions I think Im looking to get answers to:
1) Is a dyno the best/only way to measure this with a swap. Or is a MAF reading or other data log a good indicator for performance change
2) While it may not produce better hp&tq, maybe under the curve, throttle response, sound, and certain other positives can be gained outside of peak gains
3) If there are side effects, but potential - is it something that can be tuned with the SCT or a tuner?
4) Why is the OEM design a contraction design? Taper --> Expansion
5) Has anyone attempted installing either the 75 or 80mm unit ALREADY on a gen2 LS and have any feedback?
For reference:
BBK Product Page
This thread discusses that a stock F150 TB indeed works on our cars, but there isn't really a size increase benefit to it. As both LS and F150 TB's have a 70mm throttle plate but different before & after dimensions, making the oem TB swap moot.
I took measurements of the stock LS throttle and intake elbow. It is a tapered design but then flares back out before meeting the elbow. So it isn't a true taper in that it does not maintain or reduce an ID after the plate. It goes back up before meeting the elbow... see below:
Intake (K&N) I.D. = 82mm
TB Inlet I.D. = 82mm
TB Plate O.D. = 70mm
TB Outlet I.D = 75mm
Intake Elbow I.D. = 82mm
The path form air filter to intake mani elbow starts and ends at 82mm, but contracts in the middle. I get the velocity boost/venturi effect of the taper, but why flare it back out? And why not bring the TB up to 82, vs 75 to match the elbow inlet? Curious what Ford/Lincoln/Jag decided if anyone wants to speculate.
My initial and novice thoughts are:
-Power/Torque requirements
-Velocity or flow based inherent design to stock system components
- Drivability / throttle sensitivity (Lincoln customer?)
- Sound (Lincoln customer?)
- something beyond my comprehension - mpg, atomization, forcing the air to be centered... I am not an engineer here.
Replacements:
Stock LS replacements are from $150-350 depending on where you go and what reman/brand you trust. F150 is a bit cheaper and more readily available. Some Jag S-Types look to have different connectors.
BBK Offers two version for the F150, a 75mm (part# 1758) and an 80mm (part#1759) for the 4.6 and 5.4 F150's, respectively. They also offer a 70mm V6 stang that looks like it would work but apparently the 3.9 TB exceeds this in size. Maybe a non starter there. All three of these appear to be parallel in nature, and not a tapered design. Stock F150 ones are tapered, so BBK made some sort of decision to not carry that through.
So - i've reached out to BBK to see if this taper vs non taper went into their design intentionally. I thing regardless of what we speculate or deduce from their response or our own hypothesis, its going to be hard to say "well what works on the mustang/f150/other engine, will likely work on the LS in the same way." But, Maybe... its worth a shot.
Questions I think Im looking to get answers to:
1) Is a dyno the best/only way to measure this with a swap. Or is a MAF reading or other data log a good indicator for performance change
2) While it may not produce better hp&tq, maybe under the curve, throttle response, sound, and certain other positives can be gained outside of peak gains
3) If there are side effects, but potential - is it something that can be tuned with the SCT or a tuner?
4) Why is the OEM design a contraction design? Taper --> Expansion
5) Has anyone attempted installing either the 75 or 80mm unit ALREADY on a gen2 LS and have any feedback?
For reference:
BBK Product Page