It seems like a common question in 4.6l 2v world, is what throttle body or plenum will yield the most horse power. This thread is aimed more for naturaly aspirated bolt on cars, but I will include dyno sheets for forced induction applications as well.
The common question (especialy by individuals just begining to mod their cars) is how big of a throttle body do i need, and what company makes the best throttle bodies and plenums, and what are the best combos.
Forced Induction applications will react more to upgraded throttle body and plenums, but naturaly aspirated applications will react as high to simple mods such as this.
I am going to start right away by saying that C&L plenums combined with a 75mm throttle body, make the best results on a naturaly aspirated bolt on gt.
C&L plenum and 75mm BBK throttle body were added
the car already had the following........
C&L 85mm Mass Airflow System with C&L inlet pipe
Timing adjuster set to 12 degrees
Off-road X-pipe with Mil Eliminators
Magnaflow 2 1/2" cat-back exhaust
before plenum and throttle body- 263.5 horse power and 301.38 torque
After plenum and throttle body- 277.5 horse power and 318 torque
That is a 14 horse power gain and a 17 ft lb of torque gain
link to dyno sheets C&L Intake Plenum For 2V 4.6L Mustangs
Back up pulls were done and a pull was done with a 70mm throttle body which resulted in a 3 horse power loss.
K&N Cone Filter
Timing adjuster at 12 Degrees
Mac Pro-Chamber H-pipe
Baseline- 257.2 HP and 298.2 ft/lb of torque
with C&L plenum and 7mm tb- 266 HP and 307 ft/lb of torque
gain of 8.8 HP and 8 ft/lbs of torque
again a 70mm tb was swapped on and a 3 horse power loss was seen
link C&L Intake Plenum For 2V 4.6L Mustangs
supercharged application car 3
10# P1sc S/C kit with a 3 core intercooler
Euro Focus pump (returnless friendly and flows 260+ lph)
Lightning 90mm MAF
Bassani cat-back Air/Fuel Ratio graph from the dyno testing of Dan Hourigan's Supercharged Mustang GT
MAC off road H-pipe
Custom tuned Autologic chip
C&L plenum+ 75mm bbk tb gained 15- 20 horse power
NON PI 1997 automatic gt
Gains ranged anywhere from 7-10 rear wheel horsepower, depending on engine RPM.
Torque was improved by as much as 10-15 Ft/Lbs in the low to mid RPM's, with an average improvement of around 5 ft/lbs throughout the upper RPM's.
MOdular DEpot did a show down between trickflow, accufab, dragon, and C&L StockAccufabC&LDragonTrick Flow
RWHP265.97272.38 (+6.31)271.13 (+5.16)270.69 (+4.72)270.19 (+4.22)
RWTQ303.54310.42 (+6.88)306.05 (+2.51)307.27 (+3.73)306.61 (+3.07)
these were done with a accufab 75mm throttle body
modular stated that they would have crowned accufab winner but the results vary from car to car that it could change. I reality all plenums were fairly close.
link The Plenum Showdown Part II
I hope this thread has helped provide some good info, and crush the theory that a 75mm is to much for a bolt on gt.
This research makes me feel better about my decision to spend money on a C&L plenum with accufab 75mm throttle body.