Intake comparison on 4AGE 20V BlackTop

on Tuesday, 07 February 2012. Posted in Using PerfExpert

Performances difference between the original plenum and open velocity stacks

Here's a little comparison that has been done on Stephane's Toyota AE82 Twin Cam GT : seeing with PerfExpert the difference in torque and power between the original plenum (without the air filter) and open velocity stacks.

To perform reliably this test it was necessary to proceed as following :
- Always launch the car from the same mark on the road
- Always WOT at the same mark on the road
- Take measurements at the same direction of travel
- Be sure to follow the PerfExpert basic measurement procedures (phone calibration performed, impeccable phone fixation, little wind, free road, lift windows...)
- If the car remained parked in a while then drive a few minutes at medium speed to cool the engine bay in order to always make the measurements under similar engine bay temperature conditions 
- For each setup (plenum or open stacks), perform at least two measurements having less than 2% deviation to confirm their reliability. Indeed non-repeatable measurements (differences of more than 2%) reflect a poor phone fixation or poor conditions (road, wind...).


Toyota Corolla AE82 Twin Cam GT


At first, measurements with T3 open stacks

Toyota 4AGE 20V blacktop open stacks

PerfExpert 4AGE 20 blacktop cornets 1

PerfExpert 4AGE 20 blacktop cornets 2


Here are the results with this setup :
- 159.6hp at 7300rpm et 131.8Ft.Lb at 5500rpm
- 159.1hp at 7300rpm et 133.2Ft.Lb at 5300rpm



Lets see now the results with the OEM plenum and OEM stacks. Unfortunately we didn't have a cold air feed to the plenum for the tests. And note that the curved OEM stacks had been cut by the previous car owner...


4AGE 20V blacktop plenum 14AGE 20V blacktop plenum

PerfExpert 4AGE 20V blacktop plenum 1

PerfExpert 4AGE 20V blacktop plenum 2


Here are the results with this setup :
- 150.4hp at 7200rpm et 128.2Ft.Lb at 5200rpm
- 151.3hp at 7200rpm et 130.4Ft.Lb at 5200rpm

This shows a clear advantage of open stacks in power (more than 5%), and a slight advantage in Torque. But the most interesting is to see the curves comparison. Here is a Google Doc with an overlay made ​​from a fusion of data exports made ​​from the application :

Toyota 4AGE 20v blacktop : open stacks VS plenum

Not enough room for the legend so I'll give more details here :
- P1 & P2 are the 2 power curves in open stacks setup
- T1 & T2 are the 2 torque curves in open stacks setup
- P3 & P4 are the 2 power curves in plenum setup
- T3 & T4 are the 2 torque curves in plenum setup

Note that with the plenum there is a little more torque before 4000rpm and less torque after. So really, even if the open stacks give more torque maximum value, the plenum give a more torquey engine at low rpm.
A pity that we didn't have a 100% stock plenum (whose stacks are not cut) and the original airbox + filter. The comparison would have been even more interesting.

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