This page contains data for the flow rate of our cotton gauze air filters when tested without a canister
Product Image | Part Number | Description | Size (mm) | CFM | Graph Number |
 | 152mm K&N Cotton gauze cone remote filter with spun alloy 75mm exit | 152 Diametre x 200 high | 200 | ||
| 152mm K&N Cotton gauze cone remote filter with spun alloy 100mm exit | 152 Diametre x 200 high | 280 | 1 | |
| 152mm K&N Cotton gauze cone remote filter with spun alloy 85mm exit | 152 Diametre x 200 high | 240 | ||
 | 152mm K&N cotton gauze remote filter (bare) | 152 Diametre x 200 high | 300 | ||
 | K&N panel filter for use in lid of interlagos 425X and 425Y | 380 x110 | 342 | ||
| K&N Panel filter for use in Ultima GTR air box (requires two filters) | 380 x110 | 457 | ||
 | K&N Round Can-Am filter | 355 diametre x 80 high | 692 | ||
 | K&N 435 x 152 x 42mm performance element | 435 x 152 x 42 | 458 | ||
| K&N 435 x 152 x 54.5mm performance element | 435 x 152 x 54.5 | 595 | ||
| K&N 435 x 152 x 66mm performance element | 435 x 152 x 66 | 720 | ||
| K&N 445 x 152 x 96.5mm performance element | 445 x 152 x96.5 | 1071 | ||
 | K&N Cotton Gauze cone filter with 152 diametre rubber neck exit moulding (short version for use with filter adaptors) | 152 Diametre x 115 high | 285 | 2 | |
 | K&N Cotton Gauze cone filter with 152 diametre rubber neck exit moulding (short version for 152mm ducting / non ducted) | 152 Diametre x 115 high | 285 | 2 | |
 | K&N high flow performance element for Suzuka pro air filter canisters | 195 Diametre x 275 high | 746 | 3 |
An inlet that is too small will cause a pressure drop inside the air box restricting performance. The Snorkel sizing guide shows the minimum recommended inlet and ducting snorkel size for a power output category. The larger the power output of an engine the more air it will require to run at peak efficiency, therefore a larger snorkel is needed as power increases. Multiple smaller snorkels can be used to achieve the same open inlet area as a larger snorkel for example if a larger snorkel won’t fit on the air box multiple smaller snorkels or oval exit snorkels could be used to create a comparable open area. High flow alloy straight trumpets can also be used as intake snorkels.
| BHP Category | Open Area (cm²) | Snorkel Diameter (mm) |
| 1 - 150 | 44.18 | 75.0 |
| 150 - 205 | 56.75 | 85.0 |
| 205 - 265 | 78.54 | 100.0 |
| 265 - 325 | 127.68 | 127.5 |
| 325 + | 181.46 | 152.0 |
On typical engines 150CFM is required for each 100BHP
On high performance engines 130CFM is required for each 100 BHP
The formula below shows the formula for required airflow to the engine in cubic feet per minute.
CFM = Engine Capacity (Cubic Inches) / 3464 * Max RPM
1L = 61.0237in³
For example a 5.7 litre engine requires 703CFM of air at 7000rpm :
703 CFM = 347.84CI / 3464 * 7000RPM
Or if supercharged...
CFM = (CI * RPM / 3456) * (boost [psi] / 14.7 + 1)
ReVerie Limited & its product range are not connected with Lotus Cars Limited or Lotus Sports
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