Technical & Installation Questions

Selecting A Foster SC Mods Kit

"Install was a breeze, took me less than 30 mins. Everything fit great and sounds even better. Wonderful Job on this kit!!"

Will Rollins at Whipple Superchargers ( left ) after fitting a Foster Stage 2 Sound Kit to Mike's 500 GT - another happy customer!

Which Kit is Optimal For Your Vehicle?

2010-2014 Mustangs all have the same firewall access area behind the shock tower for the sound tube connection at the firewall.

The difference in stage 1 & 2 kits is the sound tube connection point to the inlet induction area.

It can be either in the closed airbox or half airbox (open on top) this connection and kit adds 25% increase in whine and is called stage 1 closed air box.

The other connection point is in the inlet induction pipe near the MAF. This kit is called stage 2 open filter inlet, but can also work with closed airbox, as well.

Stage 2 Adds adds 75% increase in cabin whine because of its direct connection to the inlet pipe capturing all the rotor pulses.

Pro Tip:Using electric tape wrapped tightly around the end of the sound tube, will narrow the tube end allowing it to slide in to the greased, lubricated grommet.

Do All Kits Require Drilling the Firewall?

(Drill bit provided)

2015-17 Whipple Stage 1 NO

2015-17 Whipple Stage 2/3/4 YES

2015-17 Whipple Cobra Jet YES

2015-17 Kenne Bell Stage 2 YES

2015-17 Roush Stage 2 YES

10-14 Mustang Kits: We recommend to enlarge existing hole but not necessary (Reduced whine if not hole enlarged)

2012-2015 ZL1 Camaro Kit: Drilling steering shaft rubber grommet.

With a FOSTER SC Sound Tube Kit, you can be sure that:

No recalibration is required

No power loss or gain

No restriction or loss of airflow

No smell or fumes

Pro Tip: For easy installation use grease or WD40 when installing sound tube through grommets and when pushing over hose barb ends.

To help select your kit, read our technical FAQ's below

The amount of whine heard is dependent on throttle openings and load on the motor and the kit purchased.

Whine will increase as load and rpm increase from 3k rpm to redline. It's also typical to hear some slight whine and whistle at light throttle application.

You may hear the sound of the induction and supercharger whistle at idle and light throttle on some models depending on exhaust loudness and if windows are up or down.

30 minutes to an hour depending on kit purchased.

Drilling the firewall is actually one of the earliest parts if directions and tips are followed.

Using light oil on the hole saw teeth and drilling on low speed is required to not damage or dull the saw.

Stopping twice to let it the hole saw cool and re-oil is required also.


At cruise speeds speed kits are quiet, but you may hear a slight whine or whistle at low loads during acceleration and out of boost.

No, this is an in car whine mod only.

It uses our custom made sound tube to capture the natural rotor pulses and transfer them into the cabin for the driver to hear.

Only the 2015-2017 Mustang Whipple Stage 1 kit uses a part of the stock sound tube.

If you don't have your takeoff I may have some subject to availability.

You could always go to stage 2, 3 and 4 kits that don't require any part of the stock sound tube.


The inlet pipe version uses a diaphragm cap on the inside of the sound tube end in the cabin.

This keeps the sound tube and inlet air tight. The diaphragm material allows sound waves to travel through but remains air tight.

A power drill and common hand tools would be needed, but all our kits are made for an easy DIY installation at home. Kits are complete with all hardware like drill bits and connection materials for installation.

Kits are complete with all hardware such as drill bits and connection materials for installation.

As long as your car has a Twin Screw Superchargers, and we can find access through the firewall with your help we would be willing to develop a custom kit for your car.

Yes it will work with loud exhaust, but I do recommend going with our stage 2,3 or 4 depending on model.

The inlet path kits offer the loudest whine and increase it by 75%.

Windows rolled up will always allow you to hear more whine.

This is our upper kit and attaches to the OEM sound tube for easy installation and significantly increased in-cabin rotor sound This is our lower kit and offers higher levels of in-cabin rotor sound and attachment through the firewall

This combines the Upper & Lower Kits and offers the maximum in cabin rotor whine. This involves fitting both Stage One & Two. Requires firewall drilling

This Whipple kit offers the maximum in cabin rotor whine and a direct path from the inlet pipe through the firewall.

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