Turbo Blanket Affect on IS38+ Boost Onset

Turbo Blanket Spool Up Evaluation


This is the first test of a series that will be conducted to evaluate the affect that a turbocharger blanket has on my Mk7 GTI.  This test is to support evaluation of the affect that the turbo blanket has on the time it takes for the Shuenk IS38+ turbocharger to develop boost pressure.

The turbocharger blanket is manufactured by Forge Motorsports.

Forge Turbocharger Blanket
Forge Turbocharger Blanket

Across various brands of these products the commonly stated performance gains related to boost onset are:

  • Faster boost onset / Reduce turbo lag
  • Peak torque earlier

Test Procedure:

The GTI will be operated in third gear out of boost and the accelerator will be depressed to full throttle.  Once boost pressure increases past 20 psi the accelerator pedal will be moved to a coasting position.  Use of this method for testing boost onset has been previously explained.

The test procedure will be run multiple times starting at different engine speeds to help generate a boost onset curve.

Boost pressure readings from the vehicle MAP sensor will be recorded for analysis.  The time for the boost pressure to build from 1 psi to 20 psi will be the measure used for comparison between the before, no blanket installed case, and after, turbo blanket installed case.

Test Results:

The chart compares boost onset times for the two test cases for several different starting engine speeds:

Turbo Blanket Affect on IS38+ Boost Onset
Turbo Blanket Affect on IS38+ Boost Onset


The data recorded during this test does not support a claim of the turbocharger blanket causing faster boost onset / reduced turbo lag, from the turbocharger.

Torque was not recorded during this test, although due to the contribution that boost pressure has on torque production there is no reason to believe peak torque would occur earlier since boost pressure onset is unaffected by the turbocharger blanket.

Note: Results are for a IS38+ equipped Mk7 GTI.

3 thoughts on “Turbo Blanket Spool Up Evaluation”

  1. Appreciate the work. I use a turbo blanket to keep under the hood engine temperatures down. Also downpipe wrap.

  2. Did you measure inlet temps with and without as that is usually the biggest gain from fitting a turbo blanket?

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