Bosch VE Pump LDA

All LDA parts for Bosch VE pumps, genuine and performance: cam, spring, diaphragm, machined cap, complete LDA and LDA Kit. Dimensions and compatibility listed on each product page.

What does the LDA do?

The LDA (from the German Ladedruckabhängiger Volllastanschlag, boost-dependent full-load stop), also called a boost compensator, matches maximum fuel delivery to turbo boost pressure. Boost acts on a diaphragm, which pushes down a tapered cam. Following the cam’s profile, a lever allows more or less fuel. Without boost, the LDA limits fuel delivery to avoid smoke. As boost builds, it progressively releases full delivery.

What each part changes

  • The cam: its profile sets the fuel curve against boost pressure. It is the key part of an LDA setup.
  • The spring: its stiffness determines at what pressure the cam moves down.
  • The cap: it carries the preload adjustment screw. The machined cap allows finer, more accessible adjustment.
  • The diaphragm: replace it if it is porous, as a leak stops the LDA from working.
  • The LDA Kit: cap, cam, spring and diaphragm together, with the setup guide.

Setting up your LDA

A modified LDA is set according to the engine, turbo and use.

Frequently asked questions

Are the parts compatible with my pump?

All LDA parts fit all VE pumps, except the LDA cam. A few uncommon pumps use an 11 mm cam, while the vast majority use a 12 mm cam. The performance cam is 12 mm: if in doubt, measure yours before ordering.

My engine smokes under acceleration, is that normal?

Excess smoke usually means the full-load stop screw has been turned in too far, or the LDA releases too much fuel for the available boost. The preload or cam profile needs adjusting, and smoke opacity must stay within roadworthiness test limits for a road-going vehicle.

What is the 12 mm LDA well for?

The 12 mm well converts 11 mm LDAs to 12 mm, so you can use the performance cam, which remains the most important part of an LDA.

Are the modifications difficult?


No, LDA modifications are simple. They are done without removing the pump, except for the well swap, which requires removing the LDA. Fitting a cam, a spring and a cap usually takes about 5 minutes. Adjustment takes a little longer but is straightforward. A short fitting and quick setup guide is sent by email after purchasing a cam.