But you'll need to tune it for your car/engine. There is a lot more than just the rear flap door spring…. LOL. Here, i'll throw a short list....
- rear flap door spring... the obvious one... it's how fast it comes open
- how far the flap door comes open... yes it's adjustable by the tab and important.
- metering rods - and the steps at the bottom. tuned with a small allen wrench. very important
- How far the back barrels come open.... believe it or not, not 100% completely vertical is probably correct.