Summary

What do you end up changing for driveability when you add a cam or something like that? So the first thing to understand is with a camshaft, you are going to be sacrificing some drivability, particularly with the larger cams so you really need to weigh this up when you are choosing a cam, yes you're going to make a lot more power in the top end.

00:00 - What do you end up changing for driveability when you add a cam or something like that? So the first thing to understand is with a camshaft, you are going to be sacrificing some drivability, particularly with the larger cams so you really need to weigh this up when you are choosing a cam, yes you're going to make a lot more power in the top end.
00:19 In our own demo car we picked up 100 wheel horsepower going to a large cam but what that results in is a loss of fuel economy, and a loss of power and torque below around about 3000 RPM and you're also going to get the car pushing a little bit when it's in gear because the idle speed needs to be higher so there is a limit to what we can do, there are simply some sacrifices to be made with a camshaft.
00:44 One of the areas we can get an improvement though is by actually reducing, purposefully reducing the ignition timing down in the low RPM area and the reason we do this is that it reduces the engine torque.
00:56 Now normally you'd think that that would be a bad thing but what it can do is it reduces that lope of the camshaft and reduces the desire of that camshaft to make the engine push a little bit.
01:08 The biggest single problem I see with camshaft tuning though is tuners who don't understand the required changes that are necessary to the idle setup.
01:18 There's a raft of changes that are needed there from simply choosing a more realistic higher idle speed target to setting tables like our base running airflow in order to get the engine to actually idle without stalling and that's the biggest problem I see cars that keep stalling every time you come up to a stop and that's not obviously something we want with a cam.
01:39 That question was taken from one of our free live lessons.
01:42 If you like free stuff, and you're the type of guy who wants to expand your knowledge, click the link in the description to claim your free spot to our next live lesson.
01:51 You'll learn about performance engine building and EFI tuning, and you'll also have the chance to ask your own questions which I’ll be answering live.
02:00 Remember it's 100% free so follow the link to claim your spot.