Originally Posted by
RoketRdr
Yes he's completely wrong. If your idle hangs after a WOT run and then drops its because you're too lean on the HSN. If you're car drops to normal idle and then begins to idle up after that then your LSN is too lean. Any time your idle hangs or goes up on its own you're too lean on the top end or bottom end. If you're car idles down normally then up and down again like you said then you need to be checking for air leaks in your fuel system, carb and engine. I suspect your have a bad fuel tank cap seal. With a proper tune your engine should immediately drop to idle after WOT and stay there. After about 10 seconds it should start to blubber and richen up then almost die. At no time should your idle increase or hang on its own.
I wouldn't say he is completely wrong!! Those guys are factory Reds and Kyosho team and a very very quick driver with lots of top end results.
There are two trains of thought relating to engine setup. The method in the video is the 2 stage idle technique and has its merits however the method described by RoketRdr is also valid.
My preference is the 2-stage as I find the engine generally has more punch out of corners and is better (cleaner?) off the line. The engine is also more reliable and less likely to stop in the event of a crash leading to the car being upside down while the marshal gets to you.
As I said both have merits and this is why you've heard different folk recommend a different thing. I see more engines setup by the 2 stage idle method than anything else.
To say Elliot's mechanic is wrong however is absolutely not the case.
Having said that they are discussing offroad engines!! Now we can talk about onroad setup which is slightly different.
Here we do look for the engine to drop to idle quickly but the size of the engine also matters. For example a.12 engine will have a tenancy for the idle to run on after WOT on the straight for example. This is normal as long as it returns to idle within around 2-3 seconds. The bigger engines shouldn't run on however.