Race Car Idle

[drunkenalan20v]

Over the last couple of years i have been building a UR rally replica. it has been completely rebuilt and is nearing completion we are well pleased with the result so far.

however the engine is to smooth and a bit too quiet, we want the car to as well as look and go like it should do, it now needs to sound the part.

what causes race/rally/top performance cars to idle like a bag of spanners? I know that longer duration cams would help. what else can be done and at what cost.

the engine is basically a 3b altho it is fairly well modified already. Im not interested in too much more power!!! altho you can never have enough.

[Markarina]

one of things I implemented during my time in F1 for one of the teams, was a rotating cylinder cut for when the car was sat on the grid idling, the idea was to prevent the engine overheating on the grid

[Henka]

The lighter the flywheel (and internals too), the rougher idle. The more inertia the engine has to overcome to rotate, the smoother it gets. So, by cutting down on rotationg mass, your engine will be more prone to stall. Add to that long dur cams and you've got your self an engine that really doesn't like idle.

[4WheelDrifter]

Get it tuned by Dialynx? Their demo cars always sound like **** when they idle.

[S2central.net]

Lol

[mark_s2]

Only if you want your car to stay there for 3 months and be rusting when you get it back.

They all do that sir.

[aelred]

You would be also told that you need Motec ECU, custom made wiring and a lot of other special parts.

[drunkenalan20v]

not really helping! is there any electrickery out the that can upset the idle?

[4WheelDrifter]

How much more help do you want?
I would lighten the engine's rotating internals a little more, and stick some hairier cams in.

[aelred]

Cams in turbo engines need to be relative mild else with the overlap as you are pumping in it comes out of the exhaust before the firing stroke.
A good mapper could get you engine sounding like the modern WRC cars on idle by playing with the idle load sites.