idle rpm

[xeonjiahao]

i notice that all engine idle at 800rpm, so my thought is to have a slider just like the max rpm bar but for idle rpm.

[Daffyflyer]

We'd rather not add anything that has pretty much 0 gameplay effects and takes up UI space though.

[RobtheFiend]

Tie it to the cam profile slider, 600 rpm under 25 cam, increase to 1100 for cams over 85.

[Daffyflyer]

Tie it to the cam profile slider, 600 rpm under 25 cam, increase to 1100 for cams over 85.

I like that plan! Will look into it.

[SamSheepDoq]

Tie it to the cam profile slider, 600 rpm under 25 cam, increase to 1100 for cams over 85.

I don't see why it's even needed to be honest. A friend of mine got a smaller cam set for his truck and the rev is the same, but now he gets better fuel economy. According to Engineering Explained, there is an IAC valve (Idle Air Control) for determining idle rev.

If you want to watch that video, go here: https://www.youtube.com/watch?v=oMjAtDGdWRM

[ilorioc]

Tie it to the cam profile slider, 600 rpm under 25 cam, increase to 1100 for cams over 85.

I don't see why it's even needed to be honest. A friend of mine got a smaller cam set for his truck and the rev is the same, but now he gets better fuel economy. According to Engineering Explained, there is an IAC valve (Idle Air Control) for determining idle rev.

If you want to watch that video, go here: https://www.youtube.com/watch?v=oMjAtDGdWRM

That may be the case for your buddy's truck going to a smaller spec cam.
When I got a cam with higher lift specs I had to have the idle raised to 800. At the standard 600 rpm it stalls unless I had my foot on the accelerator pedal to keep the rpms up.
Even at the current 800 rpm idle the lower rpms cause it to buck and surge. One of the cons of going to a bigger cam. Perfectly smooth at >1K and will pull all the way up to 8K though.
Although if you install in a big enough cam you'd need a auxiliary vacuum pump to keep the brakes working properly at low rpms.

[SamSheepDoq]

Huh, I wouldn't have known this. Would you mind PMing me about how you changed the idle rev? It seems like an interesting topic.

[Zabhawkin]

With modern cars its done by the ECM, older carbureted cars there is an idle adjust screw that actuates the throttle.

[Daffyflyer]

With modern cars its done by the ECM, older carbureted cars there is an idle adjust screw that actuates the throttle.

Though in many ECU controlled cars (at least older once) there is an idle adjust screw that sets the minimum amount of air that the idle air valve lets in, and then the ECU controls opening that valve further to maintain idle at different temps/with A/C on etc.

[gt1cooper]

Our '69 idles at 1100 rpm, with AC on it idles at 900 and is nearly stalling. I am pushing my dad to let me take a video of it running for you guys; you can hear it is not happy at that rpm. It's a screamer, max power comes after 8000 RPM. 600 RPM wouldn't even start it, and if you tried pulling the throttle to start it you would just flood the carb.