Idle confusion

[MustangMatt1966]

Hey guys, i have a quick question..i have been struggling to find the optimum idle point for my car. It was set at about 1,100 rpm and then i felt it was too high, so i changed it too about 700-800 and then the camshaft i have is too big for that idle range and wants to stall....so now i have it at about 900 but im still not sure what to have it at??? any help would be appreciated..

matt

 

[84convertablegt]

auto or manual tranny? service specs are like 550rpm in drive for auto and 700? rpm manual in neutral, but if your cam limits it from going this low like my car, then its up to you. i have a c4 auto and mine is about 800rpm in drive and 900-950 in park. works well and still sounds great!

 

[302 coupe]

what are the cam specs? You may have a problem somewhere that isn't allowing the engine to idle properly, other than cam overlap.

 

[MustangMatt1966]

manual trani, 5 speed t-5, dont have the cam card with me, but i do know its one of the bigger cams that you can put in a heavily modded 289...damn, wish i had the cam card...sorry i can be of more use

 

[2nd Mustang]

My 302 with a 4-speed toploader, Crane hydraulic roller cam, doesn't like anything below 1000 rpm at idle. The car shakes too much below a thousand. Best idle for me is 1100-1200 rpms.

 

[MustangMatt1966]

2nd mustang, that seems like what mine should be at

i think i am going to set it at around 1000 like it was tomorrrow....

 

[1965pony]

Hi Matt, sounds like your in need of a good carb tune. Increase the idle fuel/air ports. Edel's(AFB) are can be tricky, if you don't have the required tools any tune shop can work it out for you. Good luck and let us know how it comes out.
Vin

 

[Route666]

Matt I'd suggest the lowest you can go without stalling tendencies as well, but I know carbs can be tricky and it's possible to have a car stalling at one speed and idling smoothly at a lower speed with proper carb settings. That could be the case, but if you've got an huge cam in a 289 I can understand it not liking to idle low.

If you want lower idle (and better low-speed throttle response) go to weber IR throttle bodies. Better yet, to save the hassles of tuning eight individual runners, get their fuel-injected version.

 

[MustangMatt1966]

thanks vin and route666....i will play with the carb some and play with the idle to see where the right spot is, you guys are right, its all just tunning to get it right...thanks all for your help, and as usuall you came trhough..

Matt