Chassis Dyno Q for Carb'd Motor

[BowtieFox]

Can anyone recommend a place for a chassis dyno tune for a carb'd motor? Also can they read the mixture through my exhaust system, or do I need an O2 bung in my headers?
Thanks

Uhh, just thought.......are there any guy's on here that run carbs? :confused:

[Blue91]

Yeah, there are a few dinosaurs lurking. :D

[Saleen91]

I know Conley's will dyno tune carb motors as I've seen some 10.5 cars on his dyno before. They can, and so can most other shops, read your A/F ratio through the exhaust.

[FE_rex]

Can anyone recommend a place for a chassis dyno tune for a carb'd motor? Also can they read the mixture through my exhaust system, or do I need an O2 bung in my headers?
Thanks

Uhh, just thought.......are there any guy's on here that run carbs? :confused:

What will an O2 bung tell you a few passes on the dyno won't. Make a pass look at the plugs - look for detonation on your plugs - set timing for best power - set jets for best power. Need to change at least 2-3 sizes before you will see a difference.

[BowtieFox]

What will an O2 bung tell you a few passes on the dyno won't. Make a pass look at the plugs - look for detonation on your plugs - set timing for best power - set jets for best power. Need to change at least 2-3 sizes before you will see a difference.
That's the way I've always done it with a regular Holley carb. I have a modified HP now with adjustable top bleeds as well as emulsion jets and IF restrictors. As far as I know, the top end plug color doesn't tell you what's going on in the idle and intermediate circuits which effect power up till around 4500 rpm. I'm leaving off of foot brake (auto) at 3k, so I would like to get everything dialed in for the best 60'. Any other thoughts appreciated.

[Todd358]

I was curiouos about that too. A lot of the shops by me are run by guys that got into racing in the FI era and can tune the heck out of an injected car but don't know much about carbs. I just found a local Dynojet not too far from the house...don't know about the tuner though. Here in South Florida, a reputable shop is very hard to come by.

Oh, my 'stang is carbed. Dinosaur or not, I don't think I'll ever build another FI toy.

[red95gts]

Whether the motor is EFI or carbed, you are tuning for the same end result. The A/F ratio will get you in the ballpark and keep you from going horribly lean (BOOM!). Pulling plugs can do the same, except it's far more subjective and more difficult to get a feel for A/F ratio throughout the entire RPM range of the motor.

If it's an all-out race car...pulling plugs works fine as you are tuning for one "strategy" (EFI term there) - Wide-Open Throttle.

On a street car, pulling plugs will be a lot more time consuming than a A/F measurement off an O2 sensor. Can it be done?....sure! Been done that way for many years.

IMHO, one advantge to the "pulling plugs" method is that you can get a feel for the conditions in each individual cylinder. The A/F probe, at best, gives you a feel for the combined A/F ratio of the entire bank of cylinders. In theory, a lean cylinder could be "masked" by a rich cylinder and the overall A/F ratio would be acceptable.

Good Luck!