Dynoed with Webbers

[Rick Parker]

Generally the seat of the pants increase in acceleration is the first thing that is felt with the Webers, it is very seductive. Webers do not disappoint when it comes to this. In retrospect that is probably why they were used by Shelby on the 289 Cobras in the 60's. They increased torque in a way nothing else can short of NOS. Given they were raced on road coarses with many various speeds through the turns, the Webers shortened the time from one turn to the next.

[Gaz64]

Jim,

I'd say going from your dyno results, you had a fairly flat torque curve with the dual Edelbrocks.
Now you have a real midrange peak that falls away, the Edelbrocks made more upper rpm torque (hence hp) than the Webers do, but the Webers make a heap more in the middle.

The engine probably doesn't peak out as well as it did, but the big midrange would more than make up for it.

Now the big question is how are you carbs setup?

44 IDFs come with 36mm venturis, if they are still fitted there's your hp loss.

You need something around 40mm, I run 38s in a 304 cuber.

I'd also say you would make more high mid to top end with 48 IDFs.

[Silverback51]

Glad to hear you are happy with the results. That's all that matters.

Do they have a Mustang or Dynojet dyno?

[RICK LAKE]

race-it Jim there is something way out of wack with the dyno numbers. A good set of webers should pick you up about 40HP and 20-30 pounds of torque in the mid range over any carb. This is where they make the big power. Unless your motor turned diesel, there is somethng wrong. If you are running a 347 with 44 mm you may be too small for your motor. If your torque number is 330, that would be right but HP is lost. Can't get one without the other. A leanout at high RPM could cause this in 1 cylinder. Where there sniffers in both tail pipes or O2 sensors?? We just got done at my dyno place with a bad O2 senser in my side pipe. The A/F ratio was low from the carbon on the sensor. Wide range dyno sensor are not cheap, about $750 for wide band. I would tell you to find another dyno shop and rerun the car for a tuneup. Get yourself either a F.A.S.T or LM-1,or 2, A/R meter for the car and have bungs instlled in both side pipes. You can run and hide the box in the glove box and do your own testing for how the motor is running. I will look and see if I can find the old chart for basic setups for 351 motors with 48mm webers. Any chance of you putting up the dyno runs on here and the numbers chart to look at. Rick Lake

[Dwight]

can you post pictures of your motor with carb's & Webbers?

Dwight

[race-it]

The first DYNO was done at Turbo Technologies last summer with duel quads
Runfile: oo1.drf Max Power = 252.50
Runfile: 003.drf Max Power = 266.96

Runfile: oo1.drf Max Torque = 270.46
Runfile: 003.drf Max Torque = 292.25

Last week Dynoed at Carbs Unlimited with 44 Webbers
Runfile: 001 Max Power = 283.45
Runfile: 003 Max Torque= 450.70

Idle Jet .060
Air Corr Jet .180

DWIGHT: pictures of duel quads in my picture file. Click in camera. Will post new picture of webbers later today.
Main Jet .145