45DCOE's - what idles jets do you use

Carbs

You are about to experience the difference between vintage Weber internals and Emission carbs.

I suggest using 50 F 11. They are a shade leaner than F8 commonly used. and should be a bit better in low/mid range where things go rich.
If too lean they can be drilled to 55s easy enough.

alfaparticle said:

After 15 years of playing with 40DCOE's I am about to start with 45's. I think that I have a good handle on main jets and air correctors but which idle jets are you guys using? My venturis are 36mm and the motor is a 2L Nord.
Thanks.

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Ed, what model of 45 are you using ?

Steve

Ed, what model of 45 are you using ?

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45DCOE152

In my experience of 152's, they tend to like the slightly richer idle jets. Not sure why, but in every case of fitting 151's and 152's versus their earlier counterparts, I've found that, almost without exception, they prefer the richer ones.
If you have them try both and let us know the outcome.
Steve

I have used 50F11, 50F14 and 50F8 on earlier series 45DCOE on a 2- liter and 50F8, 55F8, 55F9 and 55F12 on a 1600 twin plug. All when using F16 emulsion tubes. With F9 emulsion tubes on the 2 liter idle jet requirements change slightly.

I have used 50F11, 50F14 and 50F8 on earlier series 45DCOE on a 2- liter and 50F8, 55F8, 55F9 and 55F12 on a 1600 twin plug. All when using F16 emulsion tubes. With F9 emulsion tubes on the 2 liter idle jet requirements change slightly.

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Thanks for that. I have F16 emulsion tubes. The carbs have 55F8's. Seems like I should order some 50F8's.

Emulsion tubes

Some of you are using F16 emulsion tubes and others F9. Would someone who switched to F9's explain the pro's and con's?

Also, has anyone changed from the stock .45 pump jet and .40mm bleed back?
Thanks.

Be sure to order a set of jet drills too !

I have used both on the same engine.

I use F16 for motorsport. That set-up uses much larger main jets - 150 if I remember correctly. It uses way more fuel and there seems to be more power everywhere. 50F8 gave better transitions on that set-up than 50F11 or it may have been 50F14 rather ... not sure would have to look in my notes.

The F9 work fine on the street with 135 mains. Fuel consumption is much better but power is less.

The F16 set-up was jetted on an engine dyno for maximum power. The F9 set-up was set up on the road with a wide band.

alfaparticle said:

Some of you are using F16 emulsion tubes and others F9. Would someone who switched to F9's explain the pro's and con's?

Also, has anyone changed from the stock .45 pump jet and .40mm bleed back?
Thanks.

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This is what I am running. To be honest I had these parts but happy with this setup as car runs good. One day I would like to get this tuned on a Dyno.

WEBER 45
Venturi 36
Main Jet 145
Emulsion Tube F16
Air Correct 170
Idle Jet 55F8

I have used both on the same engine.

I use F16 for motorsport. That set-up uses much larger main jets - 150 if I remember correctly. It uses way more fuel and there seems to be more power everywhere. 50F8 gave better transitions on that set-up than 50F11 or it may have been 50F14 rather ... not sure would have to look in my notes.

The F9 work fine on the street with 135 mains. Fuel consumption is much better but power is less.

The F16 set-up was jetted on an engine dyno for maximum power. The F9 set-up was set up on the road with a wide band.

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Thanks, that is a big help. I have 150 mains and 200 AC's and the AFR's look pretty good.