Weber Advice

[CamBiscuit]

I'm currently running Weber 40IDTP 3CI's which I imagine are from the original 2.2 T motor belonging to my car ('71 T) which is in the shed in various pieces. They seem to have original spec internals which are:
Venturis - 27
Main jets - 110
Pre Atomiser 4.5
Air correction - 185
Emulsion tube - F1
Idle Jets - 55 (not original)
Pump jet - 45
Idle Air Bleed - 145

I'm currently running a 2.4 with 'S' cams and 2.2 'S' pistons (higher c/r) and wondered if I should go through the motions of changing venturi's, main jets, emulsion tubes, idle jets etc to suit the more up spec engine?

The car seemed to run ok but I'm wondering if there are performance benefits to be had with making the changes? And are the internals all interchangeable between the 40 series carbies?

Any ideas would be appreciated.

Cheers from the tropics

[rick2]

Don't know what your altitude is but you definately can go larger. Venturis 34, mains 135, F3 emulsion. That should be a good start.
Rick

[Eric911S]

Hello: This setup will put a big smile on your face. Start with 36mm main venturis,140 main jets, 160 air jets, 60 idles,F3 emul, tall secondary venturis and tall manifolds. This should idle well and give you strong pulling power above 4000 rpm. You may have to change the main jets or air jets depending how much above sea level you are. I'm at sea level. Good luck and you should see about 15 more horse power or so. It will feel like 50 though! Thanks Eric

[Paul Schooley]

Eric, would those settings work well with webers on a 2.7 with mild head porting? I'm having those nasty backfirings when you let off the gas and a bit of starvation/hesitation when you're rolling quickly and punch it.

[rick2]

There is a great thread on Pelican about addressing this problem. T Bird gives an excellent tuning lesson. I printed it out and is my guide now.



http://forums.pelicanparts.com/showt...rbin+and+weber



Rick

[Eric911S]

Paul: I've got a good one for ya if you have some cams in your 2.7. I use 38mm main venturis,160 mains and 160 airs, 60 idles, tall secondary venturis,and F3 emul. if you are using S cams or F26 for hotter than S cams. This runs a little rich but pulls like a train. This also works for 3.0 engines. This is my favorite setup for 40IDA Webers on hot 2.5-3.0 engines. Like I say you may have to lean it out a bit or just burn that extra fuel for cooling. It is also a great sound with watershields and my sport muffler. Have fun. Thanks Eric

[CamBiscuit]

Thanks guys.

I've also noticed in the past that the engine stalls under heavy breaking with the clutch in.

Does this sound carb related?

[Eric911S]

Hello: If your float level is set to high it can throw raw fuel down the intake. Check float level and adjust. I actually adjust them a little on the low side for track cars. You must also make sure you have a good fuel pump as well. Hope this helps. Thanks Eric

[CamBiscuit]

Thanks Eric,

I'm having the carbs rebuilt so I'll make sure the float levels are all done, my mechanic had suspected the same thing. He is pretty knowledgeable about Porsches but doesn't have a lot of experience with the early models.

Thanks, attached a photo of the car (and cousin) at Hidden Valley Raceway recently.

[Eric911S]

Hello: Those are some nice looking cars you have there. Hope the info helps you out and have fun. Cheers Eric