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Join Date: Jun 2006
Location: Adelaide Australia
Posts: 886
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Weber advice needed
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 Aussie tropics.
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'74 RS 3.0 Replica Porsche 968 Clubsport SOLD '70 911E Bahia Red SOLD '71 911 S/T Replica 2.3 Twin plug BEAST  SOLD
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07-07-2006, 04:28 AM
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Yes, I believe that you'll find a fairly noticeable improvement in the mid-to-high rev range by optimising the carbs for a 2.4S engine.
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John '69 911E "It's a poor craftsman who blames their tools" -- Unknown "Any suspension -- no matter how poorly designed -- can be made to work reasonably well if you just stop it from moving." -- Colin Chapman |
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07-07-2006, 04:40 AM
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I agree with John. Your venturis and jetting are too small for optimum power with a 2.4S engine. See the chart at Larry Turner's site for a better starting spec, and then put it on a dyno to fine tune. Something like 32mm venturis, 135 mains, 180 air correction, and 60 idle jets is suggested for a 2.4S.
TT
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Tom Tweed Early S Registry #257 R Gruppe #232 Rennlist Founding Member #990416-1164 Driving Porsches since 1964 Last edited by ttweed; 07-07-2006 at 07:10 AM.. |
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07-07-2006, 07:07 AM
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Thanks guys, much appreciated.
Might try Larrys suggested specs for the 2.4S, I assume these parts are all interchangeable on the 40 series carbs? Im looking forward to some extra horses!!!
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'74 RS 3.0 Replica Porsche 968 Clubsport SOLD '70 911E Bahia Red SOLD '71 911 S/T Replica 2.3 Twin plug BEAST SOLD
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07-07-2006, 07:47 PM
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Adrenaline Junkie
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I usually run mine with all of the vents open on the bottom, especially when I am floggin the hell out of it! Try it. You'll agree!
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07-07-2006, 08:41 PM
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Quote:
Not to worry, when you get things lined out and want to run with the big boys, here is what you will need.  
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2021 Subaru Legacy, 2002 Dodge Ram 2500 Cummins (the workhorse), 1992 Jaguar XJ S-3 V-12 VDP (one of only 100 examples made), 1969 Jaguar XJ (been in the family since new), 1985 911 Targa backdated to 1973 RS specs with a 3.6 shoehorned in the back, 1959 Austin Healey Sprite (former SCCA H-Prod), 1995 BMW R1100RSL, 1971 & '72 BMW R75/5 "Toaster," Ural Tourist w/sidecar, 1949 Aeronca Sedan / QB |
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07-07-2006, 09:03 PM
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Hayabusa
My mum used to do a pretty good Webber too... Also the car sometimes stalls under heavy breaking with the clutch in. Any ideas anyone? Thanks again.
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'74 RS 3.0 Replica Porsche 968 Clubsport SOLD '70 911E Bahia Red SOLD '71 911 S/T Replica 2.3 Twin plug BEAST SOLD
Last edited by cameron.arnott; 07-08-2006 at 03:14 AM.. |
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07-08-2006, 03:11 AM
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Your float level maybe too high causing flooding at fast stops or steep driveways...I hope your nice and warm up there.
Last edited by dimps8; 07-08-2006 at 03:35 AM.. |
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07-08-2006, 03:32 AM
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Cheers Damon,
Yeah pretty nice weather up here at the moment... Hopefuly the carb rebuild might help solve the problem if the floats were out. Hey have you joined the TYP 901 Register yet? Cheers
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'74 RS 3.0 Replica Porsche 968 Clubsport SOLD '70 911E Bahia Red SOLD '71 911 S/T Replica 2.3 Twin plug BEAST SOLD
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07-08-2006, 04:53 PM
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One last question (I think) for the carb Gurus.
Is there any differences between the intake manifolds for the early carbied cars and later ones? And if so are there any worthwhile modifications than can be done to the 'T' manifolds to suit the above suggested changes to the carb internals for the 'S' spec engine? Cheers & Beers 
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'74 RS 3.0 Replica Porsche 968 Clubsport SOLD '70 911E Bahia Red SOLD '71 911 S/T Replica 2.3 Twin plug BEAST SOLD
Last edited by cameron.arnott; 07-09-2006 at 05:46 AM.. |
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07-08-2006, 09:57 PM
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Quote:
When I read this, I flashed on the epic 60+ page thread from 2003 on the Rennlist racing forum about GhettoRacer and driving student's cars. It tangentiated about page 39 into a parody concerning "BBQ events" (BEs) and "Can I drove your grill?" that had me rolling in the aisles. I think it is the longest running thread on that forum, and definitely the best haiku came out of it!TT
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Tom Tweed Early S Registry #257 R Gruppe #232 Rennlist Founding Member #990416-1164 Driving Porsches since 1964 |
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07-09-2006, 12:07 PM
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1969 Porsche 911E 2.0 E
911
Ultima GTR
LeGrand DSR
GT3
2000 Suzuki Hayabusa
1966 Porsche 912 coupe big bore, hi compression
