 Larger chokes (venturies) on my Webers? |
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| Eddie914 |
 Oct 19 2004, 07:35 PM
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#1
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Unregistered  |
I have removed the Weber 40IDC 3A carbs for a rebuild.
They currently have 32mm venturies. Will larger venturies give more top end power? The engine is 2.7 from a '77 911. Internals (P/Cs, compression ratio, Cams) are unknown. Bursch Headers with megaphones (with removable baffles). The car is 90% track. Weighs less than 2100lbs. Thanks Eddie |
 
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| J P Stein |
Oct 20 2004, 06:00 PM
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#2
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Irrelevant old fart  Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
QUOTE(Eddie914 @ Oct 20 2004, 09:33 AM) The power curve is fairly linear. The rev limiter is at about 6700rpm (distributor rotor limiter?). 3500-4000 seems to be the fat part of the power curve. The power seems to flatten out over 4500-5000. Sounds like CIS cams to me. That being the case, there's nuthin' to be gained by winding the thing over 6-6.5K.....thus, the bigger chokes won't help (tho 34s might work)....and well may hurt the bottom. The CIS cams have very little overlap and thus minimal cylinder scavenging.....which is what one needs for top end power in a NA motor. |
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Posts in this topic
Eddie914 Larger chokes (venturies) on my Webers? Oct 19 2004, 07:35 PM
TimT Yes you will get more top end, but you will give... Oct 19 2004, 07:44 PM campbellcj I could be wrong (it happens every few years :sha... Oct 19 2004, 09:29 PM fiid Did you know if you spell carbs wrong you get crab... Oct 19 2004, 10:06 PM nebreitling LMFAO... Oct 19 2004, 10:23 PM Eddie914 I pulled the carbs apart tonight.
Current jetting... Oct 20 2004, 01:43 AM J P Stein It's not a good idea to just change one aspect... Oct 20 2004, 02:03 AM Joe Ricard Well Maybe I'm and idiot (I doubt it) But CIS ... Oct 20 2004, 06:23 AM Root_Werks For something cammed like a 2.7S engine you will w... Oct 20 2004, 08:50 AM Thorshammer Since the SCCA has stuck me with 34mm Venturis, I ... Oct 20 2004, 10:09 AM Eddie914 The power curve is fairly linear. The rev limiter ... Oct 20 2004, 11:33 AM Root_Werks Probably, they are going on a cutomers 2.8 tonight... Oct 20 2004, 11:39 AM Eddie914 Dan,
Oops!
I meant to ask if the 40/36 Weber... Oct 20 2004, 11:44 AM Root_Werks Hmm, I might have another set we could use though.... Oct 20 2004, 11:46 AM Eddie914 I'll do the antipercolation modifications and ... Oct 20 2004, 12:38 PM Eddie914 JP,
What are the specs on your 2.7?
What are the... Oct 21 2004, 08:50 AM Root_Werks Hey Eddie,
Put those 40/36's on that guys 2.8... Oct 21 2004, 09:08 AM J P Stein ... Oct 21 2004, 12:52 PM
Eddie914 Dan,
Thanks for the offer. I'd love to try ou... Oct 22 2004, 12:01 AM |
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