Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> Jetting Webers on 2.7 911 engine., Tuning.
914Toy
post Oct 5 2018, 10:52 AM
Post #1


Senior Member
***

Group: Members
Posts: 710
Joined: 12-November 17
From: Laguna beach
Member No.: 21,596
Region Association: Southern California



I recently installed a "double" Innovative air/fuel (A/F) gauge with sensors in both headers of my 1977 2.7 911 engine, which is stock except for: ignition, Weber carbs, reground cams (modified SC) for spirited street performance with the carbs, and exhaust headers (MB911). The A/F gauge has assisted final tuning, including fine balancing of the carbs (well worth it).

Ignition is Clewett crank fire with ignition timing set at: 10 deg. idle 800 rpm, 29 deg at 3000 rpm, and 33 deg at 6000rpm.

Carbs are Weber 40IDA's with 34 main chokes and tall secondary chokes. Jets are: 145 main's, 180 air correction's, F3 emulsion tubes, and 60 idle's.

Engine is running very smoothly at all rpm's, no carb "spitting" or exhaust popping, no hesitation under any acceleration, and instant accelerator response with plenty of power. In other words, running great. However, A/F's are not perfect with 10.5 at idle, 12.5 to 13 at cruising, and high 13's up hill WOT. On a recent uninterrupted 180 miles run on 101 at 3400rpm (78mph), fuel consumption was 24miles per gallon (IMG:style_emoticons/default/smile.gif)

I have discussed the A/F ratio issue with several carb "experts" - mostly Old School guys. Consensus is my numbers are as good as it gets vs. near perfect 14.7 A/F one can expect from EFI.

Any comments will be welcome.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
914Toy   Jetting Webers on 2.7 911 engine.   Oct 5 2018, 10:52 AM
gereed75   Agree with "experts". Those A/F's ...   Oct 5 2018, 02:09 PM
TravisNeff   Is this an S spec engine, or standard? (35mm ports...   Oct 5 2018, 02:46 PM
914Toy   Is this an S spec engine, or standard? (35mm port...   Oct 5 2018, 04:53 PM
TravisNeff   I got a vent and jet kit from PartsKlassic, they s...   Oct 5 2018, 04:59 PM
TravisNeff   I got a vent and jet kit from PartsKlassic, they s...   Oct 5 2018, 04:59 PM
TravisNeff   I got a vent and jet kit from PartsKlassic, they s...   Oct 5 2018, 04:59 PM
PanelBilly   Sounds like you’ve found a sweet spot. I’ve be...   Oct 6 2018, 07:36 AM
larryM   see jetting chart here http://forums.pelicanpart...   Oct 6 2018, 11:18 AM
914Toy   see jetting chart here http://forums.pelicanpar...   Oct 6 2018, 01:10 PM
IronHillRestorations   You can lean it out a bit by just opening the air ...   Oct 6 2018, 08:11 PM
porschetub   You can lean it out a bit by just opening the air...   Oct 7 2018, 12:38 AM
larryM   more info check this site - Mike Pierce is ...   Oct 6 2018, 10:25 PM
GeorgeRud   Paul Abbot’s Performance Oriented site also has ...   Oct 7 2018, 07:11 AM
gereed75   i Am not a “Weber guru”. I have worked pretty ...   Oct 7 2018, 07:43 AM
porschetub   i Am not a “Weber guru”. I have worked pretty...   Oct 7 2018, 04:16 PM
914Toy   Thanks for all the responses. After carefully adju...   Oct 7 2018, 04:41 PM
72hardtop   Thanks for all the responses. After carefully adj...   Oct 9 2018, 04:22 PM
IronHillRestorations   If I resort to reaming jets, I use a Sharpie on th...   Oct 7 2018, 04:51 PM
914Toy   Thanks Perry. This process is above my paygrade :(   Oct 7 2018, 11:04 PM
DaveO90s4   Hi Toy914 and all, Did you use the Innovate ...   Oct 7 2018, 11:51 PM
914Toy   Hi Toy914 and all, Did you use the Innovate ...   Oct 8 2018, 08:25 AM
72hardtop   With regards to jetting.... If you're using a...   Oct 8 2018, 04:48 AM
gereed75   Hardtop, that is a very good graph and if you un...   Oct 8 2018, 08:20 AM
72hardtop   Hardtop, that is a very good graph and if you u...   Oct 8 2018, 08:47 AM
jfort   I have a recently completed 2.7 with DFI, PMOs, JE...   Oct 8 2018, 09:32 AM
gereed75   Hmmm. Interesting. Did not think that the Weber...   Oct 8 2018, 09:54 AM
72hardtop   Hmmm. Interesting. Did not think that the Weber...   Oct 8 2018, 10:37 PM
Larmo63   Earlier this year, I had a guy I know tune my Webe...   Oct 8 2018, 10:47 PM
72hardtop   Earlier this year, I had a guy I know tune my Web...   Oct 8 2018, 10:54 PM
gereed75   Spent some time with the Samba thread - very infor...   Oct 9 2018, 09:10 AM
72hardtop   Spent some time with the Samba thread - very info...   Oct 9 2018, 11:48 PM
Larmo63   2.4S spec Euro 7R block 36mm heads & manifolds...   Oct 9 2018, 02:23 PM
Larmo63   RE: Jetting Webers on 2.7 911 engine.   Oct 9 2018, 02:24 PM
gereed75   Larmo, That is exactly what I am running on may...   Oct 9 2018, 06:53 PM
914Toy   My engine is running well at all speeds, except fo...   Oct 10 2018, 02:03 PM
gereed75   I am not sure where I got these but they graphical...   Oct 10 2018, 03:22 PM
72hardtop   My engine is running well at all speeds, except f...   Oct 10 2018, 08:17 PM
914Toy   After further research and inspection of the carbs...   Oct 11 2018, 12:43 PM
72hardtop   After further research and inspection of the carb...   Oct 11 2018, 03:40 PM
914Toy   After further research and inspection of the car...   Oct 12 2018, 08:49 AM
72hardtop   [quote name='72hardtop' post='2656524' date='Oct ...   Oct 12 2018, 10:32 PM
914Toy   [quote name='72hardtop' post='2656524' date='Oct...   Oct 13 2018, 08:31 AM
72hardtop   [quote name='72hardtop' post='2656881' date='Oct ...   Oct 13 2018, 08:54 AM
914Toy   [quote name='72hardtop' post='2656881' date='Oct...   Oct 13 2018, 11:26 AM
914Toy   [quote name='914Toy' post='2656955...   Oct 13 2018, 11:31 AM
914Toy   Update. Installing "hatchet" shaped acc...   Oct 16 2018, 08:40 AM
72hardtop   Update. Installing "hatchet" shaped ac...   Oct 29 2018, 12:42 AM
larryM   y'all may also find this thread relevant http...   Oct 16 2018, 11:15 PM
914Toy   Update: I installed the "hatchet" cams ...   Oct 29 2018, 11:18 AM
JmuRiz   Good to know, never heard of the hatchet cam, I...   Oct 29 2018, 11:41 AM
914Toy   Update: After much reading and testing ideas to di...   Nov 7 2018, 01:29 PM
gereed75   Hmmmm....very interesting and extreme diligence on...   Nov 7 2018, 05:51 PM
mb911   Interesting.. I actually need a few of those cup w...   Nov 8 2018, 05:01 AM
914Toy   Interesting.. I actually need a few of those cup ...   Nov 8 2018, 09:54 AM
TravisNeff   You can find a lot of the little parts at partskla...   Nov 8 2018, 08:55 AM
72hardtop   FYI.... There are also 2 types of idle jets used ...   Jan 29 2019, 03:06 PM
Mark Henry   I'm running same, just a bit bigger main jet o...   Jan 29 2019, 04:40 PM


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 29th March 2024 - 09:54 AM