Weber 44 IDF Question |
|
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. |
|
Weber 44 IDF Question |
orbit398 |
Nov 1 2016, 09:57 AM
Post
#1
|
Member Group: Members Posts: 139 Joined: 29-April 15 From: League city, Texas Member No.: 18,681 Region Association: Southwest Region |
Just looking to see if someone can help pin point an issue I am having – assume it’s a carb issue.
Here is what I have: 2.0 liter with flat top pistons (euro style), has ~160 psi on all cylinders, carb cam, bursch exhaust, dual Weber 44 IDF carb set up, idle jet = 55, main jet = 145, F11 emulsion tube, 200 air correction. Carbs are synced and pull the same at idle as well as about 1500. I live in Houston (sea level). I have read and followed several write-ups on tuning the Weber carbs. Overall, the car runs great above about 2200 rpm. It idles excellent. Issue: Still getting the occasional popping. More importantly, while under easy acceleration (throttle slightly opened/just limping along in traffic) ~around 2000/2200 rpm, the engine seems to be missing or it shutters. If I open the throttle just a bit more, it disappears and runs great. I cannot replicate this by just revving the motor up in neutral; does this only under a load?? What could be the issue here? I plan to recheck synchronization/insure carbs pulling equally, spray carb cleaner/starter fluid to check for air leaks, try to ensure butterflies are opening equally. Just puzzled at what it could be. |
jmill |
Nov 4 2016, 03:20 PM
Post
#2
|
Green Hornet Group: Members Posts: 2,449 Joined: 9-May 08 From: Racine, Wisconsin Member No.: 9,038 Region Association: Upper MidWest |
My car with new dual 44mm EMPI carbs linked with a Crossbar (103mm cylinders) is popping like crazy as well. The mechanic wants to open up the valve gaps. Is that making sense to the brain-trust, as a solution to this problem? or is it solely an issue with the adjustments of the carbs? Lean pops through the carb is usually a fuel problem or ignition is way advanced. Increasing valve gap IMHO is silly. You won't get full lift out of your cam and leave power on the table. Back off the advance or richen up your mixture. At what RPM or situation does it pop? What size idle, main and AC jets do you have along with what ET and vent size? |
HansJan |
Nov 4 2016, 04:11 PM
Post
#3
|
Member Group: Members Posts: 395 Joined: 5-April 16 From: Sugar Land TX Member No.: 19,860 Region Association: Southwest Region |
My car with new dual 44mm EMPI carbs linked with a Crossbar (103mm cylinders) is popping like crazy as well. The mechanic wants to open up the valve gaps. Is that making sense to the brain-trust, as a solution to this problem? or is it solely an issue with the adjustments of the carbs? Lean pops through the carb is usually a fuel problem or ignition is way advanced. Increasing valve gap IMHO is silly. You won't get full lift out of your cam and leave power on the table. Back off the advance or richen up your mixture. At what RPM or situation does it pop? What size idle, main and AC jets do you have along with what ET and vent size? Sorry, must be misunderstanding. These pops Im talking about is more like gun-fire coming from the exhaust pipe. Seems to happen most when slowing down or steady speed. Under accelaration it is a lot less. But am I highjacking some one elses post? |
Lo-Fi Version | Time is now: 3rd June 2024 - 03:37 AM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |