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 )

> All you Weber Pro's, A couple of questions
Grelber
post Mar 28 2007, 03:48 PM
Post #1


Insert favorite Don Rickles joke here.
***

Group: Members
Posts: 690
Joined: 30-May 06
From: McKinney, Texas
Member No.: 6,107
Region Association: Southwest Region



When I hold the rpm steady at around 3200 or so, I get a "surge" back and forth (not a lot). Is this due to unbalanced Webers?

Also, where is the best place to get a flow meter so I can get them balanced.

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
Gint
post Mar 30 2007, 07:06 AM
Post #2


Mike Ginter
***************

Group: Admin
Posts: 16,082
Joined: 26-December 02
From: Denver CO.
Member No.: 20
Region Association: Rocky Mountains



Took me less than 5 minutes to find one. Different date though.


QUOTE(9146986 @ Jul 5 2005, 11:13 AM) *

ummmmm, back on topic anyone?? Now that's a thought <!-- emo&:lol: -->(IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)<!-- endemo -->

Here's the post I made back in Sept of last year when Trekkor was having carb tuning problems, now he's a carb GURU!!!

Also note these instructions were for the 3 barrel Webers, so you'll have to adapt & survive.



Assumptions: the carbs have the optimum jet and venturi package (good luck on this one), the float level in the carbs is correct, the cams are correctly timed, the valves are properly adjusted, the ignition timing is dead on, you have the proper spark plugs for your engine, the linkage is good, the fuel is good, the engine is good.

Remember that the mixture and air bypass adjustment screws are precision needle valves, not head gaskets. Use your fingers to tighten them, not your fist.
Start and warm up the engine.
Make sure the two drop links for the throttle linkage are exactly the same length, and disconnected. You can use a 8mm thin igntion wrench to snap them off.
Turn the mixture screws all the way in and then 5 half turns out.
Turn the air bypass screws all the way in.
Turn the idle speed screws out til it just touches, and then in 5 half turns.
Put on your hearing protection and start the car.
Use your STE and find the barrel that pulls the most. We'll call this one baseline.
Balance the barrel in the other carb that pulls the most with the idle speed screw. (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter)
Go back to the other carb, with the baseline barrel. You will have one all the way in, then use the air bypass screws and balance the other two barrels.
Go to the other carb and do the same thing.
Snug the jamb nuts on the air bypass screws.
All six barrels should pull the same amount of air at this point, if not repeat air adjustment proceedure.
Snap the throttle linkage drop links back on the carbs. If the idle changes then you need to barely adjust the linkage mounts so snapping the drop links on, doesn't change the side to side idle balance.
Use the hand throttle or a vice grip and rag to lock the linkage between 1400 and 1800 rpm.
Start back at the baseline barrel and adjust the mixture screw in or out, to get the smoothest running and highest idle, then turn it in 1/4 turn.
Do the same with the five other mixture screws.
If you have to turn the mixture screws more than two turns either way, you've got the wrong jets.
Recheck side to side and individual air balance, adjust as needed.
Road test the car.
If you get snapping and poping out the intake, it's generally a lean condition.
If you get heavy exhaust fumes, or pboofing out the exhaust it's probably too rich.
If you get a flat spot or popping out the intake at between 2800 and 3200 rpm, you probably need larger idle jets.

That's a rough, five minute draft of my carb tuning proceedure, hope it helps!

If it goes good it should take about 45 minutes, if not about three years.

PK <!-- emo&B) -->(IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)<!-- endemo -->
User is online!Profile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
Grelber   All you Weber Pro's   Mar 28 2007, 03:48 PM
r_towle   Please dont bother to try to get thhe car tuned wi...   Mar 28 2007, 03:49 PM
Joe Ricard   Uni-syn with a ball in tube kinda sucks but the mo...   Mar 28 2007, 04:02 PM
Hammy   Uni-syn with a ball in tube kinda sucks but the m...   Mar 28 2007, 04:25 PM
chris914   I set my 914 @ 3000 RPM. both carbs get synched ...   Mar 30 2007, 12:01 AM
Joe Ricard   I have a fabbed up bell crank piece. sorta like t...   Mar 28 2007, 08:43 PM
Borderline   I have a fabbed up bell crank piece. sorta like ...   Apr 1 2007, 07:39 PM
9146986   Geez, I had a comprehensive tuning post on the old...   Mar 30 2007, 06:51 AM
Joe Ricard   Geez, I had a comprehensive tuning post on the ol...   Mar 30 2007, 07:12 AM
9146986   That would fall under the assumptions I made at ...   Mar 30 2007, 07:34 PM
chris914   Like from Adjust valves and do a tune up with ne...   Apr 1 2007, 07:09 PM
9146986   Remember the search feature is your friend. Searc...   Mar 30 2007, 07:03 AM
Gint   Took me less than 5 minutes to find one. Differen...   Mar 30 2007, 07:06 AM
Gint   Actually Perry, that thread had some other good in...   Mar 30 2007, 07:15 AM
mudfoot76   Here is a link to the STE flow meter recommended i...   Mar 30 2007, 07:28 AM
Joe Ricard   Maybe this is a great place to drop names of thos...   Mar 31 2007, 08:44 PM
9146986   Maybe this is a great place to drop names of tho...   Apr 1 2007, 03:25 PM
rhodyguy   easist way to turn up the idle for tuning is leave...   Apr 1 2007, 10:55 AM
Gint   Perry Kiehl How would you like to see your carb...   Apr 1 2007, 11:16 AM
9146986   Perry Kiehl How would you like to see your car...   Apr 1 2007, 03:23 PM
SGB   An important addition to Perry's excellent syn...   Apr 1 2007, 04:25 PM
Joe Ricard   Nah not pointing at you. But If I read one more s...   Apr 1 2007, 07:08 PM
9146986   I've also found that alot of "carb proble...   Apr 1 2007, 08:25 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: 6th June 2024 - 06:37 AM