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 )

 
 Reply to this topicStart new topic
> F.I. switch to carbs
karmanbuilt
post Feb 17 2009, 08:30 PM
Post #1


???
**

Group: Members
Posts: 72
Joined: 7-July 08
From: Emmett, ID.
Member No.: 9,262
Region Association: Pacific Northwest
[size=1]After fighting the stock F.I. on my '76 2.0L, and lots of $$$ since 2002, time for carbs. I know all the talk about F.I. is better, I will lose power and milage. The stock cam is not set up for carbs...etc,etc. All I need to know is what changes need to be made to make the dual 40's happy and getting back on the road. Hope I have not up set all you die hard F.I. folks......
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SirAndy
post Feb 17 2009, 08:39 PM
Post #2


Resident German
*************************

Group: Admin
Posts: 41,640
Joined: 21-January 03
From: Oakland, Kalifornia
Member No.: 179
Region Association: Northern California
QUOTE(karmanbuilt @ Feb 17 2009, 06:30 PM) *

[size=1]After fighting the stock F.I. on my '76 2.0L, and lots of $$$ since 2002, time for carbs. I know all the talk about F.I. is better, I will lose power and milage. The stock cam is not set up for carbs...etc,etc. All I need to know is what changes need to be made to make the dual 40's happy and getting back on the road. Hope I have not up set all you die hard F.I. folks......



Pretty simple, you'll need:

- Carb Fuel pump. The rotary pump from CB performance is the best one i have seen.

- Jumper your relay board to run the new fuel pump using the stock wiring.
http://www.914world.com/bbs2/index.php?showtopic=25954

- Get a good crosslinkage for your carbs. Again, CBP has the good stuff.

- Oil vapor catch can. Again, CBP. (I sound like a infomercial (IMG:style_emoticons/default/biggrin.gif) )

- Distributor. You'll hear a lot of opinions on that one.

- Thick FI runner to head gaskets to insulate the runner from the hot heads.

- Adjust valves before you try to sync the carbs.

- Backdate the exhaust system and get SSI heat exchangers. That'll free up some HP.


I'm sure there's more, but that'll get you started.
(IMG:style_emoticons/default/bye1.gif) Andy

PS: (IMG:style_emoticons/default/welcome.png)


Attached Image

Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
reverie
post Feb 18 2009, 04:07 AM
Post #3


Senior Member
***

Group: Members
Posts: 783
Joined: 14-March 03
Member No.: 427
Region Association: None
If you need help with the carbs, there's a good VW hot-rod shop in Boise.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JoeSharp
post Feb 18 2009, 05:01 AM
Post #4


In Irvine, Ca. May 15-18
****

Group: Members
Posts: 3,947
Joined: 9-July 03
From: DeLand, Florida
Member No.: 898
Region Association: South East States
If you go with Solex singles you won't suffer from all of the preconsived stuff that everyone tells you. One of the Team NARP cars with a 1.7 got 49 MPG without trying and the drop in power is minamal. Today that car is going to be a 2L with the same carbs. I'm betting we can get it to get over 50 MPG. I run the same carbs on my 2110 Super Beatle and it smokes the tires in 1st and 2nd while getting about 35 on the street if I keep my foot out of it.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
gothspeed
post Feb 18 2009, 12:35 PM
Post #5


Senior Member
***

Group: Members
Posts: 1,539
Joined: 3-February 09
From: SoCal
Member No.: 10,019
Region Association: None
QUOTE(Joe Sharp @ Feb 18 2009, 03:01 AM) *

If you go with Solex singles you won't suffer from all of the preconsived stuff that everyone tells you. One of the Team NARP cars with a 1.7 got 49 MPG without trying and the drop in power is minamal. Today that car is going to be a 2L with the same carbs. I'm betting we can get it to get over 50 MPG. I run the same carbs on my 2110 Super Beatle and it smokes the tires in 1st and 2nd while getting about 35 on the street if I keep my foot out of it.

Good info there Joe .......... I am still pondering programable FI or Carbs on the 914 I haven't bought yet ......... (IMG:style_emoticons/default/wink.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
karmanbuilt
post Feb 19 2009, 01:14 AM
Post #6


???
**

Group: Members
Posts: 72
Joined: 7-July 08
From: Emmett, ID.
Member No.: 9,262
Region Association: Pacific Northwest
Hey.....thanks for the 411 on the switch to carbs. I know this question has been asked so many times. First 914 was '71 1.7L, and I left it stock with the F.I. no problems, sold it in 1996. My '76 has a hydraulic package so no valve adjustments, maybe the cam isn't stock.....unknown. Keeping the stock fuel pump, and adding a pressure regulator. Also keeping the dizzy, it's hooked up to a Comp-U-Fire....may work O.K.
P.S.-Sir Andy.....I could only hope my 2.0 was half as clean as yours.......now the big question.......which carbs????
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
So.Cal.914
post Feb 19 2009, 07:49 AM
Post #7


"...And it has a front trunk too."
*****

Group: Members
Posts: 6,588
Joined: 15-February 04
From: Low Desert, CA./ Hills of N.J.
Member No.: 1,658
Region Association: None
I have been running weber 40 IDF 's for many years. Very little problems.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rhodyguy
post Feb 19 2009, 09:17 AM
Post #8


Chimp Sanctuary NW. Check it out.
***************

Group: Members
Posts: 22,080
Joined: 2-March 03
From: Orion's Bell. The BELL!
Member No.: 378
Region Association: Galt's Gulch
you're planning on using the high pressure fi fuel pump, adding a regulator AND an ACURATE gauge? for what you'll spend on those items you can purchase the proper pump and be done with it. too many additional hose connections too.

k
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JoeSharp
post Feb 19 2009, 09:33 AM
Post #9


In Irvine, Ca. May 15-18
****

Group: Members
Posts: 3,947
Joined: 9-July 03
From: DeLand, Florida
Member No.: 898
Region Association: South East States
Kevin's right, what ever carb you put in you need to get the C.B. rotary pump. BTDT on all the others including the stock with a return line. It causes problems when the tank is below half. I have used the other pumps and nothing works like the C.B.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Bleyseng
post Feb 19 2009, 11:04 AM
Post #10


Aircooled Baby!
**********

Group: Members
Posts: 13,034
Joined: 27-December 02
From: Seattle, Washington (for now)
Member No.: 24
Region Association: Pacific Northwest
QUOTE(karmanbuilt @ Feb 18 2009, 11:14 PM) *

Hey.....thanks for the 411 on the switch to carbs. I know this question has been asked so many times. First 914 was '71 1.7L, and I left it stock with the F.I. no problems, sold it in 1996. My '76 has a hydraulic package so no valve adjustments, maybe the cam isn't stock.....unknown. Keeping the stock fuel pump, and adding a pressure regulator. Also keeping the dizzy, it's hooked up to a Comp-U-Fire....may work O.K.
P.S.-Sir Andy.....I could only hope my 2.0 was half as clean as yours.......now the big question.......which carbs????


The "hydraulic package" is why the djet didn't run too well...switching to carbs will help.....Now Ljet doesn't mind the hydro lifters.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Tom
post Feb 19 2009, 11:46 AM
Post #11


Advanced Member
****

Group: Members
Posts: 2,139
Joined: 21-August 05
From: Port Orchard, WA 98367
Member No.: 4,626
Region Association: None
I'm not sold on the hydraulic package making the D-Jet run poorly. My 76 has hydraulics and D-Jet and runs great. Howeveer, I don't know what cam is installed with the hydraulic lifters. I know many here don't like the hydraulics, but I haven't had any problems with mine yet. I did back fit to the earlier SSHE's and a Triad exhaust system, so I may have gained back what was lost in power by installing the hydraulics.
Tom
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SirAndy
post Feb 19 2009, 12:01 PM
Post #12


Resident German
*************************

Group: Admin
Posts: 41,640
Joined: 21-January 03
From: Oakland, Kalifornia
Member No.: 179
Region Association: Northern California
QUOTE(karmanbuilt @ Feb 18 2009, 11:14 PM) *

Keeping the stock fuel pump, and adding a pressure regulator.


Please don't !!! (IMG:style_emoticons/default/icon8.gif)



Attached image(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
karmanbuilt
post Feb 19 2009, 11:15 PM
Post #13


???
**

Group: Members
Posts: 72
Joined: 7-July 08
From: Emmett, ID.
Member No.: 9,262
Region Association: Pacific Northwest
SirAndy........I spoke with an owner of a German shop, who told me I could use the stock F.I. fuel pump. Said just put a pressure regulator in line w/it.....guess I got the wrong info.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Spoke
post Feb 20 2009, 06:39 AM
Post #14


Jerry
*****

Group: Members
Posts: 6,978
Joined: 29-October 04
From: Allentown, PA
Member No.: 3,031
Region Association: None
Just out of curiosity, what is wrong the operation of your engine with FI? What items have you replaced?

I'm partial to FI since FI has provisions for cold engine operation and the cam is tuned for FI where carbs do not have engine and air temp sensors and the cam is not set up for carbs.

When I bought my 71, it had a center progressive carb. The shop that did the work said they couldn't get the FI working so changed to carbs.

A couple of years later when the shop moved, they gave me a box full of FI parts.

I cleaned and checked each component and found the vacuum advance on the dizzy to have a huge vacuum leak. The MPS (D-Jet) also had huge vacuum leak. I bought a new dizzy, fixed the MPS leak, checked and cleaned everything, put it on the replacement engine for the 71, and it runs and runs good.

If you changed a lot of parts but it still doesn't work right, then in general you haven't touched the one or two issues afflicting the engine.

Vacuum leaks wreak havoc on FI. Have you checked for vacuum leaks with carb cleaner spraying everything like hoses, gaskets, etc., listening for a change in engine tone?

I used a vacuum pump from HF for vacuum brake bleeding to check the MPS and Dizzy as well as hoses.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

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

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 17th May 2024 - 06:21 PM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
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 ...