Fuel injection to Carbs? Options

[Superhawk996]

@osnabruck914

(IMG:style_emoticons/default/smilie_pokal.gif) good info for OP.

[Shivers]

I can’t vouch for the complete accuracy (not my data) but it captures the jist of the 009 flaws

Too much total advance and too soon in the RPM range. This causes you to dial back the timing at low rpm. Off the line it will bog (flat spot) then at some point things catch up between carb airflow and ignition and then it screams for a bit and then falls a bit flat near redline because it was dialed back initially to keep total advance around 27 -29 degrees. My carbed 1911 (with cam & raised CR) used to start to ping around 29-30 degrees.

The 009 “worked” but was a compromise until re-curved


Source:
http://www.914world.com/bbs2/index.php?showtopic=275097

Wow, that is exactly what mine does, 40’s and an 009. Not a big deal on a twisty, but yeah on the fwy it gets to a certain rpm and hits a wall.

My 2056 with Elgin cam, 009 and Weber 40 IDF's pull nicely to 6k in 1st, 2nd, 3rd and 4th gears I do not have any history with the 009 other than it was laying around and seems to work ok.

Probably dumb luck

It is 5th gear that it fails. Pulls nice after the flat spot on the bottom in 1st, Like on a two cycle and you come up on the pipe, then smooth pulls till I hit 5th. I think I get to maybe 5000 rpm. I do not know. I think I'll look into changing the curve like stated above.

[emerygt350]

Why is the advance and retard even a part of this? Retard works at closed throttle and ported advance works at a feather throttle (and yes, they play against each other in cool ways) but they only do that. Not sure what kind of performance 'gain' is being imagined here. Retard gives you a nice idle when you have a bunch of advance dialed in, advance burns better at cruise. Before, what, 73?, it was advance only? Then it was both for a year and a bit, then just retard. Carbs have ported and manifold vacuum, you should be able to continue with both if your dizzy actually has them. Dipping into the throttle, maybe you might get a hair of a feel but jamming it to wot, there is no time for ported vacuum to do anything for you. Now when you jam it off closed throttle with retard doing its thing, certainly you get an extra immediate 10 degrees advance but it just brings you to what you would have without it.

[Spoke]

In the process of swapping the FI, on my 2.0L to Empi carbs.

Care to elaborate on what is happening/not happening with the FI right now? As others mentioned, carbs can get you running fairly quickly but are not optimal w/o changing the cam and the dizzy.

I have all the parts from a 2L FI system and would love to put them back on my 2056 although I do not know if the cam was changed. Plus my 911 is down with an engine R&R so I need to have one P-car running at all times.

How is the status with your 930?

I'm working on removing all the intake, exhaust, and all other components so I can get it to @mepstein for his guys to totally tear the engine down and rebuild. Also sending the transmission for his guys to tear apart and reseal. I think I want him or someone to go over the CV joints. They too have 180k miles on them.

[Superhawk996]

Why is the advance and retard even a part of this?

Because vacuum canisters are designed to work between specified vacuum levels.

When you go from a situation where vacuum source was designed to be taken off a common plenum / throttle body and then is switched to carb, often with a single cylinder vacuum source, the distributor behavior changes. The result often being that you don’t get enough advance during transient part throttle conditions. This ends up being mistaken for and feeling like a carburetor problem which it isn’t.

Don’t disagree with you about wide open throttle behavior being unchanged when vacuum signal is very low and centrifugal advance dominates as RPMs climb. However, most people aren’t driving WOT for any significant percentage of a drive cycle.

[Superhawk996]

Hopefully we haven’t completely overwhelmed OP.

OP - now you understand the first round of comments (IMG:style_emoticons/default/lol-2.gif)

[torakki]

OK, way more info than expected. Let me try and catch up. Reason for going to carbs was that I could not get the FI to run right. Fast idle then slow idle. Took it to 3 different shops that "specialize" in old Porsches, and VW type 4. No one could get it to run right. So, go to carbs. So, it makes sense that the timing would not advance correctly. The carbs are at the mechanic shop so have not seen them in person. Don't know if they have a vacuum port. Don't know SVDA.
Superhawk. No, not bad news. Good info. Looks like I will be going to a new dizzy based on info from this post. Currently have 8 cars and a few need different things (two window regulators, brakes, timing belts, etc..). BTW - have a Boxster FS.
Maybe, as Jeff post, recurving by Sprkworx may be an option with more research.
Well, hope to have the car back next week sometime and see how it actually drives.
Thanks for all the comments and info.

[emerygt350]

You could put the carbs on and try it with the existing dizzy. If it's not good, get a 123.

Or you could fix the fuel injection (IMG:style_emoticons/default/wink.gif). It really is quite simple once you get used to it. Sadly, 'shops' are not likely to be able to fix it, it's the kind of thing that takes more time and knowledge than parts.

Maybe I should quit my job and start a d-jet shop...

[Superhawk996]

You could put the carbs on and try it with the existing dizzy. If it's not good, get a 123.

Or you could fix the fuel injection (IMG:style_emoticons/default/wink.gif). It really is quite simple once you get used to it. Sadly, 'shops' are not likely to be able to fix it, it's the kind of thing that takes more time and knowledge than parts.

Maybe I should quit my job and start a d-jet shop...

(IMG:style_emoticons/default/agree.gif) On all points. I’ll look forward to the grand opening BBQ / car show

[GregAmy]

Or you could fix the fuel injection (IMG:style_emoticons/default/wink.gif). It really is quite simple once you get used to it. Sadly, 'shops' are not likely to be able to fix it, it's the kind of thing that takes more time and knowledge than parts.

Ditto. It's incredible how much knowledge and talent there is on this board. There's not much this group doesn't know, or couldn't supply to repair it.

I'd wager a dollar to a donut your prob would be fixed here. Quickly. - GA