MAP for ignition with Weber IDF - Suitable port?

Fuel Supply & Ignition Systems
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

Okay, going to be going ignition first then switching to full EFI once I have my head around that.
Crank trigger etc are on the way but I know I will need to either measure throttle position (TPS) or Manifold Air Pressure (MAP)..
Are the vacuum ports on the bottom edge of Weber IDFs suitable? These are NOT used for vacuum advance on a dizzy as they are not exposed by the butterfly, they are used normally for syncronising using a manometer.

Suitable?
Obviously I need a MAP sensor and some way of combining these 4 ports.. Suggestions?

Or is a TPS the way forward, and if so I do you fit one to weber IDF with Sync-Link?

Will get some pics this weekend and start head scratching and planning etc.

Thanks,
Sam
Steve Arndt
Posts: 7420
Joined: Sat Mar 10, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by Steve Arndt »

Yes those ports work for map. Watch for a pulsing signal. I use all four ports, run them into a small averaging plenum, then to a restrictor right before the map sensor.

I wouldn't bother with TPS for a basic ignition setup. You just need RPM and load (map). A coolant reference is nice because you can run extra advance to help cold running manors.
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

Got cht and can easily add inlet air temp.. Any use?
Steve Arndt
Posts: 7420
Joined: Sat Mar 10, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by Steve Arndt »

You can certainly play around with those later on for extracting the most from the combo.
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

Excellent, thanks for that. Was planning on using all 4 to give a true picture of what's going on anyway.
Any idea of the diameter (id) hose needed for this?
What do people use for an averaging plenum? What sort of volume is needed?
Would an anti-pulse valve be of use as well?

Thanks once again.
Sam
User avatar
pdub
Posts: 76
Joined: Tue Feb 08, 2011 4:20 pm

Re: MAP for ignition with Weber IDF - Suitable port?

Post by pdub »

I use those ports for my MAP on my MS2. Im not sure what size vacuum line I used but it is small ID. Probably around 1/16". I use a stock fuel filter for evening out pulses. CHT/IAT sensor can be used to add timing when cold or pull when hot, assuming your ECU has this capability.
User avatar
Dale M.
Posts: 1673
Joined: Mon Oct 05, 2009 8:09 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by Dale M. »

The ports on Webers are 4 x 0.75 mm threads and there is a model airplane engine crankcase pressure tap that will fit port... Just for your FYI...

Somebody here on this site mentions it in a thread... Or maybe it was on samba..

Dale
"Fear The Government That Wants To Take Your Guns" - Thomas Jefferson
1970 "Kellison Sand Piper Roadster"
User avatar
trbugman
Posts: 119
Joined: Mon Apr 01, 2002 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by trbugman »

2333(103x70) Type 4 DTM MS3+X on 73 Karmann Ghia ignition only with LS2 truck coils firing in sequential, fuel next.
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

trbugman wrote:Here you go.
Perfect, thanks. Have found the same on Amazon UK and have ordered 9 nipples (4 for the carbs, 5 for the plenum).

Going to be using MS3 of some description for spark only initially, adding efi later.

Thanks again,
Sam
User avatar
Jadewombat
Posts: 1447
Joined: Sat Jun 22, 2002 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by Jadewombat »

Some example ignition maps to get you started:

http://www.shoptalkforums.com/viewtopic.php?t=98618
http://www.shoptalkforums.com/viewtopic.php?t=110006

You can start out with an ignition map similar to a distributor curve and then revise adding more advance with whatever you feel comfortable with. You'll find that crank-trigger systems can give the engine a LOT more advance though than a distributor because the systems make a far more efficient spark.
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

Excellent, thanks for that.

MS3Pro has been ordered along with ls2 coils, coolant temp sensor, crank and cam sensor is already ordered.. Wideband is already fitted, as is CHT and Oil Temp.

Been tidying up some of the 'historic' wiring lately, getting rid of crappy connectors, fitting better (weatherpack) connectors where needed and replacing wires if there were questionable lengths/connector uses (blue bullet connector used to 'extend' a piece of wire that was too short to name but one)

Fortunately wiring is one of those jobs I enjoy!
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

Been collecting parts for a while now, just waiting on a shipment from Mario. In the meantime I put together a plenum to merge all 4 MAP signals into one.

Image

Image
Steve Arndt
Posts: 7420
Joined: Sat Mar 10, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by Steve Arndt »

That will work as long as it is perfectly vacuum proof. I made mine out of PVC and JB. I would advise putting it in a bucket of water and blowing air pressure into it to make sure it doesn't leak. Vacuum is harder to seal than + pressure but it will give an idea.
User avatar
samcat
Posts: 1088
Joined: Tue Jun 12, 2001 12:01 am

Re: MAP for ignition with Weber IDF - Suitable port?

Post by samcat »

Good call.. I did run a bead of impact glue around it, but am not convinced.. Will give it a test.
Post Reply