AEM Air/Fuel Monitor installed

[CDN OpelNut]

I got my AEM A/F sensor and gauge installed today. Not too bad.

I'm not much of a welder (only having done it once before) so placing the bung on the exhaust was the time consuming part. (Which I #%@#ed up by putting it at the wrong angle when my clamp moved so may have to be redone ).

Anyway other than that it went ok. The unit I bought is an AEM unit that has the sensor and gauge as a kit. I got it on E-Bay for $157 which is a decent price. pic 1

I made a little pod for it out of fiberglass which sits in the ashtray hole and angles it toward the driver and wired in a switch so as not to crowd my fusebox any further. Pic 2.

can't seem to upload photos right now....add them later

Now I just have to figure out what to do with it.

BTW, when warm and idling at 1000rpm it reads about 12.5, then when I give it gas to about 2000-2500 rpm it drops to about 10.5. Rich I guess. It's a place to start tuning this DCOE.

[wrench459]

Originally Posted by CDN OpelNut BTW, when warm and idling at 1000rpm it reads about 12.5, then when I give it gas to about 2000-2500 rpm it drops to about 10.5. Rich I guess. It's a place to start tuning this DCOE.

Welcome to your newest addiction!
Tuning is half art and half science. Make sure WOT stays under 13:1 and 10.5
is very rich for an NA motor.

When you start data logging over time with a big cam/carb you'll find wild swings from rich to lean. Check around you'll find some very good charts on this site with real life Opel A/F readings.

[CDN OpelNut]

Anyone care to give a quick "How to" on tuning with the A/F monitor?

After finally figuring out that the car won't run well with the carb fuel bowl vent blocked off...... , I'm ready for some road tests.

Is there a good system to tuning or do I just drive at different speeds and rpms and record the ratios?

[wrench459]

I like to get the motor to idle first.
Then do a no load step.
After getting the low rpm A/F close. I'll make a full throttle pull in third gear at the lowest possible rpm.
performance :: another pull picture by wrench459 - Photobucket

If at any time during the WOT pull the ratio goes over 16:1 abort!!

[tekenaar]

Originally Posted by CDN OpelNut Anyone care to give a quick "How to" on tuning with the A/F monitor? After finally figuring out that the car won't run well with the carb fuel bowl vent blocked off...... , I'm ready for some road tests. Is there a good system to tuning or do I just drive at different speeds and rpms and record the ratios?

. . . but, how about listing your entire "jetting" in your carb currently?!

[hrcollinsjr]

Originally Posted by tekenaar . . . but, how about listing your entire "jetting" in your carb currently?!

Maybe even like a quick list of engine specs and the AFR after each jet change to?

Harold

[CDN OpelNut]

Originally Posted by tekenaar . . . but, how about listing your entire "jetting" in your carb currently?!

I'm working out of town for the next few days so won't get to this until weekend.

From memory:

• Choke 32
• Aux Venturi 4.5 (on the way)
• pump jet 50
• pump valve 50
• Emulsion tubes F2
• main 145
• idle 50F8
• air correction 200
• needle is 225 I think

Specs for the car are in my signature plus header, 2.25 exhaust. pegged at ~125 hp by Mr. Legere.

[tekenaar]

Originally Posted by CDN OpelNut I'm working out of town for the next few days so won't get to this until weekend. From memory: Choke 32 Aux Venturi 4.5 (on the way) pump jet 50 pump valve 50 Emulsion tubes F2 main 145 idle 50F8 air correction 200 needle is 225 I think Specs for the car are in my signature plus header, 2.25 exhaust. pegged at ~125 hp by Mr. Legere.

Geeze . . . 32 chokes in a 45 SSD carb on a 2.4 flat-top piston engine? . . . you're literally "choking" the life out of this engine with those main venturis (chokes), IMO!

Remember, you don't need to worry as much about AV signal strength in an SSD carbed engine as each barrel feeds TWO cylinders (1200cc), doubling the flow volume per combustion cycle in each barrel compared to a DSD engine! I prefer staying around an 85% "choke-to-throttle-size" ratio in SSD engines, so 38 chokes in your 45DCOE!

I'm running 42 chokes and the largest AV available in my 48 DSD, 10.6CR 2.2CIH GT. Search old posts for SSD tuning info as I posted complete jetting recomendations for a 40/45 SSD on a flat-top 1.9 some years ago . . . of course you'll have to adjust "jets and airs" to optimize mixtures for the much higher flow volumes in your carb.

[CDN OpelNut]

Originally Posted by tekenaar Geeze . . . 32 chokes in a 45 SSD carb on a 2.4 flat-top piston engine? . . . you're literally "choking" the life out of this engine with those main venturis (chokes), IMO!

Well, I've got to tell you Otto, that I had the same concerns and went so far as to call the most local Weber dealer in Vancouver to order some 34's and was talked out of it. He recommended staying with the 32's for low end grunt. I may yet order a few more choke sizes to play with.

I know that main Weber deal in Calif. says to never use anything smaller than a 34.

ps - not flat tops in this car........

[tekenaar]

Originally Posted by CDN OpelNut Well, I've got to tell you Otto, that I had the same concerns and went so far as to call the most local Weber dealer in Vancouver to order some 34's and was talked out of it. He recommended staying with the 32's for low end grunt. I may yet order a few more choke sizes to play with. I know that main Weber deal in Calif. says to never use anything smaller than a 34. ps - not flat tops in this car........

. . . you probably said "SSD", while he most likely "heard DSD" and recommended accordingly! Whenever you talk about any "sidedraft" installation on a four cylinder engine, the immediate assumption is DSD and that's what's "heard/understood"!

Get the "Speedpro Series" book titled "How to build & power tune WEBER & DELLORTO DCOE & DHLA Carburetors" by Des Hammill . . . It'll answer most of your questions about DSD and SSD installations and has some good volumetric jetting info for small and large 4-cylinder engines, individual and siamesed runner heads . . . and it's in English!

[CDN OpelNut]

Originally Posted by tekenaar . . . you probably said "SSD", while he most likely "heard DSD" and recommended accordingly! Whenever you talk about any "sidedraft" installation on a four cylinder engine, the immediate assumption is DSD and that's what's "heard/understood"! Get the "Speedpro Series" book titled "How to build & power tune WEBER & DELLORTO DCOE & DHLA Carburetors" by Des Hammill . . . It'll answer most of your questions about DSD and SSD installations and has some good volumetric jetting info for small and large 4-cylinder engines, individual and siamesed runner heads . . . and it's in English!

He's well aware it's SSD. (and the video is on You-Tube)

I'm working my way through "Weber Carburetors" by Pat Braden at the moment. Another good one.

[wrench459]

It's not perfect.
Lets see if you can get the carbs to do this.
Forget the top graph look at the bottom one.
wed_pull_5.jpg