Stock Air Filter Housing

[70spider]

Hey I have a bit of a dilemma. As most of you know it is getting colder and with the Weber 3" filter set-up the car takes a long time warming up so I thought I would try to put the stock air filter housing on. With the stock set-up it warmed up a lot quicker, but after driving it around for a bit it wouldn't start. I took the top off the housing and it started no problems. So is the stock system to restrictive for the Weber 32/36 carb? The air filter in the stock is what came with the car when I bought it and has no manufacture or part# on it, so maybe a better filter would work A side note, the engine noise was a bit less which the wife liked. Any thoughts?

[ebrown0104]

When I bought my car it had the stock air filter on a 32/36 DFEV and it ran fine.

If it started cold but not when it was hot, it sounds like it's running too rich. I'd maybe turn the mixture screw in a 1/4 turn or so to compensate.

I can't remember for certain, but could you run the lid flipped over, leaving the outer edge open for more airflow?

[70spider]

it sounds like it's running too rich

I replaced the primary idle jet with a smaller one but it still runs rich. Ill try to dial the carb in a little better, I'm not very good at it.
Thanks for the reply.

[70spider]

Update. I got a new air filter and readjusted the mixture screw and the issue seems solved. However it still smells like it is running rich so I ordered some new jets and will try to fine tune the carb when the get here. I will let you all know if rejetting the 32/36 worked.

[baltobernie]

http://www.redlineweber.com/html/Tech/c ... _best_.htm

Very good info on determining if low-speed jet is the correct size. See the info under "Simple Rules".

[70spider]

Thanks Baltobernie. When I got the carb I replaced the primary idle to a 47.5 the stock one was 60. This helped on the extremely over rich condition but the carb isn't exactly dialed in. It works but there are flat spots so I will try to fine tune it or mess it up, education is best learned when we mess up

The 32/36 DFEV stock jets are: Idle p=60 s=50, Main p=137 s=140, Air Corrector p=165 s=160.
aircooled.net has suggestions on how to set up the 32/36 progressive carb:

Primary idle jet, 45-50 at sea level, 40-45 @ 5k’. Secondary idle jet 10-15 larger than primary idle. Weber supplies them with the primary idle larger than the secondary, WHICH IS STUPID. The result with this is that the engine runs too rich on the primary, then leans out when the secondary opens.

Remember, the more intake preheat you have, the smaller your idle jetting will need to be, since the fuel metered by the jet actually stays vaporized, it’s not puddling and condensing before it gets to the cylinders!

Progressive Main Jets, 125 primary. 180-190 secondary (not a misprint). I’ve even seen some engines need 210 secondary mains. If you do not stagger your secondary jetting, you WILL have the same problem of severe lean out when the secondary opens up, since airspeed drops so much due to air flowing thru both carburetor barrels. We want to be lean (around 16:1) on the primary (for mpg and cool running), but richen up to ~13:1 when the secondary opens. Most people are not aware of this and jet the primary and secondary the same. So when airspeed drops to <1/2 when the secondary opens, the vac signal the main circuit sees is also < halved, and your pride and joy leans out like crazy. causing a massive flat spot or spitting/sputtering back up the carburetor. This is why we recommend that the secondary main be much larger than the primary main.

Progressive Air jets. 160-180 will work, we generally use 160 on primary, and 180 on secondary. If you use a 180 secondary air, you may need to go up 10 more on the main, to a 190-200 secondary main. Do NOT be scared of the “huge” secondary jet, it WILL WORK PROPERLY. I’ve setup hundreds of these carbs, and know what works and why.

If you are at elevation, we recommend that for every 4k’ rise

drop both idles 5
drop both mains 5
increase airs 10-15.

So I emailed them to see if these suggestions would work for our motors and they replied that the guidelines would be a good place to start.
When I get the jets I am going to set it up like this: Idle p=47.5/s=60, Main p=130/s=180, AC p=165/180.
If anyone has some thoughts on how to fine tune the Weber 32/36 carb for our application let me know.

[baltobernie]

I don't think I would intentionally shoot for an A/F ratio of 16:1 under any operating conditions. Modern EFI systems can hit the "magic number" of 14.7:1 for normally-aspirated engines with every piston stroke. Our carburetors are prehistoric by these standards, and particularly with progressive barrel Webers, I've been warned to shoot for high 13's to be safe. Remember that Weber-equipped motors spend a lot of time on the primary jet only. I think if you talk with dyno operators, they'll give you the same advice, as do Redline and Weber Carbs Direct. If you choose to go with AirCooled.net's suggestions, listen carefully for a lean miss, and check your plugs regularly. A wide-band O2 meter has been my best tuning aid. You can watch in real time how RPMs and load affect real-world driving conditions.

[70spider]

Baltobernie,
Thank you for your help.

A wide-band O2 meter has been my best tuning aid

Which one did you get? The one from Holley is $450 It would be great to get one though.
I thought the aircooled guy was a bit aggressive that is why I was going to change the jets in increments until I was satisfied. I was curious do you have the Weber 32/36 DFEV on your Spider? If so did you tune it differently from the factory specs?
Well thanks again, I do like the idea of the O2 meter.

[131]

A wide-band O2 meter has been my best tuning aid

Which one did you get? The one from Holley is $450 It would be great to get one though.

This is what I'd be looking at if I was to go down that path.

http://www.14point7.com/products/sigma- ... e-plus-2-1

[70spider]

331, thanks for the option it seems to be a better and more complete design but at $275 w/sensor is a little out of my range. I have been looking around and found this one AEM 30-4110 WIDEBAND O2 UEGO CONTROLLER AIR FUEL RATIO GAUGE KIT (Bosch 4.9 LSU) on ebay for $160. It is basic but I think it may work for what I need at the moment.

[baltobernie]

Which one did you get?

I got the AEM one for less than $200, including bung and sensor. Interestingly, the gauge size is identical to the smaller instruments on our cars. However, I attached a cigarette lighter plug to the power cord, and use the device only occasionally.

I have the 36DCD, so no baseline info was available. If you really want to understand how Webers work, get a copy of Passini's book Weber Carburettors; tuning tips and techniques. It will give you either great confidence or complete despair.

Y'know, lots of your 32/36 models have been sold for our cars. I wonder if a thread could be devoted specifically to this, i.e. Displacement, compression mods, cams, exhaust specifics, and best jets, emulsion tubes, etc. each user decided upon.

[70spider]

Y'know, lots of your 32/36 models have been sold for our cars. I wonder if a thread could be devoted specifically to this, i.e. Displacement, compression mods, cams, exhaust specifics, and best jets, emulsion tubes, etc. each user decided upon.

+2 good thought.
+2 on tha AEM an affordable do. (tax return list )
Thanks