4af Weber conversion

[DBguy]

Hey guys,
I'm thinking about doing a weber conversions on my 4af, tired of dealing with the emissions computer and all its crap I'll probably spend more buying new switches, solenoids etc.. What are your thoughts? From what I've heard they make a little more power too

This is the kit I was thinking of going for, I know it's for the 4ac, I can't find one for the 4af but from what I've researched they are physically the same.
My only concern would be jetting but they are both 1600...
http://cgi.ebay.ca/Weber-Carburetor-Kit-Toyota-Corolla-4AC-79-87-32-36-/250815629236?pt=Motors_Car_Truck_Parts_Accessories &hash=item3a65c6c7b4#shId

If I do go through the conversion I'll post up a brief how to with pics - just tryin to give back a little

[eage8]

that's more or less the same kit I had on my 4-AF (I had the dual 38 DGES kit). It'll fit just fine.

The emissions computer doesn't really do anything though...

I'll be interested to see how yours ends up, my engine went when I only had about 100 miles on mine (not carb related), so I didn't even have it tuned right yet.

with that kit you'll probably see a good fuel economy increase too

you'll need a fuel pressure regulator. Webers run at 2 psi and the stock system runs at 6 psi.

[Evo_lucian]

Do it . Would be a really interesting project. Webber jetting is easy, plenty of sites to help you out.

[DBguy]

I think the emissions computer actually does do something, for example, if I unplug it there's a noticeable difference in rpms and mixture. It is a feedback carb system to it has to be taking info from the o2 sensor and relaying it to the mixture solenoid. I have checked over and over the vacuum lines and I'm almost sure there's no leak so my next guess is that because the system is not in its stock setup it's trying to compensate for something by leaning out the mixture. I don't really know, I'm just tired of it and I'll probably spend the $300 trying to figure it out.

I'm pretty sold on the setup right now, thanks for the reminder about the fpr, almost forgot. Saw your post about the 38 eage8, I'm probably just gonna stick with the 32/36 for now, cheaper and the problem is if I start going bigger carb then I'm gonna want cams and exhaust to match and...well you get the point

[DBguy]

Alright so I got all the parts and mounted the new carb it will start and run fine with no load. When I start driving it there's a lot of hesitation and flat spots. I hooked up the vacuum lines to this diagram and plugged everything else:



Uploaded with ImageShack.us

I'm not 100% sure the distributor is working properly, if I put vacuum to the large diaphragm and one of the lines on the sub-diaphragm the distributor will react/advance. However the 2nd line off the sub-diaphragm does nothing at all and will not hold any vacuum - I'm not sure if it should be doing something or if there's a hole in it somewhere??

Also I started messing around with timing, any suggestions on what the timing should be with the weber??

[DBguy]

Took the car to an empty parking lot today and got it all dialed in, not sure what the timing is actually at, I basically turned the distributor counterclockwise all the way and kept turning it clockwise t'ill I found the sweet spot - basically ended up advancing the timing a bit. Tomorrow I will spend some time fine tuning the mixture.

Now this engine is in a dune buggy but the conversion should be the same regardless. I do not have cruise control, A/C, power steering or a brake booster.

Alright so as promised here's the write up:

Here's what comes with the kit, carb, adapter, throttle linkage and air filter. You should also get a fuel pressure regulator.




First off take everything off, the 4 bolts that hold the carb, all the vacuum switches, vacuum lines and rails, egr and modulator - I literally took off EVERYTHING. I plugged all the vacuum ports except 1 for the large canister on the distributor.






Make sure you plug the manifold with a shop towel or something the last thing you want is to drop anything down there. Now would be a good time to get some carb cleaner or something and clean the whole are.



You will still need the carb base and if you're running in cold weather you may or may not want to run power to the heater element - I chose not to since it's a summer car mostly...I also made an egr delete plate (still gotta clean it up and paint a little).

The rest is literally plug and play, bolt the carb an adapter, connect the linkage, connect the 2 vacuum hoses like the diagram above and hook up your fuel pressure regulator (I know mine isn't hooked up in the pics below, I was having trouble with it but it will be back in soon). The engine fired up right away with the baseline setting (given with the kit). I realized when driving that there were a couple flat spots but after playing with the timing it all smoothed out.




Overall I gotta say it was a really simple conversion mostly plug n play. It looks much cleaner and performs waaay better. I haven't had the car on a dyno and it wasn't really running right stock to begin with but the difference is night and day, smooth and pulls hard all the way through.

Hope the write up helps - let me know if you guys have any questions

[Elizle]

I'm thinking about doing the same but using a Holley 5200. If I was going to buy this:
http://cgi.ebay.com/ebaymotors/Holle...#ht_500wt_1182

What else would I need?

[canadianae92]

holley is ok, i personally prefer weber but holley carbs are tried and true, you see them very often on american muscle

[Elizle]

My dad had one in his 1970 Mustang. I just can't justify spending much more money on this car until I get a better job. I just graduated and I got my bachelor's degree in Information Technology, but I'm pushing carts at Walmart right now. So, I need to get a different gig. But the Holley route should be a bit cheaper and I am starting to think I need a new carb. My car isn't even starting when I prime it because it sat for 2-3 months.

[eage8]

holley is going to end up being more expensive because you'd have to fabricate an adapter plate for it.... the weber comes with one.

[Elizle]

http://cgi.ebay.com/ebaymotors/Weber...ht_2147wt_1165

So this wouldn't work with the Holley 5200? I thought it was a clone.

[djfoxx]

hi guys i also have the 4af bt in its original car haha.ive got a cone on now bt is the weber better?i heard that it eats up petrol?