Autolite 1.14 vs. 1.21 experiences?

[80Stang]

Just wondering if somebody tried 1.14s and 1.21s on the same engine and what came out of it in means of power, driveability, mpg and so on. What differences in tuning components you possibly had?

I'm asking because I'm hours away from swapping the 1.14 to 1.21. That 1.14 is running pretty well with 59 jets and 6.5 PV. I have loaded the 1.21 with 63 jets and 4.5 PV, and mixed some 1.14 choke parts into it because the vacuum diaphram that is some kind of choke pull down on top of the carb is not readily available. I plugged the vacuum passage to the carb top to avoid vacuum leak as the diaphram is not there.

Found this David's comment in a previous thread:

We just upgraded Dennis' hot 200 from a 1.08 to a 1.21 this spring and loved the results. It will take some tuning with idle screws, float levels, pump shot and jets, as well as timing, but it is a great upgrade and not at all too much carb for an engine like you are putting together. We are learning more about what works with what all the time. Our original assessment was with a relatively stock 200, with the carb mounted via a funnel adapter.

Somewhere else was a comment on the 1.14 being worse than 1.08, so this is encouraging.

 

[Anonymous]

Interesting thread, I am going to mount a 1.08 on my 200, but it will "blown through" by a turbocharger.

 

[CZLN6]

Howdy:

Here's a excerpt from a 5/9/04 post that will give you some data, tune up specs and hope. Note that the 1.14s preceded the 1.08 carbs. The 1.08 has a leaner idle circuitry and are slightly smaller in total CFM. Tuned right for the application, I don't see much difference in the two.
**************************
"We focused on 1.08’s, 1.14s, & 1.21s. We need more 1.23’s & 1.33s to look at before we can make any generalities about them.

The test mule was Dennis’ “Hot6Tâ€￾ Falcon Ranchero. It has a flat-top ‘78 head modified with larger exhaust valves, Ported & polished, 9.7:1 compression, a 264 Clifford cam, dual outlet headers & DSII ignition with a hot coil. All through a T5 and a 7 1/4â€￾ 3.50:1 rearend. The vehicle weighed in at 2,760lbs. The measuring instrument was a G-Tech accelerometer. This was our first use of the G-Tech meter. It is very sensitive and took some trial and error to get consistency. We were measuring Max HP only. Once we determined reliable comparisons we did not move it or unplug it from power. We tried to find the most level part of back roads and averaged at least five runs, going in three directions to compensate for wind. A total of 33 runs were made with the only malady being a blown header gasket.

Dennis’ Ranchero has a well modified 200, using a modified flat-top log head so that the Autolite 2 barrels were all mounted directly- no adapter. A baseline was taken, followed by a good ignition and timing tune up. Base-lined again with no significant improvement. Ironically, the ignition tune-up made little difference in peak HP. It did start, drive and idle better.

The next test was to determine a baseline with the junkyard 1.08. The 1.08 gave good reliable performance and good mileage (21.8 mpg for 1,270 miles). It was not in bad shape at all. That was followed by mounting a rebuilt 1.21, jetted at #50. It marked an average of a 25% increase over the 1.08 in Max HP according to the G-Tech meter. A statistical comparison of the two carbs is:
Venturi CFM rating Throttle bore Main Jet Shifts
1.08 287 1.55â€￾ 49 5,000
1.21 351 1.68â€￾ 50 5,500

It was clear that a modified log head on a modified 200 can benefit from more CFM than we had previously thought. The 1.21 drove well, but has a high idle problem that we will try to solve this PM. It appears that the 1.21 will have a permanent home on the “Hot6Tâ€￾ 200- that is until we can find and try a 1.33 Autolite!

We also discovered inconsistencies in Throttle Bore (TB) sizes that are somewhat puzzling. A 1.08 had a larger TB, but with a smaller Venturi!!! We have another garage of carbs to measure, but it appears that 1.08s (‘68 - ‘73) could have a 1.42â€￾ or a 1.55â€￾ TB, 1.14s (‘64 -’67) have 1.42â€￾ TB and 1.21s could have 1.55â€￾ or 1.68â€￾ Throttle bores.

We had one 1.23 to measure and it had the 1.68â€￾ TB."

 

[Anonymous]

using a modified flat-top log head so that the Autolite 2 barrels were all mounted directly- no adapter.

How is that possible?? Any pics?


My 1.08 has a throttle linkage the would hit the log if I tried to do that.
I figured I needed at least 3/4" to clear.

My TB are 1.55" (1968 or 69 F-100 w/302)

 

[CZLN6]

Howdy back Linc:

The carb is sitting on a 1/2" thick piece of aluminum and the bottom piece of the linkage that interfers with the log is cut off.

For photos, check out our website in my signature.

Adios, David

 

[80Stang]

Thanks for comments.

I did NOT swap the carbs last weekend, as I thought that the 1" spacer I have below the carb has too little throttle bores in it. It is a spacer originally from a 260. Haven't measured the bores yet.

I spotted another spacer that my friend has. It is a C4 casting, cast in '68, and has been on a 302 with 2V Autolite. Bores measured 41mm (1.61") and right under the carb 43mm (1.69"). I measured throttle bores for the 1.21, and they are 1.6875" (42.86mm).

I'll get that in hands tomorrow and see if I can adapt it easily to my car. Need to get the 1.21 tuned and roadtested before the dyno on 8th June and I may have to have the spacer welded and threaded a little before that...
Well, if I run out of time I'll dyno it with the current 1.14. I may end up with having the shop enlargen the bore of the new spacer to 1.69" all the way. Hope they have time on Thu or Fri...

David, what would you suggest with the jetting? Will the 1.21 call for bigger jets than 1.14 on same engine?

 

[CZLN6]

Howdy Back Teppo:

"David, what would you suggest with the jetting? Will the 1.21 call for bigger jets than 1.14 on same engine?"

Yes, slightly, because it can pass so much more air. My guess at sea level will be in the low to mid fifties. But I start with what ever is in the 1.21 and go from there.

Good luck.

Adios, David

 

[80Stang]

Thanks David. My 1.14 has 59s, I loaded the 1.21 with 63s. I have no jets in between, so if needed I'll mix. I'll adjust jets according to readings on the A/F meter.

Should I enlargen the bores of the spacer, what do you think? I need the spacer just for clearing some throttle shaft parts from hitting the log.

 

[Anonymous]

Should I enlargen the bores of the spacer, what do you think?

I don't think the current size will hurt performance.

 

[80Stang]

Thanks. Just got the #2 spacer in hands. It is a 289-stamped piece and it sure is strange how much quality differed at Ford back in the old days. This piece is noticeably worse casting than the 260-piece.

The ridge at the transformation point near the top of the bores (where 43mm chokes to 41mm) is rough, as are the bores too. I'll give it a quick lesson with carbide bit to smooth out the transition, as well as some sanding on the bores. Small things, but it just looks bad "the original way".

I sure need to have this spacer welded too, and one hole tapped for a banjo fitting (to the PCV). I Hope to get this running in time, as then I could take the 1.21 as the baseline and make an interesting test with a Holley 500cfm for another run on the rolls. If the 500's huge plates have space to turn on the spacer...don't remember how big they are.

 

[CZLN6]

Howdy back Teppo:

Yes, enlarge the spacer bores to 1.69". That will accommodate the largest Autolite throttle bores, at 1.68", as well as the Holley 500 which has 1.69" throttle bores.

On main jets, I'd start with the #63 in the 1.21 already. It is much safer to move from too rich than to start too lean. The reason Dennis" main jets were so much smaller was that were were here in Idaho at 5,000 ft elevation. I think he increase jet size when he got home to N.D. and less elevation.

I'm looking forward to your results. Keep the progress coming.

Adios, David

 

[80Stang]

Called the shop today. They'll do the job latest by Friday. So next weekend the 1.21 goes in.

Got that spacer punished:

You can see the untouched ugly bore. Now both the bores are done and they clear the 1.21 and the holley500 throttle plates with ease. The spacer is not going to be a problem. All I have to check now is the fuel lines and throttle cabling to work ok...

 

[Anonymous]

80Stang, your website is GREAT!

http://www.ponikorjaamo.com/ti80/


I love the engine pictures.....and your interior is BEAUTIFUL!
That's probably the nicest 1980 Mustang I have ever seen.

 

[80Stang]

Glad you like it, Linc. I hope I had time to do it, that is just quick and dirty stuff.

Back to the car, which got the 1.21 in today. It was not a piece of cake job once again, but swallowed a few hours to do. The spacer finished nicely but then the 2V adapter on the log had a slightly smaller oval hole than the spacer holes, so it needed to be removed and modified so that there would not be a ridge against the mixture flow.

Nowadays I fill the bowl in with gas when I change carbs, toggle the throttle a little to spray some gas so it was no surprise that it fired right up. Needed some idle speed tuning and idle mixture screws more out to have a decent mix at idle and then to test drive.

Turned out that this 1.21 with 63 jets runs leaner than 1.14 with 59 jets. It behaves at around 10 inHg down to the point where PV opens much the same way as the 1.14 did; occasionally the mix leans out totally and some part throttle steady conditions are way too lean. With better vacuum numbers the mixture stays better, but is still a little leaner than w/1.14 while cruising.

I'm going towards pretty big jets here. I already changed one jet to 68 (which is secondary jet from a Autolite 4100-4V) so now I have a mixed set with 63 and 68, theoretically averaging around 65.5. It was evening already, so I just checked that it runs and adjusted the idle screws 1/4 turns in, so the test drive of that setup waits for tomorrow when I drive to work.

With 63 jets, Butt-O-meter says no gains in low rpm operation, but I think it got more power above 4500 rpm so as soon as the cam starts really working after 3000rpm it pulls strong all the way to where I dare to rev it to. Slight laziness may be due to lean mix, but let's see how it drives tomorrow. If needed, I'll throw in the other 68 jet too.

 

[80Stang]

A pair of 68 jets in now, and it still cruises in mid stoich! And still has some lean outs while under light load w/less than 12 vacuum ro so. Now I don't know where to go...

 

[80Stang]

There must be something wrong with the 1.21. Threw in the Holley 350 and that woke the engine up - clear difference after the 1.21. Holley's got 58 jets, and it runs richer than 1.21. But still there are some lean conditions, and my parking yard hesitation is still there = it is not a carb problem as it has occurred with Autolites 1.14 and 1.21 and now the same way with the Holley.

Seems like Autolites are not going to see to dyno tomorrow.