blodi

Update: I ordered and installed 35mm chokes just to spilt the dif and get a bit more top end back from the 34s. No flat spot and pulls nice up top. So great there. Still have the 155 mains and 195 airs in. Result is lean:

Got the 155 mains and 195 correctors in now. But haven't had time to do any testing yet. (Having a 2 year old and 4 month old severely limits my time ) I'll report back with the results and we will go from there.

Here is a log (one of several) with the 150 mains and 195 air correctors..... AFR-6817 by blodi, on Flickr Much leaner throughout but the top end is pretty good. So, I'm thinking put back in the 155 mains and leave the 195 correctors. I didn't mess with the accel jets this go around.

OK, ordered 195 correctors and I have 150 mains at home already that I can swap in. I'm lost on the bolts in the bowls part. Replace the exhaust jets with bolts? Aren't the 00 jets basically a block already?

Awesome feedback as usual! Thanks. Yes, I did stomp on it at the start of the run. It did stumble for a split second when I did that too. Would I need smaller accel jets or exhaust jets that actually have an opening? Larger corrector at the top makes sense. How much larger is the question? I have 185's in now...do I go 195? 205? Also, The results have been repeatable...I did 5 logs and they are all similar.

1. Plugs look good overall, light tan. Carbon on the outer portion. I can take a pic and post later. 2. I think the ideal is 12.5-13.0 from what I've read at WOT? 3. Just using the Innovate pickup that works with the LM-2 that clamps on one of the spark plug wires. I can try again to get a better reading with the rpm...but just started doing logs yesterday and today. Overall, the car runs great and pulls hard. But just in the "fine tuning" now I guess. Seems to go a bit too rich up top...is that the air corrector based on what I've seen in this chart I found?:

Took a log of a 3rd gear pull with the innovate today. The RPM sensor was off but I marked the pull...basically 3k-7k....what do you guys make of this? AFR6117 by blodi, on Flickr Current setup: 34mm chokes, 155 mains, 185 air F16 emulsion, 65F9 idle 45 pump, 00 exhaust

Drove the Z in today. Flat spot is totally gone with the 34's ! I'll monitor my wideband for a while and see if tweaks are needed, but, overall the car seems to run really well!

I ordered 34mm chokes and they arrived yesterday. I installed them last night. Haven't had a chance to drive the car yet though. I'll have to re-sync the carbs as I had to remove the air bleeds to put in the new chokes. I will report back though! I was surprised just how much smaller the 34 looks compared to the 36.

Pump jets arrived the other night finally. I had a chance to install them and basically...not much change. Still a bit of a flat spot in the transition. I think you guys may be spot on with the choke size being too large so my next step may be going to 34mm chokes.

I think if the accel jets don't resolve my issue; smaller chokes will be my next step.

The innovate is exactly what I was using actually. I am using their lm-2 wideband tuner setup. Ordered the next two larger accel pump jets today. I'll report back on that when they come. I also need to work on my throttle linkage for better idle return.

With the sensor in the tail pipe I was getting readings at idle in the 30's and 40's...which doesn't make any sense. Now at idle I have it in the 14's. I'll have to recheck afrs at cruise but I believe it was ~14.5.

Ok Updates.... Bung welded in....so much more accurate and comprehensive readings than the tailpipe clamp the wideband setup came with! Getting useable readings at idle now/etc. Put the 65F9 idle jets in and adjusted idle mixture as needed. Much improvement yet again. Overall...it's idling well..driving at low speed well and AFR's look good at cruise and full throttle. I also put back in the 185 air jets since I didn't really need to richen up the top in in the first plate. The only issue now is if I roll in or stab the throttle quickly....so I'm thinking accel pump jets...right? I have 45's now....go to 50/55? the exhaust jet/valve is the closed off version.

With my brand new webers I was getting different readings between both barrels on all 3 carbs. The rear/right barrel was reading lower on all 3. But got them all dialed in now with the air bleeds. Bung is being welded in as we speak. Idle jets here tonight....

I checked the throttle plates vs the progression holes and the plate is closed past them at idle. New idle jets show up tomorrow and I am also getting a bung welded into the collector so I can get a better reading than my current tail pipe clamp on setup. I'll report back.

Ok, just re-synced carbs by first lowering idle to ~600rpm then using air bypass valves to bring it back up to ~900 all in sync. Test drive.....it's 75% better! Still a bit of a "hole" in the transition, but certainly a big improvement. I did order the 65F9 idle jets. So I'll install those when they come later this week and report back.

^ thanks! Great input. I guess the easier (cheaper) one for me to try first is B. I already raised the float height a bit. I set the floats at ~12mm when touching the ball valve. I can order richer idle jets (one step/ 65F9?) I do have the air bypass screws on my carbs...so I can try setting up the idle using those...they are all closed now. If those steps don't work...I'll attack the main/choke.

I did see the pump working when I was looking at it last night. At least on the rear carb...I'll check the other two. I did change the jets to what is in the first picture. Currently that is what I am running but switched back to the 170 air correctors that came with the carbs to see if that fixed the lean spot...which it didn't. Chokes are 36's that came with the carbs. Timing is set to about 18-20. Vacuum advance is disconnected. Thanks for the help! So to recap, right now my setup is 36mm chokes, 155 mains, 170 air, (have 185's as mentioned above) F16 emulsion, (should I go to F11? Seems to be richer?) 60F9 idle 45 pump, 00 exhaust So....55 pump jets? Where do I get the stiffer springs? Or should I do a F11 E Tube?

The carbs are brand new. So everything is good to go. The pump jets are 45's.

So my "flat spot" is a lean spot in the transition as I found with my wideband. I double checked the float heights, also tried putting in the 170 air correctors I had on hand to try to richen it up a bit. So...where do I start? I hate to just buy a bunch of jets randomly. Richer Idle jets? Richer Mains? Accelerator pump jet? The accelerator discharge valve I have is the one with no hole in it....not sure if that helps or not. The flat stop isn't there when on the highway and the revs are up...probably because it's already running on the main circuit by that time. At lower speeds if I stomp on it or roll into it, the engine just loses all power until I let back off the throttle.

I hadn't seen that thread yet, thanks! The choke X 4 theory means I need to go back to the 145 mains that came with my carbs and can keep my 185 air corrector most likely. For all I know the settings he had above were for 38 chokes since it was for a race car. Gives me a good spot to start!

Thanks for the reply! Fast forwarding here..I have installed a set of 45's and installed the jets as seen above. I just got the car up and running this last weekend and have driven it a couple times. Chokes are 36's Idle is great...900rpm...mixture screw is 2 3/4 turns out which seems good for the later 152 45's. I synced the carbs as well. The car right off idle and low throttle driving around is great...great response off the line. As you roll into it or if you stomp on it a lower RPMs...there is a big stumble or even complete lack of power. So I assume this is the "transition" phase and there are like 4 things impact that. High RPMs...holy crap! It's a completely different beast now than it was with the SU's...1st is all wheelspin and so is most of 2nd. So where do I start with tackling the transition flat spot? I have a tailpipe O2 sensor I can plug in and see if it's going lean or rich where the stumble is. The engine seems good with running in traffic and such. I put 2K miles on it last summer with the SU's. The idle is certainly a bit lumpy, but sounds good and holds...doesn't overheat. I kept the stock flywheel on it so I think that helps it out at idle and such.

The bottom/73 one is exactly what I need! How much? Paypal address? Thanks!

Hi, Looking for the throttle hook rod off a flat top setup. I believe the flat top version is shorter and I need it for my triple weber setup. The one I have of my round tops is about 12+" long. The one I need is at least a couple inches shorter. Let me know if you have one! Thanks