Jet height HIF 44

[Shrimps]

Based on the needle you mentioned at the start of this thread and the two needles Dave recommended, I plotted them in the "MintyLamb" site (screenshot attached below).

How does one read those charts?  In the chart is the BCE overall richer or leaner than the BDL?

Thanks.

[MPlayle]

Yes, BCE is overall richer than BDL.

The charts are read left to right, bottom to top.  The lower left is the idle station.  WOT is at the top right.

The station numbers are along the bottom with the pointy end as #16.

Lean is at the bottom, rich at the top.

On the MintyLamb site, enter the needle to be graphed in the "Search Needles" box.  To remove a needle from the graph, click on the colored needle name above the graph.

[Shrimps]

Thanks for clarifying. I must have been reading the old Minty Lamb chart wrong. I put several needles I've tried into new chart and the way my current needle behaves checks out on the chart as it's a BDK which is lean down low & likely explains the light  throttle hesitation/stumble I have.

I too need to get my O2 sensor installed.  But I've been saying that for several years now!

[bikewiz]

So here are my numbers after modifying a BDL needle with 1000 grit paper and metal polish in the my lathe.

Idle @ 1000 rpms 10 degrees advance 13.3 - 14.2 pretty steady idle now.
2000-3500 accelerating 14.1 - 15.2
Steady state 50 mph/3000 rpm 14.4 - 15.2
Steady state 70 mph/4000 rpm 15.5 - 15.8
Accelerating on the highway from 70 mph leans it out to 16+

Other notables LZX 2085 damper with 20/50 oil (this was recommended by AC Dodd), MED stub stack w/ITG MED foam filter, BP6ES plugs

I started with the jet height at .075 but have since brought it up but I didn't remove the vacuum chamber to remeasure it.

[94touring]

What are the wide open throttle numbers?

[bikewiz]

What are the wide open throttle numbers?

I'll check as I drive it more.
I kind of wish I had mounted the gauge on the dash up higher in front of me so I don't need to look down when driving.

[94touring]

When you say accelerating, approximately how much throttle?  Is it hesitating at 16+ when you're at 70mph+?  Or is it a momentary lean spike?

[bikewiz]

When you say accelerating, approximately how much throttle?  Is it hesitating at 16+ when you're at 70mph+?  Or is it a momentary lean spike?

So I drove it after work with some secondary roads and highway.
If you you just pin it in 4th at 70 it spikes lean and stumbles, I'm just not sure you would actually drive the car like that. If you accelerate "normal" to pass it leans to 16 or so but doesn't feel like it has a flat spot. It probably could be a little richer on the top to help that a little.
Most everywhere else it drives pretty good. I didn't have time to do a plug chop during the highway run to get a look at the plugs.
I have another BDL I could mod to see if I can get it better and save this modded BDL as a reference.

[94touring]

There's no point looking at the plugs, you have a wideband. I need rough throttle positions and the numbers to give advice.  If you're full throttle and 16:1, you'll melt pistons eventually.  Take it out in 3rd gear on a long straight road and at full throttle starting around 2k rpms, run it up to whatever your redline is and see how lean it is.  Myself personally I let off the throttle tuning once I hit 14s at full throttle.  Drive back to the shop and adjust/file needles, make jet changes, or redo fuel cells on the cars with programmable fuel injection.

[94touring]

You'll have 16 stations (can't remember if it's 1/16 or 1/8" incriminates) starting around station 10 is your WOT (wide open throttle) stations.  Work slowly by removing material from 10 gradually tapering down towards 16.  The last 3 or so stations do nothing.  Remove until you get yourself around 13:1 at full throttle through your entire rpm range.  Depending on your heads and cam, you may expect to see rich dips at lower rpms, about 3k rpms for myself it dips to around 11:1, but then works it's way back to 13:1.  Once you get your WOT air fuels in a safe mixture of 13:1, you can play with spring rates to dial in cruise air fuel.  Ideally you can get that 16:1 maximum fuel economy at light throttle cruise.  Use a lighter spring to get a leaner cruise.  Use a thicker dash pot oil to richen the mixture  in the transition from light throttle to full throttle if you have lean spikes and hesitation.

[bikewiz]

You'll have 16 stations (can't remember if it's 1/16 or 1/8" incriminates) starting around station 10 is your WOT (wide open throttle) stations.  Work slowly by removing material from 10 gradually tapering down towards 16.  The last 3 or so stations do nothing.  Remove until you get yourself around 13:1 at full throttle through your entire rpm range.  Depending on your heads and cam, you may expect to see rich dips at lower rpms, about 3k rpms for myself it dips to around 11:1, but then works it's way back to 13:1.  Once you get your WOT air fuels in a safe mixture of 13:1, you can play with spring rates to dial in cruise air fuel.  Ideally you can get that 16:1 maximum fuel economy at light throttle cruise.  Use a lighter spring to get a leaner cruise.  Use a thicker dash pot oil to richen the mixture  in the transition from light throttle to full throttle if you have lean spikes and hesitation.

I'll work on the #10 to 16 sections of the needle. The book I have says it's 1/8" stations, I'll mark it all out before I spin it in the lathe an let you know how I make out. I plan on measuring the stations and recording them before I reinstall it so I have a new baseline needle.

[bikewiz]

So this is what I've come up with modifying my existing BDL needle. I made a holder for the needle to hold it straight in a collet. Sanded off a little with 1000 grit and polished it with metal polish.
 
Position   Before    After
9           735       730
10          725       715
11          705       700
12          695       680
13          650       640
14          630       620
15          595       590

The jet height is .0445

I didn't get to drive it a lot but on hard acceleration from 70 in 4th I saw a momentary 16 spike and then it richened up to high 13's to briefly low 15's. Generally speeds around 30-50 I was around 14 to 15. In lower gears on acceleration it would dip into the 12-13's. What kind of numbers should I be looking for at idle when the car is warmed up? Right now I'm still at low 13's to 14 at idle. I'm a little concerned it will richen it too much at idle if I change the jet height too much.
I also realized it's a bit of a problem looking at the gauge, tach, and driving. It does have data logging, I may consider setting that up later.

I'm amazed at how such a small amount off the needle can make such a big difference.

[94touring]

13-14s at idle is perfectly fine.  It's whatever the leanest you can get at idle and it still idle ok. Sounds like you're getting closer.  Lean spikes on initial throttle are to be expected.  Just keep working at it a little at a time till you can maintain that 13 target at WOT.