14point7 Spartan 2 install, Holley 4150 tuning, & exhaustcapades

Bustedknuckle

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Jun 5, 2020
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I confirmed the power valve size. 5.5 should be correct, but I think as insurance I may pick up another 5.5 PV when I pick up the sensor bung from the parts store.

Edit: The more I think about it I think I'll pick up a 4.5. I think I should err to the lower side with this, and since it was somewhere in the 10-11 inch range for vacuum, I'm going to go with 10 which would require a 4.5 power valve. Since they don't carry a 4.5 PV, I guess I'm at a standstill with actually going farther with the carb once I get the gauge installed. So this escapade will continue for at least a few days.....

IMG_20200422_114551__01.jpg
I like going a bit smaller, just a tad lean at full tilt, on the power valve; Tune the accelerator cam and squirter size to cover a hole in the fuel curve, if there is one. Then tune the secondaries
 
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LILCBRA

I wish I didn't have all of these balls in the air
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My personal choice was to go a tad rich, especially under load. As I understood the effects of AF ratios before and over the course of going through this, lean conditions can lead to detonation which in turn can lead to engine damage. Then I found this video on the YouTube which helped to reinforce everything. It sounds like it's a common misconception that the AF ratio being a little lean produces the maximum amount of horsepower, but these guys dynoed an engine and produced the curves to prove that that is false and also explain the reasoning behind it. It logically made sense to me and reinforced what I had felt for a long time.

View: https://youtu.be/JzbLrn-2jyw
 
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extra_stout

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I didn't know about that myth... but interesting to know that such BS goes around. With carb instead EFI it is a little more complicated because the amount of fuel is controlled by the volume flow. But the mass flow changes with temperature even if the volume flow is the same. This means if the car is tuned in warm weather near lambda 1. It can happen that if its cold outside you get lean condition. For partial load and idle that is not a problem IMO. But for WOT you should always be a little bit rich.
And exhaust popping can also come from lean condition...
 
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LILCBRA

I wish I didn't have all of these balls in the air
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I've had it out a couple times, but nothing of interest to post about. It's running great now though! A/F stays in the low 12s to mid 13s most of the time. There was a couple times where it popped into the high 14s/low 15s upon acceleration, but only for a split second and dropped back into the 12s/13s. I attribute that to shifting. It would be awesome if I could record the gauge for longer than a couple minutes to show instead of explaining it through text. :shrug:
 
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2Blue2

will be trying this sex one when I can find it
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Need to go track and get some new times
 
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LILCBRA

I wish I didn't have all of these balls in the air
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So I happened to run into this video last night and thought it might be relevant to share either in this thread or in my dyno thread. I'm excited to see what kind of difference having my carburetor set up more properly vs what it was when I had it dynoed the first time.

View: https://youtu.be/HXX4zcPr9IE
 
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LILCBRA

I wish I didn't have all of these balls in the air
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Another quick update: When I ordered the 50 cc accelerator pump I also ordered jet extensions and baffle tubes for the bowls. I finally got around to installing the extensions this past weekend and readjusted the float. I had the car started for a little while and what I noticed on the gauge is it was still reading in the 13-15 range. While I had the carb off I ended up replacing the secondary squirter with the only one I had laying around that was bigger - I believe it went from a 25 to a 32, but since I'm not at home to confirm that's just a guess for now. The weather is starting to get a little nicer here so I'm wanting to take the car out, but the last time I drove it it ended up leaving me stranded on the side of the road a couple different times. I tried to coordinate with a buddy of mine to be on standby in case it does it again, but he wasn't available last weekend. Maybe I'll be able to take it out this weekend at some point. As far as why the car was dying and leaving me stranded, I believe I found a partially bare power wire for the MSD that was above the brake booster. I'm pretty sure I've got the problem remedied, but I'd still feel more comfortable having someone on standby when I take it out again. :shrug:
 
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429MII

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I like going a bit smaller, just a tad lean at full tilt, on the power valve; Tune the accelerator cam and squirter size to cover a hole in the fuel curve, if there is one. Then tune the secondaries
Anything in the 224-230 @.050 range for a cam and I use a couple sizes up on the jets ( a little more on the secondary) a 2.5 power valve and the lightest vac adv. spring. Seems to work great.
 
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LILCBRA

I wish I didn't have all of these balls in the air
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I finally have another update of sorts on my car.....

I decided on Friday night at about 7:00 that I was going to give it a try with no one on standby. It had almost no gas in the tank, so I dumped about a gallon in from the lawn mower can. I was just going to run up to the gas station about a mile or 2 away then decide what to do from there. When I get there their card readers are down and I have no cash. So I leave to come back home. Before I get to the next light it starts chugging and my AF gauge is reading really lean. Apparently the gallon I put in the tank wasn't quite enough to ensure the pick up would keep the pump fed. The funny thing is that it died in the exact same spot it did the last time I had it out. :cautious: So I start the walk home and the distant thunder I heard earlier finally reached my area. So now I'm walking in the rain..... :mad: I get home, hook my trailer and go pick it up. I run the opposite way to the nearest QT and give it about a half tank while it's on the trailer then take it home and unhook. Yesterday I went out just to see if it would start and it popped right off, but that's as far as I got as I had other plans yesterday. I might try to take it out again today, but I dunno..... We'll see what the day brings. But I'm fairly confident that I've gotten the prior issue solved, but I still would like to confirm it before I do much else with it.....

IMG_20210801_072218.jpg


Btw - having that winch is AWESOME!!!!
 
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2Blue2

will be trying this sex one when I can find it
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An adventure every time.
 
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LILCBRA

I wish I didn't have all of these balls in the air
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Tried it again tonight. Took the same path, but this time it didn't even make it back to the stoplight. But now I'm not so sure it's electrical. I think I have a fuel delivery issue as it was backfiring through the carb and I had to pump the go pedal a few times and then hold it to the floor to restart it. I fiddled with some wires under the hood and lost my A/F guage too, then after a minute or 2 of trying to keep it running I lost power to the starter altogether. I'm seriously contemplating pulling the whole harness from the engine bay and going through it wire by wire. I guess that would serve a couple purposes: I'd be able to tie up and take care of any loose or exposed wires IF I come across them, and I'd be able to clean up the harness and give it some new loom tubes. The wiring under the hood is a complete mess right now and could use it anyway if, for no other reason, to make it look a lot better.....
 
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extra_stout

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I'm seriously contemplating pulling the whole harness from the engine bay and going through it wire by wire.
Sounds more like a good job for winter. If it is a fuel delivery issue, it will not solve your problem.
Just because it seems it was my problem: did you re-torque the intake manifold bolts? On my 66 coupe I re-torqued them every season for 5 years, till they "hold" the torque/pre-load.
 
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LILCBRA

I wish I didn't have all of these balls in the air
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Sounds more like a good job for winter. If it is a fuel delivery issue, it will not solve your problem.
Just because it seems it was my problem: did you re-torque the intake manifold bolts? On my 66 coupe I re-torqued them every season for 5 years, till they "hold" the torque/pre-load.
I had thought about that during my walk and will recheck them once I start working on it again. And you're right, it will most likely be a winter job. I'm too involved with other projects for me to start ripping into the car. I imagine it's going to take me some time to chase all of the wires in the harness to ensure that they are intact as well as re-loom the harness. I think that will be my number one priority when I decide to get into it. After I'm convinced that the wiring is up to snuff, I will get into my fuel system. I am thinking of doing exactly what I think you've done and install an electric pump near the tank to push fuel to the mechanical pump. I'm not sure if I believe it's vapor lock or if it's actually that the mechanical pump is starting to go bad or what the deal is, but I think I'd like to eliminate that variable. While I'm tearing into the fuel system I will most likely tear down the carburetor and give it a once over. I think it's very possible that I have a blocked passage somewhere that's not allowing fuel to pass as it should. I've also thought about eliminating the carburetor altogether and just going with a fuel injection system. I'd really like to go with multi port, but for ease of installation I'd probably go with the throttle body system. I have a lot to think about in any case..... :shrug:
 
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extra_stout

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After I'm convinced that the wiring is up to snuff, I will get into my fuel system. I am thinking of doing exactly what I think you've done and install an electric pump near the tank to push fuel to the mechanical pump. I'm not sure if I believe it's vapor lock or if it's actually that the mechanical pump is starting to go bad or what the deal is, but I think I'd like to eliminate that variable.
Because I'm using the explorer front dress, I can't run a mechanical pump, so I only have the electric fuel pump. If there where the possibility to run a mechanical pump I would get rid off the electric pump.
On my 66 coupe I run a 65 front dress with only a mechanical fuel pump. I never had issues. The 65 pump has a integrated fuel filter:
9350A_STD.jpg

You also can run a pipe with flared end from the pump to the carb to reduce hose connections.
 
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LILCBRA

I wish I didn't have all of these balls in the air
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My carb is a dual feed, so I'd have to locate and/or make the connecting pieces to be able to run a single line to flared fittings at the carb. Otherwise I think you're right, I really shouldn't have any problems supplying the carb with fuel as long as everything is good. I mean it used to be fine and I haven't changed anything in that regard, so I believe it's ok, that's why I'm going with the wiring issues first. I know there's an issue there and I have a fairly good idea where it's at, but if I'm going to dig into it I may as well do it all and make sure it's all correct, then beautify it. I think the fuel issue is more of a loose manifold or dirty carburetor issue than anything else. But that's not stopping me from shopping around for my pipe dream list! I mean IF I decide to go down that path, I may as well make the trip worth the effort.... :D

IMG_20210806_131858.jpg
 
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