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Got pissed off trying to fix a new truck I picked up so I decided to work on the sand rail a bit.

Took the carbs and everything back off and tapped the intakes for vacuum. I teed them together close to the manifold and then again right at the BOV. Should have great signal now so when I actually can drive the thing I can tune the BOV appropriately.

Fixed the minor fuel leak

Gapped and installed DR8EA plugs.

Interesting. Hadn't thought about how to get signal when running dual carbs/tb's. Is that normal? I don't recall seeing that many hoses on other peoples.

Not sure if its normal, but it should work. Also, its symmetrical

Will you run all 4 into a common manifold/plenum then to the ECU ?

Don't think he using a ECU ? It's just for his Blow off valve

Yeah they all 4 run into 1, and then go into the BOV. It could be used for a boost/sprak retard box if I end up going that route someday. Right now im just using an 009 with 7.5* at idle, and a limit of 24* maximum.

Got a chance to take to the street for a couple of pulls.

Blow off valve works now!

Wide band works now! The only change was switching to DR8EA resistance plugs from D8EA. Its a night and day difference. Im surprised it was this easy.

Idle is 13.8:1

Cruise is 14.5:1

Wot is uh, a little leaner than I expected. running like 15.5:1. This is without the modular plates and with turbo emulsion tubes.

Carb Setup is:

Dual 40IDF
32 vents
135 main
52 idle
220 air


Open to suggestions as I seem to be pretty far off on main and air. I need to install the mod plates also to see what effect it produces. Since I wont really be tuning until its dry out Ill have some time to get jets on order. Id rather be over rich and lose some efficiency/power than over lean and lose a piston.

interesting o the plugs, i brought non resistor plugs and tried them but didn't fix an issue which i thought was fouled plugs. so switched back to my old R plugs, but now i've seen this i'll just be buying R plugs from now on

thats really lean at WOT.... like you say, better to start rich and work down

There is nothing wrong with your idle and cruise.
I cruise at 14.1-15.1 all the time.
My idle is around 12.8 cold and 13.3 warm so if anything you could richen the idle up a hair but if you are setting it as Best Lean Idle and it runs nice there..... then I would leave it for a while and see how it works.
You do need to richen up the WOT to at least 12.5 and preferably to 12.0 or a hair richer if you have higher advance or no IAT cooling.

There are people that talk about running the ACVW at 16-17:1 at cruise but my engine does not like it. If you are turbo you have a performance engine...not a economy engine......keep it on the safer side until you know what it wants.
Carefully listen for detonation.....it can hurt.

Aside from the emulsion tube swap, this is the same carb setup as I was using N/A. Just gotta get that WOT ratio down. I was thinking of targeting 11.5-12:1 since im non-intercooled.

Got a jet kit in, and a nice day so I've done a little work.

Installed Mod Plates (Previously no plates)
Main jet 145 (Previously 135)
Air jet 175 (Previously 220)
Idle jet 52 or 55 (no change)

Idle is still good, sitting at 14.5:1.

Cruise has gone rich, from 15:1 to 12:1. This is done at 3rd gear at 3k RPM. I honestly didnt have a great sample last time so this might not be 100% accurate.

WOT has gone hyper rich, from 15:1ish to RICH. So its running sub 10:1, through a long pull it will start creeping up on low 10:1 range.

Looks like the mod plates are working. This was a lot of changes at once and I didn't expect it to be right, but I did expect it to be rich. I also had no idea how much the mod plates would contribute to the equation. There is also a slight stumble during the transition which I kinda expected. I was running the 220 airs when NA to drown this area out.

Going to move one step down on mains and one step up on airs. Depending on the reaction I will likely start going only one step on one jet at a time.

1915 dual 40 Turbo Wideband Results:

Specs:
1915cc
110 cam
Dual 40 HPMX
32mm vents
52 idles
tb25 turbo at 8-10PSI
60* airtemps
600ft elevation

No mod plate
135 main
220 air
14.5:1 cruise
15.5:1 WOT

29mm Mod Plate Installed
145 main
175 air
12:1 cruise
10.1:1 WOT

29mm Mod Plate Installed
135 main
185 air
13.8:1 cruise
11:1 WOT

29mm Mod Plate Installed
130 main
195 air
14.5:1 cruise
12.2:1 WOT

29mm Mod Plate Installed
130 Main
185 Air
14.5:1 cruise
11.7:1 WOT

The final jetting mentioned is what Im going to run for the moment. Im going to continue to monitor them with the wideband as temperatures go up and adjust as needed.

Should be ok for the boost your running. Just listen for ping and add fuel if needed.

I have opened my mod ring size to 34mm from 32mm, I'm expecting the WOT afr to show leaner , I can then up the main jet to get back to the 11.5.1 regain. I did this to de restrict the air entry point .

What size vents are you running? Mine are 32 so I was going for 30mm rings, but they cleaned up at 29mm so I thought id give it a shot before opening them.