Tunnel ram or no tunnel ram...

Rat Bastid

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In case of IFR my understanding is that these restrictors deliver only gas so they can be rather small. In my case t-slot restrictor was not allowing the engine to pull right amount of gas in the transition slot which resulted in very lean condition.

I understand. But all the circuits over lap so IMO until you clean up the idle circuit, reduce the emulsion, make sure the main jets/power valve/PVCR are right for a cruise you really can’t get the T slots correct.

Thats why I do the T slots last.

I get that you took the restricters out and it made the engine happy(er) but you haven’t tuned the rest of the carb up yet.
 

Miszny

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I understand. But all the circuits over lap so IMO until you clean up the idle circuit, reduce the emulsion, make sure the main jets/power valve/PVCR are right for a cruise you really can’t get the T slots correct.

Thats why I do the T slots last.

I get that you took the restricters out and it made the engine happy(er) but you haven’t tuned the rest of the carb up yet.
In this case you would be unable to leave t slots restrictors as they were to tune last because there was no driving between standing still and 3000 rpm, also I could not get it leaner than 12.8 afr in park. I even tried 40 degrees advance to lean it out and nothing helped. I had good afr in gear at 14.5 but this resulted in 12.6 in park. I played with iab size and the only difference it resulted in was amount of turns on the mixture screws. I tried various sizes from 60 to 90. Now I have size 80 IAB which gives me full turn on mixture screws.
My t slots in primaries are just under square and barely visible on secondary. This gives me 1000rpm in park and crispy 850rpm in gear. Lambda shows 13.5 in park and 14.5 in gear which is how it idled with my dominator.
I used 28 mab as you suggested and it seems to work well I don’t feel or see any change when slowly or quickly accelerating from standing stil. Lambda is consistent. This is better than in case of my dominator. The car also cruises better than with my dominator but it’s on the lean side in 3rd gear at 3500 rpm with 14.5 afr. Impossible to test wot well but when I tried it showed 12.8-13.0 afr which again is as with my dominator.
When my car was on dyno, it made best numbers with that lambda value.
If this can be made better, I’m all in!! It’s depressing that weather is in the toilet and I can’t play with it some more. I am waiting for set screws and air bleeds, got blank since I also bought all the drills you suggested.
Also buddy of mine got a 1050 2 circuit dominator for his 500ci barracuda. This will most likely be another post about carburetor tuning alone ;-)
I thank you again for all the help and support. I will for sure come back to this when weather comes back to normal. There should be nitrous plumbing on that intake by then.
 

Miszny

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Should I get parts to make these carbs progressive? They are almost 1:1 now.
 

Rat Bastid

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Should I get parts to make these carbs progressive? They are almost 1:1 now.

As long as you aren’t cruising on the secondary main jets you can leave it.

If you are cruising on the secondary main jets you either need to make it 1:1 and add a power valve in the secondary metering blocks and then make the tune up for the secondaries the exact same as the primaries or you need to get it further from 1:1.


You can do either one.
 

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The Indy tunnel ram doesnt have the volume you would think it does. I'd pour both intakes and see what the difference is in plenum volume. I'd bet the TR is only 100cc ish larger. You should be able to pick up 25-30hp easy. AED makes a linkage kit.
 

Miszny

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It’s low deck
This is great. Please try to measure volume. You probably can try with water by weight difference. You could sit it down on electronic weight with lexan siliconed to seal off the runners.
I will do this with my single plane. Would be interesting to make a comparison. Unfortunately I didnt think of that when mine was off engine.
 

Miszny

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Storage time… Last look at the car before I put the cover on.
It was a nice drive, but carbs need tuning for sure :)

DEA0FFD5-CBCE-437C-8DF3-AD97BE42FC9A.jpeg
 

Miszny

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Did some drilling and tapping. PV channels had to be tapped to 8-32.
Also did some measuring and it turned out 2 bottom emulsion holes on each side are 0.033” and verified the top one at 0.029”.

I’m trying to understand this setup. What’s the role of bottom emulsion holes? Do they deliver extra air at wot?

AA132509-B5E6-4B34-A7B2-52167EA92642.jpeg
 

Rat Bastid

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It depends on what boosters and main air bleeds you have but generally the lower hole affect WOT.

That’s too much emulsion and there is no way I’d block the primary power valves like some guys do. They are pig fat rich at cruise.

I’d make them .026 and tune from there.
 

Miszny

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Small update.
Since the plan is to move the ifrs down low I decided so see how they impact the way the car drives.
I started drilling them out .001” at a time. These restrictors are very sensitive. Every .001” makes a difference. I opened them up to .035” and there is no slightest hesitation remaining, it was almost good with .034” but o2 showed 15+ sometimes. My o2 sensor now shows 14-14.8 cruise in 3rd gear before primaries kick in.
I also noticed that throttle blade adjustment in case of primaries need 1 full turn on adjuster screw to have good t-slot window, but secondaries only need 3/4 turn to give the same result. That kind of setting results in very stable idle.
Overall for now, I’d say I could drive this as is. Plugs look good also, actually they are a bit too clean but I will probably put new ones for spring testing.

I wonder what further mods will do.
 

Rat Bastid

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Small update.
Since the plan is to move the ifrs down low I decided so see how they impact the way the car drives.
I started drilling them out .001” at a time. These restrictors are very sensitive. Every .001” makes a difference. I opened them up to .035” and there is no slightest hesitation remaining, it was almost good with .034” but o2 showed 15+ sometimes. My o2 sensor now shows 14-14.8 cruise in 3rd gear before primaries kick in.
I also noticed that throttle blade adjustment in case of primaries need 1 full turn on adjuster screw to have good t-slot window, but secondaries only need 3/4 turn to give the same result. That kind of setting results in very stable idle.
Overall for now, I’d say I could drive this as is. Plugs look good also, actually they are a bit too clean but I will probably put new ones for spring testing.

I wonder what further mods will do.

What size is your idle air bleed? That IFR sounds way too big.
 

Miszny

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What size is your idle air bleed? That IFR sounds way too big.
IAB is 76, MAB is 36 they are in full stock form as they were initially built.
Roads are not good enough to test wot but I managed to get my hands on 77 jets and I also have 76, 75 and 74 jets x8 just in case.
Everything seems rather large, MAB is big, IAB is big, lots of air open in metering blocks with big holes etc.

I verified my Dominator IFRs and they are size .042”. Also it has 2 emulsion holes size .028” and 68IAB + 28MAB
Now that I have drills I can check everything no problems which is great thing.

B7CC723A-F16D-4F51-A558-B699318DF542.jpeg
 
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Miszny

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I found a video that’s shows o2 readings driving with my Domiantor.

 

Rat Bastid

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IAB is 76, MAB is 36 they are in full stock form as they were initially built.
Roads are not good enough to test wot but I managed to get my hands on 77 jets and I also have 76, 75 and 74 jets x8 just in case.
Everything seems rather large, MAB is big, IAB is big, lots of air open in metering blocks with big holes etc.

I verified my Dominator IFRs and they are size .042”. Also it has 2 emulsion holes size .028” and 68IAB + 28MAB
Now that I have drills I can check everything no problems which is great thing.

View attachment 1716016394

Ok, looking at your emulsion makes the rest of the tune up make some sense.

I‘m not a fan of all that emulsion. IMO that’s way too much. The problem is you are close with what you have and to change the emulsion will mean everything else will change too.

So you’d be basically starting over.
 

Miszny

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Ok, looking at your emulsion makes the rest of the tune up make some sense.

I‘m not a fan of all that emulsion. IMO that’s way too much. The problem is you are close with what you have and to change the emulsion will mean everything else will change too.

So you’d be basically starting over.
Beautiful thing is that I can screw in restrictors to plug whatever I need and change sizes on whatever I need also because you are suggesting smaller sizes than what is drilled in block fixed emulsion holes. Changing air bleeds and jets is no big deal so I’d like to try the other approach as well to see what works best in my car.
If it won’t work better all I need to do is put back jests and air bleeds I have now + remove all the screw in restrictors. No big deal. I already bought everything to do it anyway.
There will be whole summer to play with it and my only plan is to do minor transmission work from mechanical stuff + new vinyl top from not important stuff…
 

Miszny

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I took an oportunity to drive the car as the weather cleared for a few days.
I miss driving this car, finaly felt alive!


Did some work like, put split mono leafs and cal tracs, also seems to sit 1" lower in the back.
I'm surprised how well it launches even on cold surface.

Got some extra parts for the carbs like squirters at size 25 to start with and drill out to the size at which it works best. Currently I have 4x 35 in there. Also got cams for pumps, some blank BLP air bleeds for alternative metering blocks configuration etc. Crusing is very nice at 14.5 o2 and plugs look good but if I move my foot on the pedal o2 instantly shows 12.X.
Also I finally got uni sync and managed to synchronize the carbs. Now I can get away with around 950 rpm in park, which makes it around 850rpm in gear.

Also I got spintech mufflers to try out, very curious about the result.
 

71GSSDemon

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I took an oportunity to drive the car as the weather cleared for a few days.
I miss driving this car, finaly felt alive!


Did some work like, put split mono leafs and cal tracs, also seems to sit 1" lower in the back.
I'm surprised how well it launches even on cold surface.

Got some extra parts for the carbs like squirters at size 25 to start with and drill out to the size at which it works best. Currently I have 4x 35 in there. Also got cams for pumps, some blank BLP air bleeds for alternative metering blocks configuration etc. Crusing is very nice at 14.5 o2 and plugs look good but if I move my foot on the pedal o2 instantly shows 12.X.
Also I finally got uni sync and managed to synchronize the carbs. Now I can get away with around 950 rpm in park, which makes it around 850rpm in gear.

Also I got spintech mufflers to try out, very curious about the result.

Pretty awesome! I see little clearance from the carbs to the hood scoop. Are you not intending to use air filters of any kind? I had considered a scoop pan and put a filter at the scoop inlet.
 

Miszny

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Pretty awesome! I see little clearance from the carbs to the hood scoop. Are you not intending to use air filters of any kind? I had considered a scoop pan and put a filter at the scoop inlet.
I need to remove these flow rings to run 2.5” dual air cleaners and thats the plan. Waiting for larger package with parts now.
I wanted to use these small dominator air cleaners but not enough room…
 

ValiantS

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I need to remove these flow rings to run 2.5” dual air cleaners and thats the plan. Waiting for larger package with parts now.
I wanted to use these small dominator air cleaners but not enough room…
I'm glad you showed that pic but it isn't 100% clear to me (the distance and the innerworkings of the scoop in relation to the carbs). START FIXING THINGS HERE first because frequently people chase tuning issues due to less than idea air management. Good luck! Keep at it!
 

Miszny

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I'm glad you showed that pic but it isn't 100% clear to me (the distance and the innerworkings of the scoop in relation to the carbs). START FIXING THINGS HERE first because frequently people chase tuning issues due to less than idea air management. Good luck! Keep at it!
Flat base air cleaner will be exactly in line with hole of the scoop. In the movie I was looking down the scoop at an angle. I was driving with and without hood without any change. At this point changes to the carbs will be experimental to see the difference. Besides momentary rich condition every time i touch the throttle, everything looks very good. I'm quite impressed, car runs better than with single dominator without a doubt.
 
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