Tunnel ram or no tunnel ram...

Rat Bastid

Dunamis Metron
Joined
Nov 23, 2020
Messages
3,001
Reaction score
3,069
Location
22 The Avenue
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
Should I get parts to make these carbs progressive? They are almost 1:1 now.
 

Rat Bastid

Dunamis Metron
Joined
Nov 23, 2020
Messages
3,001
Reaction score
3,069
Location
22 The Avenue
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.
 

Jeremiah

Well-Known Member
Joined
Oct 2, 2013
Messages
388
Reaction score
377
Location
Rogue River, OR
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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

Dunamis Metron
Joined
Nov 23, 2020
Messages
3,001
Reaction score
3,069
Location
22 The Avenue
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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

Dunamis Metron
Joined
Nov 23, 2020
Messages
3,001
Reaction score
3,069
Location
22 The Avenue
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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
 
Last edited:

Miszny

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
I found a video that’s shows o2 readings driving with my Domiantor.

 

Rat Bastid

Dunamis Metron
Joined
Nov 23, 2020
Messages
3,001
Reaction score
3,069
Location
22 The Avenue
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

Well-Known Member
Joined
May 24, 2012
Messages
666
Reaction score
333
Location
Warsaw
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…
 
Top