Restrictor Tube Discussion

Joesixpack said:
Its pointless to put the restriction after the turbo, more pressure = more flow.
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Please tell me you are joking...

Hell, guys have gained increases in HP (even if only marginal) by increasing intercooler tubing size a slight amount or just getting rid of bends or neckdowns, so telling me putting a restriction after the turbo will not affect it I believe to be incorrect from all I have learned.


You are correct that if there is 20PSI on one side of a restrictor it will flow more than if there is 10PSI, but unrestricted (or less restrictive) will always flow more than when it's restricted in this application. Consider the existing intake tract as baseline. Baseline will flow X, any restriction in that intake tract will flow less than X. There may be a point where there is ideal diameter given a specific volume of air, and a point where tubing is too big (for ideal flow) given that volume, but I don't think we have gotten there yet with existing tubing dimensions which are often dictated by intercooler inlet/outlet sizes and space restrictions within the engine compartment.

Any science/physics guys want to prove or disprove this?
 
zstroken said:
80's bushed to 2.6 seem to run pretty darn good!
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Has anyone dynoed with that? If so, what HP/TQ. Also as stated was that straight 2.6 non MWE or with MWE?

Not doubting, just trying to establish baselines for testing a restrictor vs. no restrictor.
 
Leadfoot said:
Has anyone dynoed with that? If so, what HP/TQ. Also as stated was that straight 2.6 non MWE or with MWE?

Not doubting, just trying to establish baselines for testing a restrictor vs. no restrictor.
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Lets say not quite 4 digits. I wouldn't be surprised if there are some 4 digit ones out there though.
 
Iron-Hyde said:
I already stated that MATPA here in western massachusetts will be using the restrictor tube next year for at least WS, if not our 3.0 too. I am more than happy to do dyno/track testing beforehand to prove it works to the club, the forums, anyone. I just need the trucks, preferably 8 more, the materials, and a best guess on how they should be profiled and placed.
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I'll offer my truck up for testing. Aaron's, yours, Derrick's, and Todd's would be good guinea pigs as you are running aftermarket chargers. I will talk to any or all of them. R.A.D. has a chassis dyno. I'm sure I could talk to Stevie and pull a few strings to see if we can get a discount rate for before and after testing.

I will talk to some machinists to see if we can make a modular bushing that has a 2.6 center section and taper's out on both ends to X, then a slip on spacer (secured with a set screw) that continues the taper from X to Y, then another spacer that would taper from Y to Z. It would make it a smooth transition from Z all the way down to 2.6 (or whatever dimension we choose).

The X, Y, and Z would be whatever OD is the most common ID of intake tract hoses for easy hookup when testing. What size intake hose are you planning to run and what is Aaron running. I will speak with Todd and Derrick and see what they run.

This will take some work and coordination, but should not be hard. The sooner we can get this going the better as I will be down for a while after my surgery on 11/11.
 
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Leadfoot said:
Please tell me you are joking...

Hell, guys have gained increases in HP (even if only marginal) by increasing intercooler tubing size a slight amount or just getting rid of bends or neckdowns, so telling me putting a restriction after the turbo will not affect it I believe to be incorrect from all I have learned.


You are correct that if there is 20PSI on one side of a restrictor it will flow more than if there is 10PSI, but unrestricted (or less restrictive) will always flow more than when it's restricted in this application. Consider the existing intake tract as baseline. Baseline will flow X, any restriction in that intake tract will flow less than X. There may be a point where there is ideal diameter given a specific volume of air, and a point where tubing is too big (for ideal flow) given that volume, but I don't think we have gotten there yet with existing tubing dimensions which are often dictated by intercooler inlet/outlet sizes and space restrictions within the engine compartment.

Any science/physics guys want to prove or disprove this?
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:nail:

Lets look at the basic restriction we have right now....our tiny valves in the 24V heads.

Engine A has a 2.6 charger on it.

Engine B has a "Hell Yeah" set of Mod class twins on it.

Same head....same Basic restriction.

Not going to take a Science/Physics guy to point out which engine is going to make more power right?
 
Joesixpack said:
:nail:

Lets look at the basic restriction we have right now....our tiny valves in the 24V heads.

Engine A has a 2.6 charger on it.

Engine B has a "Hell Yeah" set of Mod class twins on it.

Same head....same Basic restriction.

Not going to take a Science/Physics guy to point out which engine is going to make more power right?
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you are making more power from not only more velocity, but also more CFM. I can use the same example in the dmax engine and dyno them before and after ported heads and in BOTH cases, after porting the heads (IE Removing restriction) they will make more power

in your example, it seems you would argue that porting heads does not yield gains...simply because velocity is decreased
 
Iron-Hyde said:
you are making more power from not only more velocity, but also more CFM. I can use the same example in the dmax engine and dyno them before and after ported heads and in BOTH cases, after porting the heads (IE Removing restriction) they will make more power

in your example, it seems you would argue that porting heads does not yield gains...simply because velocity is decreased
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How on earth does that suggest porting heads does not yield gains????

OK same example......the identical PORTED head on both engines.....guess which makes more power?

To be effective the restriction tube goes on the suction side.....google up "Choked flow of gases" to get a handle on it.
 
Joesixpack said:
How on earth does that suggest porting heads does not yield gains????

OK same example......the identical PORTED head on both engines.....guess which makes more power?

To be effective the restriction tube goes on the suction side.....google up "Choked flow of gases" to get a handle on it.
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OK, the restriction on the intake side is going to be more effective (answered that question well), but restriction on the output side is still a restriction. Does a Big Block Chevy breath better and perform better on a single 1.5" exhaust or dual 2" exhaust? Restriction to flow is restriction to flow, air doesn't care if it's being moved by 8 cylinders or a single turbo.

If what you are saying is true, we should place a 1" diameter outlet on the outlet side of the compressor as "more pressure = more flow"....????
 
Never said on the pressure side it wasn't a restriction.....just that it can simply be overcome with pressure. Right......this is pretty simple to grasp, as pressure goes up, mass flow through the restriction goes up.

However on the suction side, once your at choked flow.....don't matter how hard you try, just not going to pull more air through the restriction.
 
Joesixpack said:
Never said on the pressure side it wasn't a restriction.....just that it can simply be overcome with pressure. Right......this is pretty simple to grasp, as pressure goes up, mass flow through the restriction goes up. I think we are arguing the same thing from different sides. If pressure goes up given the SAME RESTRICTION then you are absolutely correct, the problem is in an open intake tract from compressor to intake there is a DIFFERENT restriction (less) than if you necked it down to 2.6, so you are comparing Apples and Oranges. Where I think we agree if I am reading what you are saying correctly, is that if you were to compare a truck with a restrictor with a small turbo and then with a big turbo, the turbo that produces more pressure would feed the motor more which is why I agree the intake side is where the restrictor should be (maybe you are explaining yourself wrong and we are on the same page), but a restriction is still a restriction and limit power (which you just agreed with). I also feel that a big turbo would still be choked with a restrictor after the compressor as you need airflow to spool and build pressure and the larger the turbo, the more the choke, but as stated on the suction side make more sense for many reasons.

However on the suction side, once your at choked flow.....don't matter how hard you try, just not going to pull more air through the restriction. Agreed
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I think we might be on the same page, just looking at it differently.....and to be honest your explanation was a little misleading at first.
 
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Joesixpack said:
How on earth does that suggest porting heads does not yield gains????

OK same example......the identical PORTED head on both engines.....guess which makes more power?

To be effective the restriction tube goes on the suction side.....google up "Choked flow of gases" to get a handle on it.
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I used that example because the non-ported heads would be the post-charger restriction (in place of a restrictor, say on the compressor outlet for instance) but I was also trying to point out that comparing a 2.6 single with 3.2 twins is irrelevant because there is more lbs of air being moved with twins (yes at a higher velocity but the quantity is what makes the hp). I agree with you that the restrictor is better suited in the intake, however, any restriction post charger is going to reduce power, maybe not as uniformly because of differences in velocities and mass of air in each application, but it will be reduced. you may have been saying that and we miscommunicated...... not sure.
 
Iron-Hyde said:
I used that example because the non-ported heads would be the post-charger restriction (in place of a restrictor, say on the compressor outlet for instance) but I was also trying to point out that comparing a 2.6 single with 3.2 twins is irrelevant because there is more lbs of air being moved with twins (yes at a higher velocity but the quantity is what makes the hp). I agree with you that the restrictor is better suited in the intake, however, any restriction post charger is going to reduce power, maybe not as uniformly because of differences in velocities and mass of air in each application, but it will be reduced. you may have been saying that and we miscommunicated...... not sure.
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I do believe that is what he was trying to state. Unfortunately it did not come out that way. I believe we are all on the same page :Cheer:

I know I have tried to "write" something on these forums and I know what I'm trying to "say", but don't put it into words well and has caused issues. In the end I end up arguing the same point as someone else who is arguing with me...

The internet is a great thing, but can also lead to unneccessary conflict.
 
zstroken said:
I am not one to put out exact numbers, some people are very protective of them. LOL
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There are quite a few 4 digit 2.6's out this way.

I can't see how they wouldn't work. They reduce power on the Audi's and Puegots in the LeMan's Series I do not see how they would not work on pulling truck's. To what extent is to be seen.
 
What is the length of this tube (will it fit in the valley of a v-8 motor without running into issues with the intake elbow). Not a problem for me, just curious for the masses.

And I agree with a lot of the people in the other 50 2.6 threads going on. Put the restrictor in place for WS if you want and leave 2.6 to protrusion. There are so many people in these threads that don't pull or want to sell parts and its getting sickening. Get the same rule for all organizations and lock it down for 3 years. I don't care about dual wheels but I'm against them since I don't run them.:hehe:
 
05smoker said:
What is the length of this tube (will it fit in the valley of a v-8 motor without running into issues with the intake elbow). Not a problem for me, just curious for the masses.
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Part being sent this week to be tested will be used on a Duramax.
 
RP.jpg
 
SPEAKSUP said:
There are quite a few 4 digit 2.6's out this way.

I can't see how they wouldn't work. They reduce power on the Audi's and Puegots in the LeMan's Series I do not see how they would not work on pulling truck's. To what extent is to be seen.
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It will for sure work. The HP will be a direct function of the bore diameter.

So you test 3 or 4 sizes, plot the curve, run a regression on it, choose the HP you want, and bingo, there's the diameter.

One thing I hope it doesn't get into is fiddling with the diameter every year by rule tweakery syndrome.
 
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