Restrictor Tube Discussion

A velocity stack is NOTHING like the choke that is being talked about in the topic of this thread......

Pressurized fluid on the backside of a orifice is a poor example to demonstrate the function of the restrictor.

Those who think it won't reduce HP will be shocked when they bolt one on.

Still hate it.
 
Leadfoot, all those parts are already needed on 2.6 trucks (super duper trans parts, huge axles, bigger ujoints & yokes, major engine work, etc.).

I don't see that rationale behind the theory that a restrictor will bring the high flowing chargers waaaay down but not also do the same to a lower flowing charger?? For the most part, the effect is on a linear path. Maybe slightly arched curve but I don't think it's a drastic curve?? Or is it?? The harder the turbo sucks the air through the orifice, the more effect it has at reducing the mass flow??


Dangit I'm gonna have to get my books out & check out calcs on flow through nozzles... Ug
 
A regular charger is not pulling through the inducer at choked flow....(Modified chargers arguably are).
 
SmokeShow said:
Leadfoot, all those parts are already needed on 2.6 trucks (super duper trans parts, huge axles, bigger ujoints & yokes, major engine work, etc.).

I don't see that rationale behind the theory that a restrictor will bring the high flowing chargers waaaay down but not also do the same to a lower flowing charger?? For the most part, the effect is on a linear path. Maybe slightly arched curve but I don't think it's a drastic curve?? Or is it?? The harder the turbo sucks the air through the orifice, the more effect it has at reducing the mass flow??


Dangit I'm gonna have to get my books out & check out calcs on flow through nozzles... Ug
Click to expand...


My understanding of what the tekies are saying is put a vacuum(not the differential) on the charger and the charger won't suck any more....
 
RAWdiesel said:
any type of restricter or bushing will not make different size chargers flow even. this may work to reduce the power of these race cars, which it will do. but this is not an effective way to make s480's and s465s flow the same. call me stupid or what have you. it has already been proven with bushings. Clipping the wheel and make it a true 2.6 bore is the best way to do this, and to further make it more effective, loose the map groove.
Click to expand...

It's comical the lack of understanding in this thread. If the flow is unrestricted before a 2.6" bushing or bore with the wheel protruding, it can still draw air through the MWE groove. If the air is restricted to a 2.6" orifice before the compressor inlet, there is no way to allow excess flow around the inducer. It doesn't matter if the compressor can flow 125lbs if it can only be fed 95lbs through the restriction, a wheel closer to the size of the orifice will produce the same hp as a larger wheel, with less lag. Protrusion wheels with big exducers will effect hp, but more so in the lag department rather than total flow, even if the MWE is removed. This would not be the most common rule in motorsports to limit hp on a turbocharged application if it didn't work.
 
Last edited:
SmokeShow said:
Leadfoot, all those parts are already needed on 2.6 trucks (super duper trans parts, huge axles, bigger ujoints & yokes, major engine work, etc.).

I don't see that rationale behind the theory that a restrictor will bring the high flowing chargers waaaay down but not also do the same to a lower flowing charger?? For the most part, the effect is on a linear path. Maybe slightly arched curve but I don't think it's a drastic curve?? Or is it?? The harder the turbo sucks the air through the orifice, the more effect it has at reducing the mass flow??


Dangit I'm gonna have to get my books out & check out calcs on flow through nozzles... Ug
Click to expand...

That's my point. Those parts are already needed and yet guys are trying to PUSH it even more. At some point all the upgraded parts in the world won't last a full season, or 1 part (most likely t-case) even with the best of the best parts, won't be able to handle it (most likely the case itself).

If guys don't think/believe/etc that a "spec" restrictor will not bring power down (if sized at 2.6 for a minimum length), AND bring the competition closer together, then I can't make them. But I'm willing to bet if the testing is properly done and this goes into effect, that it exactly what they will find regardless of theories or the "I thinks...". How much can you suck through a soda straw in 30 seconds vs. a drink straw?

Let's forget about "turbos" and think about 1 ton drivelines. That is the limiting factor in this class. Once you exceed the limits it's hard to "pull back". It's easier to limit it up front as it's already grown leaps in bounds over the past several years.

As for those that have already been there and done that in other classes, you will have guys wanting to go open driveline as it's cheaper in the long run, then you'll have the guys who spent a fortune on upgraded parts who will ***** that it's unfair.......You'll end up pissing off one or the other (if not both) and quite a few will end up spending a ton of cash. I'm just trying to keep that from happening as it benefits no one (pullers, fans, promotors, etc).
 
Smokem said:
It's comical the lack of understanding in this thread. If the flow is unrestricted before a 2.6" bushing or bore with the wheel protruding, it can still draw air through the MWE groove. If the air is restricted to a 2.6" orifice before the compressor inlet, there is no way to allow excess flow around the inducer. It doesn't matter if the compressor can flow 125lbs if it can only be fed 95lbs through the restriction, a wheel closer to the size of the orifice will produce the same hp as a larger wheel, with less lag. Protrusion wheels with big exducers will effect hp, but more so in the lag department rather than total flow, even if the MWE is removed. This would not be the most common rule in motorsports to limit hp on a turbocharged application if it didn't work.
Click to expand...

I agree from my LIMITED knowledge on the subject. The problem is you can explain and talk to you are blue in the face, but until someone actually bolts these on 3 "high profile" (ie. known performers) trucks (say 1 true 2.6 no MWE, one 2.6 with a modified MWE, and one big 3.0 turbo) and run them down the track, there will be alot of naysayers. Running them on a dyno (doing before and afters will help as well).

I am willing to help however I can. I will donate time, money, call in favors, etc. to help facilitate the testing as I believe it to be in the best interest of the sport, but I live in "nowheresville" USA when it comes to truck pulling, so it would be more beneficial to do this testing in Ohio or Indiana, you know the truck pulling Mecca :-). Again I'm willing to help if we can get volunteers.

Any "big names" willing to offer up their trucks for testing?

Edit: Basically put up or shut up. I could be wrong myself, but there is only ONE way to find that out and I'm willing to try...
 
Last edited:
Smokem said:
It's comical the lack of understanding in this thread. If the flow is unrestricted before a 2.6" bushing or bore with the wheel protruding, it can still draw air through the MWE groove. If the air is restricted to a 2.6" orifice before the compressor inlet, there is no way to allow excess flow around the inducer. It doesn't matter if the compressor can flow 125lbs if it can only be fed 95lbs through the restriction, a wheel closer to the size of the orifice will produce the same hp as a larger wheel, with less lag. Protrusion wheels with big exducers will effect hp, but more so in the lag department rather than total flow, even if the MWE is removed. This would not be the most common rule in motorsports to limit hp on a turbocharged application if it didn't work.
Click to expand...

What color is your pulling truck? If you don't actively sledpull, I will need a 150 page thesis with supporting 3D video (RGBY only, standard RGB will not be sufficient) substantiating this claim. I need it boiled down to the atomic level because in sledpulling, scientific method does not build upon existing/parallel studies or theorems.

If you've got a pulling truck, your opinion is gospel. (Notice I said opinion, facts are irrelavent if you sled pull)
 
Here is an idea, go make a restrictor plate class, leave the current 2.6 as a protrusion, and report back the results.
If it takes off, then others will follow, if not guess we figured that one out!
 
Last edited:
When i read the title i was thinking more towards restrictor tube being inline after the turbo? I know i am not a turbo geru or anthing, but i saw were somebody compared it to nascar restrictor plate. In that case the carb will still let all the air go through it, but is limited by the restrictor plate. That was my thinking here have your restrictor tube inline of boost tubes. But thinkin of it that way i dont see too much power loss there.
 
zstroken said:
Here is an idea, go make a restrictor plate class, leave the current 2.6 as a protrusion, and report back the results.
If it takes off, then others will follow, if not guess we figured that one out!
Click to expand...

Not really looking to replace the 2.6" or 3.0" protrusion rules for this year, but try it out in the Workstock class. If it is found to be a viable option, then we can go from there.
 
zstroken said:
Here is an idea, go make a restrictor plate class, leave the current 2.6 as a protrusion, and report back the results.
If it takes off, then others will follow, if not guess we figured that one out!
Click to expand...

That's an option, and to be honest the way it will most likely be due to the majority's mentality. What happens though when 2.6 goes beyond the limits of the drivetrain...? An ounce of prevention costs less than a pound of cure (less headaches as well).

Trying to be proactive instead of the normal truck pulling mentality of reactive (as we've seen where that has led in the past). Ideally this idea of a restrictor would be great for a workstock class (limiting power substantially), and in a class such as the 2.6, limiting power to work within the limits of the drivetrain. It's no secret guys have already toasted ring and pinions, axle shafts, driveshafts, t-cases, tranny's, etc. (just look at the truck pull section of any diesel forum), not limiting the class is not going to make it any better (only worse). I know most truck pullers cringe at the idea of limiting HP (I've been there myself), but there comes a time when something has got to give (hopefully it's not a t-case or ring and pinion). If you want to go beyond those restrictions, that's what an open class or unlimited driveline class is for.

Most seem to think with the "I" or "me" mentality. People need to start thinking about "others" and the "sport".

I don't run in the 2.6 class but I do spend a great deal of time traveling and going to meetings from clubs across the Northeast as well as our own trying to get people not only on the same page rule wise, but to make rules that make sense (not just make rules or "non rules"). Allowing power limits beyond the driveline is just an exercise in stupidity. That's just allowing deep pockets to rule (maybe that's what some people want, but not those who I speak one to one to).

Sorry if myself and/or others are "trying" to make the sport better across the Nation. If it hurts your back yard pull (and it may), I am truelly sorry, but if it's in the best interest of the sport, I make no excuses.

(steps off soap box)
 
jones95runner said:
When i read the title i was thinking more towards restrictor tube being inline after the turbo? I know i am not a turbo geru or anthing, but i saw were somebody compared it to nascar restrictor plate. In that case the carb will still let all the air go through it, but is limited by the restrictor plate. That was my thinking here have your restrictor tube inline of boost tubes. But thinkin of it that way i dont see too much power loss there.
Click to expand...

A restrictor would work either before the turbo or after (it would be interesting to see which one if any would have the greater effect), but I think most agree plumbing into the intake prior to the turbo would be easier than post turbo (less likely to blow a boot as well). I think that is why people are looking to place it before the turbo. Plus removing and installing clamps post turbo to check a restrictor adds a chance for a loose connection and loss of boost or blowing off a boot. FWIW
 
Leadfoot said:
A restrictor would work either before the turbo or after (it would be interesting to see which one if any would have the greater effect), but I think most agree plumbing into the intake prior to the turbo would be easier than post turbo (less likely to blow a boot as well). I think that is why people are looking to place it before the turbo. Plus removing and installing clamps post turbo to check a restrictor adds a chance for a loose connection and loss of boost or blowing off a boot. FWIW
Click to expand...


Its pointless to put the restriction after the turbo, more pressure = more flow.
 
zstroken said:
Here is an idea, go make a restrictor plate class, leave the current 2.6 as a protrusion, and report back the results.
If it takes off, then others will follow, if not guess we figured that one out!
Click to expand...

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.
 
a 504$ bushing would solve all of this. cheap and easy to tech. limit the big turbos and the proper size ones will be just fine. what is the line when bushing a big turbo down actually cuts its nuts?
 
You must log in or register to reply here.
Back
Top