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Red tube "mod" lets finally put this one to rest

105K views 68 replies 32 participants last post by  ccarley 
#1 · (Edited)
Ok I want to clear up this red tube debate once and for all. I see differing opinions everyday on how and why this works and whether its bad or not.

Let me start by explaining how it works. Attached is a diagram of how its routed. The red line comes out from the intake spyder right next to where the map line comes out. It then goes and SPLITS, one goes to the wastegate solenoid and one goes directly to the wastegate actuator. So the red line is directly connected to the boost pressure from the intake spyder. The way that the solenoid is able to control it (via PCM control) is by closing and the pressure that is normally routed back into the intake(pre-turbo) is closed and causes the pressure from the spyder to be exerted on the wastegate actuator instead thus allowing the exhaust gases to bypass the inducer wheel.

So what happens when you unplug it?

The actuator will no longer be able to open AT ALL regardless of boost pressure. What happens is then the turbo is able to spool unharnessed by the wastegate which then allows the boost to build sooner and faster than normal because the wastegate isnt activating and bleeding off boost incrementally relative to boost being produced. The problem with that is potential over boosting the stock turbo under heavy load or acceleration. You need to have a boost gauge if you do this so you can monitor it because the boost builds fast!

Now why do some people report loss of mpgs?

Well under higher boosts the PCM is telling the wastegate solenoid close a bit to curb the climbing boost but it cant because the red tube to the actuator is no longer attached so it bleeds out allowing boost to be leaked and anyone with a boost leak will attest even a small one can kill mpgs. The solution to that is to plug the red line after your unplug it. I opted to just put it on the end of one of my intercooler hose clamp bolts, it fit well enough for me.

Why doesnt the OBS or a van have a wastegate?

They have larger AR(aspect ratios) so the turbo doesnt build boost(spool) until much later in the power band so the likelihood of overboosting is much less a possibility under normal operating conditions. The stock turbo on the SD is a bit too small IMO and obviously in Fords eyes as well because they put a wastegate on it to prevent people from blowing it up.

All in all the red tube "mod" is perfectly safe as long as you watch your boost pressures and dont let off the throttle to quickly at high boost levels because that causes turbo stall and thats a whole other story.

Anyone have any questions or corrections please let me know
 

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#2 · (Edited)
Where do you get all these PDF's? lol I was looking for one like that when trying to explain that to Steve.

But I'll add.

In regards to wiring the waste gate shut completely like some people will say to do, that's one of the stupidest things you could do to your turbo. A wastegate's function is to protect the turbo by limiting boost. The reason for this has already been said, the factory turbo is a bit too small and can be pushed too hard with factory injectors if you completely disable the wastegate.

With the wastegate red tube disconnected, the spring pressure is all that's holding the wastegate shut. Eventually enough back pressure will overpower that spring and open the wastegate a little bit. This will be different on all trucks, depending on the condition of the spring. That's actually a good thing, wiring it shut will prevent this from happening

If you are getting to that point where it's being forced open, you are already putting extreme stress on the turbo, and this is the last thing keeping you from REALLY stressing it hard. By wiring it shut you will open yourself up to seeing insane Drive pressures.

Drive pressure ratio is Drive pressure(backpressure):boost, as close to 1:1 as possible is good. Once you start getting to say 1.6:1 for example you are putting extreme side load on the bearings, which causes early failure.
 
#4 ·
Where do you get all these PDF's? lol I was looking for one like that when trying to explain that to Steve.

But I'll add.

In regards to wiring the waste gate shut completely like some people will say to do, that's one of the stupidest things you could do to your turbo. A wastegate's function is to protect the turbo by limiting boost. The reason for this has already been said, the factory turbo is a bit too small and can be pushed too hard with factory injectors if you completely disable the wastegate.

With the wastegate red tube disconnected, the spring pressure is all that's holding the wastegate shut. Eventually enough back pressure will overpower that spring and open the wastegate a little bit. This will be different on all trucks, depending on the condition of the spring. That's actually a good thing, wiring it shut will prevent this from happening

If you are getting to that point where it's being forced open, you are already putting extreme stress on the turbo, and this is the last thing keeping you from REALLY stressing it hard. By wiring it shut you will open yourself up to seeing insane Drive pressures.

Drive pressure is Backpressure:boost, as close to 1:1 as possible is good. Once you start getting to say 1.6:1 for example you are putting extreme side load on the bearings, which causes early failure.
Ive got a whole library of pdfs and pretty much every wire diagram for OBS and SD trucks. Makes things way easier when doing mods and explaining stuff and i fixed the turbo surge/stall(i dont know why i said surge:tard:)

But yes wiring it shut just is idiotic. And yes if you are to the point of forcing it open by back pressure then you probably have some melted pistons by then.
 
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#3 ·
Awsome write up RAMM, now lets hope it becomes a sticky so we dont have to keep answering this question haha.
 
#6 ·
I'll stick this thread for y'all.:thumb:
 
#7 ·
Just FYI... Its perfectly find to have a 2:1 ratio, once you are at higher boost levels...

I keep a 1:1 until about 25-30psi, then it ramps up from there.

At 50psi I am at 60-62psi EBP... Pretty damn good.
 
#8 ·
Just FYI... Its perfectly find to have a 2:1 ratio, once you are at higher boost levels...
If you have a turbo like your H2e that can handle it. We are talking about stock GT38's

I keep a 1:1 until about 25-30psi, then it ramps up from there.

At 50psi I am at 60-62psi EBP... Pretty damn good.
You are talking about something completely different. We are talking about the stock turbo, which would not even dream of staying alive at 2:1.
 
#9 ·
My truck, even tuned won't barely hit 25psi. I assumed the spring was weak, nevertheless a 38r is replacing it.


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#12 ·
Awesome explanation. It's much better than "it is what it is cause I said so"

My boost goes up to about 33 max when i push it and then drops to about 25 so I am assuming my spring is weak enough to blow it partially open. I'll leave it as is until I swap this engine into another truck.
 
#16 ·
For those of us with a deleted/blank pedestal, and with no ebps(mine doesn't have one) how do I install a drive pressure gauge?

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#19 ·
There's actually a point on the same mounting spot as the WGC Solenoid where you can plug the "Red Tube" like it intended to be that way.. I've done that to most of our trucks.
 
#23 ·
All in all the red tube "mod" is perfectly safe as long as you watch your boost pressures and dont let off the throttle to quickly at high boost levels because that causes turbo stall and thats a whole other story.
Please elaborate on this other story. Can turbo stall cause the engine to stall as well, sometimes when I'm stuck in the sand and let off I get the big turbo "whoosh-whop-whop-cooosshhh" and the engine will stall out. Fires right back up like nothing happened, but I know it can't be good.
 
#24 ·
Well no its never good to have the engine stall out especially if its an automatic. No i cant forsee any reason the turbo stalling would cause the engine to stall maybe bog down suddenly but i dont push my turbos that hard so ive never had it happen. Someone else may shed light on it.
 
#25 ·
Sorry for not getting this up yesterday...



I unplugged the line for this pic, but you can see where it's clean between the hard lines and the electrical plug.
 
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#26 ·
The1laf, you justnoulled the redtube from its original location and moved her there?
 
#28 ·
Pulled* sorry
Correct, I just unplugged it from the wastegate and plugged it in there.

I must be suffering from a weak wastegate diaphragm spring as well, the best I can do is 25psi, I might have to wire it shut for a day so see what I can get..
 
#27 ·
Pulled* sorry
 
#31 ·
I'm at 29-30 psi with ww2 and redtube connected. Thinking of doing a boostfooler till I can afford a 38r
 
#33 ·
Aren't out motors supposed to defuel @ 24 psi? This is why I thought I'd try wiring the wastegate shut to see if I was defueling or not..
If you're past that you probably don't need a boost fooler..
 
#34 ·
I'll leave her then, and my service engine light comes on as a soft code and goes away after a minute once I hit 22or so psi.
 
#35 ·
Ok, that's the same thing Jody told me when I first installed my DP chip... Now where I think there is still a bit left unclear in this thread (might as well make it the all inclusive red-tube and waste gate interaction sticky) -

How does the modification to the waste gate of turning the arm to adjust the pressure fall into this... An explanation if that, and if it relates at all once the tube is unplugged would be awesome. Thanks

(In my application with stock wheel and dp tunes with red tube unplugged and stuck on a boot clamp stud I get up to 33 psi. I have a ww2 sitting in the garage that's going on in conjunction with my fuel upgrade project- should I leave as is or make any adjustment to the waste gate via the turning method most people talk about online)


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#36 ·
Ok, that's the same thing Jody told me when I first installed my DP chip... Now where I think there is still a bit left unclear in this thread (might as well make it the all inclusive red-tube and waste gate interaction sticky) -

How does the modification to the waste gate of turning the arm to adjust the pressure fall into this... An explanation if that, and if it relates at all once the tube is unplugged would be awesome. Thanks

(In my application with stock wheel and dp tunes with red tube unplugged and stuck on a boot clamp stud I get up to 33 psi. I have a ww2 sitting in the garage that's going on in conjunction with my fuel upgrade project- should I leave as is or make any adjustment to the waste gate via the turning method most people talk about online)


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Its not really related itself to the red tube mod because rather than bypassing the wastegate actuator your modifying the length the rod has to travel in order to start activating the wastegate in the turbo.

Personally i have always been against adjusting the wastegate actuator rod because if you tighten it the wrong way you will be bleeding boost all the time. If you tighten it the right way then all your doing is forcing the actuator piston farther in the wastegate actuator housing and will eventually bottom it out.

The only way to CORRECTLY increase the actuating boost levels is aftermarket wastegates. Which to me is a huge waste of money. The turbo is designed to go a certain speed and provide a certain amount of boost at that speed, if you are then having to install a device that limits the amount of boost because the engine exceeds that limit then either you need a larger turbo or you need better pedal control. Only benefit i see to a wastegate is for compound turbos

Thats my personal opinion and im sure people will disagree.
 
#37 ·
Turning the wastegate tighter increases the spring tension, which since you have the red tube blocked off will do very little 99% of the time. What that will do is make it so it will take more drive pressure to force the wastegate open as the spring will be holding it tighter.

33PSI on a stock turbo is not good for longevity though, the whole point of a wastegate is to limit boost to protect something. In our case it's to protect the turbo itself because a tuned 7.3 can go well into the danger zone. I wouldn't make a habit of going past 30PSI if you want that turbo to last more than a couple years.

big X2 on the banks wastegate and such being a waste of money.
 
#39 ·
You're not going to hurt anything that I know of. I ran it plugged untuned on mine for about 4 years with no problems.
 
#41 ·
I did a lot of research ALOT on this and I said you know what it's very hard to accurately put a "is this ok" " should I go ahead and try it" but I went ahead and did some info tracking myself. First I just unhooked it I gained on my stock truck about 10psi which made a huge diff , but being a six speed when I would shift I got this terrible turbo sound from the turbo trying to stop due to no where for the air to go while exhaust was still flowing. This didn't seem "safe" not reliable to me. The auto guys who don't quite get the performance from there " handicapped" trucks like we do might not see this. So I put the red tube back on , but I wanted those extra psi back. It takes a little time but I adjusted the rod to where my waste gate opens right at 22-24psi . Now that my truck is tuned I hit those psi levels a lot faster , no noise, and my truck is working almost at its maximum and staying safe. If that not enough for you then you have a lot of money to spend. Sorry auto guys real truck don't shift themselves .....! I've noticed a ton of things I've researched and all the auto truck guys info is slightly inaccurate when it comes to a standard truck the turbo works much much differently when it's not under the thumb of a tourque converter .. standard guys when it comes to drivability issues beware to seek correct knowledge. They were not all made equal
 
#43 ·
All in all the red tube "mod" is perfectly safe as long as you watch your boost pressures and dont let off the throttle to quickly at high boost levels because that causes turbo stall and thats a whole other story.
So, from this statement, I assume it's a bad idea to do this mod on a straight drive truck? Since you're dropping the throttle at high boost with every shift?
 
#44 ·
I wouldn't risk it.

There was already someone else who has a ZF6 that tried this and said their turbo made an unwelcomed noise when they'd left off to shift.

I think there's better/safer ways to go about searching for power.
 
#49 ·
Will/can the insight read higher than 24 psi?
 
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