Ford Powerstroke Diesel Forum banner

1 - 20 of 69 Posts

·
Registered
Joined
·
2,974 Posts
Discussion Starter #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
 

Attachments

·
Registered
Joined
·
2,431 Posts
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.
 

·
Registered
Joined
·
609 Posts
Awsome write up RAMM, now lets hope it becomes a sticky so we dont have to keep answering this question haha.
 

·
Registered
Joined
·
2,974 Posts
Discussion Starter #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.
 

·
Registered
Joined
·
2,431 Posts
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.
Actually I'm going to admit being stupid here. I wired mine shut, after disabling the red tube. In my defense, I have an s467 about to go on so I really don't care if I blow this turbo.

But With the red tube disabled I couldn't get over 26 PSI, but wiring the wastegate completely closed I'm getting over 30 ( gauge pegged so I dunno). I'm seeing stupid as hell drive pressures, I bet this turbo wouldn't last 6 months like this.

Just offering it up there to say that it may be forcing open lower than you think if your wastegate spring is weak, or not tightened enough.
 

·
AMERICA!
Joined
·
22,936 Posts
I'll stick this thread for y'all.:thumb:
 

·
Registered
Joined
·
6,168 Posts
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.
 

·
Registered
Joined
·
2,431 Posts
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.
 

·
Winning DUHHH
Joined
·
2,389 Posts
My truck, even tuned won't barely hit 25psi. I assumed the spring was weak, nevertheless a 38r is replacing it.


Sent from AutoGuide.com App
 

·
Registered
Joined
·
6,168 Posts
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.
Were not talking about anything different... I ran a stock turbo with 230/100's for 5 months, hitting 35+ psi at 55-60psi drive pressure. Was it perfect, no... But the turbo did not blow up the first time it happened.

At 25psi, most factory turbos are already running 40psi drive pressure... Throw a gauge on there and watch.
 

·
Registered
Joined
·
2,431 Posts
Were not talking about anything different... I ran a stock turbo with 230/100's for 5 months, hitting 35+ psi at 55-60psi drive pressure. Was it perfect, no... But the turbo did not blow up the first time it happened.

At 25psi, most factory turbos are already running 40psi drive pressure... Throw a gauge on there and watch.
Nobody said it would blow up right away. But that kind of drive pressure is going to severely shorten the life of the turbo which is what this whole thread is about. People disabling the wastegate because they read it on the internet then a few months later have shot bearings
 

·
Banned
Joined
·
1,312 Posts
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
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.
 

·
Registered
Joined
·
6,168 Posts
Nobody said it would blow up right away. But that kind of drive pressure is going to severely shorten the life of the turbo which is what this whole thread is about. People disabling the wastegate because they read it on the internet then a few months later have shot bearings
I'm curious how many of you have ever installed a drive pressure gauge? Have any miles using one?

Your NOT going to get a 1:1 ratio out of a stock turbo past about 22psi, no matter what mods you do. PERIOD... Just not in the compressor map to do it.
 

·
Registered
Joined
·
2,431 Posts
I'm curious how many of you have ever installed a drive pressure gauge? Have any miles using one?

Your NOT going to get a 1:1 ratio out of a stock turbo past about 22psi, no matter what mods you do. PERIOD... Just not in the compressor map to do it.
Who said you would? I said you want as close to 1:1 as possible. Which is true.

You've completely missed the point of this, which is making sure people who have no idea about turbo's, and who want their turbo's to last the 15-20 years they are supposed to, don't disable this safety device and get burned, because of some crap they read on the internet.

It's the whole reason I went with a small S400 turbo rather than a big S300. Your turbo, and the S400 can handle drive pressures that are a bit out there. ( the 1.2:1 you mentioned really isn't much anyway). That's on the advice of Barder.

I haven't installed a pressure gauge on a 7.3 yet, but I will be. I have had them on three separate 2.3T setup's though, with about 60 000kms driving collectively.
 

·
Doesn't Even Care
Joined
·
18,044 Posts
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?

Sent from AutoGuide.com App
 

·
Registered
Joined
·
2,431 Posts
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?

Sent from AutoGuide.com App
Get a gauge for it, and it installs just like a pyro, put it in the same spot on the manifold you don't have the pyro sensor on
 

·
Super Moderator
Joined
·
31,744 Posts
I'm curious how many of you have ever installed a drive pressure gauge? Have any miles using one?

Your NOT going to get a 1:1 ratio out of a stock turbo past about 22psi, no matter what mods you do. PERIOD... Just not in the compressor map to do it.
Correct Joe theres just no possible way. I ran 238/80s on a stock turbo and wicked wheel in one of our old work trucks. Was it ideal? NO. DID IT LIVE? Yes. Last I heard they put 15k miles on it like that

Sent from AutoGuide.com App
 

·
Registered
Joined
·
560 Posts
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.
 
1 - 20 of 69 Posts
Top