Wastegate questions

[TN farmer]

My question is about blocking the wastegate and producing more boost. I did this yesterday and it took about 5 minutes. As a result it increased my boost by 5 pounds to reach about 28 pounds. My question is how much will I benefit from this and are there any drawbacks?

[kerry witherspoon]

What did you do to increase boost?

[RVGuy]

TN Farmer,

Could you go through the procedure you used to block the wastegate? Much appreciated!

[TN farmer]

I used a turnbuckle like the one used in this picture on a cummins.

http://***performance.com/truck%20pictures/dodge_pictures6.htm

The letters deleted are w j s performance

The location on our trucks is under the 6.6 cover on the passanger side you should find the linkage. Since the wastegate is shut the clamp just keeps it in that position.

[ 01-04-2003: Message edited by: TN farmer ]</p>

[mackin]

I think what we need in this thread is Mr. Eloquent himself Steve.... smile.gif

Some info =&gt;
================================
What does the "Wastegate" do, and does it work along with "Boost"?

* The simple explanation: a wastegate limits the maximum boost generated by the turbocharger.
* How it works and what it does: The wastegate uses a pressure activated diaphragm and rod to operate an exhaust bypass around the turbocharger and thus limit the maximum boost that the turbocharger can produce. This permits an engine manufacturer to use a "fast" turbo charger with a small exhaust housing to produce useable boost at low engine speed and load. To prevent excessive boost at higher engine speeds, the wastegate limits the maximum boost to a safe level for the engine, and prevents turbocharger over-speed.

and=&gt;However, the turbo could overspeed and/or the exhaust restriction from small exhaust housing ports could choke the flow and horsepower at higher rpm. Therefore, a wastegate is used. This wastegate helps to limit total boost, because it opens at a preset amount of boost. Enough gas is bled off so that boost effectively is limited to that value (18-23 lb for most engines). The higher rpm hp is still choked by the small housing ports, but for emission purposes, it is more important to build some boost very quickly so that fuel can be allowed without smoke.

and=&gt; Turning up the wastegate will increase the air volume that is stuffed into the cylinder. This *may* reduce the EGT, but will not increase power. How do you get more power? One way: more fuel = more power. To increase the power, the fuel rate must be increased. The boost should only be increased to match the fuel curve for smoke and EGT control. Several tests have been done where a truck was run on a dynamometer, the boost was increased by blocking the wastegate signal, and the truck was re-tested on the Dyno. In every case reported, no power increase was measured.
=========================================
I got all this from a link from a TDR buddy....


I have only reached 32 PSI under load....These guys seeing 35-40 PSI Man your testing the limits.....It has been reported hear that we are wasting our time with this as I strictly am doing it for an EGT purpose as to performance as I feel it is nothing similar to an air cleaner mod.....

I have seen my EGT'S stay in check HOT Juice under duress...I would only say do this at your own risk and I'm not absolutely sure it's worth the risk,especially the ones reporting astronomical numbers with such a little turbo that we have.... Forty PSI??? WOW!!!!!!

There is more info here as this has been discussed before in length ,try the search feature....

Play nice,this is one of those opininated threads.......


MAC

;)

For some reason most here report HIGHER boost levels (28 PSI)with the Juice stock wastegate, as if it is somehow accommodated the Juice fuel curve....No one here has every explained how a mechanical wastegate could be affected...Beats me, and I guess a whole lot of us....As I'm to believe it's a pressure activated diaphragm that cause a bypass to open,release excess, as stated above at 21 ish PSI....

[ 01-04-2003: Message edited by: mackin ]</p>

[TN farmer]

Thanks Mackin,

Let me make sure I have got this. As long as I am running @28 pounds of boost I should not be pushing the limits of the turbo, and I will benefit from lower EGT.

Just wanted to make sure I read your post correctly.

[mackin]

TN farmer

I would say that is a pretty safe range,7 or 8 #'s above stock ,but I will admit,I'm no expert,but have been told this......

I have seen no problems ,yet,at the levels I've seen ,but I really have to be under a good load to achieve 30+(grade climbing)....Normal range for me is 28 and under hard acceleration,wastegate deprived...

I used vacuum caps and clamps,I didn't chain mine up...I blocked the wastegate signal,so I guess some may leak by the wastegate flap????.....Proceed with caution,as always.....

MAC



:cool:

[ 01-04-2003: Message edited by: mackin ]</p>

[CPMac632]

I was having trouble with egt so I thought turnbuckling the wastegate was the answer. It did lower egt by around 100 deg. but would increase boost from 34 to 40psi. After having it on a dyno and seeing no difference either way in hp and after I ruined my boost sensor I suppose maybe that wasn't the way to go.

[SoCalDieselNewbie]

You couldn't pay me to turnbuckle the bleed hose into the wastegate and, as of right now, I don't see any benifit of blocking it.

1) The Hot Juice, TTS or whatever are all pulling fuel out by 2200 rpm to redline because the tranny can't hold it. The extra boost really does nothing at this point because you are already burning the availible fuel.

2) Like it or not, the wastegate is a saftey device for the turbo.

3)If you want extra boost, you can move the bleed off hose from the turbo outlet to the engine intake. It will give you about 2-3 psi more of GOOD boost.

4)The wastegate, Hot Juice or whatever else, still opens at the same PSI as it did when stock. Unlike the Ford, the wastegate is not electronically controlled. It is a mechanical device. The increase in boost is seen because the wastegate can't bleed it off quick enough but the upper portion of is "bad boost" in that it usually fluctuates 1-2 psi.

[sdaver]

hey newbie glad to see your still around........i was worried about about the fate of us all in your absence.....no seriously hope you had a great holiday and i look forward to reading your post :D dave

[ 01-05-2003: Message edited by: sdaver ]</p>

[RVGuy]

SCDN,

You say: 3)If you want extra boost, you can move the bleed off hose from the turbo outlet to the engine intake. It will give you about 2-3 psi more of GOOD boost.

Can this be done without drilling? I mean, is there a connection just waiting for this hose?

[chevmeister]

Once again the wastegate fairy rears its ugly head!

[Maverick]

You guys that are running over 23 psi......aren't you seeing SES "turbo overboost" codes?

I can get my truck to set a SES light under certain conditions. To be continually pumping excessive over boost into any engine I would be afraid of causing a head gasket failure. I have had both head gaskets replaced on my 3500 and God only knows if it was caused by overboost. Just don't think its a good idea but it your engine.

[CPMac632]

Maverick my programming keeps it from kicking codes and I'm crossing my fingers on the head gaskets, ok so far. SCDN they don't all pull fuel at 2200 Mine definately doesn't but I don't have a slipomatic either.

[RealBigTruck]

Blocking the wastegate just sounds like a bad idea to me. There is no way to control boost at all.

If I wanted to raise boost pressure to some predetermined limit I would use one of two devices. The cheap one is a manual boost controller. This is a valve that is put inline in the hose that goes from the fitting on the compressor outlet to the fitting on the wastegate. It bleeds off pressure in the hose to "trick" the wastegate. It takes higher boost pressure to cause the wastegate to open since some of the pressure is being bled off. It's as easy to adjust as tightening or loosening the screw on the valve and is very consistent. And, the wastegate will still work. You can use this to increase boost by a little or a lot. They can be purchased for this specific application for about $10.

A more expensive option is to use an electronic boost controller. This also intercepts the hose going from the compressor outlet to the wastegate, but it has an additional line that goes to the intake manifold (post intercooler). This device senses pressure at the compressor outlet and at the intake manifold and controls the wastegate using a solenoid to control the pressure that is sent to the wastegate. This gives very good control of boost and has other features, such as multiple boost settings, gain controls for boost ramp-up, scramble settings for preset overboost pressures for specific amounts of time, etc.

I haven't read about anyone using either of these devices on the diesel forums. Seems a hell of a lot better than clamping the wastegate closed.

[SoCalDMAX]

** The following information is for educational purposes only and is in no way an endorsement or encouragement to do the same ***

I currently have my wastegate hose disconnected and plugged. This way, there's no mechanical stress on the wastegate trying to push on an immovable object. The wastegate simply never gets a signal. I'll explain why I do it.

1. Decreased EGTs under extreme towing conditions. I think we all agree that increased air equals decreased EGTs.

2. I feel there is also a *slight* increase in power under certain conditions. Here's why.
I look at boost numbers as the backpressure of the air that is trying to get into the intake. If one increases boost from 20psi to 30psi, with no other changes to the engine, slightly more air HAS to be going into the engine.

When towing up a steep grade, the boost rises higher due to the resistance the engine is feeling from the load. This is when I want lower EGTs, not just at idle. If I look at my exhaust at 1600rpm in 5th under load, I see a little smoke. I feel a little more air to help burn that unburned fuel is going to help make more power.

3. Some say you can't control the increased boost. Yes, I can. The only time the boost rises above the normal 20psi is under load or when drag racing, and then only for a second or 2 before a shift. When under load, I can back off the throttle 1/4" if necessary and drop boost levels back to low 20s. The only time boost ever rises above 20psi is under heavy load, again when you really want lower EGTs and more power. Under normal commuter conditions, boost never even reaches 20psi.

4. Are we overspeeding the turbo? At 30psi, I don't *think* so, but I'm not a turbo expert. At 40psi, I imagine your odds are much higher. At 30-32psi, I haven't heard anything but smooth turbine whistle. I've read of Ford and Dodge owners speak of "barking" the turbo, but have yet to hear of a Dmax owner doing it. As always, it's the law of diminishing returns. The first extra 6 or 7 psi is probably helping, and it diminishes after that.

5. On a related topic, I have SPA boost senders mounted in the intake and the boost hose (pre and post intercooler.) I see exactly the same amount of max boost in both locations. Pehaps under part throttle conditions they may vary, but at max boost they're both identical. It makes sense to me, since pressure equalizes throughout the vessel.

I hope this answers some questions. Once again, I think it's useful only under heavy towing conditions and I am in no way endorsing or encouraging anyone else to do it.

Regards, Steve

[tpitt]

SoCalDMAX,
What is the highest boost you've seen? I had my wastegate blocked off when I was dragging at the October Showdown in Tulare, and mine peaked at 38#. I have the X-monitor so it retains the highest reading. I am going to dyno the "hot juice" in a couple of weeks and was thinking of blocking it again. The main thing that bothers me about running the "hot juice" is that I can slip my transmission. I don't think the dyno will hurt it though as we won't be in 5th. My transmission also will slip a little in 3rd. Time for tranny upgrades. I'm a dealer for ATS diesel performance and BD and am waiting patiently to see which one works the best. BD is still working on their upgrades. tpitt

[SoCalDMAX]

I've seen as high as 32.4psi, but it's recorded as high as 34.x psi, I just don't know when it occured.

Regards, Steve

[matt-max]

you mention 'barking' the turbo.

not sure if this is what you are referring to, but:

if you powerbrake the truck and let boost build up until the rear tires are just about to start spinning and then let off of the throttle you will get a 'bark' from the engine bay. it may be more accurately described as a chirp/squeak.

my best guess was that this is the wastegate doing its job and allowing all the excess pressure to release.

i suppose that this would not happen if the wastegate was not operable and may or may not cause some sort of damage.

any ideas?

matt

[mackin]

I don't think turnbuckle'ing your wastegate is a good idea.....

I think if your dead set like some who have had the "VISIT" that vacuum clamps at the signal is your best bet......Mine had the visit near a year ago.....

But again proceed with caution ,I don't want the haunt coming back on me.....As stated this is a safety device......

I moniter my gauges and will let up but 32 (analog) is about what I've seen as max......Your results may vary.....I'm tapped into intercooler inlet....

MAC

[CPMac632]

Mine will bark when shifting every time over 35psi. Tpitt when you dyno try it both ways mine was +3 hp when wastegate was functional.

[ 01-06-2003: Message edited by: CPMac632 ]</p>

[Kennedy]

"Barking" the turbo is what happens when the boost generated by the turbo reverses and momentarily stops the turbo due to a rapid fall of in exhaust pressure/energy. Basically, the intake manifold has say 30 psi of pressure and the engine load drops causing the exhaust back pressure to fall to a fraction of the boost psi. This air just flows backwards causing the sound you hear. My '96 has a non wastegated turbo that will do this when it locks into OD sometimes.


I'll agree with CPMAC that when I blocked the wastegate, my HP and torque peaks were slightly earlier AND lesser. What you are doing is increasing the back psi even more than the resultant boost so you are defeating the purpose. The key is, to find where the point of diminishing return is. Hopefully, the Turbo Master wastegate control will allow us to explore this area more...

[ 01-06-2003: Message edited by: kennedy ]</p>

[RealBigTruck]

Kennedy,

Are you sure about that? It makes sense with a gasser motor because with the throttle closed all that pressure has nowhere to go (hence the blow-off valve). But a diesel motor is still going to eat a lot of air really fast at 3400rpm, even with no fuel.

At 3400rpm, the engine is pumping 187 liters of air every second (ignoring volumetric efficiency). I wonder what the post compressor intake volume is at 30psi. Either way, I think the engine would eat most of that volume in as little as a tenth of a second.

[CPMac632]

He just told us his 96 would do it so I know he is sure.