So, WHY do you NEED a wastegate?

[MCummings]

Okay, here's the deal.



I have straight piped my truck, and peple say it sounds good,, but I have had a few comments about how my truck sounds like it has thrown a bearing when the wastegate opens. ( it sounds like an old wagon wheel being spun to fast,, like "br-r-r-r-r-r-")



So people smile when I get on the gas, then nearly fall over puking when I shift gears. (A friend said he expected pieces of metal to come flying out the tail pipe. )



Well anyway, I told my Dad,, (he is part owner of this truck) That I was going to disable my wastegate, and put a "Boost fooler" for the computer, (I didn't tell him the "Boost fueler was going to be a PE COMP )



ANyway, he was telling me how, the truck needed a wastegate, with the reasoning, "Why would they put a wastegate if it didn't need one"

and I was saying "But the truck doesn't NEED one, it's just to,, uh,, let the pressure off,, I think"



So, I need to know, WHY should not I disable the wastegate,, besides lower EGT's and more boost.



And WHY SHOULD I disable it.

I am saying, just go ahead and do it,, it's the "Normal" thing to do,

He says "If it needed the wastegate disabled, it wouldn't have one in the first place"







SO, What Should I do?

Would it be bad to disable it?



All I need is some reasoning on to Why I should disable it.

What are the pluses of doing it?





Thanks for any info.



MerrickNJr



Sorry for the long post. But I thought I was in the know for the wastegate, and then I am finding out, that I have no "Hard" reasoning for disabling it.

 

[Bad340fish]

Thats not the wastegate your hearing. Its just the turbo spooling down when you let off the throttle. The wastegate will not open until your seeing around 20PSI.



The way the wastegate limits boost is it bypasses exhaust around the exhaust turbin of the turbocharger. Thus giving the turbo less "fuel" and not letting it build as much power.



Without a muffler your hearing everything that turbo is doing. When your on it at 20psi and you let off the air ramming into the motor kicks back for a second and TRIES to stop the turbo and turn it backword.



I noticed since I put guages in my truck that you do not really see the wastegate opening via the boost guage. My old turbo gasser(87 Conquest with 16G turbocharger) would spike really bad. Build boost so fast that it would overshoot max boost setting by like 4psi. You could watch the guage and see everyting the wastegate was doing. Running on the ragged edge of needing alot more fuel those spikes cost me alot of spark plugs. I did see my fair share of fire in the rearview.



This is just my opinion... I am no turbo Guru by any means lol

Clark

 

[Evan A. Beck]

If you are going to be running 40psi or less, you don't need the wastegate. Just put a plug in the compressor housing of the turbo. Upwards of 40psi, with the excpetion of twin turbos, a wategate is needed to prevent excessive turbo speed.



You can't hear the wastegate functioning, what you are hearing is exactly what Clark said--turbo spool down.



The ISB's in motorhomes and heavier trucks run at 28 psi or more. They are wategated, but it doesn't open until about 35 or so. Also, they do not have a de-fueling parameter in the ECM to limit power when boost reaches 20psi. The limit at 20psi is a Chrysler add-on.



I have my wastegate disabled, and have NO plans on enabling it again. Don't need it, don't want it.



When setting the opening of a wastegate, it is important to note two things. One is the pressure at which it begins to open. The other is more important, and this is how much it actually opens. 1/16"-1/8" is optimum for Fords and Dodges. If it opens too much, it will bleed exhaust pressure off too fast, and actually limit your boost AND take away some of it.



Hope this helps, email me if you have any more questions.

 

[Ted Jannetty]

Wastegates

You Do need a wastegate for many reasons;

1) to control turbine shaft speed and keep it at a safe limit

2) to control back pressure in the exhaust manifold.

3) to prevent excessive heat in charge air.

4) to control boost so proper Air/Fuel ratios are maintained.

5) to prevent HIGH EGT from backpressure.



21 Psi will support 350 hp flywheel with clean tail pipe and EGT well within spec.

When you raise boost you raise charge air temp which in turn raises EGT for all reasons listed above.



Every turbocharger is sized to run at a specific boost level, where the turbo can make COOL Boost, when you go above that it makes HOT boost, NO GOOD!!!



So many people are concerned with backpressure when it comes to turbine housing size, BUT NO ONE takes that in to consideration when disabling wastegates.



Don't do it You Don't Need it, it won't make any more power, Probably less.

 

[Diesel Freak]

DO NOT DISSABLE A WASTGATE!



Ted hit the nail on the head. If you dissable a wastgate you run the possibility of pushing the turbo out of it's efficiency envelope. The HX-35 is good to about 35 psi..... after that you are just wasting fuel.



Yes you can push the turbo to generate more boost, but after about 35 psi you will see little benefit and actually should go with an HX-40.



-Cliff

 

[Archive]

Ted does not post very often, but when he does, its well worth reading. Thanks once again, Ted!

 

[Diesel Freak]

I have been thinking for a long time that I may be producing too much boost. Now that I have a boost gage that shows that I can produce up to 35 psi I may be correct. I am going to lower boost down to 28-30 psi and see what happens.

-Cliff

 

[JR2]

Can Ted or Evan or someone tell me how to adjust the wastegate on HY turbo to get it to open at 30 lbs or so. I have high egt and I belive it is because my turbo it running up around 38-40 PSI at WOT. I think if I can limit the boost to the turbos operating range that I will be better off.

 

[Diesel Freak]

Originally posted by JMoglia

Hey Ted, thank you for that thread it made a lot of sence I have a 981/2 24 valve with auto trans,b-d brake and have not done any other mods except exhaust,could you tell me how to check that vacume solinoid to see if I need to adjust that rod ? i'm not sure if i'm getting the most out of my e-brake or does that waste gate have anything to do with it,I have not ever touched that adjusting rod and have 37k on rig any reply's would be appreciated, thanks

JDMJOE/ JMoglia

I'm not Ted, but the wastgate and exhaust brake are two completely separate entities.

The wastgate does not use vacuum, it uses the boost pressure created by the turbo to open the wastgate... ... there is not a solenoid on the wastgate, it is a spring loaded diaphragm.



If you want to adjust your wastgate setpoint all you have to do is either install a boost elbow and tweak the setscrew, or adjust the spring pressure of the actuator by turning the actuating rod a turn or two... . just do it in small increments and then test it using the boost gage in your truck. I would not attempt the latter method unless you are no longer under warrantee, or have the proper test equipment to properly set the wastgate (boost gage or a variable air pressure source).



If you have a HY-35... ... I have no suggestions since I have never looked at one very closely, but you could try changing housings to a 12cm or a 14cm.

-Cliff

 

[Max340]

Comment and Question

Comment: Given the comments, it seems to me that no matter what the answer about needing the wastegate, its not what makes the objectional sound that was the original question. Thus disabling it would not stop the sound.



Question: Ted, I assume the comment you made about Air/fuel ratio was more aimed at gasoline engines. If not, please explain how it matters to a diesel. Is it because of emissions and soot?

 

[Ted Jannetty]

Max340, The objectionable sound is due to the fact that he has no muffler to properly cancel sound waves.



Air fuel ratio has all to do with all internal combustion engines, in the case of Diesels, too rich and you have soggy performance, black smoke and High EGT.

Too lean, i. e. more air than you need for proper complete combustion, Lost performance.

Too much boost, or more than you need causes many Deficiencies.

High back pressure, high charge air temps, high egt. etc.



Everything is a balancing act.



Simple test if you have a boost and egt gauge,

Lower boost a little at a time, you will see EGT drop then rise again as you go down, find the point were you have balance for you combo.

 

[Dieselnerd]

Thanks a lot Ted. That's some really good information. My boost goes to 32# at WOT and since I only have the 230HP plate it sounds like I would be better off if I lowered my boost a few pounds.

 

[KWIKKURT]

Originally posted by Ted Jannetty



Air fuel ratio has all to do with all internal combustion engines, in the case of Diesels, too rich and you have soggy performance, black smoke and High EGT.

Too lean, i. e. more air than you need for proper complete combustion, Lost performance.

Too much boost, or more than you need causes many Deficiencies.

High back pressure, high charge air temps, high egt. etc.



Everything is a balancing act.



Simple test if you have a boost and egt gauge,

Lower boost a little at a time, you will see EGT drop then rise again as you go down, find the point were you have balance for you combo.

Best post on boost that I have ever read.



For easy adjustment of many wastegates hook up a small airpressure regulator to the boost line. You can run it into the cab and have easy "Dial a Boost" at your finger tips. This is great for changing settings when testing different "box" settings and changing to a Lower power setting when Towing.

 

[Max340]

Ted, This info follows what I had always believed about diesels, but am told by a number of diesel tractor pullers around here that more smoke is more power. Never could see how that followed, since smoke is incomplete combustion.



As to the method of setting boost, I assume one sets up to be in that "cool dip" from what ya say, is that correct?

 

[Ted Jannetty]

Tractor pulling and trailer pulling are two completely different situations.

The tractor guys can get away with stuff that is not possible in day to day use, the engines will expire!

They only run for a few seconds.

They build custom turbos that exceed 100 psi boost, initially they smoke but then go clean with flames shooting out of the pipes.

Cool as hell but not practical.



The cool dip is correct.

 

[Max340]

Nah, these guys dont run the fantastic stuff ya see in arenas... just the locals running big fuel into more or less stock diesels. Still dont see how it works better, so much heat lost to the cooling effect of over fueling.