turbo& wastegate

[APAGE]

How can you tell if turbo and waste gate are fuctioning properly? I removed hose fromturbo and looked at impeller looks good no looseness. Tried to move wastgate at acutatorcould not move by hand. Thanks in advancefor your input.

 

[illflem]

Your turbo is probably ok. If you have compressed air you can put it to the wastegate actuator and see if it opens and closes. Don't exceed 30 psi or you can rip the actuator diaphragm. If the actuator doesn't move the diaphragm could already be torn or the gate is carboned up and stuck. Usually just moving it by hand will free it though it may take some effort, vicegrips on the rod will make it easier. Sometimes the line from the injection pump is disconnected, melted or kinked and will cause the wastegate to stay closed. If the wastegate is stuck closed you will see high boost pressures at high rpms even when not under load.

 

[pathaymond]

I too Have wondered how I know if the waste gate is operating right I am saving some money for gauges. that will tell alot but I hear alot about a hose from the injection pump? I see nothing from the pump to the waste gate there is a hose if you will from the front area of the turbo to the waste gate larger hose like 3/8 od. . ? Maybe my 98 is diff? or maybe its been modified Prior to my ownership I bought at 28K dont know why it was so new and at a Kia dealership. had some trouble all fixed by the dealer and alot of patience on my Part I love this 12 valve model year. thanks for any input Pat

 

[illflem]

The wastegate tube runs along the firewall , the area that sometimes melts is right above the exhaust manifold. There are two other larger lines to your turbo, an oil pressure and return, they head towards the oil filter.

 

[The patriot]

If you take the clip off the wastegate arm that connects to the rod, you should be able to work the gate easily.

You'd have to be king kong to be able to do it with the w/gate actuator connected, especially in that spot.

Eric



PS Welcome aboard. 98 12 valves rule, dont they?

 

[Champane Flight]

Wastegate question.

Ok, guys. If the stock settings for the wastegate actuater on a 95 is 28#. Yet the boost never goes over 17-19#. Does this mean your wastegate is never opening? Or does this mean that the wastegate is opening to soon, wastegate set wrong?

 

[LarryB]

What is so important about keeping the boost low? All the guys with super duper turbos and 16cm housings have no waste gate. I'm just wondering. To my way of thinking higher boost means the turbo is pumping more air than the engine can swallow. If this is the case, why are some going to HX40 et al? I have some idea that the bigger turbos actually require less exhaust power to spin them fast enough to get the required boost. Too much boost in the smaller turbos means there is too much restriction and wasted energy being used on the exhaust side. This is where the waste gate comes in. Too much restriction on the exhaust side = higher EGT. I think it's getting clearer just by talking it out.



SO! Actually the bigger turbos don't pump more air but less? They are also less restrictive on the exhaust side? lower EGT right? Is this compensated by the higher exhaust pressure/volume coming out of the engine from added fuel? AHhhhh, but then low pressure/restriction at low speeds would lead to lag until fueling comes in with a puff of smoke. Wow, what a viscous circle.



Mmmm... . realy gets the ol thinker workin...

 

[pathaymond]

Thanks for the input guys. I will check the area closer for the described parts Now to Larryb and his thoughts I agree I have thought the same thing I guess what is being said is does it matter if the wastegate is stuck closed? I would expect open not to be good but is closed a bad thing?? again I guess I will understand more when the gauges go on. . Patrick

 

[illflem]

I sort of chuckle when folks here post about getting 60 psi of boost, almost half of it is a waste and will cause higher EGTs without any increase in power. The more is better theory doesn't work with boost, anything over 34 psi on our trucks is just not necessary. Besides higher EGTs intercoolers have been known to split open, then are only rated to 50 psi.

 

[Pthomas]

i agree illflem

boy it gets hot!

 

[Joseph Donnelly]

On Dodge 12 valve applications the wastegate opens at about 18 psi except 215s which open around 23-25 psi. More boost helps up to a point, depending on resultant cylinder pressure and on how hot the air got being compressed. The efficiency map of different turbos varies regarding cfm and boost psi. My Ram is a good example because all the air comes through the turbo, no nitrous to make the turbo almost redundant. I get hp readings in the 565-614 range depending on turbo and other settings including fueling. Boost also varies, 36-43 psi.

 

[Pthomas]

This is what ive been trying to learn about !

At the holset site there are effiency maps for the

various stock turbos they make. I would really like to learn what the best pressures would be with a stock head/gasket/pistons and cam.

My package now makes over 44psi and the air charge temp im guessing is way too high with the hx35 and non wastegated 16cm at 44psi?

Holset claims the hx35 is efficient up to almost 300hp?

Im not sure on any of this, but i have a custom HX40w on the way. any ideas on the gate psi settings? Joe I would expect you may know.

care to share?

thanks for the great fuelsystems description and the story on how you got "sickly" in the new tdr 35!

 

[Pthomas]

I know of some that have lowerd compression and marine pistons and modified cams that run boost pressue over 50psi but thats not the package most of us run. ANYONE ever test boost pressure's on a dyno care to share some results?