External wastegate. Exhaust manifold or O2 housing?

[Rice Over Wheat]

How about someone try posting some comparison tests between runner vs o2 instead of all this hearsay? I'd like to see some data.

Let's discuss plug wires now...

 

[firebirdvert305]

I have mine mounted on the #1 runner, everytime I pull the plugs, they all looks the same, who cares about pressure differences between cyl #1 vs cyl #4? Its not doing any harm. I know for a fact tho 02 housing externals arent the way to go due to the size of mitsu housings. Stick with the tried and true method and you will see proven results.

 

[tbTalonES94]

We couldn't really "test" how each perform really unless all components were the same and someone just moved the gate around. We'd probably have to test things on a flow bench of some sort to see which flows greater and equally. The o2 mounted location is just fine as long as some work is done on the waste gate hole in the turbine housing. Ported is usually needed. Sometimes not though.

A friend of mine had to port his mitsu bullseye housing for his Holset hx35 because it would creep. o2 mounted waste gate...after porting it controls boost solid with no problems.

Another friend of mine swapped on an off-the-shelf mitsu bullseye housing for his evo16g and it has Zero problems controlling boost with an o2 mounted gate. No porting.

 

[Rice Over Wheat]

My O2 works great. That's all I need to know. And it makes for a much cleaner installation to boot.

 

[drivemusicnow]

Your correct in form of mathematics. You forgot though that the exhaust comes out in pulses through each cylinder. Not every cylinder is expelling exhaust gases at the same time. So while #1 cylinder is expelling gas..to others aren't. You also have to realize that when the gate opens, pressure has to equilize accross the exhaust manifold. The other 3 runners are going to try and back-track to the waste gate, which would cause as you can imagine serious turbulance.

We've already stated undoubtably that the gate on the #1 runner will work, and will control boost. It just doesn't do it as efficient and ideal as a collector mounted gate or o2 housing mounted gate.

Simply put...the best place for a waste gate hands down is where ALL cylinders are feeding into it. Go look at any really well designed exhaust manifold for any turbo application. If it has been researched and developed to add power and work right...the gate is ran off the collector...NOT the #1 runner. It is a cheap way of controlling boost and that is it. Yes it works, yes it's cheap, and no it is not efficient.

You're trying to apply logic for a system in which flow is seperating to one in whic flow is combining.

First and foremost, you can assume that the exhaust gasses are of the most turbulant kind in ANY exhaust manifold setup. They are too hot, and expanding to quickly to be anything but turbulant.

Second, if you have 30 psi of exhaust gas in a manifold, (low estimate) how much are the compressions and rarifactions actually effecting flow?

I agree that in theory a collector mounted wastegate would be more ideal. I am thoroughly not convinced that you will lose preformance, or somehow decrease the wastegates ability to bypass gasses around the turbine.

Tell me how I'm going to lose horsepower by doing this, or somehow lose ability to control boost in a typical DSM application (say between 10 and 30 psi) and we'll go from there.

 

[tbTalonES94]

I never said you would lose any power. I don't see why you guys argue. A wastegate on ONE runner of a manifold can't be as efficient as one on the collector. It just doesn't make any sense. The gases from cylinder 2-4 will try and back track to cylinder 1 to escape through the wastegate...you can't tell me that isn't restrictive and/or creates turbulance.

Put it this way. It would be like putting your o2 sensor in the exhaust manifold in one cylinder. It would probably work, but it doesn't make any sense because you'd want all four cylinders hitting it. Same with the wastegate.

I'm not debating on what works and what doesn't work. I'm debating that the collector or o2 mounted gate is better (in my opinion to fray from anymore debate) compared to the #1 runner. I believe it is ideal to have ALL four cylinders expelling gas evenly out of the wastegate and not just one.

 

[tbTalonES94]

Here are a few pictures of my friend's Evo16g w/bullseye housing and 38mm tial on the o2 housing set-up. Again this controls boost perfectly fine and also looks like a stock set-up if you just glance!

without turbo

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everything installed

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bullseye housing un-ported

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here's my old set-up on my 1g with the bb 50-trim and 38mm external re-routed

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[dsm-onster]

First, the purpose of this post is to say that I do not in any way wish to argue, nor did I. I did not THINK i was coming across argumentative.... I apologize if you perceived otherwise.

Comparing o2 sensor location to wastegate location actually goes hand in hand w/ what I was saying. An o2 sensor NEEDS to be located in an exhaust stream that is the sum of all the runner streams so that an accurate measurement of percent oxygen can be taken.

Concerning a wastegate application, how could there be a difference in pressure loss by taking small percentages of particles from all the streems or just 90% of the particles of one stream? Work done on the turbine wheel is directly proportional to the pressure differential between the exhaust pipe and exhaust manifold. Relieving pressure anywhere in the exhaust manifold lowers this differential. Even if zero gasses from the other runners evacuate the manifold because of turbulance or any other function the pressure loss is still apparant, predictable, and significant. Ideology is maintained. Full control of compressor speed is maintained.

Turbulance or entropic activity or, better to say, a sudden change in the momentum vector and scalar quantity for a particle suggests that less work will be done on the particles original destination. If the path to the turbine is disrupted so that turbulance takes place, the particles do not strike the turbine blades with the same force and do not convey the same work. The introduction of turbulance itself causes the work function to decrease. It is MUCH easier for a particle to travel from runner 4 in the head through runner 4 inthe manifold and flow to the lower pressure in runner 1 (because of a hole to the exhaust pipe).

As well, all systems of particles strive to achieve a state of higher entropy or randomness. We can deterime the amount of entropy change in a particular system through a variant of Ludwig Boltsmann's formula, where S = k(Boltsmann's Constant) X ln W(number of ways the state can be achieved):

∆S = R ln [V(final)/V(initial)]

Or,

∆S = R ln [P(initial)/P(final)]

S = entropy, R = gas constant, P = pressure V = volume

Rearranging we find that any positive change in entropy will change pressure. Opening a hole in the system will allow entropy. As the volume goes up (now the exhaust piping is included in the system of particles), entropy increases. Opening a hole in the number 1 exhaust runner will cause the gasses to rush to the number 1 runner (turbulantly or not). This is is because of the gases tendancy to achieve a higher state of randomness and a lower state of energy. Turbulant or non turbulant, the gases are no longer rushing to the turbine wheel as the path to lowest energy. Whether or not the path is long or short, the act of changing course causes the reduction of pressure on the turbine blades. No matter the instantaneous flow out of the wastegate, there is the same likelyhood there will be flow part way up runner 1 as there will be in running out of the collector.

 

[tbTalonES94]

Yea i guess arguing was the wrong word. I didn't mean for it to seem like this was a big argument where we were trying to prove eachother wrong.

Turbulant or non turbulant, the gases are no longer rushing to the turbine wheel as the path to lowest energy. Whether or not the path is long or short, the act of taking the path causes the reduction of pressure on the turbine blades.

So basically you are saying...it's going to work regardless if it causes turbulancy or not. We've already stated it works just fine. I just believe the collector/02 mounted location works more efficiently.

We could go on and on for days never ending story

 

[pitbull419]

sorry i missed all that im in the middle of moving.
Has anybody ever done any test on this.
If not i think i might as soon as the weather gets better.
Im really interested in it now.I have seen a few threads about it and tons of opinions most with logic some with none.
I belive there wont be much difference if any at all between the o2 or the collector.

 

[gsxtacy]

so anyways, my setup is STILL working great..EWG's off the 02 sensor hoousing work great..Ebay WG's and professionally fabbed custom o2 sensor housings rock. This guy has a jig for OEM fitment...hit him up
www.hesspower.com

 

[drivemusicnow]

I won't ever recommend ebay wastegates. Let's think about this one really quick, What happens when that wastegate fails?

two possibilities: It fails while open, thus leaving your car without boost for a while until you can replace it.
Option two, It fails closed, creates an overboost situation and you blow your engine up because you don't realize it's failed when you go WOT on the highway and hit 35 lbs of boost before you noticed your boost gauge is pegged.

This is not something I'm willing to cheap out on. Wastegates deal with temperatures over 1500* and 30-40 PSI or higher. I am not willing to put some chinese metal knockoff designed piece of shit in charge of making sure my engine doesn't blow up.

There are parts you can cheap out on. like boost controllers, or catch cans etc. Parts that are critical to your engine operating in a somewhat controlled fashion are not those parts.

 

[dsm-onster]

This is not something I'm willing to cheap out on. Wastegates deal with temperatures over 1500* and 30-40 or higher. I am not willing to put some chinese metal knockoff designed piece of shit in charge of making sure my engine doesn't blow up

But what about my homemade homedepot boost controller !!!???

. . .Just teasing you.

 

[tkelly27]

It would be really difficult to fail completely shut the way they are designed. Eventually the exhaust back pressure will push against the valve and pop it open, especially if the diaphragm fails and the spring tension is reduced.

There are a lot of people with much faster cars than yours running ebay waste gates on daily drivers. They have been for a long time too.

They are Chinese pieces of crap, but it is a very simple device. I've seen people "upgrading" internal gates with washers from home depot. I even plan on making my own in the near future, as I can't even justify the cost of an ebay unit.

You are very much right though, if you can't afford a real external gate, you should be questioning weather or not you really need one.

*shops for tubular O2 housings on Ebay*

 

[tbTalonES94]

I've ran an ebay wastegate for about 1.5yrs, and the gate is still currently functioning perfectly on a friends car for about 6months now. Still holds boost like the day I bought it. I thought the same about the gate...always cautious if it would fail, so i bought a real Tial and replaced it. Same effect and I wasted $220. I guess the Tial does look a lot nicer though

 

[fourreGsixty3]

Reading this thread is really funny, because every other post is either formula's (dsm-onster ) or going back and forth on the same thing, just to realize your both agreeing with each other in different way's .

I guess I can throw in my .02.

All this will do is go round, and round until we get real world test's done to proe one way or another. My vote is for the manifold collector just on the mere fact that I want the exhaust gases regulated before the turbine wheel, and the gases will always be going directly to the collector unlike having to travel through the collector and to runner #1 to get the the WG. It is true that the exhaust gases are VERY turbulant do to the high temp's, and the gases being far apart, and bouncing off of each other quickly, and this can be debated time, and time again on if it has any effect as to if the location of the WG will reduce this turbulance or have any effect at all on it. So long story short...my choice is a Punishment Racing T4 manifold with a Tial 38mm WG flanged off the collector with a similar set-up as Anthony's future E3 manifold set-up due to the fact that I have no PS so I have added room to work with.

 

[Maglin]

One thing most are not realizing on the O2 mounted WG is that even though the hole is only like 32mm it's totally different then running internal. The internal flapper hardly goes past 45* and thus is a restriction in it's self. When you put an external on the O2 housing that flapper should be removed and the majority of it's restriction is gone and the set up will be effective enough for 99% of the community. Once you get into large frame turbo's this would probably be an issue if you wanted to only run say 20 psi. But those of us running large frame turbo's are usually running 30+ psi and thus don't need a large gate to control boost.

Running off #1 is also ok. It's not crap. It does have a slight side effect of lowering the back pressure of #1 over the other 3 cylinders thus causing a VE flux across the engine causing #1's VE to increase. This in lamins terms will cause a slight lean condition in #1 during gate operation. This could be seen if you have WBO2 on each runner but the equipment is costly and probably never going to be tested.

Running off the collector is of course the 1st choice in my book. Pressure drop is fairly proportional across all 4 cylinders during gate operation.

You are right about pressure losses in a single chamber. It would be equal but you are not putting individual runner size into account which causes pressure to rise in it's perspective runner. So again #1 would be lower than the other 3. It's enough w/ a 38mm WG for about 99% of this community. If you are running more than 500 HP I wouldn't run it as the lean condition caused in #1 could be damaging, and if nothing else the riching of the mix to compensate for the knock along with the lean #1 will cause a power loss.

In the end. All 3 work well. It usually comes down to 2 things. Money and power output. Those that output 500+ HP should have the money to get a tubular manifold with a external gate off the collector. Under that power output all 3 would be safe to run and work well. Going off the O2 is the cheapest solution. Less parts to buy.

I'm building a motor right now with a pump gas output of around 400ish HP. Running the DNP manifold with 38mm tial that dumps into their O2 housing. It is very sexy and very functional. It will support the later power output of 550+HP that the car will see in a few years. But I had a budget and it is the cheapest way to go and do it right for future development.

Their is no need to post equations that only maybe 1% of the board will understand. Just give good clear examples. If I'm not clear enough say so.

 

[dsm-onster]

But those of us running large frame turbo's are usually running 30+ psi and thus don't need a large gate to control boost.

Amen! I've believed this to be true and hav eseen this on many setups that are not DSM but nevertheless my own. . .

Running off #1 is also ok. It's not crap. It does have a slight side effect of lowering the back pressure of #1 over the other 3 cylinders thus causing a VE flux across the engine causing #1's VE to increase. This in lamins terms will cause a slight lean condition in #1 during gate operation. This could be seen if you have WBO2 on each runner but the equipment is costly and probably never going to be tested.

Running off the collector is of course the 1st choice in my book. Pressure drop is fairly proportional across all 4 cylinders during gate operation.

You are right about pressure losses in a single chamber. It would be equal but you are not putting individual runner size into account which causes pressure to rise in it's perspective runner. So again #1 would be lower than the other 3. It's enough w/ a 38mm WG for about 99% of this community. If you are running more than 500 HP I wouldn't run it as the lean condition caused in #1 could be damaging, and if nothing else the riching of the mix to compensate for the knock along with the lean #1 will cause a power loss.
________________________

. . . If I'm not clear enough say so.

I am specifically debating this. . . It doesn't "drop into the groove" of my research and training. The transfer of the gasses from the other runners to the runner w/ the gate will move so fast that no amount of rpms will make this noticable. . . BUT! i've seen ideals not apply. So has there been a verification that the runner w/ the gate in fact increases VE in that cylinder?

 

[Maglin]

it's pretty simple. You are effectively making that runner shorter as the exhaust has less distance to travel and their will be more of a pressure drop on that runner as where the other 3 runners have to travel a bit farther to exhaust from the WG. I'm sure most of the other 3 ends up through the turbo but their isn't really a way to find that out. And the more back pressure you have the lower the VE goes cause it's forcing exhaust to stay in the clyinder. With enough valve overlap and boost you can overcome the back pressure caused by a turbo but cruise is effected greatly so it's only really used in drag cars.

The walls of the runners will cause some pressure build up in the runners. That is what I'm saying. So putting the WG on the #1 runner can effect the VE of #1. Less back pressure means the pumping action of the piston can do it's job better and thus raise the VE of that one cylinder. I don't really have anything off hand to validate my statement. Sorry about that. But it does seem logical. Really the only way to test this would be to take a manifold and tap 2 ports at the back of each runner. One for a WB02 and the other for a back pressure gauge. Then do some pulls on a dyno and check results. Their isn't many people that are willing to do something like this and plus their is the manifold that is sacrificed.

 

[eldiabloz13]

here's my old set-up on my 1g with the bb 50-trim and 38mm external re-routed

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This is the exact set up i want. Can you please tell me what you have here. Wastegate,manifold,etc....

 

[tbTalonES94]

Well I have the PTE BB 50-trim set-up for external wastegate on the o2 housing

-custom made 2.5" tubular o2 housing for 38mm gate re-routed
-Tial 38mm wastegate
-SBR version1 manifold

that's about it. You could get a similar o2 housing from Punishment but mine kept the gate closer towards the block so i could fit a stock or slim fan very easily for the a/c.

 

[eldiabloz13]

do you got any pics of the o2 mani. Im looken to keep both fans. But crunch a 50 trim with external gate and the heat shield

 

[tbTalonES94]

that's the best i've got for a picture of the set-up ^^. I don't have any pictures of it off the car.

 

[Maglin]

do you got any pics of the o2 mani. Im looken to keep both fans. But crunch a 50 trim with external gate and the heat shield

Well just putting a 50 trim on will require you to loose one fan. If you have the money to get a turbo and external WG then you should also have the cash to get some slim fans. If you are worried about your car overheating I would ask you how many people have you seen with overheating issues? Almost none and It's almost always either a t-stat or the fans are not working.

If you are going for a stock look don't bother. The 50 trim kills that. Any tech inspector will know the difference. I just got finished putting a DNP manifold /w 38mm tail dumped into their O2 housing on a motor with a HX35. I'll take some pics before I drop it in the car just so you can see that work of art. You get get the manifold/O2/and WG for around $950 which is about the cheapest you'll find.

 

[DSM90AWD]

To add my .02 into the fray.. I just completed my latest round of upgrades along with ERL's Cast Stainless T3 manifold (which also comes flanged for Mitsu or T4) and I am pretty friggin happy at the ease at accomodating a proper 3" O2 housing/downpipe without that Tial44 whoring up all the space down low.

Haven't datalogged yet, but on a preliminary run (minus the MBC), 15psi came up fast and was rock solid thru 3rd gear. Dump noise was also suprisingly less than my old O2 mounted Tial44 setup

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