Worth going with external wastegate on 14b?

[DROOPY209]

I'm wondering if its worth it to go with an external wastegate on a 14b turbo.

Would I just need to weld the flapper shut?

are there any benefits to this?

any disadvantages?

will gas mileage suffer by going with an external wastegate?

 

[andymoraitis]

On a turbo that small I wouldn't bother. Keep in mind that the 14B can only run so much boost before it's way out of it's efficiency range and this is before the point at which the internal won't hold boost. Also, an external doesn't change gas mileage since this is dictated by the tune and your individual driving habits

Just for reference, how much boost do you want to run?

 

[Irrational]

I'm wondering if its worth it to go with an external waste gate on a 14b turbo.

Would I just need to weld the flapper shut?

are there any benefits to this?

any disadvantages?

will gas mileage suffer by going with an external waste gate?

yes if you put the w/g on the manifold you will need to weld the flapper shut

yes there are benefits the stronger the spring you use the later the w/g will open the faster you get to the desired boost. you also will not creep

disadvantages are noise if you dump it, price, and having to beat the ho's off with a stick for sweating your bling waste gate.

gas mileage will suffer severely from you always flooring it to hear the waste gate

 

[fourreGsixty3]

I agree with Andy. The amount of boost for you to be running to justify an externally gated set-up would be high, and when running boost out of turbo's efficient range it will begin to blow hot air, and the stock side mount cant cool all of this, so your intake temps will be higher then wanted, and on a turbo'd car we want cool air intake, becaused that hot intake charge can lead to some big problems down the road.


Dustin

 

[Auto RS T]

I agree with Andy and Dustin, I don't see any reason to externally wastegate a 14b, the easy way to fix boost creep is by porting that thing up and possibly geting a new flapper installed, and it should costs a lot less. Running large amounts of boost will blow hot air, just like Dustin said, at this point with the sidemount you are fighting yourself. Try turning down the boost and getting a solid tune, this will give more power than maxing out efficiency and heat soaking the intercooler.

Are you still on the stock fuel pump? I hope you are not boosting too high. Get that datalogger!

 

[Steve93Talon]

I agree with Andy and Dustin, I don't see any reason to externally wastegate a 14b, the easy way to fix boost creep is by porting that thing up and possibly geting a new flapper installed, and it should costs a lot less. Running large amounts of boost will blow hot air, just like Dustin said, at this point with the sidemount you are fighting yourself. Try turning down the boost and getting a solid tune, this will give more power than maxing out efficiency and heat soaking the intercooler.

A larger flapper is the LAST thing I'd want on a 14b. You could weld the flapper shut and it still wont hold over 20psi to redline. I was running 23-24psi on mine, and it dropped to 18psi over 6k with HKS 272s. This was on a stock flapper. I was also on a SMIC and even with alot of heat soak and knock in 3rd and 4th, The car was still faster at 23psi than it was at 18-20psi with no knock.

 

[Auto RS T]

A larger flapper is the LAST thing I'd want on a 14b. You could weld the flapper shut and it still wont hold over 20psi to redline. I was running 23-24psi on mine, and it dropped to 18psi over 6k with HKS 272s. This was on a stock flapper. I was also on a SMIC and even with alot of heat soak and knock in 3rd and 4th, The car was still faster at 23psi than it was at 18-20psi with no knock.

I was referring about the flapper to help eliminate boost creep, not to help max out the boost. I assumed this was the reason he wanted to go external.

I apoligize for my final statment about making more power. I believe I was looking for the word "consistant" there. I need to keep my post numbers down when I am tired I can see.

Pushing the car to the very edge should make it faster.

 

[brute]

Pushing the car to the very edge should make it faster.

Unless of course you're totally maxing out the turbo and it's way out of efficiency. I'll bet a 14b at 27psi would be slower than one at ~22psi.

I see no problem running the external gate if you're planning to upgrade to a large turbo later down the road. You can do a manifold mounted one, get it all set up, then when you get a turbo, you don't have to buy an extra $600 worth of external wastegate set-up because you already have it.

If you're sticking to the 14b (or even upgrading to a 16g of some sort), save money and time and stay with the internal gate.

 

[vintagemuscle]

i'm probably one of the only people that have a external wastegate setup with the 14b. Don't bother unless you eventually plan on going with a much larger turbo. It does however hold the boost exactly where i want it.

 

[DROOPY209]

i'm probably one of the only people that have a external wastegate setup with the 14b. Don't bother unless you eventually plan on going with a much larger turbo. It does however hold the boost exactly where i want it.

I like your setup. I plan on running my GM MAF-Translator setup for a while. Eventually end up with AEM EMS. I have (2)
1gB's so one car will have the piggyback setup and the other will have the AEM EMS...no wasted money.

Exactly why I want to do this. I already have this SBR 7cm cast manifold with external wastegate flange:

http://www.slowboyracing.com/more.php?id=1891&mods=25-8415,28-5473,36-8419


I want to be able to control boost as best as I can. I am NOT going to be replacing this turbo anytime soon. The turbo will be the last upgrade on my cars. I want to have the car FULLY supported before the turbo upgrade, that way I take the 14b to its full potential. The way things are going, I might end up with a TDO6H-20G with an external wastegate setup.

All I need now is an external wastegate and a dump tube for it.

So, should I do it?

I think my internal wastegate on my 14b has some small cracks on it, so welding the flapper shut and having an external wastegate should be better then having a crack around the flapper, leaking.

 

[DROOPY209]

Whats the differences between the springs that come in the external wastegates?

what does each do?

 

[andymoraitis]

Different springs will hold different boost levels. Here's a listing from Extreme PSI that wil give you a general idea of spring combinations that are available:

http://www.extremepsi.com/store/customer/product.php?productid=16469&cat=446&page=1

Have fun,

Andy

 

[Kevin Jewer]

Unless of course you're totally maxing out the turbo and it's way out of efficiency. I'll bet a 14b at 27psi would be slower than one at ~22psi.

This is an internet myth. I have never run faster times on a given turbo than when it was completely maxed out (boost dropping with airflow/time flatlined). Turning down the boost will not increase power unless there is another reason for it. For example, turning down the boost increases timing or changes the AFR, etc. I also feel that compressor efficiency is a worthless parameter. With any kind of respectable intercooling (SMICs need not apply) any difference in compressor efficiency is cut down drastically. The extreme example I like to use for the sake of illustrating the point, despite being impossible, is that with 100% IC efficiency compressor efficieny would be of absolutely no concequence

That being said, I don't see any reason not to go with an external. They do a much better job. 14Bs may run lower boost, but they also run more restrictive 6cm housings (look at all the cracks compared to a 7cm housing, and then to an 8cm housing). That will increase the pressure on the flapper and increase the likelyhood of it blowing open. And nitrous just compounds the problem for poeple going that route. And of course, the external WG is a good investment for future turbos anyway, so there is no loss there.

 

[DROOPY209]

Thank you 95gsxracer. I plan on running a nice sized FMIC also.

I don't wanna just blow a bunch of hot air when i can just cool it all down with a FMIC.

I know you can control boost a lot better with an external wastegate, but can you make your boost kick in sooner? That would be great for a street/strip setup.

 

[andymoraitis]

Lowering spool is a function of air/fuel tuning and cam timing. The external has no effect in this regard. The way a 14B spools, it's not like you've got anything to worry about. I'd love to have your spool characteristics on my setup! The only way you'd see an improvement is if you had wastegate cracks that were bleeding boost and slowing spool. Once you weld the flapper shut and hook up the external, you'll be able to gauge just how much of an effect, if any, those cracks had.

 

[brute]

This is an internet myth. I have never run faster times on a given turbo than when it was completely maxed out (boost dropping with airflow/time flatlined). Turning down the boost will not increase power unless there is another reason for it. For example, turning down the boost increases timing or changes the AFR, etc. I also feel that compressor efficiency is a worthless parameter. With any kind of respectable intercooling (SMICs need not apply) any difference in compressor efficiency is cut down drastically. The extreme example I like to use for the sake of illustrating the point, despite being impossible, is that with 100% IC efficiency compressor efficieny would be of absolutely no concequence

I'm going to disagree with you, but do so respectfully, and, of course, back my beliefs up.

When the compressor wheel does its job and compresses the ambient air, the air molecules bang together more and more, which is commonly known as friction. Friction creates heat as we all know. This is why companies market products like intercoolers, cold air intakes, and the like. Cold air going into an engine is always exponentially better than hot air. The compressor pushes out hot air, which then gets cooled by the intercooler, and then enters the engine relatively cold.

This is why choosing the right size turbo means everything. If you choose a compressor that's too small, it spins very fast, very quickly. When you start pushing more boost through it, it continues to spin faster and faster and the air is getting hotter and hotter. However, there is a point in which the turbo begins to spin so fast that it cannot create any more boost, and just begins pushing hot air. This is known as the choke line on compressor maps. It's more than likely the right side of the map. The maximum centrifugal compressor volume flow rate is normally limited by the cross-section at the compressor inlet. When the flow at the wheel inlet reaches sonic velocity, no further flow rate increase is possible.

Basically, when a turbocharger is run deep into choke, turbo speeds will increase dramatically while compressor efficiency will plunge. When efficiency is down, very high compressor outlet temps exist, and turbo durability is compromised. Sure an intercooler will cool the charge down, but intercoolers have limits as well. Intercoolers generally have about a 72% efficiency, depending on what style (tube/fin, bar/plate/hybrid).

So let's have an example. I live in Albuquerque, NM, where summertime temps are generally over 90*F. Let's say I'm out one day with my 14b and I'm planning to run a mere 20psi. At full spool, the compressor would be spinning so fast that boost is no longer being created, and extremely hot air is being put into the motor. This is where I stand on the 14b's compressor map:

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Note how I'm way past the choke line and the compressor is spinning at over 170,000rpm. This is creating a compressor outlet temperature of approximately 694*F. Even with an intercooler running at 72% efficiency, it still only cools the intake charge to 259*F.

Now let's try the same boost, same RPM range, same redline, same atmospheric pressure, same boost, same intercooler, but with a GT35 (48-trim, 71mm) compressor wheel. This is where I am on the GT35's compressor map:

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I am in the highest efficiency island of this particular compressor: 76% And the wheel's only spinning at 115,000. This makes my compressor outlet temperature only 335*F. With the same 72% efficiency intercooler, my intake charge is cooled all the way down to 159*F.

 

[donmagicjuan]

Derek,

I agree with a lot of what you said in that post, but I don't think it disproves what Kevin was saying earlier. I think he was just saying that turning down the boost on a given turbo will never result in more power, because the cooler air at the lower boost level does not make up for the difference in airflow at the higher, less efficient level. While the air charge at the lower level has more favorable characteristics in terms knock preparation, the higher boost will still result in a greater mass airflow into the engine. Since power varies linearly with this parameter, the higher, hotter boost trumps the lower, cooler one.

 

[brute]

But if the ECU is pulling timing due to the knock and hot air, you'll make less power.

Low boost, cool air charge, more timing, no detonation
High boost, hot air charge, less timing, possible detonation

Not to mention running the turbo way out of its efficiency will greatly reduce the life on the turbo. And if you're detonating, you might as well say bye-bye to your motor as well. This is just how I see things. I don't like replacing motors or turbos.

 

[donmagicjuan]

Yes, those points are indeed valid. I was assuming we were only considering race gas tunes with no knock in either case, but I see what you're saying.

 

[Steve93Talon]

The extreme example I like to use for the sake of illustrating the point, despite being impossible, is that with 100% IC efficiency compressor efficieny would be of absolutely no concequence

pfft: http://homepage.mac.com/stevestrzem...ctures/2003-04-27 19.02.05 -0700/PC010051.jpg

63F charge temp on 90+ degree day

How do ya think Goodwill went 10s on a 14b?

 

[brute]

I never said it's impossible. I just said that the same boost with another turbo will be much more efficient and healthy or both turbo and engine.

 

[DSM90AWD]

Topic

From my own experience with an external (albeit on a larger turbo), I found the spool time measurably reduced (in my case 200PRMS to 20 psi) vs the internal gate (34mm?) mine came with. Reasoning is that the external's valve is much quicker to respond to changes in boost so stays shut longer. It also does not have any of those "cracks" around the W/G port that leak

 

[brute]

When I posted my thoughts on the topic, I was accused of saying "internet myths" instead of facts. I was simply backing my statement(s) up.

 

[Kevin Jewer]

I still maintain that on a dozen different turbos I've run the best times with the turbo completely maxed out, in most cases not even on the compressor map/chart. That does not make anything you said untrue Derek, my point is only that when talking about max power production, which implies race gas, and constant tuning, compressor efficiency is a non-issue. It has also been my experience that when increasing the compressor wheel size to get back to an "efficient" island on the map, my ET suffers due to the increase lag. So my general strategy lately has completely reversed, and I know run the smallest turbo I think will do the job. This of course comes from about 6 years of personal experience with these cars, but is not necessarily the best way to go about things for everyone.

I feel it is also worth noting that once you outrun the compressor map, it becomes impossible to create significantly more exhaust flow (without nitrous, which I may have mentioned earlier). You simply reach a state of equilibrium where airflow per time is maxed out, flow per rev follows the VE curve, and boost drops accordingly. I run the stock EVO turbo in my 05 RS with no signal to the WG actuator at all, at the track, and have been doing so for over a year. This is worth 2.5 mph over using my EBC at the highest setting.

When talking about pump gas, compressor efficiency becomes more important than on race gas, but still pales in comparison to the importance of intercooler efficiency! I think where many people make a mistake is to focus too much on compressor maps and then skimp on the FMIC they choose... To elaborate on my 100% efficient example, lets look at what happens with 100% IC efficiency and 100% compressor efficiency. With 100% IC efficiency, air entering the manifold will be at ambient. With 100% compressor efficiency, the air is still very hot, just no hotter than adiabatic compression naturally causes. Now, obviously having both systems very efficient is ideal, but my main concern is with people putting the most emphasis on the wrong one.

I see no knock as I'm maxing turbos out, but let me restate the fact that I run race gas while doing so at the track, and monitor every single run for good AFR and timing.

Steve, I am familiar with air-liquid ICs, and I'm a big fan of them! For race cars anyway. A nice PWR unit almost made it's way into my 90 talon. The project goodwill car is nasty, and Joe is one of the coolest guys I've ever met.

I realize most of this discussion is off topic, but I don't like good technical discussion to be avoided for that reason. If the mods feel this should be split off into another thread or something, feel free to do so, I have no objections.

 

[donmagicjuan]

Very nicely said, Kevin. I must say it takes a lot of competence (or, alternatively, balls of steel) to run a turbo with no wastegate signal. Very nice.