STS Thread

[Cougar1647545494]

since the other places to discuss it were inappropriate, here it is.

 

lets take a look at their faq, and put it up against the wall of basic thermo, fluid dynamic principles, shall we?

 

Doesn't heat create the velocity in the exhaust gasses to spool the turbo?

No, heat doesn't create velocity. Heat creates volume.

heat is energy. heat in a closed system won't make volume, it'll make pressure... a means of storing energy.

 

 

If you look at any of the physics laws for gasses, you will find that pressure and volume and heat are related. PV=NRT is a popular one, The V isn't for velocity, it is for Volume.

 

volume between the cylinder head and the turbo is somewhat fixed... that makes it a variable that isn't. so an increase in temperature will cause a corresponding increase in pressure. either way, its energy.

 

The turbine housing is what creates the velocity. The scrolling design that reduces the volume of the exhaust chamber as it scrolls around causes the gasses to have to increase in velocity and pressure to maintain the same flow rate.

conservation of mass applies here. The mass flow rate is equal to the density times the velocity times the flow area.

if we hold mass flow rate as constant and flow area constant, we see that velocity is inversely proportional to density.

conservation of momentum also applies.

also, for isentropic flow, change in pressure is equal to change in density times the speed of sound squared.

so if velocity goes up, pressure goes down... not up.

 

Hotter gasses have more volume, thus requiring a higher A/R which in effect means that it starts at say 3" and scrolls down to approximately 1". Lower temperature gasses are denser and have less volume, so they require a lower A/R housing which would start at the same 3" volume, as the turbine housings use standard flanges, and scroll down to say 3/4".

aren't we still in the exhaust, where's this extra "volume" coming from?

 

Now if you were to reverse the housings in application, the conventional turbo would spool up extremely quick, at say around 1500 rpm but would cause too much backpressure at higher rpms because the higher volume of gas couldn't squeeze through the 3/4" hole without requiring a lot of pressure to force it through. On the reverse side, the remote mounted turbo with its cooler denser gasses, wouldn't spool up till say around 4000 rpms but once spooled up would make efficient power because it doesn't require hardly any backpressure to push the lower volume of gas through the larger 1" hole.

 

mass flow. also, see nozzle physics above

 

How efficient is the intercooling from your tubing?

At 5 to 6 psi we typically get at least 50% intercooler efficiency numbers from our systems and some of the truck systems which have better exposure to cold air are even better. Combine this with a pressure drop of only about 1/4 to 3/4 psi and it makes for very good numbers.

Turbo outlet temps at 5 psi boost were 175F and intake temps were 115F which is about 52% efficient.

Turbo outlet temps at 8 psi boost were 225F. This is a 50F increase with only 3 psi added to turbocharger boost.

For those wanting to run more boost we recommend a front mounted intercooler. We sell bolt-on solutions for the Hemi and the GTO. We will be coming out with more applications soon.

trucks are 1+ feet in the air. plenty of ambient air around it. A car is much lower. In most sports cars, you'd have that pipe near the exhaust tunnel. The airflow it will recieve will be the heat wash off of the radiator, engine, and exhaust. its warm down there.

 

heat exchange rate is largely dependent on temperature difference between the various media. you'd need the air outside the pipe to be meaningfully cooler than the air inside the pipe. you'd also need good contact between most of the air in the pipe and the pipe, which generally means small fins and a lot of surface area. you then need similar radiative area.

their best numbers (which are probably the ones they'd post) will be with cold pipes. heat absorbtion with aluminum pipes is one thing. dumping that heat back out is another. ideally, IC efficency should be measured not as a peak.

they are probably heavily reliant on building heat in the exhaust to make that side of things work, but also heavily reliant on not building heat in the charge pipe. you might see how those are against each other.

 

Isn't there a huge pressure drop with such long intake tubes?

No, if the pipes were 100' long there would be but we are only talking a few extra feet and we size the charge air tubing so that it will flow without a large pressure drop.

is that a "well, it could be worse" answer? 10 feet of pipe is 10 feet of pipe.

at a given pressure, the greater the flow the greater the loss per foot of pipe.

 

We typically will get about 1/4 to 3/4 lb difference between the turbo compressor and the intake manifold, which is nothing compared to the pressure drop across an intercooler. With high boost applications, these numbers will increase slightly

numbers are good. numbers are even better when they have the right information attached to them for them to actually mean something.

Using the right units would probably be helpful too.

 

don't turbos have to be really hot to work properly?

Putting a torch to your turbo and getting it hot doesn't produce boost.

 

turbos being hot and the gasses being hot are *slightly* different concepts. As per the links i provided, the turbine is driven by energy. change in total energy across the turbine tells you what energy has gone into turning the turbine. less heat means less energy available to turn it.

 

 

What produces boost is airflow across the turbine which causes the turbine to spin.

NO! airflow doesn't do it. you can't run a steam turbine on the same mass flow of lukewarm water. ENERGY spins the turbine.

 

 

 

If turbochargers required very high temperatures to produce boost, Diesel trucks and Methanol Race cars wouldn't be able to run turbos. However, each of these "Low Exhaust Temperature" vehicles work very well with turbochargers when, like any turbo application, the turbocharger is sized correctly.

methanol burning cars and diesel trucks have similar peak EGT ranges. they also usually have "small" turbos for their displacement. both are generally fairly slow to come on boost still, especially given their usual power goals. methanol race cars end up running a lot of boost and size most of the turbo bits around that (or the rules). diesels shouldn't be directly compared as they are a very different beast. for a diesel, boost doesn't make power, it makes safety. they can make the power without the boost in most cases, just not for very long before something goes boom.

 

 

In a conventional, exhaust manifold mounted turbocharger system, the extra heat causes the air molecules to separate and the gas becomes "thinner" because of the extra space between the molecules. This extra space increases the volume of air but doesn't increase the mass of the air. Because the volume is higher, the velocity of the gas has to be higher to get it out in the same amount of time.

i know they've seen the PV=nRT equation before. They even tried using it. someone should explain to them how it works. honestly, them not getting this right is depressing. V is the volume... of the VESSEL.

The heat doesn't cause the "air molecules" to seperate, it causes them to move faster. temperature is a measure of internal energy. the exhaust manifold is a relatively fixed volume, so if we're going to assume that we can apply the ideal gas laws, we can assume that the increase in temp will be an increase in pressure. (or that a decrease in temp will have a corresponding decrease in pressure.)

 

 

By mounting the turbo further downstream, the gasses do lose heat energy and velocity, however, there is just as much mass (the amount of air) coming out of the tailpipe as there is coming out of the heads. So you are driving the turbine with a "denser" gas charge.

again, an example of complete misunderstanding.

yes, heat energy is lost. mass flow is the same. mass flow rate is the same.

you are driving the turbine with cooler air, and thus less energy.

 

 

The same number of molecules per second are striking the turbine and flowing across the turbine at 1200F as there is at 1700F.

go tell a power plant engineer to use cooler steam to drive his turbines because cooler is better.

 

 

Front mounted turbos typically run an A/R ratio turbine housing about 2 sizes larger because the velocity is already in the gasses and the volume is so big that the turbine housing must be larger to not cause a major restriction in the exhaust system which would cause more backpressure. With the remote mounted turbo, the gasses have condensed and the volume is less, so a smaller A/R ratio turbine housing can be used which increases the velocity of the gasses while not causing any extra backpressure because the gas volume is smaller and denser.

the volume isn't bigger when the exhaust system is shorter.

saying that there is less backpressure caused by the smaller housing with the cooler gasses is very misleading as well.

 

Sizing is everything with turbos. There is more to sizing a turbo for an application than cubic inches, Volumetric Efficiency, and RPM ranges. A turbo must also be sized for the exhaust temperatures. A turbine housing sized for 1700F gasses would have lag if the gasses were 1200F.

highlighting compromises that shouldn't be made.

 

 

This is why turbo cars have lag when they are cold and not warmed up yet.

again more misunderstanding and BS. engine temp and EGT are VERY unrelated. chances are that an STS or any other rearmount will have significantly more lag while the car (and exhaust) isn't up to temp though. probably a "other turbo cars are like that too" smoke and mirrors attempt at saving face when some customers call and complain.

 

 

Both systems work well if sized correctly.

is there a "sized correctly" on an improperly placed turbo?

 

 

Aren't the stock manifolds and exhaust system restrictive?

For certain normally aspirated or supercharged systems, stock exhaust is somewhat restrictive and can cause backpressure in the system and rob HP.

 

generalities....

 

However, with turbocharged applications, the turbocharger is the biggest restriction in the exhaust system. All of the exhaust gasses (except the ones that are vented out the wastegate) pass through the turbine housing. The inlet hole in the turbine housing is about 2"x3", however, as it scrolls around the housing it gets smaller and smaller causing the exhaust gasses to increase in velocity. At the smallest point where the gasses exit and hit the turbine wheel, the hole is no bigger than about 1" in diameter. This tiny hole will create backpressure in the entire exhaust system prior to the turbo and clear back to the exhaust valves.

they don't understand flow through a nozzle well either.

 

So sticking larger diameter pipes and high flowing headers doesn't make lots of sense when you have a 1" tailpipe hole. These additions probably won't hurt, but the money would be far better spent elsewhere. Our Turbo Camaro put down 522 RWHP and 620 RWTQ through the same restrictive exhaust manifolds and I-pipe that came stock on the car. Turbocharging is very different than Supercharging or Normally aspirated. That is good news because you don't have to spend the extra money on the exhaust system!

bigger pipes pre turbo increases the volume and surface area. that'd hurt even worse.

 

With the turbo so far back, don't you get a lot of turbo lag?

No, our turbochargers are sized to operate at this remote location. Just like any turbocharger, once the turbo is up to temperature and in the rpm range for which it was designed to operate. The boost comes on hard and fast. All of our systems will produce full boost below 3000 rpm.

so once all of the exhaust is glowing hot (as to minimize heat loss) its good to go. before that, good luck getting it to do anything...

on a *not 14 feet from the engine* turbocharger, there is no waiting for your exhaust to heat up.

 

 

If you were to take a conventional turbo and place it at the rear, you would have lots of lag and consequently, our turbo wouldn't work properly if mounted up front

they use very small housings. we get it. doesn't mean it won't work up front. it'd spool markedly faster closer to the engine.

 

With so long of intake and exhaust tubes, doesn't it take a while for the boost to build up?No, our intake tubing volume is about the same as most conventional turbo setups that are running a front mounted intercooler, and less than many of them that run large intercoolers. We aren't talking about a small compressor filling up a large air tank, we are talking about a huge compressor filling up a very small volume which only takes a fraction of a second. Our systems compress the intake tubing in about .05 seconds. So much for turbo lag..

i think there are a lot of issues at play here. one is understanding of physics. the other is expectations and experience. if you've never been in a responsive vehicle, you don't realize how unresponsive something else may be.

 

i will say that it is one thing to discuss details of turbine energy collection and something else entirely to get it completely wrong. especially the basic physics side of things.

 

innovation implies something new. there's nothing "new" about doing something the wrong way. in general, you *try* to place the turbine as close to the energy source as possible. there are often compromises that must be made that force you to put it slightly farther than you may otherwise like. taking that and intentionally putting it as far from the energy source as possible isn't "innovative" so much as unintelligent.

 

it'd be like walking up to the plate in baseball and thinking "everyone else here is trying to hit that white ball they throw at you... but i'm going to be different.i'll not hit it and see what happens." if you stand there and don't swing, and they walk you, does that mean its a good approach and a "proven" technique?

 

numbers themselves can be made to be decent. especially for one pull on a dyno. we've always known that peak numbers mean nothing. we also know that a dyno can't tell you how responsive an engine may or may not be. transitions, drivability, and responsiveness are the bits most in question here.

the efficency of the system isn't in question as we know that will be bad.

[Guest Hal]

You have too much time on your hands. Go do something constructive.

[Cougar1647545494]

what the hal - the first time you serivce something - it usually takes you alot longer correct?

 

do the same job and it takes alot less time, right?

 

same thing applies here...

[Guest Hal]

Far cry for a point there. Fact is, you put way too much time into writing that to prove your point on a forum. I'm not sure if you get off on being "right" or what.

 

On topic, STS makes power regardless of what their FAQ says. They make power regardless of what you say. They still make power.

[Scotty2Hotty]

This is better than saying something in a vendor section when they're trying to sell their product and give a discount.

[Guest Hal]

True Scott.

[Cougar1647545494]

Far cry for a point there. Fact is, you put way too much time into writing that to prove your point on a forum. I'm not sure if you get off on being "right" or what.

 

On topic, STS makes power regardless of what their FAQ says. They make power regardless of what you say. They still make power.

 

it makes more power than without the turbo on there - sure, no one has said it doesn't

[Cougar1647545494]

This is better than saying something in a vendor section when they're trying to sell their product and give a discount.

 

which is why this thread was created.

[Guest Hal]

it makes more power than without the turbo on there - sure, no one has said it doesn't

First step is admitting, good job. Now, why do you feel compelled to argue against STS. It may not be the ideal way to boost, but, I fail to see any real issue with it (apart from easy turbo theft).

[copperhead]

Too long; didn't read

[turbomark]

It is my honest opinion that there isn't a single person on here who I'd be interested in reading more than a couple of paragraphs from, especially this cougar kid. If it can't be said in a couple paragraphs then you're obviously trying way to hard to argue your point and you're more than likely misguided in your opinion anyways.

[Adam]

Too long; didn't read

 

w3rd reading that many words that aren't printed and are on the internet makes me feel stupider than when i started

[Cougar1647545494]

It is my honest opinion that there isn't a single person on here who I'd be interested in reading more than a couple of paragraphs from, especially this cougar kid. If it can't be said in a couple paragraphs then you're obviously trying way to hard to argue your point and you're more than likely misguided in your opinion anyways.

 

the quotes were from STS's FAQ, they were broken down line by line to show how STS takes a simple principle and puts a "spin" on them.

[Scotty2Hotty]

which is why this thread was created.

Day late and a buck short though. As a vendor he was posting that he had a deal and was a vendor for the company, if it's great or not that wasn't the issue. Being a shop that specializes in products such as that, I believe he knows his product from top to bottom. If someone were to ask everything about the product, then your $.02 cents would've been taken better other than "LOL @ STS."

[Cougar1647545494]

Day late and a buck short though. As a vendor he was posting that he had a deal and was a vendor for the company, if it's great or not that wasn't the issue. Being a shop that specializes in products such as that, I believe he knows his product from top to bottom. If someone were to ask everything about the product, then your $.02 cents would've been taken better other than "LOL @ STS."

 

i agree with that, which is why i concur to v8 beats's warning and asked the posts to be removed...

[Guest hotrodmama024]

I have actually been waiting on a thread about the STS turbo's, so thank you! On the other point... i did skim through... to much to want to read.

[Smokey]

I don't believe that the STS design is intended to be the most efficent or highest power system out there.

 

Would a properly designed bottom-mount turbo setup make more power on just about any car? VERY LIKELY!

 

BUT, what I believe to be the draw of the STS systems is that they're pre-made kits that are relatively simple to install and use and make good power. Most importantly they do it for CHEAP CHEAP CHEAP!!! If I had a LS1 camaro it'd be really hard to talk me out of a turbo kit for $4K.

 

On the other side, if there is not a pre-made and inexpensive STS-style kit for the car you currently own, you would be wasting time and money trying to put your own together.

[Linn1647545492]

These cars have STS kits and they seem to make good power.

 

Over 700rwhp

http://www.vetteweb.com/features/vemp_0609_2001_corvette/index.html

 

STS kit with twin 60-1s

http://smg.photobucket.com/albums/v199/GarettO/G-Z06%20Videos/?action=view&current=GZ06TTdynovideo.flv

 

The car is currently makimg 910rwhp on boost alone @13.5 pounds

http://img.photobucket.com/albums/v199/GarettO/IMG_37501.jpg

 

670rwhp @ 10 pounds on a 67mm turbo

http://www.gmhightechperformance.com/features/0603htp_2004_pontiac_gto_feature/index.html

 

 

 

What I'm trying to say is that the STS kits are making good power numbers and running great times at the track. Who cares if it's not the most efficent turbo kit out there. I know i wouldn't if i was making 900rwhp

[Guest hotrodmama024]

I have heard alot of mixed feelings on this turbo. One person tells me great turbo for my car... but then i hear NOOO bad turbo for your car. The pro's to this set up... it is cheap and easy.

Con's about this... its in the rear of the car, weather can be a factor, there has to be some what of a lag, and someone stealing it.

[Cougar1647545494]

These cars have STS kits and they seem to make good power.

 

Over 700rwhp

http://www.vetteweb.com/features/vemp_0609_2001_corvette/index.html

 

STS kit with twin 60-1s

http://smg.photobucket.com/albums/v199/GarettO/G-Z06%20Videos/?action=view&current=GZ06TTdynovideo.flv

 

The car is currently makimg 910rwhp on boost alone @13.5 pounds

http://img.photobucket.com/albums/v199/GarettO/IMG_37501.jpg

 

670rwhp @ 10 pounds on a 67mm turbo

http://www.gmhightechperformance.com/features/0603htp_2004_pontiac_gto_feature/index.html

 

 

 

What I'm trying to say is that the STS kits are making good power numbers and running great times at the track. Who cares if it's not the most efficent turbo kit out there. I know i wouldn't if i was making 900rwhp

 

whats the displacement of those cars @ 900whp?

[Linn1647545492]

408

[Cougar1647545494]

is that dyno from the same 408 vette in the above vid (twin 60-1?)

[schmuckingham]

Too long; didn't read

 

+2

 

Who cares what dyno graph is for what car and what the CC is. POWER IS POWER and unless they cant put it down it is there and useable no matter what delivery system its

[Cougar1647545494]

+2

 

Who cares what dyno graph is for what car and what the CC is. POWER IS POWER and unless they cant put it down it is there and useable no matter what delivery system its

 

yet it shows nothing about throttle response, transients, etc..

 

lets compare to Tilley's vette...

 

http://memimage.cardomain.net/member_images/3/web/2415000-2415999/2415299_34_full.jpg

 

Edit - Linn can you find the tire diameter to convert that graph over to RPM?

[V8 Beast]

This is how I feel about this thread

 

http://i70.photobucket.com/albums/i89/xxtheonlyxx/1jzdynonu8.jpg

 

 

True story