turbo charged or super charged

[FormulaLT1]

Originally Posted by KiwiBacon

I would like to read this study. Do you have a link for me?

There is a google search bar listed right in this page. Do some searching,. I can start you off on the first link though, http://www.superchargersonline.com/content.asp?ID=19 (I am sure you are going to say that because it is a site based on superchargers it will be biased notice he still states the turbo is the more efficient unit)

Edit- Also read this or just skip ahead to the intercooler section http://www.turbomustangs.com/turbotech/main.htm

Quoted from this article ( http://www.autofieldguide.com/articles/050103.html )on why car manufacturer are looking at forced induction to increase efficiency "a supercharger has a few advantages over a turbo, says Streeter. "First, it doesn't soak up exhaust heat "

[KiwiBacon]

Originally Posted by FormulaLT1

There is a google search bar listed right in this page. Do some searching,. I can start you off on the first link though, http://www.superchargersonline.com/content.asp?ID=19 (I am sure you are going to say that because it is a site based on superchargers it will be biased notice he still states the turbo is the more efficient unit)

Edit- Also read this or just skip ahead to the intercooler section http://www.turbomustangs.com/turbotech/main.htm

Quoted from this article ( http://www.autofieldguide.com/articles/050103.html )on why car manufacturer are looking at forced induction to increase efficiency "a supercharger has a few advantages over a turbo, says Streeter. "First, it doesn't soak up exhaust heat "

Those references contain only hand waving, generalisations and interviews with supercharger salesmen.

Do you have nothing more to offer? Like actual measurements of boost temps?

[FormulaLT1]

Originally Posted by KiwiBacon

Those references contain only hand waving, generalisations and interviews with supercharger salesmen.

Do you have nothing more to offer? Like actual measurements of boost temps?

Like I said do some research,,. I would also like to state that one of those links was made by a site aimed at Turbo enthusiasts and the other two talked about advantages of the turbo as well,. Do some research. You are obviously believing what you want to believe versus actual conditions based on common sense.

This thread is pretty much done. I expressed my thoughts (as well as others did) and posted up 3 links that back up my statement, anyone choosing to believe it or not , thats there choice.


Edit- Upon further thought, I am reopening this topic but anyone offering opposing view point and/or stating info is biased or incorrect. Please back up your statements with resources of technical nature to show you are not just choosing to believe what you want to believe. Instead of just requesting sources for others info and then belittling those sources,.

Also I would just like to point out I subscribe and read several different engineering publications. I traffic several different automotive tech sites. It would be damn near impossible for me to pin point and find at the drop of a hat any and all sources that I have read online as well as in paper form. However I don't form opinions at the drop of the hat, I base them on what I believe to be proven fact from knowledgeable sources on the topic.

[Alastor187]

Originally Posted by FormulaLT1

There is a google search bar listed right in this page. Do some searching,. I can start you off on the first link though, http://www.superchargersonline.com/content.asp?ID=19 (I am sure you are going to say that because it is a site based on superchargers it will be biased notice he still states the turbo is the more efficient unit)…

That first links says the following in regards to heat transfer:

Originally Posted by www.superchargersonline.com

Because the turbocharger is mounted to the exhaust manifold (which is very hot), turbocharger boost is subject to additional heating via the turbo's hot casing… A centrifugal supercharger on the other hand creates a cooler air discharge, so an intercooler is often not necessary at boost levels below 10psi. That said, some superchargers (especially roots-type superchargers) create hotter discharge temperatures, which also make an intecooler necessary even on fairly low-boost applications.

I believe the above is the point you are trying to make. That the compressor efficiency on the turbocharger is higher than that of a supercharger, however heat transfered from the turbine side of the unit creates additional temperature rise in the IAT.

This topic was brought up a while back in this thread:
http://www.automotiveforums.com/vbul...d.php?t=399086

I never did get a satisfactory answer on how heat is transferred from the ‘hot-side’ of the turbocharger to the ‘cold-side’. Nor have I heard of any effort to minimize the heat transfer. If it has such a negative impact on the turbocharger’s performance I would think it would possible to insulate the compressor from the exhaust heat.

[KiwiBacon]

Originally Posted by Alastor187

This topic was brought up a while back in this thread:
http://www.automotiveforums.com/vbul...d.php?t=399086

I never did get a satisfactory answer on how heat is transferred from the ‘hot-side’ of the turbocharger to the ‘cold-side’. Nor have I heard of any effort to minimize the heat transfer. If it has such a negative impact on the turbocharger’s performance I would think it would possible to insulate the compressor from the exhaust heat.

IME it's a myth with no basis.
The measurements I have taken show turbo outlet temps are not significantly hotter than the compressor alone (without being attached to a turbo) will produce.

The cold side of the turbo is connected to the hot side by:
- A steel shaft of maybe 8mm diameter (not a great conductor) which is bathed in oil.
- A housing which is cooled by large flows of engine oil at a temp of less than 100 deg C.
- A housing that is often cooled by large flows of engine coolant at a temp of less than 100 deg C.

A turbo running at 15psi has outlet temps around 100 deg C. That's a higher temp than the oil and water which are used for cooling.

So where is this large amount of heat-soak coming from again?

[Alastor]

Originally Posted by KiwiBacon

IME it's a myth with no basis.
The measurements I have taken show turbo outlet temps are not significantly hotter than the compressor alone (without being attached to a turbo) will produce.

The cold side of the turbo is connected to the hot side by:
- A steel shaft of maybe 8mm diameter (not a great conductor) which is bathed in oil.
- A housing which is cooled by large flows of engine oil at a temp of less than 100 deg C.
- A housing that is often cooled by large flows of engine coolant at a temp of less than 100 deg C.

A turbo running at 15psi has outlet temps around 100 deg C. That's a higher temp than the oil and water which are used for cooling.

So where is this large amount of heat-soak coming from again?

Those are interesting results.

Out of curiosity, what did you use to measures those temperatures and where in the flow were the measurements taken?

[KiwiBacon]

Originally Posted by Alastor

Those are interesting results.

Out of curiosity, what did you use to measures those temperatures and where in the flow were the measurements taken?

I used 3 wire temp sensors (can't recall the model right now) through a serial data logger to my laptop.

I had a sensor at the front corner of the engine bay, one protruding about 15mm into the piping about 150mm from the turbo exit and again about 400mm further down after the air-water intercooler.

[UncleBob]

the simple test for this is to run the engine hard, then jump out and put your hand on the compressor housing (not the exhaust housing)

You will find that its luke warm.

You could argue that this is because the air charge is taking all the heat away from the compressor housing, and putting it into the air charge, but this....theory....is ignoring the temp differential that would be present with such a situation.

As kiwi said, it looks good on paper, but doesn't hold any water in the real world.

[Black Lotus]

Originally Posted by UncleBob

the simple test for this is to run the engine hard, then jump out and put your hand on the compressor housing (not the exhaust housing)

You will find that its luke warm.

You could argue that this is because the air charge is taking all the heat away from the compressor housing, and putting it into the air charge, but this....theory....is ignoring the temp differential that would be present with such a situation.

That sounds about right.
I remember hopping out of one of my cars while it was idling after a run on the highway, and pointing a laser thermometer at the turbine and then at the compressor housing and got something like ~660F at the turbine and maybe ~120 at the compressor.
If anybody cares, I can check it again.........

[Schister66]

Originally Posted by 2.2 Straight six

you also come across as stuck-up and you're not in the least bit funny.

cool...and i care why?

[Schister66]

once you have a supercharged and a turbocharged car, then you can talk...i have a turbo GSR, it is a blast to drive. My buddy Ryan has a SC'd GSR...it is lame. I rode in it before i decided to turbo and it was slow as shit....therefore i went turbo.

On the other hand, my buddy Taylor has a Procharged Mustang and it is fast as hell....he ran an 11.8 w/ slicks and the SC...the rest of the car is stock. Superchargers have a place, but honestly i'd much rather turbo a car. Mine and Taylor's next project is a GT4088R 5.0L Mustang (fox body for those who care)

[FormulaLT1]

Lets all try to stay respectable guys.

Also to the topic at hand. It depends on alot of variables which is the better choice. Most important usually being cost followed by bay room but it also depends on supercharger model to turbo model. Obviously different supercharger with different pulleys are going to have different characteristics and same can be said of different turbo models.

We also have to look (like was pointed out, which engine is driving them). A 4 Cyc, V6 & V8 + will obviously produce different results on each. To each there own, we can all make recommendations on which we think best suits us and someone else but if power is the name of the game turbo will always be the way to go. If Ease of install (and in this case money) with added performance is your preference then a supercharger may work for you.

Each have there place and purpose but IMO they both meet the same need for different people and once driven the process of injecting that boost is identical (in centrifugal units that is)

[UncleBob]

I've seen a few articles where they take the same engine and mount different forced air systems and dyno them all at the same boost setting.

A SC (of any type) should be not terribly far off from a turbo at simular psi. The higher efficiency of a turbo, realistically, isn't a HUGE difference, not until you start getting into the really high boost numbers.

To me, its the mid range that really seperates them. Once the turbo spools, it will produce a lot more torque than either type of supercharger. The roots-style will be not too far behind, because of their linear application of boost, but the paxton/vortecs will be way below the mark, assuming the turbo is sized realistically.

The one article I'm thinking of, the paxton actually beat the turbo in peak power, but just barely, and only at redline. But the turbo made 100+ more ft/lb's in the mid range. When comparing the two graphs average HP, there was no comparison.

I can definitely see an advantage of having the paxton on a larger engine though. Sometimes, you don't want a huge hitting boost curve, because you already have traction issues as it is. A paxton is very linear and could probably keep the tires in check a lot better, but still have good peak power.

[Schister66]

the main reason i dont like superchargers is because they're not as easily upgradable as a turbo...i would have to either get a smaller pulley or replace the entire SC in order to make more power. With my turbo setup, all i need is a different turbo, different injectors and a retune...

Also, roots and Twinscrew SC's heatsoak which limits them....FMIC FTW

one of the main concerns/complaints people have w/ turbo cars is that the tend to lag...well if you properly size a turbo to an engine, it can have the same linnear powerband as a supercharger, but push a lot more air up top. When you start getting into higher HP turbo 4's you see some pretty large turbos (i.e. GT35R, GT40R, BW S300 series and so on)...at that point, you're going to have some lag, but lag isn't always bad.

My turbo lag is my traction!

[2.2 Straight six]

Originally Posted by Schister66

Also, roots and Twinscrew SC's heatsoak which limits them....FMIC FTW

you are aware that turbos heatsoak, right?

think about it, at full throttle exhaust gases leave the engine at ~1,000 deg C sometimes. the exhaust housing is fixed to the compressor housing, which soaks the heat and raises intake temps.