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why do turbos produce so much HP?

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Old 02-29-2012, 01:08 PM
  #31  
JIM5.0
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Originally Posted by Dylanjunk
it just occured to me that most mustangs that push over 1000hp use turbos. i cant think of any s/c stangs that are making that much, so why do turbos produce so much hp?
Speaking mechanically, the reason why turbos can yield more power over a supercharger is because the way they are coupled.

Supercharger are mechanically coupled (several before me already mentioned this). This means that you have to spend engine power to turn the supercharger unit. Also said before me, Ford engineers have estimated that the new 5.8L Trinity in the '13 GT500 wastes ~100 BHP to turn the supercharger on top of it, but the net gains of the supercharging outweigh the power loss.

Turbos are not mechanically coupled by hardware; they are coupled to the engine only by fluid forces of the exhaust acting on the turbine wheels.
This is the efficiency other above me are talking about, you do not waste crank power to turn it. Just the pumping power to push the exhaust gases against the turbine is required, which can be considerably less than the power required to turn a supercharger.

To be quite honest, the very high HP turbo setups use very massive lag-heavy turbos. They make a buttload of power and even torque at very high RPM, but are about useless at low RPMs, where it counts on the drag strip and on the street.
Such a set-up is really useful where racing is very much mostly where you are at high speeds where you never have to slow down to any kind of DD speeds.
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Old 02-29-2012, 02:08 PM
  #32  
essayons
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Originally Posted by JIM5.0
It is possible to counteract turbo lag without the use of such external devices added to the turbos.
Though more expensive and more complicated, compound turbos of different sizes in series or parallel do the trick.
For example, the F250+ 7.4L power strokes use a parallel turbo setup. One small turbo for off the line low power RPM, a larger turbo for higher RPM operations.

The same can be done with gasoline engines.
Like you said, though... more complicated, more expensive. BMWs problem (and anyone's problem, really) with the dual (or any multiple) turbo set up on the 335 was initially way too much heat from the compressors. The excessive heat was causing the turbos to burn out. And then there were fuel pump issues, as well, which were blamed on E10 usage.

The electric motor "primer" for the large turbo was the answer to the heat problems with multiple turbochargers.
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Old 02-29-2012, 03:53 PM
  #33  
Lil_Chef
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Originally Posted by JIM5.0
It is possible to counteract turbo lag without the use of such external devices added to the turbos.
Though more expensive and more complicated, compound turbos of different sizes in series or parallel do the trick.
For example, the F250+ 7.4L power strokes use a parallel turbo setup. One small turbo for off the line low power RPM, a larger turbo for higher RPM operations.

The same can be done with gasoline engines.
Porsche is rumored to be using three different sized twin scroll turbos for the 991 Turbo!
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Old 02-29-2012, 05:54 PM
  #34  
moosestang
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Originally Posted by Ditty
Turbos make more crank and wheel horse power b/c they produce more torque. You drive torque, you buy HP! lol.

Torque is the ability to do work. HP is how FAST you get that work done.

On the neverending debate of which is better, Turbos are more efficient and less troublesome that SC typically. That isn't to say that either can be trouble-less/troublesome. There is a reason that most factory-boosted vehicles are turboed. Effiency, gas mileage, and less prone to cause problems at lower power levels.

It all comes down to what you want for YOUR car. Instant, almost linear power (SC), or n/a cruising and mpgs with big power when YOU want it (turbo).
I'm a diesel fanatic, and I LOVE turbos! (It's also a LOT easier and cheaper to rebuild a turbo and/or upgrade the internals that it is to do the same to a SC.)
What is N/A cruising? The power to turn the supercharger pulley, while cruising, is negligible. I would wager that you would see no significant difference in mpg between a supercharger and turbo on this car. I still get 18mpg driving like a douche and I have 4.10 gears.

Turbos are cheap power, that's why the factory uses them.
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Old 02-29-2012, 06:03 PM
  #35  
moosestang
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Originally Posted by danzcool
Quite a few been done.
totally sick, and keeps me drooling.
http://youtu.be/HoHmaEqD7T8
He must have **** his paints on that last run!
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Old 03-01-2012, 08:43 PM
  #36  
LordRipberger
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Originally Posted by JIM5.0
Speaking mechanically, the reason why turbos can yield more power over a supercharger is because the way they are coupled.

Supercharger are mechanically coupled (several before me already mentioned this). This means that you have to spend engine power to turn the supercharger unit. Also said before me, Ford engineers have estimated that the new 5.8L Trinity in the '13 GT500 wastes ~100 BHP to turn the supercharger on top of it, but the net gains of the supercharging outweigh the power loss.

Turbos are not mechanically coupled by hardware; they are coupled to the engine only by fluid forces of the exhaust acting on the turbine wheels.
This is the efficiency other above me are talking about, you do not waste crank power to turn it. Just the pumping power to push the exhaust gases against the turbine is required, which can be considerably less than the power required to turn a supercharger.

To be quite honest, the very high HP turbo setups use very massive lag-heavy turbos. They make a buttload of power and even torque at very high RPM, but are about useless at low RPMs, where it counts on the drag strip and on the street.
Such a set-up is really useful where racing is very much mostly where you are at high speeds where you never have to slow down to any kind of DD speeds.
Would a turbo charger designed for higher RPMs (meaning not enough exhaust pressure coming out the back at 2000RPMs to gain the boost of the TC) cause back-pressure therefore reducing HP when the engine is not reved up.

I only know how TC are installed in theory. I have never actually done it, but if it is uses the pressure from the exhaust, wouldn't that mean that the exhaust ports (or wherever the turbo attaches too) would have to be partially blocked in order for it to force a turbine to spin?

Last edited by LordRipberger; 03-02-2012 at 09:56 AM.
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Old 03-02-2012, 12:50 AM
  #37  
siggyfreud
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Originally Posted by moosestang
What is N/A cruising? The power to turn the supercharger pulley, while cruising, is negligible. I would wager that you would see no significant difference in mpg between a supercharger and turbo on this car. I still get 18mpg driving like a douche and I have 4.10 gears.

Turbos are cheap power, that's why the factory uses them.
On more recent engines with boost bypass valves yeah. Some traditional designs don't have this, so you're stuck compressing regardless. But yes, on chargers such as the twin screw I have, you're probably only losing 1-2hp while not in boost.
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Old 03-02-2012, 10:56 AM
  #38  
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I have a centrifugal supercharger so it's basically a turbocharger that takes the place of a supercharger. I know centri's run a lot cooler than standard roots or twins scroll S/C, because they don't sit right on top of the motor. Also, they can produce more power, because IIRC they spin faster. BUT the downside is, I don't get boost at ~2k rpm, right at 3k is when I feel the boost. So I guess it basically feels like a couple turbos. Swap the pulley and it has the capacity to make 1000 hp. Of course, I would need a lot more than a stock 4.6L like I have now (running around 5lbs, ~350whp)

They are very quiet compared to roots or twin scroll. I can really only hear it when idling or up to 2k rpm, then beyond that it sounds all motor with a CAI. Sleeper is awesome. But the whine of a cobra is sick too. Depends what you want.

edit: here's a pic of the snail The cold air comes into the front, the rear is where the belt is located, driven by the crank. And there is a FMIC (front mount intercooler) = more powaaaaa

Last edited by Jas5; 03-02-2012 at 11:00 AM.
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Old 03-02-2012, 11:35 AM
  #39  
Mishri
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Originally Posted by Ditty
Turbos make more crank and wheel horse power b/c they produce more torque. You drive torque, you buy HP! lol.

Torque is the ability to do work. HP is how FAST you get that work done.

On the neverending debate of which is better, Turbos are more efficient and less troublesome that SC typically. That isn't to say that either can be trouble-less/troublesome. There is a reason that most factory-boosted vehicles are turboed. Effiency, gas mileage, and less prone to cause problems at lower power levels.

It all comes down to what you want for YOUR car. Instant, almost linear power (SC), or n/a cruising and mpgs with big power when YOU want it (turbo).
I'm a diesel fanatic, and I LOVE turbos! (It's also a LOT easier and cheaper to rebuild a turbo and/or upgrade the internals that it is to do the same to a SC.)
On the stock 3-valve engine turbo's tend to blow up engines at lower power levels than superchargers.. I'm not sure if it's how people are setting hem up or what the deal is but i've seen more issues reported from people with turbos than superchargers. It's rare that I hear someone with a stock engine and a turbo w/o any issues.

on the 5.0 so far all of the fastest 1/4 mile times on the stock engine are put up by the TVS supercharger. (in the 9's) Someone was trying to run twin turbos on a stock engine 5.0, blew it up before even getting close to 9s, it was running mid-high 10s.


so.. I can't really say why they are seeing these issues, too much heat? i don't know but unless you are building up your engine as far as i've seen turbos aren't a wise choice. Although on a forged engine they do great. Of the fastest 5 3-valve mustangs only 2 are turbo'd, running 8.4-8.9@147-164mph, and the fastest one was a single turbo, 8.4@164, 2nd was supercharged, using a procharger, 8.8@147.


btw, some of the new turbos can put out great power with very little lag. Ford could turbo or even twin turbo the GT500 if they wanted to, the Taurus SHO is turbocharged. There have been rumors of a factory twin turbo GT500. I'm betting cost and the number of people turning up the boost and blowing the engine might be a factor for why they haven't.

Last edited by Mishri; 03-02-2012 at 01:30 PM.
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Old 03-02-2012, 12:05 PM
  #40  
onederful100
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Originally Posted by moosestang
What is N/A cruising? The power to turn the supercharger pulley, while cruising, is negligible. I would wager that you would see no significant difference in mpg between a supercharger and turbo on this car. I still get 18mpg driving like a douche and I have 4.10 gears.

Turbos are cheap power, that's why the factory uses them.

great points, Moose.

i get about the same mpg's as my dads NA GT. average about 14 mpgs for both with a lot of city driving.
its a pretty accurate comparison since our driving areas are about the same.

turbo kits can be pretty cheap too.
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