DJTricky
Banned
hey 95twitt, where about im MN do you live? i would love to see your set up and maybe we could chat about how hard it would be get get me boosted. im right over in new hope.
i want boost...
- Thread starter DJTricky
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I agree. Everything you mention here is true. Perhaps a little out of context though. I think it would be fair to say, when there is back pressure on a turbo charger, but, at that same time, there is positive pressure coming in the intake, that all but neutralize that issue.
I think you would agree, it is not the same as back pressure on a N/A engine.
As far as heat goes, the higher the exhaust temperature, the faster the turbo will spin. The pressure and temperature drop across the turbine wheel, (expansion) provides the power to drive the compressor.
Bottom line: a turbocharger uses waste heat to produce boost, without consuming fuel to power the compressor.
You mentioned not having parasitic drag under vacuum. To me the concern would be, the parasitic drag, at full boost. The interesting thing to me is the Turbo requires a “waste gate” to stop the chain reaction. Otherwise the turbo would outrun the octane of the gas.
The only time exhaust restriction is an issue is in normally aspirated engines. In a N/A application, any obstruction in the air path, from air cleaner to tail pipe, is going to reduce efficiency.
I have two engines that are identical 383’s. Same heads, cam, cranks, rods, etc. The only difference between them is one is supercharged and the other is turbocharged.
They both for all practical purposes, put out the same power. The Camaro is 580 RWHP and the Tahoe is 575. The Camaro is running 15 psi boost and the Tahoe is at 12 PSI. One pound of boost, is worth about 50 hp.
In other words, if the Tahoe were running @ 15 psi boost, it would be 725 RWHP. So that would seem to be, roughly the amount of hp, the S/C is drawing.
Anyway, thanks for your input. This would be a good topic to discuss over a couple of beers.
Here are a couple of fun video’s for anyone that wants to learn more about forced induction, from the master Gale Banks……
http://www.youtube.com/watch?v=Z3iBKwcQ3Yc
http://www.youtube.com/watch?v=poCsdMrm998&NR=1
.
I will agree to disagree with you.
Using a turbo is like blowing on a pinwheel, you need a lot of air to get that thing moving, and your engine has to produce that air. Comparing an engine in a Camaro to an engine in a Tahoe would only work if you took both engines out and compared them on dynos. I would also ask what type of a dyno, as you would need to use a load bearing dyno to get real world numbers rather than an intertia dyno. Also, the type of supercharger you are using will make a big difference as well.
But like I stated, both are power makers, just depends on where you want the power. I will leave this thread alone now.
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I will agree to disagree with you.
Comparing an engine in a Camaro to an engine in a Tahoe would only work if you took both engines out and compared them on dynos. I would also ask what type of a dyno, as you would need to use a load bearing dyno to get real world numbers rather than an intertia dyno. Also, the type of supercharger you are using will make a big difference as well.
But like I stated, both are power makers, just depends on where you want the power. I will leave this thread alone now.
Why leave the thread alone? I'm assuming on PT, this has been discussed or debated to death...but here, we could all use the healthy debate!
BOSS
To anyone that is following this, sorry for the long post’s. I’m trying to keep it as brief as possible.
I understand the vehicles play a part in how much power gets to the wheels, but in this case, the Tahoe is at a disavantage, having to turn the 4L80e trans. Also the Camaro is a LT1, with reverse flow cooling, which gives it even more advantage with spark advance.
I’m not selling anything here, so I don’t have any thing to gain by being in favor of one over the other.
The Tahoe did have a supercharger on it. When I discovered the Banks system, I just had to try it, because I had bought a Banks Turbo for one of my company diesel trucks a few years earlier and it was very impressive.
I ordered up the Turbo’s from Banks and then while waiting for the system to arrive, I pulled the heads on the engine to make sure all was well. I found damage from the Nitrous and decided to rebuild it again. That is when the stock bottom engine became a 4 bolt, with forged crank and I also put a new set of heads on it. Oh, and we changed it to a roller cam and roller rockers. The only difference in the two engines other than the reverse flow coolant on the Z, is one has “D” dished pistons to get to the 8.5:1 compression and the Tahoe has “concave” dished pistons to reduce “hot edges”.
Both engines use Electromotive Tec 3 ECM’s with coil packs for each sparkplug.
Banks uses two turbo’s instead of one large one, to be able to spool up faster. The package was designed and tested by Banks, to attain 1050 hp on a small block chev engine. That is with 92 octane fuel and no after cooler.
When the package came together, I only had a “built” 4L60e trans, so we set up with waste gates, to keep the boost from going over 12 psi. The 4L60e did not last long, so now we have the 4L80e.
Gale Banks states that 1 lb of boost equals 7% more power. If we have 575 RWHP, the horsepower at the crank should be approximately 700. If we used the 7% per pound, it should be at 847 @ 15 pounds of boost. The system is capable of 20 psi as I found out one day by mistake. If it were at 20 psi, we would be at the designed 1050 hp.
I understand this is not scientific, but it all fits from several different angles. I know there are differences in superchargers too. The T Trim Vortech is a good quality S/C and had worked flawlessly. The cog belt eliminates belt slippage. I originally tried to find a roots type S/C, but none were available for the LT1.
Most people just assume that the exhaust is the one and only thing making a turbo spin. If you read reports from the tech people that are designing and perfecting Turbo’s, you find the issue of heat and expansion, being prominent.
For those that want to believe that the Turbo’s restrict the exhaust and therefore they would rather use a Supercharger, get used to seeing tail lights…..
My goal is to see if I can beat my Camaro at the strip with the Tahoe. I’m sure I will need to go all the way to 20 psi boost to get it done, but it is something to keep me amused.
Before I can take it up to 20 psi boost, I need to get another fuel line installed and switch to a 3 bar MAP sensor. It’s always something…..
I understand the vehicles play a part in how much power gets to the wheels, but in this case, the Tahoe is at a disavantage, having to turn the 4L80e trans. Also the Camaro is a LT1, with reverse flow cooling, which gives it even more advantage with spark advance.
I’m not selling anything here, so I don’t have any thing to gain by being in favor of one over the other.
The Tahoe did have a supercharger on it. When I discovered the Banks system, I just had to try it, because I had bought a Banks Turbo for one of my company diesel trucks a few years earlier and it was very impressive.
I ordered up the Turbo’s from Banks and then while waiting for the system to arrive, I pulled the heads on the engine to make sure all was well. I found damage from the Nitrous and decided to rebuild it again. That is when the stock bottom engine became a 4 bolt, with forged crank and I also put a new set of heads on it. Oh, and we changed it to a roller cam and roller rockers. The only difference in the two engines other than the reverse flow coolant on the Z, is one has “D” dished pistons to get to the 8.5:1 compression and the Tahoe has “concave” dished pistons to reduce “hot edges”.
Both engines use Electromotive Tec 3 ECM’s with coil packs for each sparkplug.
Banks uses two turbo’s instead of one large one, to be able to spool up faster. The package was designed and tested by Banks, to attain 1050 hp on a small block chev engine. That is with 92 octane fuel and no after cooler.
When the package came together, I only had a “built” 4L60e trans, so we set up with waste gates, to keep the boost from going over 12 psi. The 4L60e did not last long, so now we have the 4L80e.
Gale Banks states that 1 lb of boost equals 7% more power. If we have 575 RWHP, the horsepower at the crank should be approximately 700. If we used the 7% per pound, it should be at 847 @ 15 pounds of boost. The system is capable of 20 psi as I found out one day by mistake. If it were at 20 psi, we would be at the designed 1050 hp.
I understand this is not scientific, but it all fits from several different angles. I know there are differences in superchargers too. The T Trim Vortech is a good quality S/C and had worked flawlessly. The cog belt eliminates belt slippage. I originally tried to find a roots type S/C, but none were available for the LT1.
Most people just assume that the exhaust is the one and only thing making a turbo spin. If you read reports from the tech people that are designing and perfecting Turbo’s, you find the issue of heat and expansion, being prominent.
For those that want to believe that the Turbo’s restrict the exhaust and therefore they would rather use a Supercharger, get used to seeing tail lights…..
My goal is to see if I can beat my Camaro at the strip with the Tahoe. I’m sure I will need to go all the way to 20 psi boost to get it done, but it is something to keep me amused.
Before I can take it up to 20 psi boost, I need to get another fuel line installed and switch to a 3 bar MAP sensor. It’s always something…..
3-lot
Full Access Member
95twinTT, you hit er on the head in all your posts here, turbos do exactly what you are saying, thus no real power loss.
Turbos are becomming the normal now, and theres good reason behind it.
Turbos themselves are getting so advance that even lag is becomming a non issue.
Space really is the only factor to consider between both worlds of forced induction.
My opinion has and will always go to turbos.
Bravo, give your self a pat on the back, everyone else, all the non believers, you listen to whatever he has to tell you.
Turbos are becomming the normal now, and theres good reason behind it.
Turbos themselves are getting so advance that even lag is becomming a non issue.
Space really is the only factor to consider between both worlds of forced induction.
My opinion has and will always go to turbos.
Bravo, give your self a pat on the back, everyone else, all the non believers, you listen to whatever he has to tell you.
BlownChevy
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A turbo uses heat to create pressure? Granted, a turbo may be less parasitic than a supercharger, but they still take power to make power......but I have NEVER seen a turbo in a oven making boost.
Superchargers are making a come back, mark my words you will see more blowers on factory cars than turbos....hell look at Audi, they made a mint on turbo cars.....and now they are SUPERCHARGED.
Superchargers are making a come back, mark my words you will see more blowers on factory cars than turbos....hell look at Audi, they made a mint on turbo cars.....and now they are SUPERCHARGED.
Well, sir, if you want to get into the “future”, you need to consider what has recently been developed in diesels.
It is best described as, progressive combustion. Superchargers are not practical for diesels, because of their narrow range. Their RPM’s are limited by their gear boxes. Turbo’s can spin two to three times faster, allowing for the practical application of the newest technology in variable vanes and blade design.
Back to progressive combustion. Now that electronic fuel injection has found it way into diesel’s, they are able to use several bursts of fuel, during the combustion cycle, itself. Also keep in mind that diesel’s do not have a problem of over running their octane, like gasoline engines.
Between that and variable valve timing and boost as much as 60 psi in passenger cars, you could have a little four cylinder turbo charged engine, putting out 500 hp for performance and getting 40 miles per gallon when cruising. No ignition to worry about and clean exhaust.
I think you will find that the supercharged engines are satisfying the market for the moment, because they are cheaper and they are detuned for keeping warranty work to a minimum.
The only way you can deal with extreme boost from a supercharger, is to switch to alcohol for fuel. That’s great for the strip, but hard to travel around the country.
I’m not suggesting that everyone switch to turbo’s. Like I said before. I have both and like them both for different reasons. I think this discussion got going because of the issue of trying to figure out how much power a turbo robs from the engine, to drive it.
There is always going to be some back pressure in exhaust. Otherwise, it would not find it’s way to the tail pipe.
To learn more about turbo diesel’s, there is a link a few post’s back, from Banks Engineering that has some good info about the future.
It is best described as, progressive combustion. Superchargers are not practical for diesels, because of their narrow range. Their RPM’s are limited by their gear boxes. Turbo’s can spin two to three times faster, allowing for the practical application of the newest technology in variable vanes and blade design.
Back to progressive combustion. Now that electronic fuel injection has found it way into diesel’s, they are able to use several bursts of fuel, during the combustion cycle, itself. Also keep in mind that diesel’s do not have a problem of over running their octane, like gasoline engines.
Between that and variable valve timing and boost as much as 60 psi in passenger cars, you could have a little four cylinder turbo charged engine, putting out 500 hp for performance and getting 40 miles per gallon when cruising. No ignition to worry about and clean exhaust.
I think you will find that the supercharged engines are satisfying the market for the moment, because they are cheaper and they are detuned for keeping warranty work to a minimum.
The only way you can deal with extreme boost from a supercharger, is to switch to alcohol for fuel. That’s great for the strip, but hard to travel around the country.
I’m not suggesting that everyone switch to turbo’s. Like I said before. I have both and like them both for different reasons. I think this discussion got going because of the issue of trying to figure out how much power a turbo robs from the engine, to drive it.
There is always going to be some back pressure in exhaust. Otherwise, it would not find it’s way to the tail pipe.
To learn more about turbo diesel’s, there is a link a few post’s back, from Banks Engineering that has some good info about the future.
BlownChevy
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well, sir, if you want to get into the “future”, you need to consider what has recently been developed in diesels.
It is best described as, progressive combustion. Superchargers are not practical for diesels, because of their narrow range. Their rpm’s are limited by their gear boxes. Turbo’s can spin two to three times faster, allowing for the practical application of the newest technology in variable vanes and blade design.
Back to progressive combustion. Now that electronic fuel injection has found it way into diesel’s, they are able to use several bursts of fuel, during the combustion cycle, itself. Also keep in mind that diesel’s do not have a problem of over running their octane, like gasoline engines.
Between that and variable valve timing and boost as much as 60 psi in passenger cars, you could have a little four cylinder turbo charged engine, putting out 500 hp for performance and getting 40 miles per gallon when cruising. No ignition to worry about and clean exhaust.
I think you will find that the supercharged engines are satisfying the market for the moment, because they are cheaper and they are detuned for keeping warranty work to a minimum.
The only way you can deal with extreme boost from a supercharger, is to switch to alcohol for fuel. That’s great for the strip, but hard to travel around the country.
I’m not suggesting that everyone switch to turbo’s. Like i said before. I have both and like them both for different reasons. I think this discussion got going because of the issue of trying to figure out how much power a turbo robs from the engine, to drive it.
There is always going to be some back pressure in exhaust. Otherwise, it would not find it’s way to the tail pipe.
To learn more about turbo diesel’s, there is a link a few post’s back, from banks engineering that has some good info about the future.
lol......
