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I don't understand why so may people are saying that a turbo is best on the 2003 cobra for all out power " or on any car for that matter " , but a KB supercharger is best for a daily driver . I was to believe that 20 pounds of boost is 20 pounds of boost ... Why does it matter if it's supercharged or turbocharged boost ? Can the stock bottom end handle more boost from one to the other ? ... Just a fuzzy area for me ... I do understand for an all out race car a turbo as big as a dinner plate would make more power , but is there an advantage to a turbo on a stock motor ...
 

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it takes energy to spin a blower or turbo.

roots blowers are less eficcent (i.e. take more power to run) than tubos. This is the basis of all the arguements
 

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Boost is not boost

20lbs on a KB is going to make a hell of alot more power than 20psi on a stock blower. If boost was boost you could run 20psi on a stock blower and made just as much power as you could at 20psi on KB....see where im going with this??

Why? Its called efficiency of the power adder. Smaller blowers or turbo's will strive harder to create more boost thus making more heat which decreases HP, cause as we all know Heat kill's HP in power adders. That is why these guys run Ice boxes and get the blowers as cool as possible.

I believe a turbo is the best way to go. It takes power to drive a supercharger plain and simple. Turbo is free,there is no belts etc etc, yes there is lag but there is more gains to be hap IMOP. Look to all the Pro50 and outlaw classes and see what those cars are running. Yes some are running centrifugal style chargers but the big thing seems to be turbo's that are settin the records. Roots style blowers make more heat than turbo's this killing power. You will never be able to cool an intake charge past ambient temperature unless your running an water to air intercooler with an icebox, most turbo setups utilize an air-to air.

I have always been advocate of turbochargers, and as soon as I can afford one the stock blower is coming off my car and a nice turbo is going on. X2C is going in the right direction and they are only scratching the surface.
 

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I am not going to pretend that I am any kind of turbo expert because I am not. But I think that I understand the basics.

My Kenne Bell blower makes about 17-19 PSI of boost and is pump-gas safe (here in NJ, we got 93/94 at the corner pump). I have driven the car with this much boost for several thousand miles and there's not even a hint of detonation.

Part of the reason for this, I believe, is the boost temperature. With the stock intercooler (I have an aftermarket intercooler now but ran the stock one for a long time) the boost temperature is very low and this greatly helps prevent detonation.

With superchargers, the boost is made thorugh inlet air. It's always fresh air from the front of the car. With turbos, boost is made through exhaust gases recycled through the engine...as well as fresh air. We all know that exhaust gases are HOT!! If it's a hot day and inlet air is hot...then exhaust gases are that much HOTTER!!

Even with a good intercooler system for a turbo, the boost temperature is always going to tend to be hotter than boost with an efficient blower. And hotter boost means exponentially greater risk of detonation.

The Kenne Bell can run 17-20 bls of boost on pump gas all day long because it's well within it's efficient operating range at those boost levels. To make the same boost, the Eaton is over-spinning badly, which creates HEAT - blower heat as well as engine heat from the parasidic loss to turn an over-reving Eaton. Also, I would think that a turbo will also have the same inlet temperature issues.

I could be wrong and I guess we will see soon...as the turbo 03's materialize. But smart money says it ain't gonna be safe at 20 PSI of boost on pump gas!

There's also the fact that you probably only need 15-16 PSI of boost from the turbo to make the same power that the KB makes with 17-20 PSI because of the parasidic loss factor. I still don't think that a turbo will be safe on pump gas with 16 PSI of boost.
 

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Hammer,

I am going to be purchasing the KB very soon and I'm curious to where you got your aftermarket intercooler from. please let me know!!! Thanks
 

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Discussion Starter · #6 ·
Thanks everyone , I'm on track now ... not that I know which one I'm going to be getting but a little closer ... thanks again
 

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You really need to go to the book store and pick up the latest copy of Hot Rod magazine, they did a great dyno aritcle comparing the same engine equipped with a roots, centrifical, turbo, and naturally aspirated. It may shed some light on some of the claims being made.
 

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With turbos, boost is made through exhaust gases recycled through the engine...as well as fresh air. We all know that exhaust gases are HOT!! If it's a hot day and inlet air is hot...then exhaust gases are that much HOTTER!!
Correct me if im wrong here, ive been messin with turbo's my whole life and at NO point in the turbo system does exhaust air enter the intake tract. True, exhaust gasses spin the wheel. There are 2 wheels in a turbo, one is the exhaust wheel and the other is a compressor wheel. They are connected yes and there is 2 sides too a turbo as well.

The cold side which is the side the compressor is on has your fresh air inlet and the portion the compressor outlet is on.

I think it is very possible to run 16psi all day long on a turbo with this motor since this motor was built for boost as well. Sure your gonna need some tuning like with any combo.

I dont care which system you have for intercooling, you will never be able to cool beyond ambient temperatures with a heat exchanger like the 03's have and with future applications of using air to air intercoolers for turbo's. A real good air to air intercooler can get intake temps within 20-30 degrees of ambient temps in some cases better.

You can cool anything its just figuring out a way to do it, you could make the stock M112 efficient at 20psi if you could find a way to cool it.
 

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You can cool anything its just figuring out a way to do it, you could make the stock M112 efficient at 20psi if you could find a way to cool it.
I dont know about that There gets a point where the hp required to spin the blower/turbo is above the hp gained for spinning it that much more even with extreme cooling you will eventually hit it and there is always mechanical limits. If you spin it too fast you break it.

I dont see why we cant use our built in ic with maybe a bigger heat exchanger in an aftermarket turbo setup. Save alot of money on the kit this way too. Thats how x2c has their setup and its fine.

Personally Im not looking for every single ounce of power under my hood. Id be just fine with a kb. when you hit the 500+ range on a street car you will get to the point where more hp just means more wheel spin.

If i was a serious racer who wanted as much hp as possible then hell yes give me the turbo but I want less maintenence, with a less radical install to keep the car well mannered off boost, she is my daily driver after all.
 

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HAMMER said:
I am not going to pretend that I am any kind of turbo expert because I am not. But I think that I understand the basics.

My Kenne Bell blower makes about 17-19 PSI of boost and is pump-gas safe (here in NJ, we got 93/94 at the corner pump). I have driven the car with this much boost for several thousand miles and there's not even a hint of detonation.

Part of the reason for this, I believe, is the boost temperature. With the stock intercooler (I have an aftermarket intercooler now but ran the stock one for a long time) the boost temperature is very low and this greatly helps prevent detonation.

With superchargers, the boost is made thorugh inlet air. It's always fresh air from the front of the car. With turbos, boost is made through exhaust gases recycled through the engine...as well as fresh air. We all know that exhaust gases are HOT!! If it's a hot day and inlet air is hot...then exhaust gases are that much HOTTER!!

Even with a good intercooler system for a turbo, the boost temperature is always going to tend to be hotter than boost with an efficient blower. And hotter boost means exponentially greater risk of detonation.

The Kenne Bell can run 17-20 bls of boost on pump gas all day long because it's well within it's efficient operating range at those boost levels. To make the same boost, the Eaton is over-spinning badly, which creates HEAT - blower heat as well as engine heat from the parasidic loss to turn an over-reving Eaton. Also, I would think that a turbo will also have the same inlet temperature issues.

I could be wrong and I guess we will see soon...as the turbo 03's materialize. But smart money says it ain't gonna be safe at 20 PSI of boost on pump gas!

There's also the fact that you probably only need 15-16 PSI of boost from the turbo to make the same power that the KB makes with 17-20 PSI because of the parasidic loss factor. I still don't think that a turbo will be safe on pump gas with 16 PSI of boost.
A turbo also uses air from the intake. The exhaust gas is used to spin the turbine in the exhaust housing, that in turn spins the compressor wheel in the compressor housing via a shaft, that then compresses the intake air and sends it off to the intake manifold, hopefully through an IC.
The exhaust gas is to a turbo what the belt is to a s/c. The turbo requires less energy from the motor because the only energy required is normally produced anyway in the combustion process. No extra belt to spin.
As far as how much boost you can run on pump gas will be determined by several factors, including the size of the turbo, intercooling and your fuel system.
BTW, I'm new to the '03 Cobra's....I'm considering getting one. I've been dealing w/ turbo cars for over 13 years, including a 900hp Supra I sold last year. I'm definitely looking forward to the turbo options that become available to the '03 Cobra's in the near future.
Scott
 

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well buddy I gotta tell you nothing new touches the 03 cobra for the motors ability to take the hp.

I know quite a few 550 hp and 600 hp daily driver 03 snakes with a 100% stock with absolutely no exaggeration block and heads. People are running up to 800 hp with no engine mods. The internals are all forged and very beefy. whether you go turbo/nos/supercharger or any combo of power adder, its tops. Cars like the ls1 and ls6 motored vettes and cameros require extensive work to generate 500+ hp. At the very least some low comp pistons. I have yet to see a 500 hp daily driven vette thats not running any form of power adder (just had to add that incase a vette guy starts to flame) Daily driver in my book is a drive to work 5 days a week not a streetable racecar that isnt street legal.

Supras kick ass btw, too bad toyota stopped making em. Blame the suv boom of the 90's!!!
 

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I dont see why we cant use our built in ic with maybe a bigger heat exchanger in an aftermarket turbo setup. Save alot of money on the kit this way too. Thats how x2c has their setup and its fine.
Thats true. I know what you mean by daily driver. Mine is my only car and daily driver so Im with you. I like to extract HP to a certain degree but my car will never be a trailer queen.

Ar least X2C took alot guesswork out of the lower intake manifold and just made their own upper using the stock lower and intercooler as you mentioned. Air they using an additional air to air intercooler as well?

I think there could be some huge gains there.
 

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nope
its just the air to water. I have friends runnuing drag cars using a vortech aftercooler reservior full of ice and water and the stock heat exchanger

One guy putting down insane low 11 sec numbers with this setup and the stock eaton with a 2.80 and a 60 shot!!
 

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Makes me wanna spray so I can run 10's.

Mine went [email protected] this weekend with just the 2.80...im so happy.
 

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broke7 im me again, i forgot to add you to my list ;p

injun33r <--me
 

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broke7 is correct. One other note, comparing psi from one power adder to another is not a direct comparison in hp.

For intance, a KB at 20psi might make 600hp, but a 106mm turbo at 20psi might make 2000.

It all boils down to compressor efficiency and how much air they will move. At some point, they go past their peak efficiency, so upping the boost more only results in very small power gains.

Turbos will always make more power because they don't have the parasitic losses that a centifugal or roots type have. Not only do they make more power, but they make it sooner with a nice flat torque curve. I'm talking about power under the curve, not just peak power.

The roots type blowers also have a similar flat torque curve with the only real drawback being that they reach a ceiling for super high hp.

But comparing a centrifugal to a turbo, they have dramatically different torque curves. Centrifugal superchargers are rpm dependant and don't reach full boost until redline. A turbo on the other hand, if properly selected will make full boost at around 3k rpm. Where do you spend most of your daily driving time...at redline or 3k rpms?

Oh, and there are ways to get intake air temps down low. Ice'd liquid-to-air intercoolers can do it and there are also some new advances in air-to-air intercoolers on the horizon that will allow similar if not better charge air cooling.
 

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I think most of us with stock Eatons see full boost well below 3000 RPM, realizing that we're only talking 8 to 10 PSI. For the street, you clearly get good boost much earlier and quicker witht the Roots blower than with a turbo. There is no lag if the system is set up properly.


Remember, internal combustion engines are only about 15% efficient, with a large part of the waste going out the exhaust. That's why turbos are the best for ultimate HP and torque. But positive displacement suprerchargers are best for every day driving.
 

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I think it really boils down to personal preference for everyday driving. If a person wants to make a wise choice, ride in one of each.

I've owned many hot rods with every form of power adder and speaking from experience, I will never have anything but turbos in my personal daily drivers from now on. I know that probably sounds biased because I own a company dealing with turbo systems, but I made that personal choice before I started this company....then it was one of the reasons I decided to start it.

Again, it's all a matter of personal choice.
 
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