Shea

Ok, I have researched many different types of twin screw superchargers, centrifugal superchargers, and single and twin turbo setups.

Here are my conclusions: For myself, I am going to be keeping my stock internals in the engine (at least for now) which limits me to about 450HP. Any of these options will make 450HP.

I believe that the twin screw is the best for me because it makes torque right off the line and keeps it right up until the 450HP it hits at redline.

Turbo would be my best option if I were going over 450HP, because it keeps on pulling up till redline, even well over 450HP (let's say I was going for 600HP).

Who agrees? Disagrees?

If boost-limited to 450HP, will a twin screw beat a turbo in the 1/4 mile?

I know this thread is similar to one already going, but I want to know specific answers for a Kenne Bell vs. Saleen twin screws vs. any single turbo on the market. Any educated opinions?

phord

I think im kinda in the same boat. Im anxiously waitng for the whipple.

Mustangfreak

Supercharger - Kenne Bell
Turbo - Single turbo

dustindu4

Turbos make the best horsepower, but only at the high end. If you're only going to only keep your motor stock I would get a twin screw. Too many people are grenading with centrifugal Prochargers. If I were you I would be exploring a KB or Saleen. Now if you were going to build your motor up I would say to give the Granatelli turbo kit some serious consideration.

Machine

This is a topic of interest for me as well...

lodom

If I was going to purchase a power adder, I'd probably buy the Saleen. It is a proven kit that satisifes all your objectives and the HP/Torque graphs from other members with this setup are very impressive.

Shea

<div class='quotetop'>QUOTE(lodom @ February 24, 2006, 3:57 PM) Quoted post</div><div class='quotemain'>
If I was going to purchase a power adder, I'd probably buy the Saleen. It is a proven kit that satisifes all your objectives and the HP/Torque graphs from other members with this setup are very impressive.
[/b][/quote]

Although I agree with you, I have to wonder, because we haven't really seen much in the way of dynos from KB or turbo-equipped Stangs. I mean, I've seen a couple, but I'd like to see more before I make a decision.

dustindu4

If I were you though I would keep the rwhp at 400-425

JST4FN

I covered this in the turbo thread around here somewhere. It will all end up being personal choice. Since I have experiences with all of them maybe I can help.

For a street car and someone who likes alot of torque the twinscrew might be best. The reason I say that it might be best is a properly sized turbo can almost create the same torque curve. The two things I have disliked about the twinscrew on my Lightning is the lack of top end power and it's alot more finicky on tuning. Anytime you can get 16 psi at 2000 rpm's at any load you need to know how to tune it. Trust me when I say a dyno tune only will not work. Some of it will need to be done on the street. By the time you here it ping it's to late usually.

If you like a car that pulls to redline and is easier to tune, then I'd go with a centrifugal. You'll gain power down low so don't let people fool you with that. You just want have that instant burst of power. One thing you need to remember here is once you accelerate from a dead stop you'll be in the upper rpm's anyway and any advantage a twinscrew might have had is gone.

Now if you want the best of both worlds a properly sized turbo cannot be beat. It doesn't rob power off the crank and it doesn't side load the crank. To that you can add that it usually has a softer boost curve than a twinscrew. By that I mean it doesn't create a ton of boost real fast like the afore mentioned 16 psi at 2000 rpms. It'll creep up on it a little. This is hard to describe, but I hope I explained it good enough. Again a properly sized turbo will pull till redline like a centrifugal, which is a half turbo anyway. Then you add in all the extra horspower and torque and well it just can't be beat. The two downfalls is complexity (lots of tubing) and heat.

I hope that helps. It's just a quick run down. Oh and do not let a person tell you a certain brand will blow your motor. They ALL can cause damage if the proper maint. and tuning is not done. Knowledge is king.

Thanks Mike

Hatchman

This is a great topic that I am also thinking alot about.

I've got a Lightning as well, and love the instant torque for a big heavy truck with an automatic and don't plan on going much over 450 on the stock block.

For the Mustang, since it's a manual, I'm thinking of going turbo. Not a lot of stress on the engine at cruise speeds, and doesn't take a lot of horsepower to turn it all the time like a belt driven twin screw or roots. The heat can be cut down by ceramic coating all the tubing inside and out, and I have a local guy who does it really cheap, with a black ceramic coat that withstands 2000F. Seems you can get a single turbo system with 8psi of boost, get a little over 400 at the wheel, and be a pretty safe daily driver. After a built block, easily mod the turbo to put out 600+ and go out and really have some fun. Though you can do that with a twin screw by swapping out a pulley.

I don't know, I like the roots in the Lightging, but getting a Whipple one of these days, and thinking of going turbo in the Mustang to try something different.

Shea

I haven't done autocross, but that is the type of racing I plan on doing. What kind of RPMs do you usually run in that type of race?

I think the RPM range will probably dictate what type of forced induction I get...

Granatelli

<div class='quotetop'>QUOTE(Shea @ February 24, 2006, 7:48 AM) Quoted post</div><div class='quotemain'>


If boost-limited to 450HP, will a twin screw beat a turbo in the 1/4 mile?

I know this thread is similar to one already going, but I want to know specific answers for a Kenne Bell vs. Saleen twin screws vs. any single turbo on the market. Any educated opinions?
[/b][/quote]

#1 it will take less boost to make 450 with the turbo then the Twin Screw

#2 Since it takes less boost it creates less stress on the motor

#3 NO - IMO a twin Screw CAN'T beat a turbo in the quarter miles with all other things being equal.

I do agree a centrifugal pulls like a freight train after the first 75 or 90 feet but a turbo pulls everywhere.

Again it is my opinion but the only place a twin screw will shine is on a heavy Auto trans car

Shea

<div class='quotetop'>QUOTE(Granatelli @ February 26, 2006, 3:16 PM) Quoted post</div><div class='quotemain'>

#2 Since it takes less boost it creates less stress on the motor

[/b][/quote]

This is a big thing for me, I need a reliable engine.

Look for another PM from me. Also, with turbo is 91 octane high enough? Some places around here don't sell 93.

clockworks

<div class='quotetop'>QUOTE(Shea @ February 24, 2006, 9:48 AM) Quoted post</div><div class='quotemain'>Turbo would be my best option if I were going over 450HP, because it keeps on pulling up till redline, even well over 450HP (let's say I was going for 600HP).[/b][/quote]
That's kind of a misleading statement because it sort of implies that a twin screw *won't* do that...?

I've know of an 03 Cobra with a Whipple twin screw that makes 600 rwhp and the owner speculates the s/c will be good up to close to 800 rwhp.

I say twin screw. Low end torque is fun and it will give you more than enough room to grow...if your engine and traction can handle it. Install is a lot easier than turbo I think. I'm a 100% novice and I installed my Saleen Series VI with the help of a mechanically inclined buddy.

Granatelli

The turbo will make more power down low. For some reason a few of you think the turbo is bad becuase it will go over 450hp. But that is not the case. Just because you car will run 155 does not meen you need to drive it that way. If all you want is 450hp then leave the kit at 8psi and you can go 200,000 miles trouble free. [img]style_emoticons/<#EMO_DIR#>/icon_mrgreen.gif[/img]

sranger

It really depends on what you want....

If you want to road race, get the turbo....

If you want to run 1/8 mile get the twin screw... ( Instant torque )

If it is a street only car, it is probably more fun with a twinscrew as you can enjoy the extra torque without having to change gears or rev the heck out of it...

I have the Saleen, but would probably recomend the KB over the Saleen as it is a more complete kit... Both kits make about the same hp at the same PSI. The Saleen looks better in my opinion, but that is about it's only advantage. If you want a Saleen, I recomend a complete kit from JDM engineering....

TURBO 05

get a supercharger if you want your car to use 20% of its power to spin it or get a turbocharger if you want closer to 100% efficiency

clockworks

<div class='quotetop'>QUOTE(TURBO 05 @ March 5, 2006, 1:54 AM) Quoted post</div><div class='quotemain'>
get a supercharger if you want your car to use 20% of its power to spin it or get a turbocharger if you want closer to 100% efficiency
[/b][/quote]
Man ... as if that's the only factor in deciding whether to get a super or turbo charger. [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img]

I'd consider three things:
1) total cost
2) ease of installation and tuning
3) end horsepower goal

People, go to modularfords.com and browse around in the 05 section. It's a haven for people with Saleen Series VI superchargers...many of whom installed themselves. It's good to read some first hand knowledge and experience.

There are a lot of Saleen units that make 420-440 rwhp with 7-8 lbs of boost. So who really gives a crap if it's not 100% efficient... [img]style_emoticons/<#EMO_DIR#>/dunno.gif[/img]

TURBO 05

<div class='quotetop'>QUOTE(clockworks @ March 5, 2006, 11:04 AM) Quoted post</div><div class='quotemain'>
Man ... as if that's the only factor in deciding whether to get a super or turbo charger. [img]style_emoticons/<#EMO_DIR#>/rolleyes.gif[/img]

I'd consider three things:
1) total cost
2) ease of installation and tuning
3) end horsepower goal

People, go to modularfords.com and browse around in the 05 section. It's a haven for people with Saleen Series VI superchargers...many of whom installed themselves. It's good to read some first hand knowledge and experience.

There are a lot of Saleen units that make 420-440 rwhp with 7-8 lbs of boost. So who really gives a crap if it's not 100% efficient... [img]style_emoticons/<#EMO_DIR#>/dunno.gif[/img]
[/b][/quote]
hey i dont really care what YOU end up spending your money on, all i am saying is that what ever you get out of a supercharger you will get more out of an equil turbo, it just doesn't make sence to me that if you maybe set your goal to 450 hp you would want to run a SC at 11psi when you can just run a turbo at 7.5 lbs. It is just a safty factor to run less boost and get the same output. Price... well turbo' s cost more cause you are getting a new exhaust system w most kits and most also have intercoolers... if you compaire a SC with a turbo kit and add to the SC kit all the extra's you get with a turbo kit you willl find that they are very compairable in price, but not so much in performance.
To each thier own though so enjoy what ever choice you make and remember as long as you can smoke them Chevys its all good [img]style_emoticons/<#EMO_DIR#>/thumb.gif[/img]

TURBO 05

"Given equivalent vehicles, the turbo would easily motor away from the centrifugal in an acceleration contest......The turbo offered massive midrange torque production, the only system to exceed 600 lb-ft. Need more convincing? At 4,000 rpm, the turbo was more than 100 lb-ft. stronger than either the Roots or centrifugal." - Battle of the Boost, Hotrod Magazine, August 2003.

Turbocharging vs. Supercharging


Text Box: Screw-type Supercharger

Text Box: Centrifugal SuperchargerText Box: Turbocharger

Similarities

Turbochargers and superchargers are similar in that they both compress air to higher than atmospheric pressures. Normal or standard atmospheric pressure is about 14.7 psi (pounds per square inch or "psi"). The job of the compressor common to both turbochargers and superchargers is to increase air pressure so that more air is forced into the cylinders ("forced induction"). This increased air volume ("boost") is mixed with a proportionately increased fuel volume which, when burned in the combustion cycle, results in increased horsepower and torque production. However, this is where the similarities between the two types of systems ends.

Text Box: Roots Supercharger

Differences

Power Curves

Because they are belt driven from the engine crankshaft, centrifugal and roots superchargers build boost as rpm increases in a linear fashion. As engine rpm increases, the supercharger compressor speed (and boost level) increases to the point of peak boost occurring at peak engine rpm. For example, a centrifugal or roots supercharger designed to produce 8 psi at 6,000 rpm may produce as little as 2.5 lbs. of boost at 3,000 rpm. Screw-type superchargers are more like turbochargers in that they build boost much earlier than a centrifugal or roots-type, but they are also belt-driven. Turbochargers, on the other hand, are exhaust driven, and come up to speed very quickly (almost instantly if properly sized), and will reach the same 8 lb. peak boost level as low as 2,500 rpm. The result is much more horsepower and torque being produced earlier at lower rpm levels with a turbocharger vs a centrifugal or roots supercharger.

Efficiency

Just like the air conditioner compressor on a car, all superchargers, including centrifugal, roots and screw-type, require horsepower to turn them. This "parasitic" drag is always present, even when the car is being driven normally, and can rob 20%-30% of the power being produced by the engine. The result is a significant decrease in fuel economy and less net power produced. Turbochargers, however, are exhaust gas driven and don't require any horsepower to spin the compressor. When driven normally, a turbocharged car will not consume more fuel and, in fact, gas mileage can actually increase. Even when under full throttle, a turbocharger system will produce as much horsepower at 9 psi as a supercharger at 12 psi

.Turbocharged Power has turbos, turbochargers, turbo kits, turbocharging kits, turbo components and turbocharging components for your 1979 to 1996 Mustang, Mustang 5.0, Mustang GT and Mustang Cobra. More turbo kits and turbocharger kit applications for other vehicles coming soon!

Reliability

Both superchargers and turbochargers require high compressor rpm to compress the air. This ranges from 30,000-65,000 rpm in superchargers and can be even higher with turbos (over 100,000 rpm). In order to achieve the high rpm levels required to compress the air to the psi required, superchargers must have a step-up mechanism (gears, belts, pulleys or a combination thereof) consisting of numerous moving parts, to convert 6,000 engine rpm to the 40,000+ rpm necessary to build boost. Turbochargers need no step-up mechanism and have only one moving part, the compressor/turbine wheel assembly (see Figure 2). The simplicity of the turbocharger is therefore less prone to mechanical problems. Superchargers must have a belt to drive them, and belt slippage or breakage is a common problem. More serious problems include crankshaft, bearing and engine damage caused by belt tension forces on the crankshaft. Turbochargers have no belt and no direct mechanical connection to the crankshaft, thereby eliminating these problems. It is interesting to note that many automobiles and nearly all large over-the-road trucks use turbochargers that regularly log in excess of a million miles of reliable performance.



Maintenance

Some superchargers have a separate lubricating system that must be maintained, but turbochargers are lubricated by the engine oil and require no additional maintenance beyond what is normally required for a naturally aspirated car.

Streetability

Superchargers are always connected to the engine, they are always producing some level of boost and cannot be "turned off". Because turbochargers only produce boost when under load (as in full throttle acceleration), performance under normal driving conditions is no different than if the engine were naturally aspirated. Turbocharged cars exhibit excellent driveability characteristics.

Upgradability and Adjustability

Superchargers are generally not upgradeable. When higher performance is required beyond the capabilities of a specific supercharger system, the entire system must be replaced. Turbocharger systems, however, are usually upgradeable by simply upgrading or installing a larger turbocharger without requiring replacement of the entire system. Further, adjusting the boost levels on a supercharger requires removing and replacing pulleys, idlers and belts. Adjusting the boost levels on a turbocharger may be accomplished with a simple turn of a boost controller **** from the comfort of the inside of the car.

Value

At first glance, turbo systems may appear to cost more. However, if you consider everything that is included in a complete turbo kit that must be purchased in addition to the supercharger kit in order for the supercharger kit to be comparable (not even considering the performance differences), you may find the turbo system is less expensive and a much better horsepower per dollar value.

Conclusion

What does this all mean? Basically, an 8 psi turbo kit will produce more peak power due to the fact that a supercharger is using a fairly large amount of power just to get it spinning. What is more important for a street car is "power under the curve" meaning the average horsepower produced. This is where the turbo really shines since you can have full boost at as little as 2500 rpm! This will make the turbo car feel like it has 50% more cubic inches (or more). The difference in torque at low rpm's can be as much as 100 lb ft in favor of the turbo due to the additional available boost....now that's performance!