Royce,

Not at you. More later.......dont have time now.

Chris

Qoute{there is not one 700-800 hp street turbo system that i know. as a matter of fact the kits avalible are prertty sad.} Go look at racer walsh. they have turbo kits for up to 1,000 hp
Also check out www.turbomustangs.com
www.x2cmotorsports.com/
Those sites will kinda of show what turbo's can do
Heck that fastest trap speed for a street legal car at my local strip is held by a daily driven supra

Well i care about torque. i like the sound of a supercharger and i like the fact that the torque curve is alot flater means more torque anywhere any damn time. ok lets say we have a 350 with a superchrager and a 327 with a turbocharger in identical corvettes. i choose two different engines because they suit the equipment better ie, 350 have a broader torque curve and 327 have a steeper torque curve and rev a bit higher. ill use 3 examples of racing situations drag race, 50mph to 130mph and a cuicut track(no ones mentioned this one. the exact same thing is goin to happen in each of these cases in my opinion. although the drag race the supercharged 350 is going to be struggling for traction infact they both will be but because of the steep torque curve of the 327 it would possibly be easier to control but more foot pedal pressure. thats why in drag racing decent cars run slicks so they can keep the pedal to the metal. i think the 327 could have a chance and could actually win because of this reason and besides in a drag race you want to be pulling high revs over the finish line, that doesnt mean to say the 350 will get dusted though. i guess im not prooving much. ok 50-130 sprint lets say they were both in 2nd gear in a 4spd manual. basically it comes down to knowing how to drive your engine using the torque curve. the 350 will be able to shift through gears alot faster therefore gettin into 4th first should make a decent geta way before the 327 comes screaming up to it and maybe passes it. see this topic is really hard to judge like this and alot of people will disagree with me because i havent taken into consideration the max rpm of both engines. Maybe if i finished school and went to university i would be bothered getting into more detail.
to the cuircut race i still prefer to have a broader torque range because theres nothing stoping it from reving high in last gear anyways.
in conclusion i havent prooved much other than a 327 would suit a turbo and a 350 suits a supercharger to make the most of the engines natural torque cuves

it does make me wonder if both superchargers and turbocharger have strange things happen when under heavy braking. ? anyone have any info about trying to stop these cars with forced induction.

another thing i wonder is whats happening in the combustion chamber, obviously if you were to buy forced induction kits youd need a new cam to take full advantage especially for turbochargers because of all the exhaust restriction? anyone wanna help me out

Royce, I was aiming at the jokers that have no idea about the babble they are preaching. Naming, the "heat factory", coatings, and streetable power limits. All of which are trying to push supers to the top. Being a turbo guy I just cant let that happen.:

NIARB, I dont know what is wrong with you. The sound of a turbo spooling up is the sweetest sound in the world.

Rockn, any forced induction engine with the throttle blades between the compressor and the engine, needs some kind of blow off or you risk compressor damage. If I let off at high RPM with the turbo spooled, the BOV screams like a banshee.

I will also address the arguement for torque curves and lower torque numbers in the low RPM due to turbo spool time. These things both used to be a problem and used to be valid arugements for the supercharger. However, modern electronics have fixed all of this and it is no longer an issue with a good engine controller. Most high end engine controllers now have an ALS(anti lag system) built in to the programming that can be set up for drag race or circle track us depending on how it needs to work.

Circle track is a little different than drag racing, but the idea is the same. In drag racing, ALS can be activated while the car is stage to begin to generate boost before the car leaves. What happens is the engine controller will retard the timing and drop fire to a certain number of cylinders in a certain sequence. This causes combustion in the headers, extreme exhaust heat and pressure, and bingo.....BOOST. As soon as throttle position changes everything is back to normal and you launch an engine at close to full boost to negate the ill effects of lag.....neat trick, huh. I will add that thick wall stainless headers and coated parts are absolutely needed. I have not got my truck to the track yet, but I have found that it makes boost instantly anyway. Lag is a split second for me so I dont have plans for ALS right now.

I saw another comment about supercharged cars having more torque curve total area or something like that. Just want to say that is not right. Turbo engines will always make more area due to many factors we have already discussed. HRM did a test a while back that proved this. They compared all compressor types with the already expected results. You can argue about the validity of their test, but I have not seen anyone else do a back to back. Some might say the roots was too small, which it was...and so was the turbo. Results remain the same. If I remember right, the turbo had the most torque and the cent. had the highest HP peak, but I could be wrong. It was an interesting read if you can find the article somewhere. Here is the cover, but I could not find the article: http://www.hotrod.com/toc/113_0308_toc/index.html

With all the electronics and technology available today, turbos are just at the top in my book. All of the old issues have been solved, and turbos are coming back with a vengence in racing. Every class where they are run, they dominate....it is just facts. But, I am a turbo junky, so you dont have to agree.

1 A super charger has a quicker response than a turbo because itis driven off the crank.A turbo has to come up on boost
2 a super charger will take power from your engine to run it because of the extra belt,s and pulley,s where a turbo dosent as it is driven of waste exhaust gases (free power no belt)
3 If set a power or torque figure and had to identical engines the amount of space the super charger takes up compared to a turbo set up,Turbos must be good because most engines have turbos on them and not super chargers

someone on here had real player with a car with twin turbos on it and when it was on the dyno it smoked the rollers when it came up on boost now that is going some todo that?
anyway see ya
stuart

okay i went to that site. which STREET turbo makes 800hp now?

yes every town has thier supra urban legend. we have one too here.80k+ invested in turbo work alone.

I am surprised that the original aticle didn't factor in the losses associated with the lack of tuned exhaust as the gases leave the exhaust port with the turbo. They simply attempted to state the losses of driving a roots blower. Overlooking those losses is misleading.

Something to consider?

Everybody knows roots blowers are inefficient and don't make big power on the big end, so I can set that aside.

To set the grounds of common sense I'm going to go ahead and restate the obvious for a moment.
Cent. SC's are mechanically crank driven, just like every other accessory on your car. If you want 70,000 rpms (someone said this was their peak before) out of your SC to hit peak boost you need to turn your engine at high rpm. There is basically a one-gear transmission inside of that supercharger. If your peak boost is 10psi at 70,000 rpms, and you shift out your small block at 7,000 engine rpms, you have a ratio of 10 supercharger rpms to 1 engine rpm. You cannot get 70,000 rpms without going 7,000 engine rpms unless you change this ratio. And if you do, you still can't go over 70,000 rpms on that supercharger or "bad things happen" as apparently stated by Procharger, which means less rpms on the engine, so you can no longer shift out at 7K.

With a turbo on a small block achieving 10psi will typically happen between 2300 and 2800 rpms. You can still shift out at 7,000 rpms, the wastegate will maintain 10psi of boost from the point it's reached all the way up.

At 2300 rpms our procharger is turning 23,000 rpms making maybe 2 or 3 psi, with a parasitic loss somewhere in the ballpark of 10%.
at 2300 rpms our turbochrgr is turning 70,000 rpms making the desired 10 psi with a parasitic loss somewhere in the ballpark of 3%

I would like to know which vehicle you guys think is making the higher horsepower figure here?

Does it matter if you can make the same peak horsepower number with a supercharger as you can with a turbocharger?
The common sense answer is simply no. Not only is this most likely impossible to achieve in the first place, peak numbers mean SQUAT.
Why do they mean SQUAT? Again I will present the reader with the obvious..

You don't race down the track at 7,000 rpm the whole time, so your SC's developed boost is always going 1..2..3..4..5..6..7..8..9..10..shift... ...7..8..9..10.. shift. Etc. Etc.
The turbo will reach 10psi, and stay at 10psi untill the race is over.

Even in the unlikely event that a supercharger could match a turbo for peak horsepower the average horsepower along the power band will always leave the supercharger lagging behind.

Extra bonus goodies for the first billion readers!!!!!!;

In high altitude thin air turbochargers actually become more efficient, not quite at the rate the lower ambient air pressures decrease power, however, they will almost completely eliminate power losses due to pressure drops in ambient air.
Because of the mechanical linkage the SC will continue to spin a peak 70,000 rpms at 7,000 engine rpms nomatter how thick or thin the ambient air pressure is. And therefore recieves the same power losses in high altitude low pressure areas that naturally aspirated cars see.

When cruising down the highway, lets say at 2,300 rpms. Not under load, the turbocharger does not cause any mentionable parasitic losses.
The SC however is still mechanically connected, so at 2,300 rpm, wide open throttle or not, it is still generating it's standard 10% power loss, and happily whistling away your fuel mileage.

And last but certainly not least, when the girlfriend or significant other needs to "borrow" the car, the turbo can literally be turned off as easily as flicking a switch. Whereas turning off your SC requires removing the drive belt. This results in a higher probability of the action being noticed by said partner. Inevitably leading to questions of trust that have no right answer, and will require the proper application of copious amounts of flowers, dinners, and creative thinking in order to resolve. And thussly furthering the evidence that turbochargers are less expensive than superchargers.

Thank you,
~S

WOW!!! you dug this thread up from the dead. You had a lot to say even though you really didn't know "what" you were saying.

While it is true roots blowers are not the most efficient at upper RPM's if you build the car and gear accordingly you can easily keep the RPM down. Torque is what gets the car moving. When it comes to top speeds or road racing a turbo or a centrif. has the advantage hands down, but with drag racing the advantage is not as you tried to make it. There is ZERO belt slippage with a roots blower (cogged belt), there for once you drop the hammer it's all about toque and power. I rev mine to about 6800-7000 tops (no need to even rev it that high typically). The size of the roots blower makes a difference too, you failed to mention or don't understand that. If you run a larger blower you can make more boost while not having to spin it as fast, this reduces the heat in the intake charge, this equals more efficientcy.

As far as centrif. superchargers, there are different pulley ratios to get your boost in the range and rpm you want it. With that you choose gears and stall speed to keep you in your power band. Just in case you didn't know, there are things called pop off valves that work much like a waste gate. This means you CAN keep your boost at a certain level if you desire with a supercharger.

Anybody that knows anything about drag racing or performance will tell you it's all about the package/combination. If you put your turbo engine in my car set up for a roots blower, it would not perform well and the same can be said for the other way around.

From the way you wrote that up I would have to assume you have a turbo charged Honda Civic or something along those lines. If you try to be more respectful people will take you more serious.

Have a good one.

Royce

No I do not own a honda. The thread got into alot of uncessarly complications that aren't required to answer the question at hand. So therefore, I say, look at the obvious, I will spell it out, there is no need to dig into the marginal and perepherial attributes of each. There are only a few major behavioral differences between the two power adders. And these very blatant and key differences are all that is necessary to determine which is superior in sheer power provided. I think I even threw in a little bit of jovial joking in there didn't I? If anybody feels belittled, offended, or insulted I apologize, it was not my intention.

I'm sorry, I said something about roots not making power at the big end in the beginning of my post. I did not mean for this to restrict my comments to dragstrip applications. I am not badmouthing a roots blower, but the conversation seemed to be geared towards.. "Who makes the most power", roots don't do this. So I merely aknowleged their existance and moved on.

Now, the most power does not mean the fastest car down the 1/4. I do understand this, as do you I'm sure. If I were to build a drag car, I would use a very big roots blower on a very big block rather than a turbo. Personally I would never run a cogged belt. I like it to slip, because when the motor coughs, the belt slips and the intake doesn't go kablooe.

This is the only application in where I think it's the better choice however.

But since the question is 'best at making power', not 'best at ET' I was merely passing over the roots.

Seeing how this is a conversation of most power, we can know that we're talking about big bad superchargers pushed to their limits, vs. big bad turbochargers pushed to their limits.
Now keep in mind the parameters in which I am speaking. I am scaling everything down so it's nice and clear. My example Procharger makes 10psi at 70,000 rpms blowing into "some smallblock", the maximum rpm for this "made up out of my head" unit. Therefore you cannot "up the boost". You cannot re-pully this supercharger to make 10psi at 5,000 engine rpms and just use a pop off valve to hold 10psi as the engine rpms climb. If you do this, you will exceed the maximum 70,000 "procharger" rpm limit and grenade the sucker.
If this were capable of 30psi, and you only wanted 10psi, then yes, you can gear the supercharger and car as you described.
My scaled down turbo also has a peak output of 10psi at 70,000 rpms. Again, you cannot "up the boost". However, because it is not linked to engine rpm, I can hit 70,000 rpms with my turbo as soon as possible, and then with the wastegate, maintain that turbo rpm even as my engine rpms increase. This is the point that is coming across here.
Understanding this basic difference alone between the two, makes it very clear. The turbodriven engine will have more power at a lower engine rpm because of the greater CFM coming from the turbo at a lower engine rpm. This means it will accelerate into higher rpms at a greater rate (just as it would accelerate the car ofcourse), and therefore make even more power in less time.
The icing on the cake is the greater efficiency, better fuel economy, inexpensive cost, ready availability in salvage yards due to the overwhelmingly higher production of factory turbocharged vehicles over supercharged ones.
The list goes on and on.

Take care,
~S

I see the point you are "trying" to make, but you still are not comaparing apples to apples. You have a few thoughts that are not correct. First a cogged belt does not pose a danger and long as you have a place for excess pressure to go. I have a pop off valve on the back of my roots manifold for this purpose and if for some extreme reason that failed I have blower studs designed to let go if there is an explosion.

No other forced induction makes the low end power of a roots supercharger. The boost is instant and ready from idle on up. This is not true of a turbo or a non cogged belt supercharger.

Now in your example you said a given supercharger would not make X amount of boost because it is RPM limited. Well you just picked the wrong blower, you should have gotten a larger unit then you wouldn't have to spin it as fast to make the same boost. You acted as if there is only one size procharger (or other centrif. available). That same theory would apply to a turbo that is too small. Turbo have RPM limits as well. You can't take a turbo off a Saab and put it on a big block and expect it to make 10lbs of boost, it will NOT happen. You won't be able to spin it fast enough to move enough air. Just like there are different size turbos there are also different sized blowers/superchargers.

I am not sure if you read through this whole post before you chimed in? If you did you will see in my first post (and the second) that I covered most of this. The original post was not which makes more power, it was which is "best". They all have their advantages and disadvantages, one is not "better" than another. You have to pick the one that will meet your needs/goal and combination.

They all have limitations.

Royce

Whit my T/A, Running on the road whit my Procharger F1 at 60 / 2000rpm
hit the floor and i do an instant burnout for several feet long whit big street tire 255/50/16!!

I have seen turbo car at the track, from the start line they need to rev Up the engine so HI just to be able to spool the turbo to have some power at start ! I start at 1000rpm whit an autom-trans & got instant power whit my supercharger ! I dont like the way a turbo restrict the exhaust as well & Heat ! No matter coated or not, they do more heat & heat the air that goes trough the turbo a lot more than supercharger.

Still Love My F-1

I think maybe you missed my point about scaling things down.

I do not disagree with you about roots making the power down low. Like I said before, I am passing the roots supercharger over, it is not one of the two elements that I am comparing and contrasting. So when I say more boost down low out of a turbo, it is in comparison to the only other thing I am talking about, and that is the centrifugal supercharger.

The #'s don't matter. You can get bigger and bigger superchargers or turbochargers or even roots blowers to a point, but somewhere someone makes the biggest there is, and you cannot go bigger. Or, more realisitically, bigger for the application simply has diminishing returns. Putting the big top fuel roots blower that takes 600hp to turn on a civic 4 banger is an extreme example of diminishing returns by going bigger, you won't be able to turn the thing enough to use it let alone get any gains. Bigger does not mean better.

I am talking about a small block. You are only going to go so big. If you prefer I can say 50psi and you can't go to 60 instead of 10psi and you can't go to 20. But it doesn't matter. The principles hold the same. Boost is a byproduct of CFM, and CFM is directly related to RPM for any one given compressor wheel and housing. The RPM of the biggest centrifugal supercharger matched to an engine for maximum power that is being worked to the max is going to hit peak rpm at peak engine rpm. Because they are mechanically linked. Therefore, the supercharger has to wait for the engine to get up to speed before it puts out maximum cfm. Only then do you see maximum power, and now it's time to shift and lose it.
The turbocharger doesn't care what the engine rpm is, it only cares how much it's driven by that engine's exhaust. A turbo matched to an engine for maximum power will reach maximum rpm before the engine reaches it's maximum rpm. So you get more power, earlier, and when you shift, you don't lose it.

I think it's reasonable to say that a turbocharger is better than a _centrifugal_ supercharger. Being that they are basically the same thing, but one is clearly more effective than the other.

Not comparing apples to apples is comparing a turbo to a roots, they are completely different beasts. Which is why I keep trying to get away from that comparison.

Just as a side note here about comparing apples with apples...

Each of the set-up can make more than the other with NOS, and we often see numbers but don't realise that there is NOS behind it...I've seen turbo's with 1500hp's with NOS and Blower's without making 1200hp's also...the inverse is also seen so you have to make sure all the details are known and all the specs before making a judgment call. I've seen to many guys shouting their prowess with their turbo's and NOS systems...just because they made better Hp's than a Carbed Supercharged engine without...See my point...

Also, from my experience, guys that are willing to "tube-in" a turbo are those that aren't going to leave the internal's alone also...hence, they will always make more power because he apples aren't compared to apples...

Everything is relative, and everything always has its wins and losses, on both sides.

Now for my personnal opinion, I am a Blower guy just for the fact that I hate the turbo's response, and I like the blower one a lot better. But Putting a Turbo on something is cheap when you know how to shop for used parts...

Yannick

Yes turbochargers do not like to spool up on the line. When you are sitting still and holding 1000 rpms, you're barely opening the throttle at all beyond idle. This means there is barely more air going through the engine than at idle. And because the turbos are driven by the air that passes through the engine, if that air isn't increased, the turbos aren't going to respond. The only way to get them going without fancy exhaust combustion is to open that throttle up and let the air scream through. Not something I like to do.

Your supercharger doesn't care if you're moving or standing still, it'll spin x fast based on your engine rpm. This really does make them great for short distance sprinting, because a very small gain at the start equates to a large gain at the end. The shorter the sprint, the larger the relative gain at the end.
If there was a 5 mile sprint league, you wouldn't see a single successful competetor with a roots blower, and the centrifugally supercharged guys would have a hell of a time trying to keep up with the turbo guys. Especially in top gear when engine rpm is not at peak and doesn't climb quickly.