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View Full Version : Turbo chargers vs. superchargers.....



sportsrumor
01-29-2005, 12:36 AM
When my car finally is out of warranty, and if I consider to make a good living, I'd love put a turbo or supercharger on my G35. I know that superchargers are superior in one sense---there is no lag.

But having driven a turbo-charged car in the past (Okay, it was my Mom's Volvo wagon) I just loved the sound of the turbo winding up and feeling the boost come one.

Are superchargers always the first choice or are turbos a decent alternative? A turbo-charged G35 would sound SWEET. A little lag and then BAM. Does know if there is a clear cut choice here or it a matter of preference?

Riffster
01-29-2005, 12:59 AM
I have had several discussions with my tuner about this and he favors superchargers for the G, and not just because of the lag issue. He feels that maintenance and upkeep with an SC is a bit less overall. He isn't against turbos at all - just that they take more care in the install and maintenance (although superchargers need their own careful tuning and maintenance too.) Turbos should also turn out to be a bit more expensive as well.

This doesn't mean don't install a turbo - just be aware that you're getting into what can be a long and costly process. Also, the turbo install is just the beginning really. If you're serious you will be doing a lot more with strengthening internals, instrumentation, etc., SC's need a lot of the same stuff, but usually not quite as much.

But if you love the turbo sound, go for it - just go into the experience aware of the costs.

- Riff

sportsrumor
01-29-2005, 01:08 AM
I've got an automatic tranny. I would have to be very careful about getting all of that power to the wheels. I'm sure that a turbo and intercooler would 100 plus horsepower..

Notwithstanding, automatic transmissions can function well with turbos, in my experience. For some reason, it seems that it's easier to keep the boost up with an auto. (If you keep the accelerator mashed). I believe, but am not sure, that boost drops a little more easily between manual shifts but I'm not quite sure that that makes sense.

Riffster
01-29-2005, 01:47 AM
The G uses the same automatic tranny as the Q45, which is 340HP, 330 TQ. From what I have heard the G's auto tranny will have its' life significantly shortened if you exceed 400HP at the crank. At that time you need to open up the pocketbook some more and get a race-strength AT like Level 10 or SGP Racing's version.

- Riff

AVS007
01-29-2005, 02:20 AM
I have had several discussions with my tuner about this and he favors superchargers for the G, and not just because of the lag issue. He feels that maintenance and upkeep with an SC is a bit less overall.



I'd tend to agree. I have a factory blower on my GTP, and the only maintenence you really need to do is replace the supercharger oil every 30,000 miles and make sure the pulley and tensioner are in good condition. I've since put 115,000 miles on that thing without any issues.

sportsrumor
01-29-2005, 02:26 AM
115,000 miles on a G35 with a supercharger is quite impressive. I'd expect to have numerous problems keeping it running well. I'm sure that you drive it hard, too. This definitely gives me something to think about.

How much horsepower are you pushing?

D_Nyholm
01-29-2005, 08:59 AM
Personally, I would favor a supercharger for its ease, but a Turbo tends to put out WAY more torque at lower rpms than a supercharger. It all depends on what you are looking for. IF you track your car, a turbo may be a bad idea. Think about a long straight with a sharp hairpin at the end. You are braking, all the while loosing boost. You get through the turn and mash the throttle. The boost builds QUICKLY and rips the rear tires free. Then you are looking at the inside wall with the rear tires spinning in the dirt. Not what I would call fun. Superchargers are more linear and there is no BAM like you called it, which can be a good thing.

Also, think about a Supra TT. All these guys put MONSTER turbo's on them and they become dyno queens putting out 700 hp to the rear wheels. Bring them to the track and it takes them 1/8 mile to spool. The little guy in the Honda civic that runs 13's blows you away for the first 1/8 mile and then you come charging by at the end finishing it off at 12.0 @ 130+ mph!! 130+ mph should be good for about a 10 second run in a N/A or supercharged car. But hey, you had to wait to spool. In essence, your car really isn't as fast as it should be! Of course, this is with BIG turbo's and cars with very low compression. On our cars with standard compression and only about 6 lbs of boost, you probably won't see it as much if any. Lag is ALWAYS there though.... http://forums.freshalloy.com/images/graemlins/frown.gif

G35BSCOUPE
01-29-2005, 09:08 AM
115,000 miles on a G35 with a supercharger is quite impressive. I'd expect to have numerous problems keeping it running well. I'm sure that you drive it hard, too. This definitely gives me something to think about.

How much horsepower are you pushing?



I get from his post that it isn't a G35 that he has the 115,000 miles on, it is a Pontiac Grand Prix GTP. He said it was a factory supercharger.

XFITINIP
01-29-2005, 09:57 AM
Stillen & DreamWorks Style vs. HKS, ATI, or Vortec Style S/C's? - The Only choices in S/C, right?

SirVinCigars
02-19-2005, 02:29 PM
I researched various superchargers prior to having a Vortech s/c with intercooler installed. I have loved evry second of it and the whine /whistle is something you either love or hate. Personally I love it. After a month or so though the urge came back and i added an injen dual exhaust and a 50 shot nitrous Zex kit. Now it really screams.
Good Luck

Eagle1
02-19-2005, 03:50 PM
Stillen & DreamWorks Style vs. HKS, ATI, or Vortec Style S/C's? - The Only choices in S/C, right?



To my knowledge there is no DreamWorks unit, and not likely to be one.
There are three basic "types" of supercharger. The Roots or Eaton blower, which is a positive displacement type, is one of them, and the type that Stillen sells. It produces boost at much lower rpm levels, but by 3200rpm or so it is all done, and actually drops off a bit in hp and torque as you go up the rpm scale. Thus it is going to be a pretty good machine for the street, or even drag, but not the best for the track where you are keeping your car up in the rpms for power, such as 5500-5800 rpms in our car.

A second type is the centrifugal type, such as ATI and Vortech. This really is quite comparable to a turbo, but is belt driven. It is "lazy" in that it really does not start to come on with power until 3000 rpm or so, but it peaks out in the 5800-6200 rpm range, and that is good for track.

The third type is the Lysholm or Kenne Bell type. It is a mated twin screw blower, hard and expensive to manufacture, but it brings power on down low like a Roots, and yet keeps pulling through the higher levels too, so it is a superior alternative (in my view) to both of the above. But since they are expensive to make they are typically limited to racing applications, you will have to hunt one down and have an engine builder do a custom application, fuel system delivery etc. It would be the way to go if you had the money and were going to be serious about performance.

All blowers have a disadvantage, in that they suffer the parasitic loss of power from driving the belt and pulley system. And thus they are noisy, have reduced gas mileage and less overall top power output than comparable turbos.

All turbos have a disadvantage of slight or serious lag and spool up needs, complexity in plumbing and significant heat build up and heat dissipation needs. But they give great power for "free" off exhaust gases, are more quiet and get better mileage. There are different configurations in turbo installations, like one versus twins, sometimes tandems too.

I like both approaches, but one is not superior to the other in all applications. If there were, we would not have both to choose from.

Just do lots of reading, books from Corky Bell are helpful if simple introductions on FI, hit the threads you find and read those, and ride with some folks that have units you are intersted in.

ZeroGen
02-19-2005, 04:21 PM
A chart that helps break down the differences between Turbos and S/C:

http://www.coloradocobras.com/whipple/superchargers/supercharger-comparison-chart.html

C-Kwik
02-19-2005, 06:18 PM
Personally, I would favor a supercharger for its ease, but a Turbo tends to put out WAY more torque at lower rpms than a supercharger. It all depends on what you are looking for. IF you track your car, a turbo may be a bad idea. Think about a long straight with a sharp hairpin at the end. You are braking, all the while loosing boost. You get through the turn and mash the throttle. The boost builds QUICKLY and rips the rear tires free. Then you are looking at the inside wall with the rear tires spinning in the dirt. Not what I would call fun. Superchargers are more linear and there is no BAM like you called it, which can be a good thing.

Also, think about a Supra TT. All these guys put MONSTER turbo's on them and they become dyno queens putting out 700 hp to the rear wheels. Bring them to the track and it takes them 1/8 mile to spool. The little guy in the Honda civic that runs 13's blows you away for the first 1/8 mile and then you come charging by at the end finishing it off at 12.0 @ 130+ mph!! 130+ mph should be good for about a 10 second run in a N/A or supercharged car. But hey, you had to wait to spool. In essence, your car really isn't as fast as it should be! Of course, this is with BIG turbo's and cars with very low compression. On our cars with standard compression and only about 6 lbs of boost, you probably won't see it as much if any. Lag is ALWAYS there though.... http://forums.freshalloy.com/images/graemlins/frown.gif



If you are tracking a car and "mashing" the throttle coming out of the turn, you can't blame the turbo for losing control. The throttle still dictaes the airflow through the motor and the turbo itself is much more sensetive to throttle application since it dictates how much exhaust energy also reaches the turbo. With turbo cars, you still ease onto the throttle coming out of the turn. Having tracked a turbo car before, there is no significant difference here. And a turbo does not necessarily build more torque at low RPM's than a supercharger. It depends on how the turbo matches the engine's airflow characteristics. And if you look at some positive displacement supercharger applications, you'll find many of these can make boost at idle speeds.

Consequently, turbo sizing is an important issue. If you build a turbo car with 700 HP that uses a very narrow portion of the RPM band in order to maximize the peak turbo efficiency, then of course you may end up with a neck-snapping boost curve. But most people tracking their cars will choose something more reasonable that gives a relatively wide peak boost curve and good overall efficiency. These also tend to have a somewhat linear boost rise. Even when you size a bit on the larger side. As far as lag, I urge you actually drive a powerful turbo car with a well matched turbo. While a supercharger's response will be instant, the turbo is not that far behind. So long as you are not severly mismatching a turbo. You also have to consider the difference between actual lag and boost threshold. Boost threshold is the RPM at which a turbo hits full boost. Lag is the time it takes for a turbo to reach full boost from the time you go from closed throttle to WOT. A turbo sized well for a car will have very little lag once you are at an RPM above the boost threshold. The lag is a result of the weight of the moving parts inside a turbo. Nothing can go from idle speed to 70,000+ RPM in an instant. A turbo can spool very quickly, but it still must obey the laws of physics. Larger turbos do have heavier parts so they can change speed as quickly, but once they are beyond the boost threshold, the engine can provide enough airflow to spool it to peak boost quite quickly. Lag in the sense of reaching the boost threshold is a matter of not having enough airflow to reach peak boost at that RPM in the first place. And if you want to see a problem with boost threshold look at a centrifugal supercharger. It hits peak boost right around redline.

I favor turbos, especially for track cars. They generally are more efficient and put less load on the crank for a given power output. They are also not boosting all the time. This means the intercooler will not be trying to cool down the air inside during braking and part throttle application. This is particularly important since track racing gives you very little time to cool the intercooler. Intercoolers not only shed heat during boost, but they act as heatsinks. Off boost driving provides a lower temperature air source inside the intercooler on a turbo car, which actually helps to cool the intercooler from the inside. An intercooled supercharger is not going to be able to do this. The cooling an intercooler provides is effectively spreadout. This also affects the cooling system in the case of a front mount intercooler set-up. While a front mount puts addtional strain on the radiator regardless of the FI type, keeping heat down here will help keep the engine happier overall.

C-Kwik
02-19-2005, 06:36 PM
A chart that helps break down the differences between Turbos and S/C:

http://www.coloradocobras.com/whipple/superchargers/supercharger-comparison-chart.html



Most of the information in there is fairly accurate. But the information about intercooling is way off. They indicate the heat build-up on the turbo is high but is low on a centrifugal charger. A centrifugal charger and turbo use the same type of compressor. Their adiabatic efficiency is about the same. He says a turbo may need an intercooler but a centrifugal charger does not. Hell, even the whipple charger has roughly the same adiabatic efficiency and he says it is often not needed. Considering the need for an intercooler is mainly dependent on the amount of heat in the charge air going into the motor, the type of charger is not the deciding factor. The efficiency and the amount of boost you are running are important factors. Air heats up when compressed regardless. If a charger of any kind had 100% adiabatic efficency the heat introduced from simply compressing the air can be enough to neccesitate an intercooler depending on the motor and the amount of boost. Interestingly, the guy does not appear to sell turbos either. He also seems to emphasize whipplechargers as well.

Eagle1
02-19-2005, 09:02 PM
I agree with C-Kwik, you really must have an intercooler on these units.
But let us also remember, that for a track car, the changes to the suspension/handling and braking are way more important that boosting hp/tq in most situations. It is managing corner speed and corner exit that gets the job done. We can all recount vividly the scenes of little spec Miatas hunting down mighty V-8 cars and dispatching them on the track, because they corner like cockroaches. If it can be managed economically, I still think that conceptually the twin screw is the best way to go. It just is typically not available for us on this car.

340HP
02-20-2005, 01:33 AM
When my car finally is out of warranty, and if I consider to make a good living, I'd love put a turbo or supercharger on my G35. I know that superchargers are superior in one sense---there is no lag.

But having driven a turbo-charged car in the past (Okay, it was my Mom's Volvo wagon) I just loved the sound of the turbo winding up and feeling the boost come one.

Are superchargers always the first choice or are turbos a decent alternative? A turbo-charged G35 would sound SWEET. A little lag and then BAM. Does know if there is a clear cut choice here or it a matter of preference?



"No lag" is incorrect. It depends on what type of SC you use. There are at least 4 types (screw, root, centrifugal, etc). Some start with 1 PSI at low range and build up to 8-9 PSI as the revs increase.

SC = no exhaust modification necessary, as boost is built from engine power, not exhaust fumes.

TC = more efficient, due to the nature that no torque is leeched from the engine to increase power.

There are so many different factors to keep in mind. Set a budget (MOST IMPORTANT THING), then set an HP / TQ goal, and do some research from there.

The VQ in your G can be taken to over 1000 HP (not daily driver of course). But 400-600 HP daily is attainable.

There is even a 430 stroker kit.

Your options are endless.

340HP
02-20-2005, 01:34 AM
Personally, I would favor a supercharger for its ease, but a Turbo tends to put out WAY more torque at lower rpms than a supercharger.



Completely the opposite. A turbo BUILDS hp / tq as revs increase. Some SC's have instant high torque. Read up on this.

C-Kwik
02-20-2005, 04:09 AM
When my car finally is out of warranty, and if I consider to make a good living, I'd love put a turbo or supercharger on my G35. I know that superchargers are superior in one sense---there is no lag.

But having driven a turbo-charged car in the past (Okay, it was my Mom's Volvo wagon) I just loved the sound of the turbo winding up and feeling the boost come one.

Are superchargers always the first choice or are turbos a decent alternative? A turbo-charged G35 would sound SWEET. A little lag and then BAM. Does know if there is a clear cut choice here or it a matter of preference?



"No lag" is incorrect. It depends on what type of SC you use. There are at least 4 types (screw, root, centrifugal, etc). Some start with 1 PSI at low range and build up to 8-9 PSI as the revs increase.

SC = no exhaust modification necessary, as boost is built from engine power, not exhaust fumes.

TC = more efficient, due to the nature that no torque is leeched from the engine to increase power.

There are so many different factors to keep in mind. Set a budget (MOST IMPORTANT THING), then set an HP / TQ goal, and do some research from there.

The VQ in your G can be taken to over 1000 HP (not daily driver of course). But 400-600 HP daily is attainable.

There is even a 430 stroker kit.

Your options are endless.



Actually no lag is very correct. All superchargers are creating the boost it is supposed to at the given RPM. As soon as you open the throttle, the only delay will be the time to fill the manifold, which should be pretty much instantaneous. What you are referring to is boost threshold. Which is terrible in a centrifugal supercharger.

Turbos in that of itself are not necessarily more efficient. Small turbos introduce a ton of backpressure. In many cases much more pressure than the boost you are making. This is one reason a small turbo makes less power for a given boost level.

Wahhaj
02-20-2005, 04:24 AM
Interesting discussion - something to keep in mind though, with the new GT-R they are mentioning a new electronically assisted turbo setup, virtually eliminating LAG; the biggest negative going for turbos. It will be interesting to see the actual application. Maybe even aftermarket setups for the Z and G within the next 4 years!

C-Kwik
02-20-2005, 06:28 AM
Completely the opposite. A turbo BUILDS hp / tq as revs increase. Some SC's have instant high torque. Read up on this.



Not necessarily. Depends on the turbo. Small turbos will reach full boost very quickly, which in turn will create a lot of torque at the lower RPM's. But they will likely run out of steam as they fall out of their efficiency range and the effects of the small turbine and excessively low efficiency create a high amount of backpressure.

johnnie2
02-20-2005, 07:19 AM
What about HKS, have they got a decent offering for the VQ engine? How do they compare with other manfacturers?

340HP
02-20-2005, 10:27 AM
Completely the opposite. A turbo BUILDS hp / tq as revs increase. Some SC's have instant high torque. Read up on this.



Not necessarily. Depends on the turbo. Small turbos will reach full boost very quickly, which in turn will create a lot of torque at the lower RPM's. But they will likely run out of steam as they fall out of their efficiency range and the effects of the small turbine and excessively low efficiency create a high amount of backpressure.



True, small TCs make quick HP/TQ gains. However, I was making a general point about SC vs TC. SC usually brings on low-end TQ almost instantly.

C-Kwik
02-20-2005, 01:54 PM
True, small TCs make quick HP/TQ gains. However, I was making a general point about SC vs TC. SC usually brings on low-end TQ almost instantly.



Depends on the type of supercharger though. Positive displacement chargers and centrifugal chargers have very different boost curves. This very directly affects how the torque curve will end up looking. Much the same way different turbos end up with different results. You were making a very big and misleading generalization about turbos.

340HP
02-21-2005, 12:04 AM
True, small TCs make quick HP/TQ gains. However, I was making a general point about SC vs TC. SC usually brings on low-end TQ almost instantly.



Depends on the type of supercharger though. Positive displacement chargers and centrifugal chargers have very different boost curves. This very directly affects how the torque curve will end up looking. Much the same way different turbos end up with different results. You were making a very big and misleading generalization about turbos.



Umm, no, the generalization is that most SC's have more torque at the low-end and turbos need to spool up to generate power / torque.

Yes some different superchargers build up boost as turbos do, but in general, a generalization, an assumption correct, is that SC has more torque, quicker, than a TC.

You know what, I don't even know why I'm responding to this. Argue all you want, I just completely lost interest in this thread.

Get a nitrous bottle, there's some torque for yoass.