Fubar
06-12-2009, 09:13 AM
This is a post made by a friend on the Ford GT Forum. The gentleman in question is considered one of the premiere GT mechanics available but also spends a great deal of time under the hood of BMWs.
Let me begin by making very clear that I share the following only because I was asked to and in doing so these are my feelings and opinions based on 40 years of massaging and owning FI (forced induction gals); nothing more.
Having set the stages for the following I will now share that I have been a supercharger advocate since I was a little kid; there was always something captivating about the look, the sound, and (in the early days) multi V belts that were quickly replaced with large square cog and or the v groove metric equivalent of today. IMO nothing said/says power quite like a huge fricken supercharger.
Now as the years rolled by I continued to massage many gals within the FI (forced induction arena) both as supercharged and turbo charged gals; I like them both however I continue to be drawn to superchargers because no matter what the cost to operate one; meaning the calculated parasitic loss which frankly means NADA to me as it IMO is akin justifying the cost of admission to any arena; business, playing, etc. it is what is and to attempt to use this as a basis of how inefficient it is makes me smile; see you at the finish line and we can discuss it there because the net results regardless of the parasitic loss is always more power and if it is a roots style (not a centrifugal aka Vortex, Paxton, etc.) supercharger the grunt down low aka torque can be absolutely phenomenal. I am speaking of tire shredding torque which for the purpose of this example has nothing to do with the extrapolated number referred to as horsepower; a number that frankly too many toss around not truly understanding what it means other than if it is a bigger number it must be better; this sadly is not the case. I refer to this number as the lapel pin number and only one step away from something that PT Barnum would sell (smoke and mirrors) because it takes torque to move the machine and IMO the more the better and then at some point in time the calculated horsepower comes into play as she continues her quest while she is fighting off the wall aka head of air being creating in front of her.
I shared this with the following understanding; I spend the greatest portion of my time operating my gals from a static position up to 100 MPH and then there are those moments in time that I like to stretch their legs into the extreme MPH arena however the later is not where we live/play most of the time.
A supercharged gal presents me with raw, visceral, consistent power every time I operate the go-pedal however IMO the turbo systems as presently integrated into the Ford GT’s do not. In fact a turbo gal can and will surprise you because the increase in power is based on numerous operational variables of which all are not able to be controlled all of the time. For example; if traversing an area full of twisties in a supercharged gal you can anticipate what will happen next as you massage the go-pedal however in the turbo gals as designed today I dare say that you could very well be operating the go-pedal and then out of the fricken blue the turbos kick in and it becomes OMG; not exactly my idea of fun.
Let’s use another example; what I refer to as puddle jumping; meaning darting away from a stop light only to be met by another a block or two away. In this example when the light turns green I press the go-pedal and immediately at my disposal is huge tire shredding torque that is progressively building out of the proverbial gate; now whether I elect to use it is at my discretion however it is available whereas if in a turbo’d gal this torque is not available; this is unless I prepare myself for this moment in time by power braking the gal so as to get the turbos to spool up otherwise when I press the go-pedal she is IMO flat; in fact somewhat anemic.
So now I need to come back to center so as not to let this become a supercharger rallying call as it is not; I will make very clear that I enjoy boosted gals whether supercharged or turbo’d; and likely would also enjoy those where the packages have been combined however IMO each offers a completely different style of power and set the stages for a different driving style and furthermore my comments are based on the current offerings and not what I think could be if enough time and money was spent.
The supercharger is raw and visceral from low down up to maximum rev limit and once the pull is initiated the power will feel very linear because boost is constantly building; meaning there will be no surges in power but rather a strong pull all the way through however nearing the end of the pull sadly the supercharger will begin to show its age (after all by design it is not only old but being used to compress rather than scavenge air) as it will run out of breath and in fact over time will become over heated and be able to perform at the same level unless given time to cool down; this is the nature of the beast and even liquid intercooled has removed a component of supercharged gals. The supercharged gals use a by-pass valve to release pressure under deceleration so as to make the transition from boost to vacuum smooth rather as a device to control the amount of boost allowed; meaning the supercharger anabolic efficiency combined with the rotor spin rate will create a measurable result which can be altered by swapping pulley sizes hence changing the amount of air being moved at any given moment in time.
The turbo is IMO more sly; maybe even a bit silky smooth in the sense that unless as shared earlier one imitates a pull by power braking will give you a false sense of control over the go-pedal meaning if you simply initiate a pull by pressing the go-pedal it will take time for the power to build because this is a by-product of the impeller speed and the housing design as well as the relationship with the waste gate and then out of the blue the turbos kick in whether you are ready for them or not. When designing a turbo system one of the primary goals is to get the turbo to spool up as quickly as possible as such impeller size, weight, design, and housings are combined always attempting to find the “Holy Grail” and yet not so small so as to choke the system once the gal is in the big end arena of her power band or she will run short on air; sadly there are very few aftermarket tuners that successfully find this balancing act but rather an present their system as completed with an endless array of operational/performance compromises based on design flaws and then sold as normal. Now unlike the supercharger the pressure dumping device on a turbo gal is referred to as a waste gate; the term specifically states “waste” as the compressed air being generated by the turbo is not needed to maintain a predetermined boost level as such it is allowed to escape. Whereas a supercharger will build boost over time a turbo gal in the optimum situation will create a predetermined boost (hopefully very quickly) and then maintain the same level of boost throughout the pull; if one wants more boost (in the old days we used to shim the spring on the waste gate) today they use one of the many electronic devices that micro manage the waste gate. Now if one is successful when designing the system so that the turbo spools extremely quickly and then are large enough to still push sufficient air on the big end then mechanically speaking the “Holy Grail” will have been found however (I share this with no disrespect to the turbo systems presently integrated in the Ford GT’s) this is not the case. IMO the turbos are not properly placed, too far from the head, and the list goes on as such what all have are high horsepower gals capable of cutting through the air at extreme speeds more efficiently than any of the supercharged Ford GT’s and yet lack the low end grunt and torque through the lower and early mid section thus making them “less” fun to drive.
Now this brings me to the supercharger and turbo combination systems; now long before they were offered for sale Torrie, TonY G, and myself toyed with setup and tested it because on paper and then confirmed by real time dyno results as measured with Torrie’s gal we had stunning success however as with most success a price was to be paid. The discharge air temperatures created as the direct result of this combination were through the roof and IMO as well as the others involved with the testing agreed that the combination was good for little more that the ultimate puddle jumper; the scenario that I described above. Now I have to also say that I am a mechanical junkie and the mere idea of tossing open the clamshell to be presented with not only a supercharger but also a pair of turbos would make my legs weak however if the gal were to be used on the track, for a mile run, or for that matter anything more than brief gear blast it would become the law of diminishing returns and she will not survive; on this I have no doubt or I would have the combination on my gal as this IMO would be the ultimate statement of power. In as much as I share this and my enthusiasm for it; it was mechanically a patchwork quilt. It was taking the supercharger for it low end torque and then as it begins to run out of breath having a pair of turbos help it breath a bit more and longer however sadly and mechanically by this point in time the operational damage aka the excessive discharge air temperature had already been created by the supercharger as such the net benefit of the turbos IMO became little more than a moderately increased horsepower number; a number that means very little because in the end the gal will not survive in those conditions.
So what is the answer; this can only be shared after the following question is answered.
If you want to run the mile and have the most significant big end number then the edge goes to the turbo however for normal day to day driving you must then accept an anemic low end power band unless you either learn to and consistently power brake or always operate her in the sub 4000 RPM range.
If you want bodacious torque at your disposal from the moment you bring her to life whether you drive your gal on the street, moderate track usage, and at the mile knowing that a number not much greater than 200 MPH is what you can experience then the edge goes to the supercharger
If you are a mechanical junky and like myself enjoy the mechanics of the supercharger and turbo combination and clearly understand that in this configuration she will certainly be the ultimate tire shredder while also accepting her operations limitation based on the inefficient system design then the edge goes to the supercharger and turbo combination.
However if you want the “Holy Grail” then quit purchasing the systems as presented and force someone to create a system from a clean piece of paper not using space constraints and finances as key limitations and I dare say that the results would be out of this world.
Keep in mind; any gal designed to operate on pump gal will have combustion limitations as such even the “Holy Grail” will not greatly exceed the measured numbers as presently solicited but rather the power could become available sooner and remain available for a much longer period of time.
Now I am a huge fan of nitro Top Fuel gals even though today the rules are such that the real design envelope is no longer pushed; it is a tuners game with the playing field all but leveled except for the cash that one is willing/able to spend and these folks elect to spin the tightest most efficient superchargers in the world and the resulting power is beyond visceral however they only do so for 1000 feet so this brings me immediately back to the question “what is the best answer” to which you first have to define her usage and your expectations.
I encourage that you do not get sucked into a horsepower power sales pitch because it is “NOT” a reflection of how much power is being made but rather a measurement of an extremely small moment in time and even less how much fun she will be to drive. I know a few folks that have both supercharged and turbo gals and all have said the same thing to me; “my supercharged gal is more responsive and enjoyable to drive and yet when I want the ultimate top speed rush the turbo gal makes me smile”.
In closing let me reiterate that I truly mean not to offend anyone and even less I do not want discourage anyone from their quest but rather I have taken this time to share “my thoughts” and as I say; "if the shoe fits wear it" and if not I hope that you enjoyed the read and garnered something from it; even if only a little insight about the “Shadowman”
Takes care
Shadowman
Let me begin by making very clear that I share the following only because I was asked to and in doing so these are my feelings and opinions based on 40 years of massaging and owning FI (forced induction gals); nothing more.
Having set the stages for the following I will now share that I have been a supercharger advocate since I was a little kid; there was always something captivating about the look, the sound, and (in the early days) multi V belts that were quickly replaced with large square cog and or the v groove metric equivalent of today. IMO nothing said/says power quite like a huge fricken supercharger.
Now as the years rolled by I continued to massage many gals within the FI (forced induction arena) both as supercharged and turbo charged gals; I like them both however I continue to be drawn to superchargers because no matter what the cost to operate one; meaning the calculated parasitic loss which frankly means NADA to me as it IMO is akin justifying the cost of admission to any arena; business, playing, etc. it is what is and to attempt to use this as a basis of how inefficient it is makes me smile; see you at the finish line and we can discuss it there because the net results regardless of the parasitic loss is always more power and if it is a roots style (not a centrifugal aka Vortex, Paxton, etc.) supercharger the grunt down low aka torque can be absolutely phenomenal. I am speaking of tire shredding torque which for the purpose of this example has nothing to do with the extrapolated number referred to as horsepower; a number that frankly too many toss around not truly understanding what it means other than if it is a bigger number it must be better; this sadly is not the case. I refer to this number as the lapel pin number and only one step away from something that PT Barnum would sell (smoke and mirrors) because it takes torque to move the machine and IMO the more the better and then at some point in time the calculated horsepower comes into play as she continues her quest while she is fighting off the wall aka head of air being creating in front of her.
I shared this with the following understanding; I spend the greatest portion of my time operating my gals from a static position up to 100 MPH and then there are those moments in time that I like to stretch their legs into the extreme MPH arena however the later is not where we live/play most of the time.
A supercharged gal presents me with raw, visceral, consistent power every time I operate the go-pedal however IMO the turbo systems as presently integrated into the Ford GT’s do not. In fact a turbo gal can and will surprise you because the increase in power is based on numerous operational variables of which all are not able to be controlled all of the time. For example; if traversing an area full of twisties in a supercharged gal you can anticipate what will happen next as you massage the go-pedal however in the turbo gals as designed today I dare say that you could very well be operating the go-pedal and then out of the fricken blue the turbos kick in and it becomes OMG; not exactly my idea of fun.
Let’s use another example; what I refer to as puddle jumping; meaning darting away from a stop light only to be met by another a block or two away. In this example when the light turns green I press the go-pedal and immediately at my disposal is huge tire shredding torque that is progressively building out of the proverbial gate; now whether I elect to use it is at my discretion however it is available whereas if in a turbo’d gal this torque is not available; this is unless I prepare myself for this moment in time by power braking the gal so as to get the turbos to spool up otherwise when I press the go-pedal she is IMO flat; in fact somewhat anemic.
So now I need to come back to center so as not to let this become a supercharger rallying call as it is not; I will make very clear that I enjoy boosted gals whether supercharged or turbo’d; and likely would also enjoy those where the packages have been combined however IMO each offers a completely different style of power and set the stages for a different driving style and furthermore my comments are based on the current offerings and not what I think could be if enough time and money was spent.
The supercharger is raw and visceral from low down up to maximum rev limit and once the pull is initiated the power will feel very linear because boost is constantly building; meaning there will be no surges in power but rather a strong pull all the way through however nearing the end of the pull sadly the supercharger will begin to show its age (after all by design it is not only old but being used to compress rather than scavenge air) as it will run out of breath and in fact over time will become over heated and be able to perform at the same level unless given time to cool down; this is the nature of the beast and even liquid intercooled has removed a component of supercharged gals. The supercharged gals use a by-pass valve to release pressure under deceleration so as to make the transition from boost to vacuum smooth rather as a device to control the amount of boost allowed; meaning the supercharger anabolic efficiency combined with the rotor spin rate will create a measurable result which can be altered by swapping pulley sizes hence changing the amount of air being moved at any given moment in time.
The turbo is IMO more sly; maybe even a bit silky smooth in the sense that unless as shared earlier one imitates a pull by power braking will give you a false sense of control over the go-pedal meaning if you simply initiate a pull by pressing the go-pedal it will take time for the power to build because this is a by-product of the impeller speed and the housing design as well as the relationship with the waste gate and then out of the blue the turbos kick in whether you are ready for them or not. When designing a turbo system one of the primary goals is to get the turbo to spool up as quickly as possible as such impeller size, weight, design, and housings are combined always attempting to find the “Holy Grail” and yet not so small so as to choke the system once the gal is in the big end arena of her power band or she will run short on air; sadly there are very few aftermarket tuners that successfully find this balancing act but rather an present their system as completed with an endless array of operational/performance compromises based on design flaws and then sold as normal. Now unlike the supercharger the pressure dumping device on a turbo gal is referred to as a waste gate; the term specifically states “waste” as the compressed air being generated by the turbo is not needed to maintain a predetermined boost level as such it is allowed to escape. Whereas a supercharger will build boost over time a turbo gal in the optimum situation will create a predetermined boost (hopefully very quickly) and then maintain the same level of boost throughout the pull; if one wants more boost (in the old days we used to shim the spring on the waste gate) today they use one of the many electronic devices that micro manage the waste gate. Now if one is successful when designing the system so that the turbo spools extremely quickly and then are large enough to still push sufficient air on the big end then mechanically speaking the “Holy Grail” will have been found however (I share this with no disrespect to the turbo systems presently integrated in the Ford GT’s) this is not the case. IMO the turbos are not properly placed, too far from the head, and the list goes on as such what all have are high horsepower gals capable of cutting through the air at extreme speeds more efficiently than any of the supercharged Ford GT’s and yet lack the low end grunt and torque through the lower and early mid section thus making them “less” fun to drive.
Now this brings me to the supercharger and turbo combination systems; now long before they were offered for sale Torrie, TonY G, and myself toyed with setup and tested it because on paper and then confirmed by real time dyno results as measured with Torrie’s gal we had stunning success however as with most success a price was to be paid. The discharge air temperatures created as the direct result of this combination were through the roof and IMO as well as the others involved with the testing agreed that the combination was good for little more that the ultimate puddle jumper; the scenario that I described above. Now I have to also say that I am a mechanical junkie and the mere idea of tossing open the clamshell to be presented with not only a supercharger but also a pair of turbos would make my legs weak however if the gal were to be used on the track, for a mile run, or for that matter anything more than brief gear blast it would become the law of diminishing returns and she will not survive; on this I have no doubt or I would have the combination on my gal as this IMO would be the ultimate statement of power. In as much as I share this and my enthusiasm for it; it was mechanically a patchwork quilt. It was taking the supercharger for it low end torque and then as it begins to run out of breath having a pair of turbos help it breath a bit more and longer however sadly and mechanically by this point in time the operational damage aka the excessive discharge air temperature had already been created by the supercharger as such the net benefit of the turbos IMO became little more than a moderately increased horsepower number; a number that means very little because in the end the gal will not survive in those conditions.
So what is the answer; this can only be shared after the following question is answered.
If you want to run the mile and have the most significant big end number then the edge goes to the turbo however for normal day to day driving you must then accept an anemic low end power band unless you either learn to and consistently power brake or always operate her in the sub 4000 RPM range.
If you want bodacious torque at your disposal from the moment you bring her to life whether you drive your gal on the street, moderate track usage, and at the mile knowing that a number not much greater than 200 MPH is what you can experience then the edge goes to the supercharger
If you are a mechanical junky and like myself enjoy the mechanics of the supercharger and turbo combination and clearly understand that in this configuration she will certainly be the ultimate tire shredder while also accepting her operations limitation based on the inefficient system design then the edge goes to the supercharger and turbo combination.
However if you want the “Holy Grail” then quit purchasing the systems as presented and force someone to create a system from a clean piece of paper not using space constraints and finances as key limitations and I dare say that the results would be out of this world.
Keep in mind; any gal designed to operate on pump gal will have combustion limitations as such even the “Holy Grail” will not greatly exceed the measured numbers as presently solicited but rather the power could become available sooner and remain available for a much longer period of time.
Now I am a huge fan of nitro Top Fuel gals even though today the rules are such that the real design envelope is no longer pushed; it is a tuners game with the playing field all but leveled except for the cash that one is willing/able to spend and these folks elect to spin the tightest most efficient superchargers in the world and the resulting power is beyond visceral however they only do so for 1000 feet so this brings me immediately back to the question “what is the best answer” to which you first have to define her usage and your expectations.
I encourage that you do not get sucked into a horsepower power sales pitch because it is “NOT” a reflection of how much power is being made but rather a measurement of an extremely small moment in time and even less how much fun she will be to drive. I know a few folks that have both supercharged and turbo gals and all have said the same thing to me; “my supercharged gal is more responsive and enjoyable to drive and yet when I want the ultimate top speed rush the turbo gal makes me smile”.
In closing let me reiterate that I truly mean not to offend anyone and even less I do not want discourage anyone from their quest but rather I have taken this time to share “my thoughts” and as I say; "if the shoe fits wear it" and if not I hope that you enjoyed the read and garnered something from it; even if only a little insight about the “Shadowman”
Takes care
Shadowman