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I just sent the following letter to 911World. Am I a sad Porsche spod or do I have a point? Rennlist (or wass it Pelican - can't remember) recently debated whether there was an in built bias in favour of advertisers in this magazine and Keith Seume had to jump in. Still, I tell it only as I see it.
"Dear Chris,
I am a long time subscriber and generally long time admirer of the magazine, however, I can't help noticing some errors in the most recent Issue and a somewhat misleading, or perhaps casually researched article. I refer to the "In at the Deep End" and "Full Stop" articles, respectively.
Looking first at "In at the Deep End", your writer, Brett Fraser (not a regular contributor?), refers throughout the article to a 911SC with a 2.7 litre engine (see the second paragraph, for example). This car is clearly a narrow body car (ie., no rear SC flares) with 15x6 Fuchs wheels on all four corners. These two facts alone, make it highly unlikely to be a SC. It is almost certainly an earlier 2.7 litre car. This is fundamental stuff and anyone familiar with 911s ought to spot the error, either at the writing or editing stage. A more minor error in the article is the reference in a photo caption to the "brake scoops" in the bumper. As there is only one scoop, replacing the bumper bellows on the RHS, and no corresponding scoop on the left, this is an obvious clue that the scoop has a purpose other than brake cooling. These scoops are usually used to supply air to the oil cooler located in front of the RH front wheel and have nothing to do with brake cooling.
Secondly, the "Full Stop" article is in my opinion somewhat misleading. It describes the Boxster monoblock swap as an upgrade which in the case of the 3.2 cars anyway is certainly debatable. The issue perhaps stems from your technical writer's view of the standard brake discs as "meaty". If the writer had any track experience, he would know that the size of the discs is at best marginal. Both pre-1984 cars and 3.2 cars, with 20mm and 24mm thick discs, respectively, will (unless they have had their weight significantly reduced) suffer from a lack of heat sink capacity if used on track with the standard brakes. In other words they have heat induced brake fade. Even with cool air ducted to the brakes, race pads and race fluid, this is still an issue. It is well known that if you race these cars you have to drive around the brake fade issue. The Boxster kit has some benefits: larger pad size, stiffer caliper, lighter caliper, more clamping force - so I concede that the kit has some benefits for road use, if nothing else. But it does nothing to address the primary problem with pre-964 brakes which is a lack of heat sink capacity. In order to fit the Boxster kit to a 3.2 you must downsize the rear rotors from 24mm thick to 20mm thick. This is not an upgrade. On pre-1984 cars you are increasing the front rotor thickness from 20mm to 24mm which is a step in the right direction. Unfortunately, one of the benefits of the Boxster kit - increased clamping force - is also a detriment if used in extremes (such as track use). In simple terms, the Boxster caliper can generate more heat with the higher clamping force. Without a larger rotor to store/dissipate the heat you actually reach the point of overheating and brake fade somewhat earlier. This is particularly apparent on 3.2s where you are not adding any disc size (you are net:net reducing disc size).
Regardless of the technical stuff, your writer is mistaken regarding what actually constitutes an upgrade. He/she talks about better brake performance and reduced stopping distances. This is completely misleading. If the standard brakes can lock up the tyres then they already exert maximum retardation and a change in calipers *cannot* do anything to reduce stopping distances - period. You need stickier tyres to reduce stopping distances. If the standard brakes cannot induce lockup of normal road tyres then there is something wrong with those brakes. While the writer does not talk of track tyres or track applications, I concede that with wider R-compound tyres, the standard brakes may be inadequate in clamping force (although this is really outside the scope of the article). If "upgrade" means something more than stopping distance then you have to look perhaps at fade resistance. As I explain in the previous paragraph, fade resistance is no better and possibly worse with the fitting of this kit. What is left? Perhaps this kit provides better pedal feel? Seems to me like a lot of money to pay for better pedal feel that might be acccomplished just with new OE discs and pads and fresh brake fluid.
A further point that the writer fails to address is the brake bias issue. I don't know the answer, but the Boxster kit presumably alters the brake bias (a function primarily of piston size, pad size and disc size). This could have a detrimental effect on braking distance as it may lead to premature lock-up at the front or rear axle depending on which way the bias moves. Further, 3.2s have a proportioning valve that comes into effect over certain brake pressures. I assume the kit requires removal of the PV, but no mention is made of this.
Maybe I am being hyper-critical, but having spent a large amount of time researching brake upgrades over the last 18 months, I know that there is no easy (or cheap) answer. The brakes have to be considered as a system and simply changing the calipers does not really constitute an upgrade. I am also concerned that this is promoted as a "new" product available from Autofarm. Both within the UK and in the USA, this kit has been available for years - at significantly lower cost than that quoted by Autofarm. I know (and like) the guys at Autofarm, and no doubt they are selling a true bolt on kit (which is not without benefit), but a simple Google search or a search on the Pelican or Rennlist, would have alerted the writer to the fact that there are alternatives to this kit and also that there are issues with the kit such as those that I highlight above. As much as I like Autofarm, I don't need an infomercial for them. I expect the magazine to be more objective.
I think 911 & Porsche World generally has a higher level of objectivity than the other specialist Porsche magazines and these two articles are, to my mind, indicative of a slide in those previously high standards. You guys can do better - and the dedicated reader deserves nothing less.
Now if you guys really want to know something about a "proper" upgrade, I am happy to share all the details of my own 964 based brake upgrade as applicable to pre 1989 911s. This has most of the benefits of the Boxster kit plus bigger discs for roughly half the cost. Interested?"
Any thoughts?
Richard
"Dear Chris,
I am a long time subscriber and generally long time admirer of the magazine, however, I can't help noticing some errors in the most recent Issue and a somewhat misleading, or perhaps casually researched article. I refer to the "In at the Deep End" and "Full Stop" articles, respectively.
Looking first at "In at the Deep End", your writer, Brett Fraser (not a regular contributor?), refers throughout the article to a 911SC with a 2.7 litre engine (see the second paragraph, for example). This car is clearly a narrow body car (ie., no rear SC flares) with 15x6 Fuchs wheels on all four corners. These two facts alone, make it highly unlikely to be a SC. It is almost certainly an earlier 2.7 litre car. This is fundamental stuff and anyone familiar with 911s ought to spot the error, either at the writing or editing stage. A more minor error in the article is the reference in a photo caption to the "brake scoops" in the bumper. As there is only one scoop, replacing the bumper bellows on the RHS, and no corresponding scoop on the left, this is an obvious clue that the scoop has a purpose other than brake cooling. These scoops are usually used to supply air to the oil cooler located in front of the RH front wheel and have nothing to do with brake cooling.
Secondly, the "Full Stop" article is in my opinion somewhat misleading. It describes the Boxster monoblock swap as an upgrade which in the case of the 3.2 cars anyway is certainly debatable. The issue perhaps stems from your technical writer's view of the standard brake discs as "meaty". If the writer had any track experience, he would know that the size of the discs is at best marginal. Both pre-1984 cars and 3.2 cars, with 20mm and 24mm thick discs, respectively, will (unless they have had their weight significantly reduced) suffer from a lack of heat sink capacity if used on track with the standard brakes. In other words they have heat induced brake fade. Even with cool air ducted to the brakes, race pads and race fluid, this is still an issue. It is well known that if you race these cars you have to drive around the brake fade issue. The Boxster kit has some benefits: larger pad size, stiffer caliper, lighter caliper, more clamping force - so I concede that the kit has some benefits for road use, if nothing else. But it does nothing to address the primary problem with pre-964 brakes which is a lack of heat sink capacity. In order to fit the Boxster kit to a 3.2 you must downsize the rear rotors from 24mm thick to 20mm thick. This is not an upgrade. On pre-1984 cars you are increasing the front rotor thickness from 20mm to 24mm which is a step in the right direction. Unfortunately, one of the benefits of the Boxster kit - increased clamping force - is also a detriment if used in extremes (such as track use). In simple terms, the Boxster caliper can generate more heat with the higher clamping force. Without a larger rotor to store/dissipate the heat you actually reach the point of overheating and brake fade somewhat earlier. This is particularly apparent on 3.2s where you are not adding any disc size (you are net:net reducing disc size).
Regardless of the technical stuff, your writer is mistaken regarding what actually constitutes an upgrade. He/she talks about better brake performance and reduced stopping distances. This is completely misleading. If the standard brakes can lock up the tyres then they already exert maximum retardation and a change in calipers *cannot* do anything to reduce stopping distances - period. You need stickier tyres to reduce stopping distances. If the standard brakes cannot induce lockup of normal road tyres then there is something wrong with those brakes. While the writer does not talk of track tyres or track applications, I concede that with wider R-compound tyres, the standard brakes may be inadequate in clamping force (although this is really outside the scope of the article). If "upgrade" means something more than stopping distance then you have to look perhaps at fade resistance. As I explain in the previous paragraph, fade resistance is no better and possibly worse with the fitting of this kit. What is left? Perhaps this kit provides better pedal feel? Seems to me like a lot of money to pay for better pedal feel that might be acccomplished just with new OE discs and pads and fresh brake fluid.
A further point that the writer fails to address is the brake bias issue. I don't know the answer, but the Boxster kit presumably alters the brake bias (a function primarily of piston size, pad size and disc size). This could have a detrimental effect on braking distance as it may lead to premature lock-up at the front or rear axle depending on which way the bias moves. Further, 3.2s have a proportioning valve that comes into effect over certain brake pressures. I assume the kit requires removal of the PV, but no mention is made of this.
Maybe I am being hyper-critical, but having spent a large amount of time researching brake upgrades over the last 18 months, I know that there is no easy (or cheap) answer. The brakes have to be considered as a system and simply changing the calipers does not really constitute an upgrade. I am also concerned that this is promoted as a "new" product available from Autofarm. Both within the UK and in the USA, this kit has been available for years - at significantly lower cost than that quoted by Autofarm. I know (and like) the guys at Autofarm, and no doubt they are selling a true bolt on kit (which is not without benefit), but a simple Google search or a search on the Pelican or Rennlist, would have alerted the writer to the fact that there are alternatives to this kit and also that there are issues with the kit such as those that I highlight above. As much as I like Autofarm, I don't need an infomercial for them. I expect the magazine to be more objective.
I think 911 & Porsche World generally has a higher level of objectivity than the other specialist Porsche magazines and these two articles are, to my mind, indicative of a slide in those previously high standards. You guys can do better - and the dedicated reader deserves nothing less.
Now if you guys really want to know something about a "proper" upgrade, I am happy to share all the details of my own 964 based brake upgrade as applicable to pre 1989 911s. This has most of the benefits of the Boxster kit plus bigger discs for roughly half the cost. Interested?"
Any thoughts?
Richard
] In all seriousness though, I think you are spot on with this. There are other moans about the usually v. good 911&PW going on in the 964RS forum. I think they seem to have taken their eye off the ball a bit here.
