The 2012 PCGB Club Championship
- Thread starter paulf968
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Steve Brookes
Moderator
Baz, it's very interesting to hear your thinking on that. Have you got any data showing that the boxster runs slower lap times with the spoiler up? My guess is that the extra speed gained through the corners (with the spoiler up) would outweigh the loss of a couple of mph on the straights. In general, it's how fast a car is through the corners that gives it a better lap time. Red Bull proved that in F1 over the last two years. Ben's video also shows that it was Paul F's great driving through the corners that kept him ahead of a couple of more powerful boxsters for such a long period of time. With two identical boxsters and two well matched drivers, it would be very interesting to see the effect of spoiler up/down on lap times during testing (or even quali if you are allowed to run some laps with up and some with it down?).
Good thoughts - thanks and I agree we need to check it but looking at the data recorder I don't think we have a problem being on full throttle in the dry out of corners - but we do drop back down the straights on some rivals. That's the feedback I have had so far from the drivers. In the wet I think it may help a bit but then better torque from bigger engines drags away from us anyway. Also I think that spoilers like that need quite a high speed anyway to operate effectively - not the slower speeds we get out of our short circuit corners - I am not an expert but I believe it is in the order of the cube of the speed - if so F1 is a different story all together. Up until now we have been just trying to find a good set up - when we have it though I'll make sure we check it out and report back. Baz
Neil Haughey
New member
Something else about the boxster and Cayman, they have a relatively wide rear track in relation to the front track. This is a bit unusual, I have just been looking back at the last couple of Ferrari mid engined models and they all had a front track wider than the rear track, typically about 2" (430/458). The 944/968 again all had a slightly wider front track and it seems to have been an accepted norm for a long time to do things this way to the point that one suspension/chassis guru I read refereed to it as a design rule. Interesting to see that Porsche went on a different path with their mid engined car, and even more surprising that reports of fitting even the weak R LSD (ZF type with practically no preload) on the Cayman indicate corner exit understeer which in turn to my mind points to issues elsewhere which must be incorrect as the car should push round with 2" more track width on the back and wider rear tyres (which would mean the contact patch on the outside rear is even further out than the 2" extra track width).
Steve Brookes
Moderator
Here's a little video from the pit wall on the Friday test day that I've been meaning to post: [link=http://youtu.be/FfLiayhqWRE]Friday testing at Oulton[/link] I've not been able to edit it because it was the wrong format for me. So you'll have to put up with the gaps between cars coming by and the banter between Paz and myself. [
] However, it gives a good indication of the speeds on the main straight and shows Mr F doing a 1:59 lap.
] However, it gives a good indication of the speeds on the main straight and shows Mr F doing a 1:59 lap.
Steve Brookes
Moderator
Some more in car video from the races to watch: [link=http://www.youtube.com/watch?v=qfiS4vH4kgE&list=UUtxvJUiKhx00q7zQHA84YdA&index=1&feature=plcp]The Goose in car video - Race 1[/link]
Steve, That's not quite right in my view. There are 2 elements at play here. Firstly, how much time on any given circuit does a car spend in the corners vs on the straight. i.e. If the car spends more time on the straights then a high speed on the straight will be worth more. The other is that carrying speed through the corner means you carry that extra speed all the way down the next straight. In terms of measuring the trade off, you need to pick a corner before a long straight, check apex speed, exit speed and final speed and compare data between wing / no-wing. I'd be suprised if the benefit of the rear wing on a boxster offset the drag down the straight, and would be suprised if there was much difference in lap times in either config. Although I dont know. Does anyone know what sort of negative lift the boxster rear wing gives.
Neil Haughey
New member
http://www.mitchellsoftware.com/DriveSim3.htm I haven't asked Baz about this but in all likelihood this is the software he is using. Interesting point about corner speed v time taking to complete a long straight. Ppl say this all the time that you carry that extra speed down the straights but its pretty obviously not true due to the huge effect of aerodynamic drag, especially on cars like ours.
Steve Brookes
Moderator
Hugh, my view is that Porsche put spoilers on all their road cars for a reason. Most notably a fixed wing on the GT3 and their race cars all have huge wings. I tend to think they know what they're doing by doing this and therefore I believe the boxster would also benefit from the aero provided by the spoiler, especially since the boxster should have the advantage over a 911 from the entry to the apex. Hence, why I suggested it would be worth looking in to for the benefit of the drivers and the team. Many of the corners at Oulton are 60+ mph at the apex for these guys (Old Hall, Cascades, Island, druids). For me these are high speed corners and a spoiler would be a benefit. In the forthcoming races at Donington where they have high speed curves - Hollywood through Craners and Schwantz curves I think they'll be able to carry more speed with a spoiler than without. I also worry that without, there is the danger that they could suddenly lose the back end on a high speed curve (especially at the aformentioned curves where they'll be into 3 figures). I find it odd that the rules insist that a 911 with an automatic spoiler must have it fixed in the up position but the 3.2 boxsters have the choice. Not so much for parity, more for safety.
Neil Haughey
New member
He has earned a living for the past few generations doing this stuff for pro race teams. Sorry I don't understand your point at all Paul. He is no different to most professional engineers in many domains. Club level motorsport is the only industry I know of that thinks like this so there is nothing unusual about your point.
If the spoiler being up was a safety issue then it would be the rule for it to always be up - not optional. There are many other issues to consider - not least of which is that larger capacity engines have flatter torque curves so while the power to weight ratio limits are worked out on peak bhp (regardless of how fair or unfair they may be) larger capacity engines should accelerate better. Now if you provided so much rear wheel loading (through aerodynamics) to enable a Boxster to make that up against 3.4 and 3.6 litre engines - you still could not get around them on the racing line until you were on the straights - when your own aerodynamics would work against you. Racing is different to single car qualifying and in this regard - I think we are doing the right thing at the moment until we get time to look at our engine performance. At the moment the engines are bog standard - but the rules allow for changing the rev limit, and the fuelling and ignition timing. The latter can always improve the low down torque (even if the maximum bhp is controlled) so we may get enough of an improvement to consider trying the spoiler some time in the future - at the moment I think it would slow us too much by ther end of the straight when we may be looking to outbrake the car in front (where most racing overtaking is accomplished). Simulation is all well and good (and extremely accurate) but I think it would have to include the baulking effect of a slower or faster car in front on the racing line to prove or dissprove the theory and compare results. Baz
Neil Haughey
New member
Its a similar argument to those stateside racing spec 944 who always say to go for the lower 5th gear swap out. As one experienced racer over on one of the US forums put it when you need to use 5th the guy with the lower 5th just drives past and there is nothing you can do to stop it, once that guy is in front your toast. You guys have a similar problem, faster cornering is useless if the guy in front is backing you up yet has the legs on the straights to make it impossible to get back past again.
On the road cars, I would guess Porsche put spoilers on for high speed stability for autobahn type speeds, i.e. speeds not achieved on a UK circuit (much), I dont see it as a safety issue. Race drivers with a loose car should be able to manage, plus they can tune the balance through setup, plus the balance wont suddenly change, the car will just oversteer. On Porsche race cars (like carrera cup), then there is significant aero that translates to differences in lap times (loss of front lip spoiler etc.), for a road car (like the boxster), I'd be suprised if the wing did much, and whether that adds more than the drag down the straight loses. The debate can rage, until some provides data with / without on a specific circuit with a consistent driver. For example, on our slicks and wings single seater, running low down force at Oulton works well, we could measure 2-3mph advantage at entry into Old Hall, and couldnt reliably detect apex difference (large we thought due to the bumpiness of the track prevented us getting the aero working effectively and us consistent). At Cadwell (smoother track) adding more wing resulted in better overal lap times. However, to put this in context, I think we found 0.5 secs on setup. With a 1:24.6 but leaders were lapping in the 1:23s. Therefore we are giving away 1.5 secs elsewhere, of which I doubt the majority is setup. As with all these things drive ability is probably of greater impact than -10kg of lift on the back of a 1200kg Boxster. Just my thoughts, happy to be proved wrong.
Steve Brookes
Moderator
Interesting thoughts Hugh. Thanks [
]. The above points were my points too! I asked a question as to why no spoiler (the answer being they have the choice) and then dared to suggest they try it with a spoiler to see if they could get a better lap. If they don't, fair enough but if they, do being in front of the 911s on the grid has surely got to be better than trying to get past them in the race. However, even though I'm happy to be proved wrong, this seems to have hit a raw nerve with some, so I'll butt out as some people are all getting too serious now! A bit like some of the team garages on race day![]You certainly have not hit any nerves with me Steve - I was just following the points raised and answering them from our point of view for the interest and benefit of others reading who may like to read about the choices and issues we have to deal with and why. We don't yet know if we are right about the rear spoiler - so time will tell - but we can at least explain our thoughts and why we have not yet chosen to test it ahead of some other things we regard as more relevant just now. Time testing is expensive and we have too many other things to compare and as we improve the car we cannot then compare some previous performance when the latest changes were not made so we have to push on until we have it basically sorted (which we have not got to yet) and then some other issues like this can be tested. It is all a matter of priority and we have to use our ability to think out the why's and where'fors to make those choices fo which tests are likely to reveal the highest benefits and frankly it is a bit of a lottery and until atest is over - you don't really know if that priority list was right or wrong.. I think it has been an interesting debate and hope it continues - your contributuion is in my opinion valuable and constructive - and I hope you carry on for the benefit of all the others who were probably thinking the same but not bothered to post the questions. Baz
vitesse
Active member
Baz, My son Nicholas(you did some work on the 944 Turbo he had a couple of years ago) & I were also in attendance at Oulton & were really quite interested to see how your cars & the 996's performed against the seasoned competition so I have been following this thread with great interest. However,I can't say that I have delved into such things as the regulations re modifications etc. You say your engines are bog standard-does this mean you cannot "blue print" them,& have you actually done your renowned cylinder & IMS mods to them?
StuartR16
New member
Yes Steve keep it up, I too am reading with interest. I can see that eventually the drag during a long straight will overcome an MPH gain on a bend but how many circuits do we have that have really long straights? Silverstone is one and what is at the end of each straight? A high speed bend. Even without the spoiler I would not have been able to keep up with Andy and David at Oulton but being able to go faster through the corners kept me up there with them as you could see on the video. As A driver it is a confidence thing as well so I will be keeping my spoiler thanks. As to Blue printing, if you can afford to you can, remember that Baz has two cars to run. But there is still the Maximum Horse power that is allowed in the regs and is probably achievable by other means.
Yes Stuart, one or two people getting a bit serious I agree. I only shared some of this information for the benefit of readers who are interested and in response to some questions they asked or points they raised. There were several Internet forums asking why we didn’t use the spoiler and some implied we might not have thought about it. I just wanted to point out that there are lots of different settings we are testing and each one needs optimising. The permutations are massive and there is not time or money to go through them all and even if there was – you need consistent weather for comparisons and it would take months if not years to get it all spot on. From our relatively inexperienced position we have to think out a priority list and work through it – mainly while racing (not ideal). I have just been sharing our conclusions – not making out that we know everything nor that our ideas fit anyone else’s needs or that they are wrong – and we may be wrong ourselves (quite likely with our lack of racing experience). For the reasons already stated the spoiler is not yet high enough on that list – but as you can see we did think about it. We have a different type of spoiler to most others (and different to the Aero deck spoiler that the 2.5 Boxster can use) and the way it works provides different considerations to the normal type (why I will keep to myself unless others post with knowledge) – I do however think that a 2.5 Boxster (I think the smallest engine and lowest power currently in the races in class 2) may well benefit from using the aerodeck spoiler and we may also if we could use it – but we cannot and the one we have does not work the same way and has different considerations. I am not telling anyone else what they should do nor commenting on their choice – I am merely pointing out what we are doing and why - that we thought out the spoiler issue and decided on a conclusion and are acting on it – we may well be wrong but we didn’t fail to consider it and with 2 podiums in the first 4 races – we could not be too far out. It may well be different racing at the front to further back (I don’t know) but near the front you cannot easily overtake on the racing line in a corner and most passes take place by out-braking which requires being close at the end of a straight. I think if you can keep station with other competitors but are faster through the corners you must logically be slower down the straights so probably right for a 2.5 to try and re-gain position through faster cornering if you can - always exploiting any benefit or advantage you may have. Regarding the engines – they do not have our alloy/Nikasil sleeves and are standard inside except for out IMS bearing and mods for the acusump and Hartech deeper sump (all for reliability not speed). There is not much you can do to increase the maximum bhp anyway with all the restrictions (that even forbid cleaning up the inlet ports) and we wanted some reliability first anyway. We preferred to have to get the handling right first and foremost (concentrating on that) and now we are reasonably competitive it is time to shift our focus on other things – like engine and braking performance etc. We are allowed to change some things within the rules but despite knowing there are some other cars out there with more than the allowed output (where owners/drivers never expect to be tested) we feel it is inevitable for us to be and so not only would not want to break those rules but would anyway get caught out if we tried (the repercussions of which would work against everything we are trying to achieve by going racing as a Porsche business). Last season we followed our dyno tune up with a trip to the Championship designated control dyno and found that it provides different results (due to different losses and different units etc) so know now what the differences are between them and can keep inside the limits without a need for that trip this time. When we do get the dyno tuning done – it is unlikely that we would be able to get more than the 5% allowance at maximum bhp anyway but we would hope to get more torque lower down the range (which is entirely legal as long as the maximum bhp is not exceeded). Raising the rev limiter may help allowing the car to run on in a gear when the gearing just doesn’t suit a circuit in a critical place. Regarding our pit garage performance - I hope the criticism was not directed at us - although I have to admit that we are finding it necessary to concentrate during practicing, qualifying or racing (and don't then have time to talk to others while we are taking readings when the car comes in, deciding how to improve it, working the pit board etc – all new to us – and we have 2 former Champions driving for us and feel the need to try our very best for them) – so there will be times when we need space and nothing to detract us from that task – but away from that we have time for people and Steve you are welcome at any other time. Fixing the clutch plate between races demanded utmost concentration but we did it (well the technicians did). I hope our concentration is not misinterpreted as arrogance – our guys have already spent their evenings helping other drivers fix their cars and we are a friendly lot – but are there to do a job we are not used to and at a high level (if we can). Our guys also like a bit of fun when appropriate (as you will see if one of them ever shows the video of his new individual powered transport system). We are racing to learn,.enjoy the competition, create a good team spirit and create interest and development for our staff (and we are all loving every minute of it and benefiting enormously as a business). If I explain what we are doing or answering questions – I am not being critical of what anyone else is doing and I am not telling them what they should do or assuming we know it all (we most certainly do not) – I am just explaining what we have done and why – but if that simple intention is misunderstood perhaps I too should just keep it to ourselves – and have no problem in doing just that. Anyone reaching the top in any profession eventually realises that they have to do it for themselves – there is always a lot of misinformation and old wives tales (some of which are right often many others are wrong or misleading). By discussing our thoughts and decisions I was merely providing an alternative view and am interested to read what others think (it all adds to the overall picture) – but please don’t misunderstand those intentions – they are entirely innocent. Role on Donnington Park – lots to do to the car in the meantime and too busy at work – so can only try our best and carry on learning and hopefully providing the sort of car our drivers can do well in. Baz
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