Startline/Tracklights!
Discussion
The startline proved very tricky for most classes at the weekend, why was new tarmac laid and wouldnt it have been better to have done this after the FIA event?. Personally I feel that we have lost out big time this past weekend. I know there was records run in certain classes the Svensson boys unbelievable well done guys! but the first couple of days lets face it the startline was dire and only really started to come round late Saturday. Im not going to mention any names but there was certain Top Fuel crew guys playing hell with the state of the startline (I heard it in the pits) and put it this way the words they were using was not "Oh the startline isnt very good". Generally Pro stock and Pro mod really struggled the first couple of days look at the numbers being run. I feel the Pod is going to lose out big time next year with the FIA events especially with the rise of Tierp I can see alot of teams not coming over to race now as we have started to see this year especially in Pro Mod with certain big names missing, they'l just race at Tierp. I know this is very negative but feel it needs saying, I have not seen anywhere stating why the new tarmac was laid and why a week before an FIA event. One last thing PLEASE Santa Pod invest some money into some decent track lights, Saturday night yes was awesome but was also damn right dangerous god knows how the drivers managed to drive down the track, well done on the drivers who did get down the track. Kenni Neergaard summed it up after his run when he said the words to the affect of "All I could see was the scoreboard" I counted at least 8 lights not working and each lampost had a mounting of 3 lights on it why on earth were they not on?. Rant over now.
i think 1 pro mod managed to put a string of reasonable laps together Marc
a couple of others had one or two good laps during the event but couldnt repeat,
MG stuggled like hell and thats not usual Andy R couldnt figure it out and hes a good bet to run good at santa pod instead he shook so hard he busted his axle case badly and couldnt continue..my first ever full lap in a pm car 4 years ago was 6.81 couldnt get near that in qualifying, johan lindberg no 8 qualifier?
i talked to a pro stock clutch guy he said they were launching 2000 rpm lower than usual to try to get away yes 2000 not 200,
we eventuly got the lowest et of any british racer but it wasnt exactly anything to shout about
bump in the 7s again.....
this time last year it was 6.50
not much else to say realy facts speak for themselves
a couple of others had one or two good laps during the event but couldnt repeat,
MG stuggled like hell and thats not usual Andy R couldnt figure it out and hes a good bet to run good at santa pod instead he shook so hard he busted his axle case badly and couldnt continue..my first ever full lap in a pm car 4 years ago was 6.81 couldnt get near that in qualifying, johan lindberg no 8 qualifier?
i talked to a pro stock clutch guy he said they were launching 2000 rpm lower than usual to try to get away yes 2000 not 200,
we eventuly got the lowest et of any british racer but it wasnt exactly anything to shout about
bump in the 7s again.....
this time last year it was 6.50
not much else to say realy facts speak for themselves
Edited by wicked fish on Monday 12th September 13:22
The new tarmac was laid because the track was going to become completely unsafe and unusable about half way through the event if they hadn't. How popular would that have been? The track held several 4.9s, a 5.65 in TMFC and a 5.88 in TFB, so the prep was good. Also it was interesting to see how each lane developed during the event.
Track lighting is there for the benefit of the spectators, not the drivers.
Track lighting is there for the benefit of the spectators, not the drivers.
Jon C said:
The new tarmac was laid because the track was going to become completely unsafe and unusable about half way through the event if they hadn't. How popular would that have been? The track held several 4.9s, a 5.65 in TMFC and a 5.88 in TFB, so the prep was good. Also it was interesting to see how each lane developed during the event.
Track lighting is there for the benefit of the spectators, not the drivers.
whatever the reasoning behind it all the classes you just mentioned have no suspension,Track lighting is there for the benefit of the spectators, not the drivers.
bikes go down the track at kunmadaras well also but no car can,
there has been talk of the scandanavians having a much bigger series at home and not comming here at all over the weekend,
with the best track in Europe in their back yard who would blame them,
I was told more than once Over the week end the reason they so willingly traveled to santa pod was for the best chance during the racing year to go fast set records and PBs
why would they come now??? actuly they wont only the guys fighting for the top spots in the fia series bothered,
dont know if anyone counted but there was 5 swedish PM teams, None from finland none from norway
Brits outnumber the Swedes in FIA pro mod at the Euro finals....WTF
Edited by wicked fish on Monday 12th September 13:19
We managed to get our car off the line reasonably ok but that was mainly due to going very soft with set up and turning the boost down off the line and trying to make it up later in the run.
A shame as we were very keen to lean on the car but couldn't as I'm sure numerous teams wanted to do also.
A shame as we were very keen to lean on the car but couldn't as I'm sure numerous teams wanted to do also.
I'm sure it wasn't done for s**** and giggles.....
Some people struggled, some people nailed it. Jimmy Alund 6.75 off the trailer? Sure it was a curve ball but for once can we please concentrate on good things instead of picking?
Storming runs for Peter Svenssen all weekend
Full passes in top fuel at night, how often do we get to see that! Risto, Micke and Kenni with bunny ears lit put tingled down my neck.
Rob and whole of the Turner team smashing the 5s and taking the win.
Top fuel pedalfest and settling the championship in the final.
Epic world class field of supertwins
A rare weekend as a full spectator I really enjoyed it, things ran well and smoothly, there was always something going on and Darryl & Colin once again did a stellar job keeping the masses informed and clued up - even for Darryl talking to 12 hours a day is a challenge
Or do we want to go back to complaining about the weather (I mean how dare it have a rain shower!?) how long it took to get out or something whiney about the toilets.
Stop being so typically British....
Some people struggled, some people nailed it. Jimmy Alund 6.75 off the trailer? Sure it was a curve ball but for once can we please concentrate on good things instead of picking?
Storming runs for Peter Svenssen all weekend
Full passes in top fuel at night, how often do we get to see that! Risto, Micke and Kenni with bunny ears lit put tingled down my neck.
Rob and whole of the Turner team smashing the 5s and taking the win.
Top fuel pedalfest and settling the championship in the final.
Epic world class field of supertwins
A rare weekend as a full spectator I really enjoyed it, things ran well and smoothly, there was always something going on and Darryl & Colin once again did a stellar job keeping the masses informed and clued up - even for Darryl talking to 12 hours a day is a challenge
Or do we want to go back to complaining about the weather (I mean how dare it have a rain shower!?) how long it took to get out or something whiney about the toilets.
Stop being so typically British....
MotorPsycho said:
Full passes in top fuel at night, how often do we get to see that! Risto, Micke and Kenni with bunny ears lit put tingled down my neck.
Yep, and Timo Lehtimäki. Also Grumpy's run in the dusk in TMD on Saturday. Maybe not the same height bunny ears as you get with the blown cars, but still present and lit for the full 1320'.
Getting technical for a moment can anybody on here explain why (if it's true) there appeared to be reduced grip on the startline following the resurfacing - I mean really technically?
I'm a civil engineer (but by no means a macadam expert). What I do know is that macadam is a flexible mix of stone (aggregate) and bitumen binder, sometimes with polymer additives to induce certain charactistics associated with the type of traffic use and expected life span of the pavement. The type of binder also affects the flexibilty of the surface and how easy it is to lay. The amount of grip is determined by the polished stone value (PSV) of the aggregate once the bitumen coating has worn away. Sometimes if the level of grip is not acheived, the surface has to be treated (e.g. water jetted) until it reaches the correct level of skid resistance. Better skid resistance can be achieved with epoxy binders and special (bauxite etc.) aggregates - hence the buff coloured 'tarmac' we all see at traffic lights etc.
However on a drag strip surely this is all irrelevant as the macadam is deliberately covered with a mixture of rubber and VHT compound (or whatever it's called these days). It was mentioned in the commentary on Saturday at the Pod that the VHT modifies the rubber layer and makes it soft and sticky. Before this I had assumed the VHT was like an 'evo stick' coating but presumably this is not the case. This implies that the mechanism of grip is not friction but some sort of chemical bonding between the tyre surface and the track coating. Adhesion rather than friction.
New macadam can take quite a while to 'cure' as the volatile compounds in the bitumen mix evaporate off. I can imagine if the volatiles were still in there when the rubber etc. was first laid down, this could affect their adhesion. But as far as I could see there was no evidence of sheets of rubber de-laminating off the macadam so what was the mechanism causing the lack of grip? Or was it that there was lots of grip on the new bit of tarmac then a sudden change of grip at the transition to the old? I noticed that when Andy Frost and a few others ran, they didn't burn out accross the sart line. Was this deliberate in order to avoid laying rubber that might subsequently de-laminate or am i reading too much into it?
I still don't get why if there is a full coat of rubber and VHT on top of the macadam how the new macadam can result in any lack of adhesion between the tyre and the surface. Neither do I understand why concrete (which is a much less flexible mix of aggregate and cement binder rather than bitumen) can affect the grip when again there is a thick layer of rubber/VHT on top of it. Yet everyone claims that concrete is a better surface.
It would be really great if somebody deeply involved in the technical spec. of the strip surface could explain these things to the great unwashed (myself included of course). Alternatively somebody who witnessed the startline at close quarters might be able to explain? Cheers.
I'm a civil engineer (but by no means a macadam expert). What I do know is that macadam is a flexible mix of stone (aggregate) and bitumen binder, sometimes with polymer additives to induce certain charactistics associated with the type of traffic use and expected life span of the pavement. The type of binder also affects the flexibilty of the surface and how easy it is to lay. The amount of grip is determined by the polished stone value (PSV) of the aggregate once the bitumen coating has worn away. Sometimes if the level of grip is not acheived, the surface has to be treated (e.g. water jetted) until it reaches the correct level of skid resistance. Better skid resistance can be achieved with epoxy binders and special (bauxite etc.) aggregates - hence the buff coloured 'tarmac' we all see at traffic lights etc.
However on a drag strip surely this is all irrelevant as the macadam is deliberately covered with a mixture of rubber and VHT compound (or whatever it's called these days). It was mentioned in the commentary on Saturday at the Pod that the VHT modifies the rubber layer and makes it soft and sticky. Before this I had assumed the VHT was like an 'evo stick' coating but presumably this is not the case. This implies that the mechanism of grip is not friction but some sort of chemical bonding between the tyre surface and the track coating. Adhesion rather than friction.
New macadam can take quite a while to 'cure' as the volatile compounds in the bitumen mix evaporate off. I can imagine if the volatiles were still in there when the rubber etc. was first laid down, this could affect their adhesion. But as far as I could see there was no evidence of sheets of rubber de-laminating off the macadam so what was the mechanism causing the lack of grip? Or was it that there was lots of grip on the new bit of tarmac then a sudden change of grip at the transition to the old? I noticed that when Andy Frost and a few others ran, they didn't burn out accross the sart line. Was this deliberate in order to avoid laying rubber that might subsequently de-laminate or am i reading too much into it?
I still don't get why if there is a full coat of rubber and VHT on top of the macadam how the new macadam can result in any lack of adhesion between the tyre and the surface. Neither do I understand why concrete (which is a much less flexible mix of aggregate and cement binder rather than bitumen) can affect the grip when again there is a thick layer of rubber/VHT on top of it. Yet everyone claims that concrete is a better surface.
It would be really great if somebody deeply involved in the technical spec. of the strip surface could explain these things to the great unwashed (myself included of course). Alternatively somebody who witnessed the startline at close quarters might be able to explain? Cheers.
jonermart,
I'm not sure you'll get too many takers on this but I'll give you a 'tuners' point of view.
In short, after a number of years, I still don't really understand how much of the grip we look for on a start line is a function of chemical bonding between the tyre tread surface and the traction compound that is applied by the start line crew and how much is due to the 'mechanical keying' with the texture of the surface.
The cars on which I have worked have a reasonably high power output and as such, are capable of applying an unreasonably high load through the tyre sidewall, thus distorting the tread belt. In order to combat this we look for an optimal 'slip ratio' ( wheel speed vs time ) which will allow the tyre carcass and tread belt to hold an acceptable shape as the car moves off the start line and through the first part of the run.
Looking at the chemical element first, history has indicated to me that an instant, strong chemical bond between the track surface and the tyre makes it extremely difficult to initiate and maintain acceptable slip ratios. The friction coefficient between the two surfaces is ( in my opinion ) not progressive and as the initial drive load builds, the tyre contact patch distorts to an unacceptable level. If the bond strength increases noticeably over a short period ( as with many adhesives ) then the difference between staging first or second ( several seconds ) can be significant. How this bond strength compares to that of the macadam, aggregate / bitumen binder is doubtless another topic.
A less 'aggressive' chemical bond and some mechanical 'keying' generally gives us a far bigger tuning range and as a result, most crew chiefs will try to position the car on what appears to be the 'dullest' part of the start line as this usually has the most suitable adhesive elements.
It would appear that the difficulty experienced by most teams at Santa Pod last weekend was the transition between the old and new surface. It would have been relatively easy to make a run on either but moving from one to the other was tough. Tuners and crew chiefs got excited because most of us aren't as smart as we think and a few of us are just thick. In our case the data was there for me to see after the first run Friday and I missed it. In fact it took three of the four runs we had before I picked it up but by then we were way behind so I guess that makes me thick. The bottom line is that the meeting was there for the taking but by close of play Saturday at least 18 people were smarter than me and we missed our shot so, you suck it up and move on.
My 2 cents worth
If you want to break records and set personal bests, move to Tierp for a few years. If you want to go Drag Racing, strap on a pair and step up to the plate.
I'm not sure you'll get too many takers on this but I'll give you a 'tuners' point of view.
In short, after a number of years, I still don't really understand how much of the grip we look for on a start line is a function of chemical bonding between the tyre tread surface and the traction compound that is applied by the start line crew and how much is due to the 'mechanical keying' with the texture of the surface.
The cars on which I have worked have a reasonably high power output and as such, are capable of applying an unreasonably high load through the tyre sidewall, thus distorting the tread belt. In order to combat this we look for an optimal 'slip ratio' ( wheel speed vs time ) which will allow the tyre carcass and tread belt to hold an acceptable shape as the car moves off the start line and through the first part of the run.
Looking at the chemical element first, history has indicated to me that an instant, strong chemical bond between the track surface and the tyre makes it extremely difficult to initiate and maintain acceptable slip ratios. The friction coefficient between the two surfaces is ( in my opinion ) not progressive and as the initial drive load builds, the tyre contact patch distorts to an unacceptable level. If the bond strength increases noticeably over a short period ( as with many adhesives ) then the difference between staging first or second ( several seconds ) can be significant. How this bond strength compares to that of the macadam, aggregate / bitumen binder is doubtless another topic.
A less 'aggressive' chemical bond and some mechanical 'keying' generally gives us a far bigger tuning range and as a result, most crew chiefs will try to position the car on what appears to be the 'dullest' part of the start line as this usually has the most suitable adhesive elements.
It would appear that the difficulty experienced by most teams at Santa Pod last weekend was the transition between the old and new surface. It would have been relatively easy to make a run on either but moving from one to the other was tough. Tuners and crew chiefs got excited because most of us aren't as smart as we think and a few of us are just thick. In our case the data was there for me to see after the first run Friday and I missed it. In fact it took three of the four runs we had before I picked it up but by then we were way behind so I guess that makes me thick. The bottom line is that the meeting was there for the taking but by close of play Saturday at least 18 people were smarter than me and we missed our shot so, you suck it up and move on.
My 2 cents worth
If you want to break records and set personal bests, move to Tierp for a few years. If you want to go Drag Racing, strap on a pair and step up to the plate.
That's a great response Rob. So could it be that too much traction compound on the new macadam area is the issue? From what you say I guess it might be that the initial 'extra' adhesion might cause an 'over-fat' tyre footprint that when it rebounds causes excessive distortion, further rebounding etc. and not a smooth transition to a 'just spinning' tyre which if I understand you correctly is ideal from a tuners point of view.
No doubt there are lots of secondary factors like the pattern of weight transfer onto the rear wheels, the uplift that presumably happens when the wheelie bars hit, the effect of the front wheels sharing more load as the weight transfers forward again - and so on. There's definitely a phd in this for some lucky student.
I expect I'm getting into Grandma sucking eggs territory but Impalakungens fantastic youtube channel has some great slo mo videos of various traction scenarios, which are worthy of study. Here's a couple - hope the links work...
http://www.youtube.com/user/impalakungen#p/u/30/FD...
and
http://www.youtube.com/user/impalakungen#p/u/31/0o...
I need to get to the bottom of this because with a fair wind I should be part of a racing partnership next year. So far we've bought the vehicle towards it. I love the technical stuff.
No doubt there are lots of secondary factors like the pattern of weight transfer onto the rear wheels, the uplift that presumably happens when the wheelie bars hit, the effect of the front wheels sharing more load as the weight transfers forward again - and so on. There's definitely a phd in this for some lucky student.
I expect I'm getting into Grandma sucking eggs territory but Impalakungens fantastic youtube channel has some great slo mo videos of various traction scenarios, which are worthy of study. Here's a couple - hope the links work...
http://www.youtube.com/user/impalakungen#p/u/30/FD...
and
http://www.youtube.com/user/impalakungen#p/u/31/0o...
I need to get to the bottom of this because with a fair wind I should be part of a racing partnership next year. So far we've bought the vehicle towards it. I love the technical stuff.
haha - great quote ! 
Mark from abbey Motorsport often gives me that look & says - this going in a straight line lark makes my head hurt !!
Mark from abbey Motorsport often gives me that look & says - this going in a straight line lark makes my head hurt !!
Barry B said:
Fascinating insight into what, to me, is a 'black art', an engineer's take and a crew chief's take, truly fascinating. Who said driving in straight lines was a doddle ?
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