[Max Well]

Originally Posted by ltym5

Don't think I'll go to track, FSociety and I both know someone that broke a driveshaft and transfer case launching at the track.

Hmmmh... trying to figure how launching at a sanctioned Strip with a groomed surface vs. on a street using Dragy to record would produce more risk? The performance pressure is definitely there at a strip as the conditions are more restrictive -lots of hobbyists and spectators and you can't do infinite number of runs, but the Physics are the same. Do you know anything about the tire psi they were running?

[hellcat2m4]

Must be some badass track prep to do that.

[floating.spirit]

Originally Posted by Max Well

Hmmmh... trying to figure how launching at a sanctioned Strip with a groomed surface vs. on a street using Dragy to record would produce more risk? The performance pressure is definitely there at a strip as the conditions are more restrictive -lots of hobbyists and spectators and you can't do infinite number of runs, but the Physics are the same. Do you know anything about the tire psi they were running?

High altitude?

[YasM3]

Originally Posted by Max Well

Hmmmh... trying to figure how launching at a sanctioned Strip with a groomed surface vs. on a street using Dragy to record would produce more risk? The performance pressure is definitely there at a strip as the conditions are more restrictive -lots of hobbyists and spectators and you can't do infinite number of runs, but the Physics are the same. Do you know anything about the tire psi they were running?

The track is MUCH stickier than the road which puts much more stress on the drivetrain and will break parts from time to time.

[serpentine]

The launch area is pretty tacky, way stickier than road asphalt, so to me that alters the physics a bit. Back in my fast and furious days I thought I did serious damage on my Type R. Wheel hop in that little FWD was unlike anything I had ever felt before. The limited slip fighting itself to transfer power between the front wheels violently shook me.

[YasM3]

Originally Posted by serpentine

The launch area is pretty tacky, way stickier than road asphalt, so to me that alters the physics a bit. Back in my fast and furious days I thought I did serious damage on my Type R. Wheel hop in that little FWD was unlike anything I had ever felt before. The limited slip fighting itself to transfer power between the front wheels violently shook me.

Its more than just the launch area at a real drag stripped that is prepped. The whole track is prepped all the way to the finish line. If you actually tried to walk on a prepped track, your feet would stick to it pretty well. Its pretty amazing. A good prepped track is a parts killer for sure and will find the weakest link in any vehicle.

[Max Well]

Originally Posted by YasM3

The track is MUCH stickier than the road which puts much more stress on the drivetrain and will break parts from time to time.

Originally Posted by YasM3

Its more than just the launch area at a real drag stripped that is prepped. The whole track is prepped all the way to the finish line. If you actually tried to walk on a prepped track, your feet would stick to it pretty well. Its pretty amazing. A good prepped track is a parts killer for sure and will find the weakest link in any vehicle.

For sure. I'm familiar with the process as I've researched how they prep in addition to getting there early and actually watching them do it. But I would suggest that has the most relevance to those with slicks and drag radials who burn out and have plenty of contact patch to grab.

My experience with my stock X3MC with OEM 21" street tires (255F/265R), especially at OEM recommended tire pressures of 33F/38R, was frequent spinning off the line, and occ between 1st-2nd as well. forza1976 recently indicated he also felt such even going from 2nd-3rd gears [ https://x3.xbimmers.com/forums/showp...&postcount=225 ]. I always go around the water and suspect many of us do, so with DSC off, unless one is at a really low tire psi to enhance grab, I was indicating more along the lines that I would think they would spin before grabbing hard enough to begin breaking parts (esp with the robust design built into these models, and moreso the Comp versions). Also, if interval times on the street (esp 0-60' and 60'-330' portions) are similar to those at the Strip, would it not imply similar traction/grab was present, assuming of course all other factors are equivalent as well (DA, etc) and thus the same forces on components?

Which is why I asked about the tire psi of the X3M owner who had the parts failure. If it was indeed lowered enough to allow enhanced grab, with that much power (St2 and above), then yes - especially if multiple launches have been done on the vehicle during it's operating life which may have lead to metal fatigue. The problem is we often don't know all the specifics on runs some share and end up just seeing the results. Another reason why the effort is being made on the 1/4 mile thread to provide all data one needs to analyze others' slips.

[YasM3]

Originally Posted by Max Well

For sure. I'm familiar with the process as I've researched how they prep in addition to getting there early and actually watching them do it. But I would suggest that has the most relevance to those with slicks and drag radials who burn out and have plenty of contact patch to grab.

My experience with my stock X3MC with OEM 21" street tires (255F/265R), especially at OEM recommended tire pressures of 33F/38R, was frequent spinning off the line, and occ between 1st-2nd as well. forza1976 recently indicated he also felt such even going from 2nd-3rd gears [ https://x3.xbimmers.com/forums/showp...&postcount=225 ]. I always go around the water and suspect many of us do, so with DSC off, unless one is at a really low tire psi to enhance grab, I was indicating more along the lines that I would think they would spin before grabbing hard enough to begin breaking parts (esp with the robust design built into these models, and moreso the Comp versions). Also, if interval times on the street (esp 0-60' and 60'-330' portions) are similar to those at the Strip, would it not imply similar traction/grab was present, assuming of course all other factors are equivalent as well (DA, etc) and thus the same forces on components?

Which is why I asked about the tire psi of the X3M owner who had the parts failure. If it was indeed lowered enough to allow enhanced grab, with that much power (St2 and above), then yes - especially if multiple launches have been done on the vehicle during it's operating life which may have lead to metal fatigue. The problem is we often don't know all the specifics on runs some share and end up just seeing the results. Another reason why the effort is being made on the 1/4 mile thread to provide all data one needs to analyze others' slips.

Track prep will affect all tires. Yes, drag radials or slicks will have more grip than stock tires, but at the track even on stock tires, they will benefit from the prep. At the power levels these vehicles are making, it can still break on the street as well. There is no set # of launches that it will break at. Adding 200+HP/TQ and hooking at the track will increase the chances of breaking parts.

Yes, if you are not burning out, going around the water is a must. But just because you didnt do a burnout does not mean the track is equal to the street. Even if tire pressures and temps are the same(street to track), the track will put more of a strain on the vehicle vs the street due to the prep.

[Max Well]

Originally Posted by YasM3

Track prep will affect all tires. Yes, drag radials or slicks will have more grip than stock tires, but at the track even on stock tires, they will benefit from the prep. ... But just because you didnt do a burnout does not mean the track is equal to the street. Even if tire pressures and temps are the same(street to track), the track will put more of a strain on the vehicle vs the street due to the prep.

Thanks YasM3, but wishing to make sure it's clear what my point was - I'm not suggesting a Drag Strip surface is 'equal' to a street surface. I'm simply suggesting for Enthusiasts like us enjoying a day at the strip with street tires, that one venue should not produce more risk than the other with LC if one is serious about achieving maximum performance (which is what the goal in this is, at least for me).

I'd really be interested in seeing what FSociety and ltym5 could share in a formal fashion, as many of us do rely on formal slips to base assessments, and consider Dragy as interesting but not definitive. FSociety was one of the stalwarts in producing documented Strip runs back in the day, and actually was one of the main driving forces for me getting interested in the Sport.

So it was an interesting read to see ltym5 was not considering running at a formal strip based on the one's experience with malfunction. That was a definite change for me to learn some may be avoiding Strips because of that.

[MaxGainz]

Was there other such problem with the f90 m5? I was under the impression that we had the same transfer box as well

[YasM3]

Originally Posted by Max Well

Thanks YasM3, but wishing to make sure it's clear what my point was - I'm not suggesting a Drag Strip surface is 'equal' to a street surface. I'm simply suggesting for Enthusiasts like us enjoying a day at the strip with street tires, that one venue should not produce more risk than the other with LC if one is serious about achieving maximum performance (which is what the goal in this is, at least for me).

I'd really be interested in seeing what FSociety and ltym5 could share in a formal fashion, as many of us do rely on formal slips to base assessments, and consider Dragy as interesting but not definitive. FSociety was one of the stalwarts in producing documented Strip runs back in the day, and actually was one of the main driving forces for me getting interested in the Sport.

So it was an interesting read to see ltym5 was not considering running at a formal strip based on the one's experience with malfunction. That was a definite change for me to learn some may be avoiding Strips because of that.

I completely understand.

As far as enthusiasts just wanting to enjoy a day at the strip. There is really no answer to that. There is always a chance parts will break, especially at the strip.

The car that broke the Tcase, he may have been 1 or 2 street launches away from breaking on the street, there is no way to tell. My point is, the track just adds that 1 extra element of risk. A prepped track will always find the weakest link in a vehicle, even purpose built drag cars with big $$ parts. It is just too hard to tell someone they wont break something. There is no guarantee, even in a 100% stock vehicle.

I am an avid drag racer for about 20 years now. I have made hundreds and hundreds of passes of seat time in my personal vehicles. I have seen many stock vehicles on stock tires break parts. My personal vehicles as well. Some of my cars saw ALOT of street abuse and never broke and as soon as I hit the track, I found the weak links. But I have also broke parts at the track.

I wouldnt take 1 instance of someone breaking to scare you away from going to the track. But no matter what vehicle you are driving at the track, you have to go into it with the mindset that something can possibly break, especially when tuning a vehicle and adding 150-200+ whp/wtq above what the vehicle was designed for. There is always a risk. You have to remember you are launching a 4600+ # vehicle, when you add 150-200TQ to that, it definetely puts alot more strain to the drivetrain.

Originally Posted by MaxGainz

Was there other such problem with the f90 m5? I was under the impression that we had the same transfer box as well

I have yet to hear of an F90 Tcase breaking at the drag strip. But an F90 is lighter than an X3M. Not by a whole lot, but a few hundred #s. So that will help in keeping it alive a little bit. Remember this is only 1 instance of a reported brakeage. That does not mean everyone will have a catastrophic failure when using LC at the track, but I think as time goes on, and more tuned X3M/X4Ms hit the track, we will probably see more of them breaking. But like I said above, there is always a risk.

[floating.spirit]

Originally Posted by YasM3

I completely understand.

As far as enthusiasts just wanting to enjoy a day at the strip. There is really no answer to that. There is always a chance parts will break, especially at the strip.

The car that broke the Tcase, he may have been 1 or 2 street launches away from breaking on the street, there is no way to tell. My point is, the track just adds that 1 extra element of risk. A prepped track will always find the weakest link in a vehicle, even purpose built drag cars with big $$ parts. It is just too hard to tell someone they wont break something. There is no guarantee, even in a 100% stock vehicle.

I am an avid drag racer for about 20 years now. I have made hundreds and hundreds of passes of seat time in my personal vehicles. I have seen many stock vehicles on stock tires break parts. My personal vehicles as well. Some of my cars saw ALOT of street abuse and never broke and as soon as I hit the track, I found the weak links. But I have also broke parts at the track.

I wouldnt take 1 instance of someone breaking to scare you away from going to the track. But no matter what vehicle you are driving at the track, you have to go into it with the mindset that something can possibly break, especially when tuning a vehicle and adding 150-200+ whp/wtq above what the vehicle was designed for. There is always a risk. You have to remember you are launching a 4600+ # vehicle, when you add 150-200TQ to that, it definetely puts alot more strain to the drivetrain.

I have yet to hear of an F90 Tcase breaking at the drag strip. But an F90 is lighter than an X3M. Not by a whole lot, but a few hundred #s. So that will help in keeping it alive a little bit. Remember this is only 1 instance of a reported brakeage. That does not mean everyone will have a catastrophic failure when using LC at the track, but I think as time goes on, and more tuned X3M/X4Ms hit the track, we will probably see more of them breaking. But like I said above, there is always a risk.

You said u broke parts at a strip. Like what?

Tnx

[AlexFL]

Originally Posted by floating.spirit

You said u broke parts at a strip. Like what?

Tnx

Like phone holders and stuff. Those break pretty easily.

[floating.spirit]

Originally Posted by AlexFL

Like phone holders and stuff. Those break pretty easily.

I was wondering how long you could hold out...

[Razel]

Need a little education here. What is it about the track that is causing higher mechanical challenges than the street? Is the track surface more challenging than the rain-groves on a concrete overpass? I realize that rain-groves in concrete isn't the only street surface out there, but it's pretty gnarly if you get a chance to look up close and it has traction galore. I imagine the surface of the track is geared toward traction, but is it such a degree that the street surfaces are that much more forgiving?
Or, is it something else other than the lane surfacing?

For me right now, I see breaking a drive shaft on the street with Draggy is going to be 50/50 with breaking a drive shaft on the strip.

I've been on a race track with a motorcycle. Sears Point and Laguna Seca. Nothing special about the track surface. As for a drag strip, anyone remember Fremont Dragstrip in the San Francisco Bay Area? Last drag strip I've been to, so no telling how much has changed.

[AlexFL]

Originally Posted by floating.spirit

I was wondering how long you could hold out...

I have more than 50 years experience in Formula One racing. I can’t hold out.

[YasM3]

Originally Posted by floating.spirit

You said u broke parts at a strip. Like what?

Tnx

Not on my X3M.

On other vehicles. Axles, differentials, transmissions. Control arms etc.

[YasM3]

Originally Posted by Razel

Need a little education here. What is it about the track that is causing higher mechanical challenges than the street? Is the track surface more challenging than the rain-groves on a concrete overpass? I realize that rain-groves in concrete isn't the only street surface out there, but it's pretty gnarly if you get a chance to look up close and it has traction galore. I imagine the surface of the track is geared toward traction, but is it such a degree that the street surfaces are that much more forgiving?
Or, is it something else other than the lane surfacing?

For me right now, I see breaking a drive shaft on the street with Draggy is going to be 50/50 with breaking a drive shaft on the strip.

I've been on a race track with a motorcycle. Sears Point and Laguna Seca. Nothing special about the track surface. As for a drag strip, anyone remember Fremont Dragstrip in the San Francisco Bay Area? Last drag strip I've been to, so no telling how much has changed.

The main difference between street and track is a drag strip is prepped with traction compound. Its sticky as hell. If you tried to walk on it, its extremely tacky to the point your feet can stick to it.

[Wills2]

Originally Posted by YasM3

Not on my X3M.

On other vehicles. Axles, differentials, transmissions. Control arms etc.

So not a broken X3M then just other cars that have broken stuff on a prepped track? I'm sure that happens as people boost the power and grip but forget the poor drivetrain.

[YasM3]

Originally Posted by Wills2

So not a broken X3M then just other cars that have broken stuff on a prepped track? I'm sure that happens as people boost the power and grip but forget the poor drivetrain.

Correct, no broken parts on my X3M. Again, I have seen plenty of stock cars break at the track as well. A prepped track always finds the weakest link.

[FSociety]

Originally Posted by ltym5

Don't think I'll go to track, FSociety and I both know someone that broke a driveshaft and transfer case launching at the track.

LOL I know someone who broke on the street, and I know another guy who revs high as hell and hasn't broken. The guy on the street was just going through a bad wheel hop.

Originally Posted by Max Well

Hmmmh... trying to figure how launching at a sanctioned Strip with a groomed surface vs. on a street using Dragy to record would produce more risk? The performance pressure is definitely there at a strip as the conditions are more restrictive -lots of hobbyists and spectators and you can't do infinite number of runs, but the Physics are the same. Do you know anything about the tire psi they were running?

They had done a few passes already on BM3 successfully, then decided to try another tune called MHD. He rev'ed out as close to 3k as he could he mentioned and bam!
Maybe too much boost off that pull, maybe over boost, maybe was just going to happen who knows.

Originally Posted by Max Well

Thanks YasM3, but wishing to make sure it's clear what my point was - I'm not suggesting a Drag Strip surface is 'equal' to a street surface. I'm simply suggesting for Enthusiasts like us enjoying a day at the strip with street tires, that one venue should not produce more risk than the other with LC if one is serious about achieving maximum performance (which is what the goal in this is, at least for me).

I'd really be interested in seeing what FSociety and ltym5 could share in a formal fashion, as many of us do rely on formal slips to base assessments, and consider Dragy as interesting but not definitive. FSociety was one of the stalwarts in producing documented Strip runs back in the day, and actually was one of the main driving forces for me getting interested in the Sport.

So it was an interesting read to see ltym5 was not considering running at a formal strip based on the one's experience with malfunction. That was a definite change for me to learn some may be avoiding Strips because of that.

ltym5 and my car are making more power than the 2 cases of some drivetrain damage, it could be or is when the tires are slipping and hooks. I spoke to both and they both had the suspension in Sport+ which is meant for Road Course track not drag strip according to manual.

From experience launching X4 M40, F80 M3, F90 M5 the suspension should be in sport setting at the drag-strip and sport+ for road course.

[AlexFL]

Originally Posted by FSociety

LOL I know someone who broke on the street, and I know another guy who revs high as hell and hasn't broken. The guy on the street was just going through a bad wheel hop.

They had done a few passes already on BM3 successfully, then decided to try another tune called MHD. He rev'ed out as close to 3k as he could he mentioned and bam!
Maybe too much boost off that pull, maybe over boost, maybe was just going to happen who knows.

ltym5 and my car are making more power than the 2 cases of some drivetrain damage, it could be or is when the tires are slipping and hooks. I spoke to both and they both had the suspension in Sport+ which is meant for Road Course track not drag strip according to manual.

From experience launching X4 M40, F80 M3, F90 M5 the suspension should be in sport setting at the drag-strip and sport+ for road course.

What I learned from the past is that after adding 30+% hp/torque, it is probably a good idea to stop launching/brake boosting etc. You can measure performance increase in rolling, no need to put so much strain on the drivetrain. Even though it is super tempting to measure that god damn 0-60 or 1/4 mile, there will always be one launch too much.