Wheel hop with launch control

[phdibart]

I tried out the launch control the other day on my 4BW 6M and was getting really bad wheel hop. It was a typical New England fall day: dry as a bone and sunny with temps in the mid-40s. My tire pressures were 35 all around, slightly warmed up to about 36 psi per the dash indicator, and I'm running the factory tires with about 7,600 miles on them. I note the conditions because it's not like these are brand new tires or I had them underpressured. I was in competitive driving mode, so no PTM mode, with launch control set to automatic. Note that I don't have the steering wheel PTM switch, so from my experience, I can only access PTM modes in track mode.

Has anyone else experienced this? Do you have any suggestions to avoid this?

I thought about (1) customizing the launch control to allow for higher RPMs and/or more slippage or (2) trying it per the owner's manual recommendation, which is in track mode with PTM set to race 2.

And even when just getting on it in 1st or with a WOT 1st-2nd shift at or near redline, I'll get wheel hop instead of slippage or squealing. I mean, I wouldn't think the factory Michelin's are that grippy.

 

[bl4ck_wng]

Try lowering your tire pressure to 32-33psi when cold and see how it reacts. IMO, the summer compound is quite firm in GM's TPC spec, so this may help you mitigate the excessive wheel hop.

I have attached the Spring Mountain tire/alignment spec sheet below (note: they operate in much higher ambient temps than we do here in the NE). Also, if your vehicle is fresh off the lot it is possible that your dealer did not remove all the excess air they put in the tires at the factory to prevent flat spots during transport/storage-- just thinking out loud on this one as this is common practice over in the bimmer world

Some of my best 0-60 times were on a set of softer PS4 all seasons @ 34psi all warmed up. OEM size tires on my OEM wheels too. I am convinced that I spin a lot more on my summer set until they are all the way warmed up.

Best of luck out there and enjoy

 

[phdibart]

Try lowering your tire pressure to 32-33psi when cold and see how it reacts. IMO, the summer compound is quite firm in GM's TPC spec, so this may help you mitigate the excessive wheel hop.

I have attached the Spring Mountain tire/alignment spec sheet below (note: they operate in much higher ambient temps than we do here in the NE). Also, if your vehicle is fresh off the lot it is possible that your dealer did not remove all the excess air they put in the tires at the factory to prevent flat spots during transport/storage-- just thinking out loud on this one as this is common practice over in the bimmer world

Some of my best 0-60 times were on a set of softer PS4 all seasons @ 34psi all warmed up. OEM size tires on my OEM wheels too. I am convinced that I spin a lot more on my summer set until they are all the way warmed up.

Best of luck out there and enjoy

View attachment 22651

Thanks for sharing the Spring Mountain specs. It's a '23 that I bought used with 6,700 miles on it, so definitely not fresh off the truck. I also have an air compressor and keep the pressures at 35 almost obsessively, but I'll try lowering them to see if that helps. But I was under the impression that lower pressures would offer more grip. Wouldn't that exacerbate the issue?

 

[bl4ck_wng]

Thanks for sharing the Spring Mountain specs. It's a '23 that I bought used with 6,700 miles on it, so definitely not fresh off the truck. I also have an air compressor and keep the pressures at 35 almost obsessively, but I'll try lowering them to see if that helps. But I was under the impression that lower pressures would offer more grip. Wouldn't that exacerbate the issue?

You are correct about the additional grip gained from lower pressures potentially making this hopping more pronounced. I have a feeling the softer, lower PSI tire has more of a chance to grip and flex before breaking friction with the contact surface outright, right before that "hop" sensation occurs. It is also worth mentioning that any temps below 50*F make already firm tires downright HARD when cold

 

[DCV]

Summer tires on a 40 something degree day, with launch control…I don’t think the GM programmers were given that task to write an algorithm for.

 

[Lithoss]

I've been thoroughly unimpressed by launch control in the 4BW.. Even at SM it didn't seem to perform well. Not sure what I'm doing wrong, it's pretty hard to do wrong.

 

[minn19]

That’s weird, when it is those temps for me (maybe a little lower), I shut T/C off or go to PTM Race 1 and its tail out or donuts at will on the stock PS4Ss.

I’ve only used it twice, it was in the summer and temps were in the mid 80s. Used the automatic setting the first time and got a low 4s. Then went Custom and set it somewhere around 2500 ish RPM and got a 4.0 flat according to the Caddy timer on the dash. Thought it worked great, I’ll probably never use it again, but is fun a couple of times.

Maybe you don’t have enough traction and weird things are happening? The summers get pretty hard under 50 degrees so they may be more prone to hop.

 

[phdibart]

That’s weird, when it is those temps for me (maybe a little lower), I shut T/C off or go to PTM Race 1 and its tail out or donuts at will on the stock PS4Ss.

I’ve only used it twice, it was in the summer and temps were in the mid 80s. Used the automatic setting the first time and got a low 4s. Then went Custom and set it somewhere around 2500 ish RPM and got a 4.0 flat according to the Caddy timer on the dash. Thought it worked great, I’ll probably never use it again, but is fun a couple of times.

Maybe you don’t have enough traction and weird things are happening? The summers get pretty hard under 50 degrees so they may be more prone to hop.

Yeah, I see you're in Minnesota, so like me, you have around 5-6 months below 40F. I have my winter tires on now, and while they are Michelin Pilot Alpine PS4 apparently developed for the Carrera in winter, I'm not sure how much I'll push them considering I'm running a square setup (narrower rear) for winter.

I'll give it another go in May when I make my way down to FL for a few weeks.