Add-on brake proportioning valve

[Rttoys]

Has it done this since day 1 or is it a new thing since you changed the brake system to manual? Technically it shouldn’t matter, but just trying to get a baseline.

 

[KSLunsfo]

How much front tire pressure are you running.

Possibly a bit more than I need to, 24-25 all around right now. I've only recently had the brakes all set up to a point of really getting them dialed in where I'm starting to do some aggressive braking. So, I had put just enough air in initially to "shut the tire warning message up".

 

[KSLunsfo]

Has it done this since day 1 or is it a new thing since you changed the brake system to manual? Technically it shouldn’t matter, but just trying to get a baseline.

I was unknowingly somewhat answering your question as well in the post above:

I've only recently had the brakes all set up to a point of really getting them dialed in where I'm starting to do some aggressive braking. So, it's a "new" issue only because I'm finally starting to push the brakes. (Unintentional Pun)

 

[Ross]

Back in post 108, I mentioned triangulating my frame... Those red circles in the front of my frame is where we welded extra bars to strengthen it.
With just the passenger bar welded in, I noticed the front of my car was braking better. Adding the driver side made it even more stable.
If you were to use a cargo ratchet strap (or a come-a-long), and triangulate your frame, does it make the car more stable when braking?

 

[Scott #321]

Possibly a bit more than I need to, 24-25 all around right now. I've only recently had the brakes all set up to a point of really getting them dialed in where I'm starting to do some aggressive braking. So, I had put just enough air in initially to "shut the tire warning message up".

I run the Nitto NT01 which seem to have a similar weight/pressure spec to the Pilot sport 275's I looked up. I run 12 psi cold front and drop that to 10-12 psi hot for autocross. I would recommend re checking to make sure nothing is loose and retesting in a safe location with lower tire pressures. FWIW I run 18 psi rear cold for street driving.

 

[KSLunsfo]

Back in post 108, I mentioned triangulating my frame... Those red circles in the front of my frame is where we welded extra bars to strengthen it.
With just the passenger bar welded in, I noticed the front of my car was braking better. Adding the driver side made it even more stable.
If you were to use a cargo ratchet strap (or a come-a-long), and triangulate your frame, does it make the car more stable when braking?

View attachment 43173

I run the Nitto NT01 which seem to have a similar weight/pressure spec to the Pilot sport 275's I looked up. I run 12 psi cold front and drop that to 10-12 psi hot for autocross. I would recommend re checking to make sure nothing is loose and retesting in a safe location with lower tire pressures. FWIW I run 18 psi rear cold for street driving.

Thanks for the ideas! I'll double and triple check hardware, joints etc and drop tire pressures a bit and see what happens. Following that I'll see if I can get some ratchet straps in there somewhere if it's still occurring at that point.

 

[KSLunsfo]

TIRE PRESSURE!

Checked out the front end, re-torquing things, didn't really find anything that wasn't torqued.

Dropped fronts to 15psi and rears to 20psi (little higher than Scott since it's a bit easier to take out).

Just got a few fairly aggressive braking events in. And so far there's no more noticeable wheel hop! I am actually skidding the driver's front tire now. So, I've backed off on the front pressure a quarter turn or so. Next time I get it out I'll see if I'm still locking the front or if it shifts to the rear, then readjust. I'm getting there... If I do encounter the wheel hop again I'll post back. But I think this has resolved it.

 

[Gtstorey]

What pressures have you been running?

 

[KSLunsfo]

What pressures have you been running?

Way too much realistically. I basically knew that but just casually driving around town and such it didn't really seem to matter. When I ever get to autocrossing or doing real things with the car was when I was going to for sure start focusing more on that among other things. But, wheel hop brought it to my attention a bit sooner.

I think I initially had 30psi all around (turns the tire warning light off). Just a dummy light/message I know... Up until I dropped them earlier they were all 24-25psi which was at least for my setup resulting in the wheel hop it seems...

 

[Rttoys]

This also goes back to alignment too. You only really need -0.5 camber up front. With this, you can adjust your tire pressure down until you have a good wide contact patch on the tire.

 

[KSLunsfo]

This also goes back to alignment too. You only really need -0.5 camber up front. With this, you can adjust your tire pressure down until you have a good wide contact patch on the tire.

Makes sense. I would have to check again to see exactly what I'm at, but I know it's around or just under -1.0 if I recall correctly.

 

[Rttoys]

Anything around -.5 to -1.0 seems to be fine. I think mine is -.5 and -.8 respectively. At autocross, I get good coverage across the face of the tire. So I’m happy with it.